[Intel-gfx] [RESEND RFC 04/18] drm/display/dp_mst: Call them time slots, not VCPI slots

[Intel-gfx] [RESEND RFC 04/18] drm/display/dp_mst: Call them time slots, not VCPI slots

[Lyude Paul]

VCPI is only sort of the correct term here, originally the majority of this
code simply referred to timeslots vaguely as "slots" - and since I started
working on it and adding atomic functionality, the name "VCPI slots" has
been used to represent time slots.

Now that we actually have consistent access to the DisplayPort spec thanks
to VESA, I now know this isn't actually the proper term - as the
specification refers to these as time slots.

Since we're trying to make this code as easy to figure out as possible,
let's take this opportunity to correct this nomenclature and call them by
their proper name - timeslots. Likewise, we rename various functions
appropriately, along with replacing references in the kernel documentation
and various debugging messages.

It's important to note that this patch series leaves the legacy MST code
untouched for the most part, which is fine since we'll be removing it soon
anyhow. There should be no functional changes in this series.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |   2 +-
 .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  28 ++---
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 106 +++++++++---------
 drivers/gpu/drm/i915/display/intel_dp_mst.c   |   5 +-
 drivers/gpu/drm/nouveau/dispnv50/disp.c       |   4 +-
 include/drm/display/drm_dp_mst_helper.h       |   6 +-
 6 files changed, 75 insertions(+), 76 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index ad4571190a90..f84a4ad736d8 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7393,7 +7393,7 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
 		clock = adjusted_mode->clock;
 		dm_new_connector_state->pbn = drm_dp_calc_pbn_mode(clock, bpp, false);
 	}
-	dm_new_connector_state->vcpi_slots = drm_dp_atomic_find_vcpi_slots(state,
+	dm_new_connector_state->vcpi_slots = drm_dp_atomic_find_time_slots(state,
 									   mst_mgr,
 									   mst_port,
 									   dm_new_connector_state->pbn,
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 9221b6690a4a..e40ff51e7be0 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -378,7 +378,7 @@ static int dm_dp_mst_atomic_check(struct drm_connector *connector,
 			return 0;
 		}
 
-	return drm_dp_atomic_release_vcpi_slots(state,
+	return drm_dp_atomic_release_time_slots(state,
 						mst_mgr,
 						mst_port);
 }
@@ -689,7 +689,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 
 		if (initial_slack[next_index] > fair_pbn_alloc) {
 			vars[next_index].pbn += fair_pbn_alloc;
-			if (drm_dp_atomic_find_vcpi_slots(state,
+			if (drm_dp_atomic_find_time_slots(state,
 							  params[next_index].port->mgr,
 							  params[next_index].port,
 							  vars[next_index].pbn,
@@ -699,7 +699,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 				vars[next_index].bpp_x16 = bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
 			} else {
 				vars[next_index].pbn -= fair_pbn_alloc;
-				if (drm_dp_atomic_find_vcpi_slots(state,
+				if (drm_dp_atomic_find_time_slots(state,
 								  params[next_index].port->mgr,
 								  params[next_index].port,
 								  vars[next_index].pbn,
@@ -708,7 +708,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 			}
 		} else {
 			vars[next_index].pbn += initial_slack[next_index];
-			if (drm_dp_atomic_find_vcpi_slots(state,
+			if (drm_dp_atomic_find_time_slots(state,
 							  params[next_index].port->mgr,
 							  params[next_index].port,
 							  vars[next_index].pbn,
@@ -718,7 +718,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 				vars[next_index].bpp_x16 = params[next_index].bw_range.max_target_bpp_x16;
 			} else {
 				vars[next_index].pbn -= initial_slack[next_index];
-				if (drm_dp_atomic_find_vcpi_slots(state,
+				if (drm_dp_atomic_find_time_slots(state,
 								  params[next_index].port->mgr,
 								  params[next_index].port,
 								  vars[next_index].pbn,
@@ -775,7 +775,7 @@ static void try_disable_dsc(struct drm_atomic_state *state,
 			break;
 
 		vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps);
-		if (drm_dp_atomic_find_vcpi_slots(state,
+		if (drm_dp_atomic_find_time_slots(state,
 						  params[next_index].port->mgr,
 						  params[next_index].port,
 						  vars[next_index].pbn,
@@ -787,7 +787,7 @@ static void try_disable_dsc(struct drm_atomic_state *state,
 			vars[next_index].bpp_x16 = 0;
 		} else {
 			vars[next_index].pbn = kbps_to_peak_pbn(params[next_index].bw_range.max_kbps);
-			if (drm_dp_atomic_find_vcpi_slots(state,
+			if (drm_dp_atomic_find_time_slots(state,
 							  params[next_index].port->mgr,
 							  params[next_index].port,
 							  vars[next_index].pbn,
@@ -873,11 +873,11 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 		vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
 		vars[i + k].dsc_enabled = false;
 		vars[i + k].bpp_x16 = 0;
-		if (drm_dp_atomic_find_vcpi_slots(state,
-						 params[i].port->mgr,
-						 params[i].port,
-						 vars[i + k].pbn,
-						 dm_mst_get_pbn_divider(dc_link)) < 0)
+		if (drm_dp_atomic_find_time_slots(state,
+						  params[i].port->mgr,
+						  params[i].port,
+						  vars[i + k].pbn,
+						  dm_mst_get_pbn_divider(dc_link)) < 0)
 			return false;
 	}
 	if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) {
@@ -891,7 +891,7 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 			vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps);
 			vars[i + k].dsc_enabled = true;
 			vars[i + k].bpp_x16 = params[i].bw_range.min_target_bpp_x16;
-			if (drm_dp_atomic_find_vcpi_slots(state,
+			if (drm_dp_atomic_find_time_slots(state,
 							  params[i].port->mgr,
 							  params[i].port,
 							  vars[i + k].pbn,
@@ -901,7 +901,7 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 			vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
 			vars[i + k].dsc_enabled = false;
 			vars[i + k].bpp_x16 = 0;
-			if (drm_dp_atomic_find_vcpi_slots(state,
+			if (drm_dp_atomic_find_time_slots(state,
 							  params[i].port->mgr,
 							  params[i].port,
 							  vars[i + k].pbn,
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 38eecb89e22d..702ff5d9ecc7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -4304,11 +4304,11 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_
 EXPORT_SYMBOL(drm_dp_mst_get_edid);
 
 /**
- * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
+ * drm_dp_find_vcpi_slots() - Find time slots for this PBN value
  * @mgr: manager to use
  * @pbn: payload bandwidth to convert into slots.
  *
- * Calculate the number of VCPI slots that will be required for the given PBN
+ * Calculate the number of time slots that will be required for the given PBN
  * value. This function is deprecated, and should not be used in atomic
  * drivers.
  *
@@ -4345,17 +4345,17 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
 }
 
 /**
- * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
+ * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
  * @state: global atomic state
  * @mgr: MST topology manager for the port
- * @port: port to find vcpi slots for
+ * @port: port to find time slots for
  * @pbn: bandwidth required for the mode in PBN
  * @pbn_div: divider for DSC mode that takes FEC into account
  *
- * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
+ * Allocates time slots to @port, replacing any previous timeslot allocations it
  * may have had. Any atomic drivers which support MST must call this function
  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
- * current VCPI allocation for the new state, but only when
+ * current timeslot allocation for the new state, but only when
  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
  * to ensure compatibility with userspace applications that still use the
  * legacy modesetting UAPI.
@@ -4365,17 +4365,17 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
  *
  * Additionally, it is OK to call this function multiple times on the same
  * @port as needed. It is not OK however, to call this function and
- * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
+ * drm_dp_atomic_release_time_slots() in the same atomic check phase.
  *
  * See also:
- * drm_dp_atomic_release_vcpi_slots()
+ * drm_dp_atomic_release_time_slots()
  * drm_dp_mst_atomic_check()
  *
  * Returns:
  * Total slots in the atomic state assigned for this port, or a negative error
  * code if the port no longer exists
  */
-int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
+int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 				  struct drm_dp_mst_topology_mgr *mgr,
 				  struct drm_dp_mst_port *port, int pbn,
 				  int pbn_div)
@@ -4392,17 +4392,17 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
 	list_for_each_entry(pos, &topology_state->payloads, next) {
 		if (pos->port == port) {
 			payload = pos;
-			prev_slots = payload->vcpi;
+			prev_slots = payload->time_slots;
 			prev_bw = payload->pbn;
 
 			/*
 			 * This should never happen, unless the driver tries
-			 * releasing and allocating the same VCPI allocation,
+			 * releasing and allocating the same timeslot allocation,
 			 * which is an error
 			 */
 			if (WARN_ON(!prev_slots)) {
 				drm_err(mgr->dev,
-					"cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
+					"cannot allocate and release time slots on [MST PORT:%p] in the same state\n",
 					port);
 				return -EINVAL;
 			}
@@ -4420,7 +4420,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
 
 	req_slots = DIV_ROUND_UP(pbn, pbn_div);
 
-	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
+	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
 		       port->connector->base.id, port->connector->name,
 		       port, prev_slots, req_slots);
 	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
@@ -4437,20 +4437,20 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
 		payload->port = port;
 		list_add(&payload->next, &topology_state->payloads);
 	}
-	payload->vcpi = req_slots;
+	payload->time_slots = req_slots;
 	payload->pbn = pbn;
 
 	return req_slots;
 }
-EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
+EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
 
 /**
- * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
+ * drm_dp_atomic_release_time_slots() - Release allocated time slots
  * @state: global atomic state
  * @mgr: MST topology manager for the port
- * @port: The port to release the VCPI slots from
+ * @port: The port to release the time slots from
  *
- * Releases any VCPI slots that have been allocated to a port in the atomic
+ * Releases any time slots that have been allocated to a port in the atomic
  * state. Any atomic drivers which support MST must call this function in
  * their &drm_connector_helper_funcs.atomic_check() callback when the
  * connector will no longer have VCPI allocated (e.g. because its CRTC was
@@ -4459,18 +4459,18 @@ EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
  * It is OK to call this even if @port has been removed from the system.
  * Additionally, it is OK to call this function multiple times on the same
  * @port as needed. It is not OK however, to call this function and
- * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
+ * drm_dp_atomic_find_time_slots() on the same @port in a single atomic check
  * phase.
  *
  * See also:
- * drm_dp_atomic_find_vcpi_slots()
+ * drm_dp_atomic_find_time_slots()
  * drm_dp_mst_atomic_check()
  *
  * Returns:
  * 0 if all slots for this port were added back to
  * &drm_dp_mst_topology_state.avail_slots or negative error code
  */
-int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
+int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 				     struct drm_dp_mst_topology_mgr *mgr,
 				     struct drm_dp_mst_port *port)
 {
@@ -4494,16 +4494,16 @@ int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
 		return -EINVAL;
 	}
 
-	drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
-	if (pos->vcpi) {
+	drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, pos->time_slots);
+	if (pos->time_slots) {
 		drm_dp_mst_put_port_malloc(port);
-		pos->vcpi = 0;
+		pos->time_slots = 0;
 		pos->pbn = 0;
 	}
 
 	return 0;
 }
-EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
+EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
 
 /**
  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
@@ -4557,7 +4557,7 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
 
 	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
 	if (ret) {
-		drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d ret=%d\n",
+		drm_dbg_kms(mgr->dev, "failed to init time slots=%d ret=%d\n",
 			    DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
 		drm_dp_mst_topology_put_port(port);
 		goto out;
@@ -5083,8 +5083,8 @@ drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
 	INIT_LIST_HEAD(&state->payloads);
 
 	list_for_each_entry(pos, &old_state->payloads, next) {
-		/* Prune leftover freed VCPI allocations */
-		if (!pos->vcpi)
+		/* Prune leftover freed timeslot allocations */
+		if (!pos->time_slots)
 			continue;
 
 		payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
@@ -5116,7 +5116,7 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
 
 	list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
 		/* We only keep references to ports with non-zero VCPIs */
-		if (pos->vcpi)
+		if (pos->time_slots)
 			drm_dp_mst_put_port_malloc(pos->port);
 		kfree(pos);
 	}
@@ -5242,28 +5242,28 @@ drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
 }
 
 static inline int
-drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
-					 struct drm_dp_mst_topology_state *mst_state)
+drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr,
+					     struct drm_dp_mst_topology_state *mst_state)
 {
 	struct drm_dp_mst_atomic_payload *payload;
 	int avail_slots = mst_state->total_avail_slots, payload_count = 0;
 
 	list_for_each_entry(payload, &mst_state->payloads, next) {
 		/* Releasing payloads is always OK-even if the port is gone */
-		if (!payload->vcpi) {
-			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all VCPI slots\n",
+		if (!payload->time_slots) {
+			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n",
 				       payload->port);
 			continue;
 		}
 
-		drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d vcpi slots\n",
-			       payload->port, payload->vcpi);
+		drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n",
+			       payload->port, payload->time_slots);
 
-		avail_slots -= payload->vcpi;
+		avail_slots -= payload->time_slots;
 		if (avail_slots < 0) {
 			drm_dbg_atomic(mgr->dev,
-				       "[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
-				       payload->port, mst_state, avail_slots + payload->vcpi);
+				       "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n",
+				       payload->port, mst_state, avail_slots + payload->time_slots);
 			return -ENOSPC;
 		}
 
@@ -5274,7 +5274,7 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
 			return -EINVAL;
 		}
 	}
-	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
+	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU avail=%d used=%d\n",
 		       mgr, mst_state, avail_slots, mst_state->total_avail_slots - avail_slots);
 
 	return 0;
@@ -5363,7 +5363,7 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 	struct drm_dp_mst_topology_state *mst_state;
 	struct drm_dp_mst_atomic_payload *pos;
 	bool found = false;
-	int vcpi = 0;
+	int time_slots = 0;
 
 	mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
 
@@ -5379,30 +5379,30 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 
 	if (!found) {
 		drm_dbg_atomic(state->dev,
-			       "[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
+			       "[MST PORT:%p] Couldn't find payload in mst state %p\n",
 			       port, mst_state);
 		return -EINVAL;
 	}
 
 	if (pos->dsc_enabled == enable) {
 		drm_dbg_atomic(state->dev,
-			       "[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
-			       port, enable, pos->vcpi);
-		vcpi = pos->vcpi;
+			       "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n",
+			       port, enable, pos->time_slots);
+		time_slots = pos->time_slots;
 	}
 
 	if (enable) {
-		vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
+		time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn, pbn_div);
 		drm_dbg_atomic(state->dev,
-			       "[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
-			       port, vcpi);
-		if (vcpi < 0)
+			       "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
+			       port, time_slots);
+		if (time_slots < 0)
 			return -EINVAL;
 	}
 
 	pos->dsc_enabled = enable;
 
-	return vcpi;
+	return time_slots;
 }
 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
 /**
@@ -5412,15 +5412,15 @@ EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
  *
  * Checks the given topology state for an atomic update to ensure that it's
  * valid. This includes checking whether there's enough bandwidth to support
- * the new VCPI allocations in the atomic update.
+ * the new timeslot allocations in the atomic update.
  *
  * Any atomic drivers supporting DP MST must make sure to call this after
  * checking the rest of their state in their
  * &drm_mode_config_funcs.atomic_check() callback.
  *
  * See also:
- * drm_dp_atomic_find_vcpi_slots()
- * drm_dp_atomic_release_vcpi_slots()
+ * drm_dp_atomic_find_time_slots()
+ * drm_dp_atomic_release_time_slots()
  *
  * Returns:
  *
@@ -5436,7 +5436,7 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
 		if (!mgr->mst_state)
 			continue;
 
-		ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
+		ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
 		if (ret)
 			break;
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 061b277e5ce7..0c922667398a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -70,7 +70,7 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
 						       crtc_state->pipe_bpp,
 						       false);
 
-		slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr,
+		slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
 						      connector->port,
 						      crtc_state->pbn,
 						      drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
@@ -344,8 +344,7 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
 	}
 
 	mgr = &enc_to_mst(to_intel_encoder(old_conn_state->best_encoder))->primary->dp.mst_mgr;
-	ret = drm_dp_atomic_release_vcpi_slots(&state->base, mgr,
-					       intel_connector->port);
+	ret = drm_dp_atomic_release_time_slots(&state->base, mgr, intel_connector->port);
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 4347f0b61797..631dba5a2418 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1070,7 +1070,7 @@ nv50_msto_atomic_check(struct drm_encoder *encoder,
 						    false);
 	}
 
-	slots = drm_dp_atomic_find_vcpi_slots(state, &mstm->mgr, mstc->port,
+	slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc->port,
 					      asyh->dp.pbn, 0);
 	if (slots < 0)
 		return slots;
@@ -1282,7 +1282,7 @@ nv50_mstc_atomic_check(struct drm_connector *connector,
 			return 0;
 	}
 
-	return drm_dp_atomic_release_vcpi_slots(state, mgr, mstc->port);
+	return drm_dp_atomic_release_time_slots(state, mgr, mstc->port);
 }
 
 static int
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index 5671173f9f37..8ab4f14f2344 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -544,7 +544,7 @@ struct drm_dp_payload {
 
 struct drm_dp_mst_atomic_payload {
 	struct drm_dp_mst_port *port;
-	int vcpi;
+	int time_slots;
 	int pbn;
 	bool dsc_enabled;
 	struct list_head next;
@@ -846,7 +846,7 @@ void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
 								    struct drm_dp_mst_topology_mgr *mgr);
 int __must_check
-drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
+drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 			      struct drm_dp_mst_topology_mgr *mgr,
 			      struct drm_dp_mst_port *port, int pbn,
 			      int pbn_div);
@@ -858,7 +858,7 @@ int __must_check
 drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
 				  struct drm_dp_mst_topology_mgr *mgr);
 int __must_check
-drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
+drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 				 struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port);
 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
-- 
2.35.3

Re: [Intel-gfx] [RESEND RFC 04/18] drm/display/dp_mst: Call them time slots, not VCPI slots

[Lyude Paul]

On Wed, 2022-06-15 at 04:28 +0000, Lin, Wayne wrote:
> [Public]
> 
> Thank you Lyude for addressing this!
> 
> VCPI is also a confusing naming to me at first glance since it stands for 
> Virtual Channel Payload Identification which is just an ID number ( we can 
>  look up these payload IDs In DPCD 0x2C1 ~0x2FF).
> 
> I also look up left VCPI terms in rest of the code. Seems like we still can
> modify 
> some parts here? Like:
> 
> /**
>  * struct drm_dp_vcpi - Virtual Channel Payload Identifier
>  * @vcpi: Virtual channel ID.
>  * @pbn: Payload Bandwidth Number for this channel
>  * @aligned_pbn: PBN aligned with slot size
>  * @num_slots: number of slots for this PBN
>  */
> struct drm_dp_vcpi {
>         int vcpi;
>         int pbn;
>         int aligned_pbn;
>         int num_slots;
> };
> 
> Would like to change the structure name to  "struct drm_dp_mst_vcp {}" to
> represent
> the virtual channel payload. Not specific to the ID.
> Would like to know your thoughts : )

JFYI - I didn't rename this structure because we actually remove it entirely
in later patches

> 
> > -----Original Message-----
> > From: Lyude Paul <lyude@redhat.com>
> > Sent: Wednesday, June 8, 2022 3:29 AM
> > To: dri-devel@lists.freedesktop.org; nouveau@lists.freedesktop.org; amd-
> > gfx@lists.freedesktop.org
> > Cc: Lin, Wayne <Wayne.Lin@amd.com>; Ville Syrjälä
> > <ville.syrjala@linux.intel.com>; Zuo, Jerry <Jerry.Zuo@amd.com>; Jani
> > Nikula
> > <jani.nikula@intel.com>; Imre Deak <imre.deak@intel.com>; Daniel Vetter
> > <daniel.vetter@ffwll.ch>; Sean Paul <sean@poorly.run>; Wentland, Harry
> > <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>;
> > Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander
> > <Alexander.Deucher@amd.com>; Koenig, Christian
> > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David
> > Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Jani Nikula
> > <jani.nikula@linux.intel.com>; Joonas Lahtinen
> > <joonas.lahtinen@linux.intel.com>; Rodrigo Vivi <rodrigo.vivi@intel.com>;
> > Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Ben Skeggs
> > <bskeggs@redhat.com>; Karol Herbst <kherbst@redhat.com>; Kazlauskas,
> > Nicholas <Nicholas.Kazlauskas@amd.com>; Li, Roman
> > <Roman.Li@amd.com>; Shih, Jude <Jude.Shih@amd.com>; Simon Ser
> > <contact@emersion.fr>; Wu, Hersen <hersenxs.wu@amd.com>; Thomas
> > Zimmermann <tzimmermann@suse.de>; Lakha, Bhawanpreet
> > <Bhawanpreet.Lakha@amd.com>; José Roberto de Souza
> > <jose.souza@intel.com>; He Ying <heying24@huawei.com>; Matt Roper
> > <matthew.d.roper@intel.com>; Sean Paul <seanpaul@chromium.org>; Hans
> > Verkuil <hverkuil-cisco@xs4all.nl>; Fernando Ramos <greenfoo@u92.eu>;
> > Javier Martinez Canillas <javierm@redhat.com>; open list <linux-
> > kernel@vger.kernel.org>; open list:INTEL DRM DRIVERS <intel-
> > gfx@lists.freedesktop.org>
> > Subject: [RESEND RFC 04/18] drm/display/dp_mst: Call them time slots, not
> > VCPI slots
> > 
> > VCPI is only sort of the correct term here, originally the majority of
> > this code
> > simply referred to timeslots vaguely as "slots" - and since I started
> > working
> > on it and adding atomic functionality, the name "VCPI slots" has been used
> > to
> > represent time slots.
> > 
> > Now that we actually have consistent access to the DisplayPort spec thanks
> > to
> > VESA, I now know this isn't actually the proper term - as the
> > specification
> > refers to these as time slots.
> > 
> > Since we're trying to make this code as easy to figure out as possible,
> > let's
> > take this opportunity to correct this nomenclature and call them by their
> > proper name - timeslots. Likewise, we rename various functions
> > appropriately, along with replacing references in the kernel documentation
> > and various debugging messages.
> > 
> > It's important to note that this patch series leaves the legacy MST code
> > untouched for the most part, which is fine since we'll be removing it soon
> > anyhow. There should be no functional changes in this series.
> > 
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > Cc: Wayne Lin <Wayne.Lin@amd.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Imre Deak <imre.deak@intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Sean Paul <sean@poorly.run>
> > ---
> >  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |   2 +-
> >  .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  28 ++---
> >  drivers/gpu/drm/display/drm_dp_mst_topology.c | 106 +++++++++---------
> >  drivers/gpu/drm/i915/display/intel_dp_mst.c   |   5 +-
> >  drivers/gpu/drm/nouveau/dispnv50/disp.c       |   4 +-
> >  include/drm/display/drm_dp_mst_helper.h       |   6 +-
> >  6 files changed, 75 insertions(+), 76 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index ad4571190a90..f84a4ad736d8 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -7393,7 +7393,7 @@ static int dm_encoder_helper_atomic_check(struct
> > drm_encoder *encoder,
> >                 clock = adjusted_mode->clock;
> >                 dm_new_connector_state->pbn =
> > drm_dp_calc_pbn_mode(clock, bpp, false);
> >         }
> > -       dm_new_connector_state->vcpi_slots =
> > drm_dp_atomic_find_vcpi_slots(state,
> > +       dm_new_connector_state->vcpi_slots =
> > +drm_dp_atomic_find_time_slots(state,
> > 
> > mst_mgr,
> > 
> > mst_port,
> > 
> > dm_new_connector_state->pbn, diff --git
> > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > index 9221b6690a4a..e40ff51e7be0 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > @@ -378,7 +378,7 @@ static int dm_dp_mst_atomic_check(struct
> > drm_connector *connector,
> >                         return 0;
> >                 }
> > 
> > -       return drm_dp_atomic_release_vcpi_slots(state,
> > +       return drm_dp_atomic_release_time_slots(state,
> >                                                 mst_mgr,
> >                                                 mst_port);
> >  }
> > @@ -689,7 +689,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> > 
> >                 if (initial_slack[next_index] > fair_pbn_alloc) {
> >                         vars[next_index].pbn += fair_pbn_alloc;
> > -                       if (drm_dp_atomic_find_vcpi_slots(state,
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > 
> > vars[next_index].pbn,
> > @@ -699,7 +699,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                                 vars[next_index].bpp_x16 =
> > bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
> >                         } else {
> >                                 vars[next_index].pbn -= fair_pbn_alloc;
> > -                               if (drm_dp_atomic_find_vcpi_slots(state,
> > +                               if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > 
> > vars[next_index].pbn,
> > @@ -708,7 +708,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                         }
> >                 } else {
> >                         vars[next_index].pbn += initial_slack[next_index];
> > -                       if (drm_dp_atomic_find_vcpi_slots(state,
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > 
> > vars[next_index].pbn,
> > @@ -718,7 +718,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                                 vars[next_index].bpp_x16 =
> > params[next_index].bw_range.max_target_bpp_x16;
> >                         } else {
> >                                 vars[next_index].pbn -=
> > initial_slack[next_index];
> > -                               if (drm_dp_atomic_find_vcpi_slots(state,
> > +                               if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > 
> > vars[next_index].pbn,
> > @@ -775,7 +775,7 @@ static void try_disable_dsc(struct drm_atomic_state
> > *state,
> >                         break;
> > 
> >                 vars[next_index].pbn =
> > kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps);
> > -               if (drm_dp_atomic_find_vcpi_slots(state,
> > +               if (drm_dp_atomic_find_time_slots(state,
> >                                                   params[next_index].port-
> > > mgr,
> >                                                   params[next_index].port,
> >                                                   vars[next_index].pbn,
> > @@ -787,7 +787,7 @@ static void try_disable_dsc(struct drm_atomic_state
> > *state,
> >                         vars[next_index].bpp_x16 = 0;
> >                 } else {
> >                         vars[next_index].pbn =
> > kbps_to_peak_pbn(params[next_index].bw_range.max_kbps);
> > -                       if (drm_dp_atomic_find_vcpi_slots(state,
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > 
> > vars[next_index].pbn,
> > @@ -873,11 +873,11 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                 vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> >                 vars[i + k].dsc_enabled = false;
> >                 vars[i + k].bpp_x16 = 0;
> > -               if (drm_dp_atomic_find_vcpi_slots(state,
> > -                                                params[i].port->mgr,
> > -                                                params[i].port,
> > -                                                vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +               if (drm_dp_atomic_find_time_slots(state,
> > +                                                 params[i].port->mgr,
> > +                                                 params[i].port,
> > +                                                 vars[i + k].pbn,
> > +
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> >                         return false;
> >         }
> >         if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) { @@
> > -891,7 +891,7 @@ static bool compute_mst_dsc_configs_for_link(struct
> > drm_atomic_state *state,
> >                         vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.min_kbps);
> >                         vars[i + k].dsc_enabled = true;
> >                         vars[i + k].bpp_x16 =
> > params[i].bw_range.min_target_bpp_x16;
> > -                       if (drm_dp_atomic_find_vcpi_slots(state,
> > +                       if (drm_dp_atomic_find_time_slots(state,
> >                                                           params[i].port-
> > >mgr,
> >                                                           params[i].port,
> >                                                           vars[i + k].pbn,
> > @@ -901,7 +901,7 @@ static bool compute_mst_dsc_configs_for_link(struct
> > drm_atomic_state *state,
> >                         vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> >                         vars[i + k].dsc_enabled = false;
> >                         vars[i + k].bpp_x16 = 0;
> > -                       if (drm_dp_atomic_find_vcpi_slots(state,
> > +                       if (drm_dp_atomic_find_time_slots(state,
> >                                                           params[i].port-
> > >mgr,
> >                                                           params[i].port,
> >                                                           vars[i + k].pbn,
> > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > index 38eecb89e22d..702ff5d9ecc7 100644
> > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > @@ -4304,11 +4304,11 @@ struct edid *drm_dp_mst_get_edid(struct
> > drm_connector *connector, struct drm_dp_
> > EXPORT_SYMBOL(drm_dp_mst_get_edid);
> > 
> >  /**
> > - * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
> > + * drm_dp_find_vcpi_slots() - Find time slots for this PBN value
> >   * @mgr: manager to use
> >   * @pbn: payload bandwidth to convert into slots.
> >   *
> > - * Calculate the number of VCPI slots that will be required for the given
> > PBN
> > + * Calculate the number of time slots that will be required for the
> > + given PBN
> >   * value. This function is deprecated, and should not be used in atomic
> >   * drivers.
> >   *
> > @@ -4345,17 +4345,17 @@ static int drm_dp_init_vcpi(struct
> > drm_dp_mst_topology_mgr *mgr,  }
> > 
> >  /**
> > - * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
> > + * drm_dp_atomic_find_time_slots() - Find and add time slots to the
> > + state
> >   * @state: global atomic state
> >   * @mgr: MST topology manager for the port
> > - * @port: port to find vcpi slots for
> > + * @port: port to find time slots for
> >   * @pbn: bandwidth required for the mode in PBN
> >   * @pbn_div: divider for DSC mode that takes FEC into account
> >   *
> > - * Allocates VCPI slots to @port, replacing any previous VCPI allocations
> > it
> > + * Allocates time slots to @port, replacing any previous timeslot
> > + allocations it
> >   * may have had. Any atomic drivers which support MST must call this
> > function
> >   * in their &drm_encoder_helper_funcs.atomic_check() callback to change
> > the
> > - * current VCPI allocation for the new state, but only when
> > + * current timeslot allocation for the new state, but only when
> >   * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed
> > is set
> >   * to ensure compatibility with userspace applications that still use the
> >   * legacy modesetting UAPI.
> > @@ -4365,17 +4365,17 @@ static int drm_dp_init_vcpi(struct
> > drm_dp_mst_topology_mgr *mgr,
> >   *
> >   * Additionally, it is OK to call this function multiple times on the
> > same
> >   * @port as needed. It is not OK however, to call this function and
> > - * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
> > + * drm_dp_atomic_release_time_slots() in the same atomic check phase.
> >   *
> >   * See also:
> > - * drm_dp_atomic_release_vcpi_slots()
> > + * drm_dp_atomic_release_time_slots()
> >   * drm_dp_mst_atomic_check()
> >   *
> >   * Returns:
> >   * Total slots in the atomic state assigned for this port, or a negative
> > error
> >   * code if the port no longer exists
> >   */
> > -int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> > +int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> >                                   struct drm_dp_mst_topology_mgr *mgr,
> >                                   struct drm_dp_mst_port *port, int pbn,
> >                                   int pbn_div)
> > @@ -4392,17 +4392,17 @@ int drm_dp_atomic_find_vcpi_slots(struct
> > drm_atomic_state *state,
> >         list_for_each_entry(pos, &topology_state->payloads, next) {
> >                 if (pos->port == port) {
> >                         payload = pos;
> > -                       prev_slots = payload->vcpi;
> > +                       prev_slots = payload->time_slots;
> >                         prev_bw = payload->pbn;
> > 
> >                         /*
> >                          * This should never happen, unless the driver
> > tries
> > -                        * releasing and allocating the same VCPI
> > allocation,
> > +                        * releasing and allocating the same timeslot
> > allocation,
> >                          * which is an error
> >                          */
> >                         if (WARN_ON(!prev_slots)) {
> >                                 drm_err(mgr->dev,
> > -                                       "cannot allocate and release VCPI
> > on
> > [MST PORT:%p] in the same state\n",
> > +                                       "cannot allocate and release time
> > slots on [MST PORT:%p] in the
> > +same state\n",
> >                                         port);
> >                                 return -EINVAL;
> >                         }
> > @@ -4420,7 +4420,7 @@ int drm_dp_atomic_find_vcpi_slots(struct
> > drm_atomic_state *state,
> > 
> >         req_slots = DIV_ROUND_UP(pbn, pbn_div);
> > 
> > -       drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p]
> > VCPI %d -> %d\n",
> > +       drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p]
> > TU %d ->
> > +%d\n",
> >                        port->connector->base.id, port->connector->name,
> >                        port, prev_slots, req_slots);
> >         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p]
> > PBN %d -> %d\n", @@ -4437,20 +4437,20 @@ int
> > drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> >                 payload->port = port;
> >                 list_add(&payload->next, &topology_state->payloads);
> >         }
> > -       payload->vcpi = req_slots;
> > +       payload->time_slots = req_slots;
> >         payload->pbn = pbn;
> > 
> >         return req_slots;
> >  }
> > -EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
> > +EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
> > 
> >  /**
> > - * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
> > + * drm_dp_atomic_release_time_slots() - Release allocated time slots
> >   * @state: global atomic state
> >   * @mgr: MST topology manager for the port
> > - * @port: The port to release the VCPI slots from
> > + * @port: The port to release the time slots from
> >   *
> > - * Releases any VCPI slots that have been allocated to a port in the
> > atomic
> > + * Releases any time slots that have been allocated to a port in the
> > + atomic
> >   * state. Any atomic drivers which support MST must call this function in
> >   * their &drm_connector_helper_funcs.atomic_check() callback when the
> >   * connector will no longer have VCPI allocated (e.g. because its CRTC
> > was
> > @@ -4459,18 +4459,18 @@
> > EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
> >   * It is OK to call this even if @port has been removed from the system.
> >   * Additionally, it is OK to call this function multiple times on the
> > same
> >   * @port as needed. It is not OK however, to call this function and
> > - * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic
> > check
> > + * drm_dp_atomic_find_time_slots() on the same @port in a single atomic
> > + check
> >   * phase.
> >   *
> >   * See also:
> > - * drm_dp_atomic_find_vcpi_slots()
> > + * drm_dp_atomic_find_time_slots()
> >   * drm_dp_mst_atomic_check()
> >   *
> >   * Returns:
> >   * 0 if all slots for this port were added back to
> >   * &drm_dp_mst_topology_state.avail_slots or negative error code
> >   */
> > -int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
> > +int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
> >                                      struct drm_dp_mst_topology_mgr *mgr,
> >                                      struct drm_dp_mst_port *port)
> >  {
> > @@ -4494,16 +4494,16 @@ int drm_dp_atomic_release_vcpi_slots(struct
> > drm_atomic_state *state,
> >                 return -EINVAL;
> >         }
> > 
> > -       drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port,
> > pos->vcpi);
> > -       if (pos->vcpi) {
> > +       drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port,
> > pos->time_slots);
> > +       if (pos->time_slots) {
> >                 drm_dp_mst_put_port_malloc(port);
> > -               pos->vcpi = 0;
> > +               pos->time_slots = 0;
> >                 pos->pbn = 0;
> >         }
> > 
> >         return 0;
> >  }
> > -EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
> > +EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
> > 
> >  /**
> >   * drm_dp_mst_update_slots() - updates the slot info depending on the DP
> > ecoding format @@ -4557,7 +4557,7 @@ bool
> > drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > 
> >         ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
> >         if (ret) {
> > -               drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d
> > ret=%d\n",
> > +               drm_dbg_kms(mgr->dev, "failed to init time slots=%d
> > ret=%d\n",
> >                             DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
> >                 drm_dp_mst_topology_put_port(port);
> >                 goto out;
> > @@ -5083,8 +5083,8 @@ drm_dp_mst_duplicate_state(struct
> > drm_private_obj *obj)
> >         INIT_LIST_HEAD(&state->payloads);
> > 
> >         list_for_each_entry(pos, &old_state->payloads, next) {
> > -               /* Prune leftover freed VCPI allocations */
> > -               if (!pos->vcpi)
> > +               /* Prune leftover freed timeslot allocations */
> > +               if (!pos->time_slots)
> >                         continue;
> > 
> >                 payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
> > @@ -5116,7 +5116,7 @@ static void drm_dp_mst_destroy_state(struct
> > drm_private_obj *obj,
> > 
> >         list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
> >                 /* We only keep references to ports with non-zero VCPIs */
> > -               if (pos->vcpi)
> > +               if (pos->time_slots)
> >                         drm_dp_mst_put_port_malloc(pos->port);
> >                 kfree(pos);
> >         }
> > @@ -5242,28 +5242,28 @@
> > drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,  }
> > 
> >  static inline int
> > -drm_dp_mst_atomic_check_vcpi_alloc_limit(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                        struct drm_dp_mst_topology_state
> > *mst_state)
> > +drm_dp_mst_atomic_check_payload_alloc_limits(struct
> > drm_dp_mst_topology_mgr *mgr,
> > +                                            struct
> > drm_dp_mst_topology_state *mst_state)
> >  {
> >         struct drm_dp_mst_atomic_payload *payload;
> >         int avail_slots = mst_state->total_avail_slots, payload_count = 0;
> > 
> >         list_for_each_entry(payload, &mst_state->payloads, next) {
> >                 /* Releasing payloads is always OK-even if the port is
> > gone */
> > -               if (!payload->vcpi) {
> > -                       drm_dbg_atomic(mgr->dev, "[MST PORT:%p]
> > releases all VCPI slots\n",
> > +               if (!payload->time_slots) {
> > +                       drm_dbg_atomic(mgr->dev, "[MST PORT:%p]
> > releases all time slots\n",
> >                                        payload->port);
> >                         continue;
> >                 }
> > 
> > -               drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d
> > vcpi slots\n",
> > -                              payload->port, payload->vcpi);
> > +               drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d
> > time slots\n",
> > +                              payload->port, payload->time_slots);
> > 
> > -               avail_slots -= payload->vcpi;
> > +               avail_slots -= payload->time_slots;
> >                 if (avail_slots < 0) {
> >                         drm_dbg_atomic(mgr->dev,
> > -                                      "[MST PORT:%p] not enough VCPI
> > slots in
> > mst state %p (avail=%d)\n",
> > -                                      payload->port, mst_state,
> > avail_slots +
> > payload->vcpi);
> > +                                      "[MST PORT:%p] not enough time
> > slots in
> > mst state %p (avail=%d)\n",
> > +                                      payload->port, mst_state,
> > avail_slots +
> > +payload->time_slots);
> >                         return -ENOSPC;
> >                 }
> > 
> > @@ -5274,7 +5274,7 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(struct
> > drm_dp_mst_topology_mgr *mgr,
> >                         return -EINVAL;
> >                 }
> >         }
> > -       drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI
> > avail=%d used=%d\n",
> > +       drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU
> > avail=%d
> > +used=%d\n",
> >                        mgr, mst_state, avail_slots, mst_state-
> > >total_avail_slots -
> > avail_slots);
> > 
> >         return 0;
> > @@ -5363,7 +5363,7 @@ int drm_dp_mst_atomic_enable_dsc(struct
> > drm_atomic_state *state,
> >         struct drm_dp_mst_topology_state *mst_state;
> >         struct drm_dp_mst_atomic_payload *pos;
> >         bool found = false;
> > -       int vcpi = 0;
> > +       int time_slots = 0;
> > 
> >         mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
> > 
> > @@ -5379,30 +5379,30 @@ int drm_dp_mst_atomic_enable_dsc(struct
> > drm_atomic_state *state,
> > 
> >         if (!found) {
> >                 drm_dbg_atomic(state->dev,
> > -                              "[MST PORT:%p] Couldn't find VCPI
> > allocation in
> > mst state %p\n",
> > +                              "[MST PORT:%p] Couldn't find payload in mst
> > state %p\n",
> >                                port, mst_state);
> >                 return -EINVAL;
> >         }
> > 
> >         if (pos->dsc_enabled == enable) {
> >                 drm_dbg_atomic(state->dev,
> > -                              "[MST PORT:%p] DSC flag is already set to
> > %d,
> > returning %d VCPI slots\n",
> > -                              port, enable, pos->vcpi);
> > -               vcpi = pos->vcpi;
> > +                              "[MST PORT:%p] DSC flag is already set to
> > %d,
> > returning %d time slots\n",
> > +                              port, enable, pos->time_slots);
> > +               time_slots = pos->time_slots;
> >         }
> > 
> >         if (enable) {
> > -               vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr,
> > port,
> > pbn, pbn_div);
> > +               time_slots = drm_dp_atomic_find_time_slots(state, port-
> > > mgr, port,
> > +pbn, pbn_div);
> >                 drm_dbg_atomic(state->dev,
> > -                              "[MST PORT:%p] Enabling DSC flag,
> > reallocating
> > %d VCPI slots on the port\n",
> > -                              port, vcpi);
> > -               if (vcpi < 0)
> > +                              "[MST PORT:%p] Enabling DSC flag,
> > reallocating
> > %d time slots on the port\n",
> > +                              port, time_slots);
> > +               if (time_slots < 0)
> >                         return -EINVAL;
> >         }
> > 
> >         pos->dsc_enabled = enable;
> > 
> > -       return vcpi;
> > +       return time_slots;
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
> >  /**
> > @@ -5412,15 +5412,15 @@
> > EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
> >   *
> >   * Checks the given topology state for an atomic update to ensure that
> > it's
> >   * valid. This includes checking whether there's enough bandwidth to
> > support
> > - * the new VCPI allocations in the atomic update.
> > + * the new timeslot allocations in the atomic update.
> >   *
> >   * Any atomic drivers supporting DP MST must make sure to call this after
> >   * checking the rest of their state in their
> >   * &drm_mode_config_funcs.atomic_check() callback.
> >   *
> >   * See also:
> > - * drm_dp_atomic_find_vcpi_slots()
> > - * drm_dp_atomic_release_vcpi_slots()
> > + * drm_dp_atomic_find_time_slots()
> > + * drm_dp_atomic_release_time_slots()
> >   *
> >   * Returns:
> >   *
> > @@ -5436,7 +5436,7 @@ int drm_dp_mst_atomic_check(struct
> > drm_atomic_state *state)
> >                 if (!mgr->mst_state)
> >                         continue;
> > 
> > -               ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr,
> > mst_state);
> > +               ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr,
> > mst_state);
> >                 if (ret)
> >                         break;
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 061b277e5ce7..0c922667398a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -70,7 +70,7 @@ static int intel_dp_mst_compute_link_config(struct
> > intel_encoder *encoder,
> >                                                        crtc_state-
> > >pipe_bpp,
> >                                                        false);
> > 
> > -               slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp-
> > > mst_mgr,
> > +               slots = drm_dp_atomic_find_time_slots(state, &intel_dp-
> > > mst_mgr,
> >                                                       connector->port,
> >                                                       crtc_state->pbn,
> > 
> > drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
> > @@ -344,8 +344,7 @@ intel_dp_mst_atomic_check(struct drm_connector
> > *connector,
> >         }
> > 
> >         mgr = &enc_to_mst(to_intel_encoder(old_conn_state-
> > > best_encoder))->primary->dp.mst_mgr;
> > -       ret = drm_dp_atomic_release_vcpi_slots(&state->base, mgr,
> > -                                              intel_connector->port);
> > +       ret = drm_dp_atomic_release_time_slots(&state->base, mgr,
> > +intel_connector->port);
> > 
> >         return ret;
> >  }
> > diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > index 4347f0b61797..631dba5a2418 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > @@ -1070,7 +1070,7 @@ nv50_msto_atomic_check(struct drm_encoder
> > *encoder,
> >                                                     false);
> >         }
> > 
> > -       slots = drm_dp_atomic_find_vcpi_slots(state, &mstm->mgr, mstc-
> > > port,
> > +       slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc-
> > > port,
> >                                               asyh->dp.pbn, 0);
> >         if (slots < 0)
> >                 return slots;
> > @@ -1282,7 +1282,7 @@ nv50_mstc_atomic_check(struct drm_connector
> > *connector,
> >                         return 0;
> >         }
> > 
> > -       return drm_dp_atomic_release_vcpi_slots(state, mgr, mstc->port);
> > +       return drm_dp_atomic_release_time_slots(state, mgr, mstc->port);
> >  }
> > 
> >  static int
> > diff --git a/include/drm/display/drm_dp_mst_helper.h
> > b/include/drm/display/drm_dp_mst_helper.h
> > index 5671173f9f37..8ab4f14f2344 100644
> > --- a/include/drm/display/drm_dp_mst_helper.h
> > +++ b/include/drm/display/drm_dp_mst_helper.h
> > @@ -544,7 +544,7 @@ struct drm_dp_payload {
> > 
> >  struct drm_dp_mst_atomic_payload {
> >         struct drm_dp_mst_port *port;
> > -       int vcpi;
> > +       int time_slots;
> >         int pbn;
> >         bool dsc_enabled;
> >         struct list_head next;
> > @@ -846,7 +846,7 @@ void drm_dp_mst_connector_early_unregister(struct
> > drm_connector *connector,  struct drm_dp_mst_topology_state
> > *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> >                                                                     struct
> > drm_dp_mst_topology_mgr *mgr);  int __must_check -
> > drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> > +drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> >                               struct drm_dp_mst_topology_mgr *mgr,
> >                               struct drm_dp_mst_port *port, int pbn,
> >                               int pbn_div);
> > @@ -858,7 +858,7 @@ int __must_check
> >  drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
> >                                   struct drm_dp_mst_topology_mgr *mgr);
> > int __must_check -drm_dp_atomic_release_vcpi_slots(struct
> > drm_atomic_state *state,
> > +drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
> >                                  struct drm_dp_mst_topology_mgr *mgr,
> >                                  struct drm_dp_mst_port *port);
> >  int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr
> > *mgr,
> > --
> > 2.35.3
> --
> Regards,
> Wayne Lin

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat

[Intel-gfx] [RESEND RFC 08/18] drm/display/dp_mst: Add nonblocking helpers for DP MST

[Lyude Paul]

As Daniel Vetter pointed out, if we only use the atomic modesetting locks
with MST it's technically possible for a driver with non-blocking modesets
to race when it comes to MST displays - as we make the mistake of not doing
our own CRTC commit tracking in the topology_state object.

This could potentially cause problems if something like this happens:

* User starts non-blocking commit to disable CRTC-1 on MST topology 1
* User starts non-blocking commit to enable CRTC-2 on MST topology 1

There's no guarantee here that the commit for disabling CRTC-2 will only
occur after CRTC-1 has finished, since neither commit shares a CRTC - only
the private modesetting object for MST. Keep in mind this likely isn't a
problem for blocking modesets, only non-blocking.

So, begin fixing this by keeping track of which CRTCs on a topology have
changed by keeping track of which CRTCs we release or allocate timeslots
on. As well, add some helpers for:

* Setting up the drm_crtc_commit structs in the ->commit_setup hook
* Waiting for any CRTC dependencies from the previous topology state

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  9 +-
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 93 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_display.c  | 11 +++
 drivers/gpu/drm/nouveau/dispnv50/disp.c       | 12 +++
 include/drm/display/drm_dp_mst_helper.h       | 15 +++
 5 files changed, 139 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index f84a4ad736d8..d9c7393ef151 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -211,6 +211,7 @@ static int amdgpu_dm_encoder_init(struct drm_device *dev,
 static int amdgpu_dm_connector_get_modes(struct drm_connector *connector);
 
 static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state);
+static int amdgpu_dm_atomic_setup_commit(struct drm_atomic_state *state);
 
 static int amdgpu_dm_atomic_check(struct drm_device *dev,
 				  struct drm_atomic_state *state);
@@ -2808,7 +2809,8 @@ static const struct drm_mode_config_funcs amdgpu_dm_mode_funcs = {
 };
 
 static struct drm_mode_config_helper_funcs amdgpu_dm_mode_config_helperfuncs = {
-	.atomic_commit_tail = amdgpu_dm_atomic_commit_tail
+	.atomic_commit_tail = amdgpu_dm_atomic_commit_tail,
+	.atomic_commit_setup = amdgpu_dm_atomic_setup_commit,
 };
 
 static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
@@ -9558,6 +9560,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		DRM_ERROR("Waiting for fences timed out!");
 
 	drm_atomic_helper_update_legacy_modeset_state(dev, state);
+	drm_dp_mst_atomic_wait_for_dependencies(state);
 
 	dm_state = dm_atomic_get_new_state(state);
 	if (dm_state && dm_state->context) {
@@ -9958,6 +9961,10 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		dc_release_state(dc_state_temp);
 }
 
+static int amdgpu_dm_atomic_setup_commit(struct drm_atomic_state *state)
+{
+	return drm_dp_mst_atomic_setup_commit(state);
+}
 
 static int dm_force_atomic_commit(struct drm_connector *connector)
 {
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 0bc2c7a90c37..a0ed29f83556 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -4395,12 +4395,16 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 {
 	struct drm_dp_mst_topology_state *topology_state;
 	struct drm_dp_mst_atomic_payload *payload = NULL;
+	struct drm_connector_state *conn_state;
 	int prev_slots = 0, prev_bw = 0, req_slots;
 
 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
 	if (IS_ERR(topology_state))
 		return PTR_ERR(topology_state);
 
+	conn_state = drm_atomic_get_new_connector_state(state, port->connector);
+	topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
+
 	/* Find the current allocation for this port, if any */
 	payload = drm_atomic_get_mst_payload_state(topology_state, port);
 	if (payload) {
@@ -4480,11 +4484,15 @@ int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 {
 	struct drm_dp_mst_topology_state *topology_state;
 	struct drm_dp_mst_atomic_payload *payload;
+	struct drm_connector_state *conn_state;
 
 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
 	if (IS_ERR(topology_state))
 		return PTR_ERR(topology_state);
 
+	conn_state = drm_atomic_get_old_connector_state(state, port->connector);
+	topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
+
 	payload = drm_atomic_get_mst_payload_state(topology_state, port);
 	if (WARN_ON(!payload)) {
 		drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
@@ -4503,6 +4511,83 @@ int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
 
+/**
+ * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
+ * @state: global atomic state
+ *
+ * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
+ * currently assigned to an MST topology. Drivers must call this hook from their
+ * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
+ *
+ * Returns:
+ * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
+ */
+int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
+{
+	struct drm_dp_mst_topology_mgr *mgr;
+	struct drm_dp_mst_topology_state *mst_state;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i, j, commit_idx, num_commit_deps;
+
+	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
+		if (!mst_state->pending_crtc_mask)
+			continue;
+
+		num_commit_deps = hweight32(mst_state->pending_crtc_mask);
+		mst_state->commit_deps = kmalloc_array(num_commit_deps,
+						       sizeof(*mst_state->commit_deps), GFP_KERNEL);
+		if (!mst_state->commit_deps)
+			return -ENOMEM;
+		mst_state->num_commit_deps = num_commit_deps;
+
+		commit_idx = 0;
+		for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
+			if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
+				mst_state->commit_deps[commit_idx++] =
+					drm_crtc_commit_get(crtc_state->commit);
+			}
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
+
+/**
+ * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies
+ * @state: global atomic state
+ *
+ * Goes through any MST topologies in this atomic state, and waits for any pending commits which
+ * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
+ * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
+ * with eachother by forcing them to be executed sequentially in situations where the only resources
+ * the modeset objects in these commits share are an MST topology.
+ *
+ * This function also prepares the new MST state for commit by performing some state preparation
+ * which can't be done until this point, such as reading back the final VC start slots (which are
+ * determined at commit-time) from the previous state.
+ *
+ * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
+ * or whatever their equivalent of that is.
+ */
+void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
+{
+	struct drm_dp_mst_topology_state *old_mst_state;
+	struct drm_dp_mst_topology_mgr *mgr;
+	int i, j, ret;
+
+	for_each_old_mst_mgr_in_state(state, mgr, old_mst_state, i) {
+		for (j = 0; j < old_mst_state->num_commit_deps; j++) {
+			ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
+			if (ret < 0)
+				drm_err(state->dev, "Failed to wait for %s: %d\n",
+					old_mst_state->commit_deps[j]->crtc->name, ret);
+		}
+	}
+}
+EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
+
 /**
  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
  * @mst_state: mst_state to update
@@ -5079,6 +5164,9 @@ drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
 	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
 
 	INIT_LIST_HEAD(&state->payloads);
+	state->commit_deps = NULL;
+	state->num_commit_deps = 0;
+	state->pending_crtc_mask = 0;
 
 	list_for_each_entry(pos, &old_state->payloads, next) {
 		/* Prune leftover freed timeslot allocations */
@@ -5111,6 +5199,7 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
 	struct drm_dp_mst_topology_state *mst_state =
 		to_dp_mst_topology_state(state);
 	struct drm_dp_mst_atomic_payload *pos, *tmp;
+	int i;
 
 	list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
 		/* We only keep references to ports with non-zero VCPIs */
@@ -5119,6 +5208,10 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
 		kfree(pos);
 	}
 
+	for (i = 0; i < mst_state->num_commit_deps; i++)
+		drm_crtc_commit_put(mst_state->commit_deps[i]);
+
+	kfree(mst_state->commit_deps);
 	kfree(mst_state);
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 186b37925d23..5475f66c0ed8 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -8446,6 +8446,7 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 	intel_atomic_commit_fence_wait(state);
 
 	drm_atomic_helper_wait_for_dependencies(&state->base);
+	drm_dp_mst_atomic_wait_for_dependencies(&state->base);
 
 	if (state->modeset)
 		wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_MODESET);
@@ -9514,6 +9515,15 @@ static int intel_initial_commit(struct drm_device *dev)
 	return ret;
 }
 
+static int intel_atomic_commit_setup(struct drm_atomic_state *state)
+{
+	return drm_dp_mst_atomic_setup_commit(state);
+}
+
+static const struct drm_mode_config_helper_funcs intel_mode_config_funcs = {
+	.atomic_commit_setup = intel_atomic_commit_setup,
+};
+
 static void intel_mode_config_init(struct drm_i915_private *i915)
 {
 	struct drm_mode_config *mode_config = &i915->drm.mode_config;
@@ -9528,6 +9538,7 @@ static void intel_mode_config_init(struct drm_i915_private *i915)
 	mode_config->prefer_shadow = 1;
 
 	mode_config->funcs = &intel_mode_funcs;
+	mode_config->helper_private = &intel_mode_config_funcs;
 
 	mode_config->async_page_flip = HAS_ASYNC_FLIPS(i915);
 
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 631dba5a2418..768312607fdb 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -2134,6 +2134,7 @@ nv50_disp_atomic_commit_tail(struct drm_atomic_state *state)
 	nv50_crc_atomic_stop_reporting(state);
 	drm_atomic_helper_wait_for_fences(dev, state, false);
 	drm_atomic_helper_wait_for_dependencies(state);
+	drm_dp_mst_atomic_wait_for_dependencies(state);
 	drm_atomic_helper_update_legacy_modeset_state(dev, state);
 	drm_atomic_helper_calc_timestamping_constants(state);
 
@@ -2614,6 +2615,16 @@ nv50_disp_func = {
 	.atomic_state_free = nv50_disp_atomic_state_free,
 };
 
+static int nv50_disp_atomic_setup_commit(struct drm_atomic_state *state)
+{
+	return drm_dp_mst_atomic_setup_commit(state);
+}
+
+static const struct drm_mode_config_helper_funcs
+nv50_disp_helper_func = {
+	.atomic_commit_setup = nv50_disp_atomic_setup_commit,
+};
+
 /******************************************************************************
  * Init
  *****************************************************************************/
@@ -2713,6 +2724,7 @@ nv50_display_create(struct drm_device *dev)
 	nouveau_display(dev)->fini = nv50_display_fini;
 	disp->disp = &nouveau_display(dev)->disp;
 	dev->mode_config.funcs = &nv50_disp_func;
+	dev->mode_config.helper_private = &nv50_disp_helper_func;
 	dev->mode_config.quirk_addfb_prefer_xbgr_30bpp = true;
 	dev->mode_config.normalize_zpos = true;
 
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index eb0ea578b227..dd74afcee888 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -576,6 +576,19 @@ struct drm_dp_mst_topology_state {
 	/** @mgr: The topology manager */
 	struct drm_dp_mst_topology_mgr *mgr;
 
+	/**
+	 * @pending_crtc_mask: A bitmask of all CRTCs this topology state touches, drivers may
+	 * modify this to add additional dependencies if needed.
+	 */
+	u32 pending_crtc_mask;
+	/**
+	 * @commit_deps: A list of all CRTC commits affecting this topology, this field isn't
+	 * populated until drm_dp_mst_atomic_wait_for_dependencies() is called.
+	 */
+	struct drm_crtc_commit **commit_deps;
+	/** @num_commit_deps: The number of CRTC commits in @commit_deps */
+	size_t num_commit_deps;
+
 	/** @total_avail_slots: The total number of slots this topology can handle (63 or 64) */
 	u8 total_avail_slots;
 	/** @start_slot: The first usable time slot in this topology (1 or 0) */
@@ -885,6 +898,8 @@ int __must_check
 drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 				 struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port);
+void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state);
+int __must_check drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state);
 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port, bool power_up);
 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
-- 
2.35.3

Re: [Intel-gfx] [RESEND RFC 08/18] drm/display/dp_mst: Add nonblocking helpers for DP MST

[Jani Nikula]

On Tue, 07 Jun 2022, Lyude Paul <lyude@redhat.com> wrote:
> As Daniel Vetter pointed out, if we only use the atomic modesetting locks
> with MST it's technically possible for a driver with non-blocking modesets
> to race when it comes to MST displays - as we make the mistake of not doing
> our own CRTC commit tracking in the topology_state object.
>
> This could potentially cause problems if something like this happens:
>
> * User starts non-blocking commit to disable CRTC-1 on MST topology 1
> * User starts non-blocking commit to enable CRTC-2 on MST topology 1
>
> There's no guarantee here that the commit for disabling CRTC-2 will only
> occur after CRTC-1 has finished, since neither commit shares a CRTC - only
> the private modesetting object for MST. Keep in mind this likely isn't a
> problem for blocking modesets, only non-blocking.
>
> So, begin fixing this by keeping track of which CRTCs on a topology have
> changed by keeping track of which CRTCs we release or allocate timeslots
> on. As well, add some helpers for:
>
> * Setting up the drm_crtc_commit structs in the ->commit_setup hook
> * Waiting for any CRTC dependencies from the previous topology state
>
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Cc: Wayne Lin <Wayne.Lin@amd.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Sean Paul <sean@poorly.run>
> ---
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  9 +-
>  drivers/gpu/drm/display/drm_dp_mst_topology.c | 93 +++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_display.c  | 11 +++
>  drivers/gpu/drm/nouveau/dispnv50/disp.c       | 12 +++
>  include/drm/display/drm_dp_mst_helper.h       | 15 +++
>  5 files changed, 139 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index f84a4ad736d8..d9c7393ef151 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -211,6 +211,7 @@ static int amdgpu_dm_encoder_init(struct drm_device *dev,
>  static int amdgpu_dm_connector_get_modes(struct drm_connector *connector);
>  
>  static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state);
> +static int amdgpu_dm_atomic_setup_commit(struct drm_atomic_state *state);
>  
>  static int amdgpu_dm_atomic_check(struct drm_device *dev,
>  				  struct drm_atomic_state *state);
> @@ -2808,7 +2809,8 @@ static const struct drm_mode_config_funcs amdgpu_dm_mode_funcs = {
>  };
>  
>  static struct drm_mode_config_helper_funcs amdgpu_dm_mode_config_helperfuncs = {
> -	.atomic_commit_tail = amdgpu_dm_atomic_commit_tail
> +	.atomic_commit_tail = amdgpu_dm_atomic_commit_tail,
> +	.atomic_commit_setup = amdgpu_dm_atomic_setup_commit,
>  };
>  
>  static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
> @@ -9558,6 +9560,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>  		DRM_ERROR("Waiting for fences timed out!");
>  
>  	drm_atomic_helper_update_legacy_modeset_state(dev, state);
> +	drm_dp_mst_atomic_wait_for_dependencies(state);
>  
>  	dm_state = dm_atomic_get_new_state(state);
>  	if (dm_state && dm_state->context) {
> @@ -9958,6 +9961,10 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>  		dc_release_state(dc_state_temp);
>  }
>  
> +static int amdgpu_dm_atomic_setup_commit(struct drm_atomic_state *state)
> +{
> +	return drm_dp_mst_atomic_setup_commit(state);
> +}

I guess all the driver specific wrappers for setup commit could be
dropped in favor of directly using drm_dp_mst_atomic_setup_commit?

BR,
Jani.

>  
>  static int dm_force_atomic_commit(struct drm_connector *connector)
>  {
> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> index 0bc2c7a90c37..a0ed29f83556 100644
> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> @@ -4395,12 +4395,16 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
>  {
>  	struct drm_dp_mst_topology_state *topology_state;
>  	struct drm_dp_mst_atomic_payload *payload = NULL;
> +	struct drm_connector_state *conn_state;
>  	int prev_slots = 0, prev_bw = 0, req_slots;
>  
>  	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
>  	if (IS_ERR(topology_state))
>  		return PTR_ERR(topology_state);
>  
> +	conn_state = drm_atomic_get_new_connector_state(state, port->connector);
> +	topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
> +
>  	/* Find the current allocation for this port, if any */
>  	payload = drm_atomic_get_mst_payload_state(topology_state, port);
>  	if (payload) {
> @@ -4480,11 +4484,15 @@ int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
>  {
>  	struct drm_dp_mst_topology_state *topology_state;
>  	struct drm_dp_mst_atomic_payload *payload;
> +	struct drm_connector_state *conn_state;
>  
>  	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
>  	if (IS_ERR(topology_state))
>  		return PTR_ERR(topology_state);
>  
> +	conn_state = drm_atomic_get_old_connector_state(state, port->connector);
> +	topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
> +
>  	payload = drm_atomic_get_mst_payload_state(topology_state, port);
>  	if (WARN_ON(!payload)) {
>  		drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
> @@ -4503,6 +4511,83 @@ int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
>  }
>  EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
>  
> +/**
> + * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
> + * @state: global atomic state
> + *
> + * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
> + * currently assigned to an MST topology. Drivers must call this hook from their
> + * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
> + *
> + * Returns:
> + * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
> + */
> +int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
> +{
> +	struct drm_dp_mst_topology_mgr *mgr;
> +	struct drm_dp_mst_topology_state *mst_state;
> +	struct drm_crtc *crtc;
> +	struct drm_crtc_state *crtc_state;
> +	int i, j, commit_idx, num_commit_deps;
> +
> +	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> +		if (!mst_state->pending_crtc_mask)
> +			continue;
> +
> +		num_commit_deps = hweight32(mst_state->pending_crtc_mask);
> +		mst_state->commit_deps = kmalloc_array(num_commit_deps,
> +						       sizeof(*mst_state->commit_deps), GFP_KERNEL);
> +		if (!mst_state->commit_deps)
> +			return -ENOMEM;
> +		mst_state->num_commit_deps = num_commit_deps;
> +
> +		commit_idx = 0;
> +		for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
> +			if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
> +				mst_state->commit_deps[commit_idx++] =
> +					drm_crtc_commit_get(crtc_state->commit);
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
> +
> +/**
> + * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies
> + * @state: global atomic state
> + *
> + * Goes through any MST topologies in this atomic state, and waits for any pending commits which
> + * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
> + * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
> + * with eachother by forcing them to be executed sequentially in situations where the only resources
> + * the modeset objects in these commits share are an MST topology.
> + *
> + * This function also prepares the new MST state for commit by performing some state preparation
> + * which can't be done until this point, such as reading back the final VC start slots (which are
> + * determined at commit-time) from the previous state.
> + *
> + * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
> + * or whatever their equivalent of that is.
> + */
> +void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
> +{
> +	struct drm_dp_mst_topology_state *old_mst_state;
> +	struct drm_dp_mst_topology_mgr *mgr;
> +	int i, j, ret;
> +
> +	for_each_old_mst_mgr_in_state(state, mgr, old_mst_state, i) {
> +		for (j = 0; j < old_mst_state->num_commit_deps; j++) {
> +			ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
> +			if (ret < 0)
> +				drm_err(state->dev, "Failed to wait for %s: %d\n",
> +					old_mst_state->commit_deps[j]->crtc->name, ret);
> +		}
> +	}
> +}
> +EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
> +
>  /**
>   * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
>   * @mst_state: mst_state to update
> @@ -5079,6 +5164,9 @@ drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
>  	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
>  
>  	INIT_LIST_HEAD(&state->payloads);
> +	state->commit_deps = NULL;
> +	state->num_commit_deps = 0;
> +	state->pending_crtc_mask = 0;
>  
>  	list_for_each_entry(pos, &old_state->payloads, next) {
>  		/* Prune leftover freed timeslot allocations */
> @@ -5111,6 +5199,7 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
>  	struct drm_dp_mst_topology_state *mst_state =
>  		to_dp_mst_topology_state(state);
>  	struct drm_dp_mst_atomic_payload *pos, *tmp;
> +	int i;
>  
>  	list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
>  		/* We only keep references to ports with non-zero VCPIs */
> @@ -5119,6 +5208,10 @@ static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
>  		kfree(pos);
>  	}
>  
> +	for (i = 0; i < mst_state->num_commit_deps; i++)
> +		drm_crtc_commit_put(mst_state->commit_deps[i]);
> +
> +	kfree(mst_state->commit_deps);
>  	kfree(mst_state);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 186b37925d23..5475f66c0ed8 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -8446,6 +8446,7 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
>  	intel_atomic_commit_fence_wait(state);
>  
>  	drm_atomic_helper_wait_for_dependencies(&state->base);
> +	drm_dp_mst_atomic_wait_for_dependencies(&state->base);
>  
>  	if (state->modeset)
>  		wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_MODESET);
> @@ -9514,6 +9515,15 @@ static int intel_initial_commit(struct drm_device *dev)
>  	return ret;
>  }
>  
> +static int intel_atomic_commit_setup(struct drm_atomic_state *state)
> +{
> +	return drm_dp_mst_atomic_setup_commit(state);
> +}
> +
> +static const struct drm_mode_config_helper_funcs intel_mode_config_funcs = {
> +	.atomic_commit_setup = intel_atomic_commit_setup,
> +};
> +
>  static void intel_mode_config_init(struct drm_i915_private *i915)
>  {
>  	struct drm_mode_config *mode_config = &i915->drm.mode_config;
> @@ -9528,6 +9538,7 @@ static void intel_mode_config_init(struct drm_i915_private *i915)
>  	mode_config->prefer_shadow = 1;
>  
>  	mode_config->funcs = &intel_mode_funcs;
> +	mode_config->helper_private = &intel_mode_config_funcs;
>  
>  	mode_config->async_page_flip = HAS_ASYNC_FLIPS(i915);
>  
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index 631dba5a2418..768312607fdb 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -2134,6 +2134,7 @@ nv50_disp_atomic_commit_tail(struct drm_atomic_state *state)
>  	nv50_crc_atomic_stop_reporting(state);
>  	drm_atomic_helper_wait_for_fences(dev, state, false);
>  	drm_atomic_helper_wait_for_dependencies(state);
> +	drm_dp_mst_atomic_wait_for_dependencies(state);
>  	drm_atomic_helper_update_legacy_modeset_state(dev, state);
>  	drm_atomic_helper_calc_timestamping_constants(state);
>  
> @@ -2614,6 +2615,16 @@ nv50_disp_func = {
>  	.atomic_state_free = nv50_disp_atomic_state_free,
>  };
>  
> +static int nv50_disp_atomic_setup_commit(struct drm_atomic_state *state)
> +{
> +	return drm_dp_mst_atomic_setup_commit(state);
> +}
> +
> +static const struct drm_mode_config_helper_funcs
> +nv50_disp_helper_func = {
> +	.atomic_commit_setup = nv50_disp_atomic_setup_commit,
> +};
> +
>  /******************************************************************************
>   * Init
>   *****************************************************************************/
> @@ -2713,6 +2724,7 @@ nv50_display_create(struct drm_device *dev)
>  	nouveau_display(dev)->fini = nv50_display_fini;
>  	disp->disp = &nouveau_display(dev)->disp;
>  	dev->mode_config.funcs = &nv50_disp_func;
> +	dev->mode_config.helper_private = &nv50_disp_helper_func;
>  	dev->mode_config.quirk_addfb_prefer_xbgr_30bpp = true;
>  	dev->mode_config.normalize_zpos = true;
>  
> diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
> index eb0ea578b227..dd74afcee888 100644
> --- a/include/drm/display/drm_dp_mst_helper.h
> +++ b/include/drm/display/drm_dp_mst_helper.h
> @@ -576,6 +576,19 @@ struct drm_dp_mst_topology_state {
>  	/** @mgr: The topology manager */
>  	struct drm_dp_mst_topology_mgr *mgr;
>  
> +	/**
> +	 * @pending_crtc_mask: A bitmask of all CRTCs this topology state touches, drivers may
> +	 * modify this to add additional dependencies if needed.
> +	 */
> +	u32 pending_crtc_mask;
> +	/**
> +	 * @commit_deps: A list of all CRTC commits affecting this topology, this field isn't
> +	 * populated until drm_dp_mst_atomic_wait_for_dependencies() is called.
> +	 */
> +	struct drm_crtc_commit **commit_deps;
> +	/** @num_commit_deps: The number of CRTC commits in @commit_deps */
> +	size_t num_commit_deps;
> +
>  	/** @total_avail_slots: The total number of slots this topology can handle (63 or 64) */
>  	u8 total_avail_slots;
>  	/** @start_slot: The first usable time slot in this topology (1 or 0) */
> @@ -885,6 +898,8 @@ int __must_check
>  drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
>  				 struct drm_dp_mst_topology_mgr *mgr,
>  				 struct drm_dp_mst_port *port);
> +void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state);
> +int __must_check drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state);
>  int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
>  				 struct drm_dp_mst_port *port, bool power_up);
>  int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,

-- 
Jani Nikula, Intel Open Source Graphics Center

[Intel-gfx] [RESEND RFC 09/18] drm/display/dp_mst: Don't open code modeset checks for releasing time slots

[Lyude Paul]

I'm not sure why, but at the time I originally wrote the find/release time
slot helpers I thought we should avoid keeping modeset tracking out of the
MST helpers. In retrospect though there's no actual good reason to do
this, and the logic has ended up being identical across all the drivers
using the helpers. Also, it needs to be fixed anyway so we don't break
things when going atomic-only with MST.

So, let's just move this code into drm_dp_atomic_release_time_slots() and
stop open coding it.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
---
 .../display/amdgpu_dm/amdgpu_dm_mst_types.c   | 29 +++----------------
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 21 ++++++++++++--
 drivers/gpu/drm/i915/display/intel_dp_mst.c   | 24 +--------------
 drivers/gpu/drm/nouveau/dispnv50/disp.c       | 21 --------------
 4 files changed, 23 insertions(+), 72 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index e40ff51e7be0..b447c453b58d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -353,34 +353,13 @@ dm_dp_mst_detect(struct drm_connector *connector,
 }
 
 static int dm_dp_mst_atomic_check(struct drm_connector *connector,
-				struct drm_atomic_state *state)
+				  struct drm_atomic_state *state)
 {
-	struct drm_connector_state *new_conn_state =
-			drm_atomic_get_new_connector_state(state, connector);
-	struct drm_connector_state *old_conn_state =
-			drm_atomic_get_old_connector_state(state, connector);
 	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
-	struct drm_crtc_state *new_crtc_state;
-	struct drm_dp_mst_topology_mgr *mst_mgr;
-	struct drm_dp_mst_port *mst_port;
+	struct drm_dp_mst_topology_mgr *mst_mgr = &aconnector->mst_port->mst_mgr;
+	struct drm_dp_mst_port *mst_port = aconnector->port;
 
-	mst_port = aconnector->port;
-	mst_mgr = &aconnector->mst_port->mst_mgr;
-
-	if (!old_conn_state->crtc)
-		return 0;
-
-	if (new_conn_state->crtc) {
-		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
-		if (!new_crtc_state ||
-		    !drm_atomic_crtc_needs_modeset(new_crtc_state) ||
-		    new_crtc_state->enable)
-			return 0;
-		}
-
-	return drm_dp_atomic_release_time_slots(state,
-						mst_mgr,
-						mst_port);
+	return drm_dp_atomic_release_time_slots(state, mst_mgr, mst_port);
 }
 
 static const struct drm_connector_helper_funcs dm_dp_mst_connector_helper_funcs = {
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index a0ed29f83556..e73b34c0cc9e 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -4484,14 +4484,29 @@ int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 {
 	struct drm_dp_mst_topology_state *topology_state;
 	struct drm_dp_mst_atomic_payload *payload;
-	struct drm_connector_state *conn_state;
+	struct drm_connector_state *old_conn_state, *new_conn_state;
+
+	old_conn_state = drm_atomic_get_old_connector_state(state, port->connector);
+	if (!old_conn_state->crtc)
+		return 0;
+
+	/* If the CRTC isn't disabled by this state, don't release it's payload */
+	new_conn_state = drm_atomic_get_new_connector_state(state, port->connector);
+	if (new_conn_state->crtc) {
+		struct drm_crtc_state *crtc_state =
+			drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
+
+		if (!crtc_state ||
+		    !drm_atomic_crtc_needs_modeset(crtc_state) ||
+		    crtc_state->enable)
+			return 0;
+	}
 
 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
 	if (IS_ERR(topology_state))
 		return PTR_ERR(topology_state);
 
-	conn_state = drm_atomic_get_old_connector_state(state, port->connector);
-	topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
+	topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
 
 	payload = drm_atomic_get_mst_payload_state(topology_state, port);
 	if (WARN_ON(!payload)) {
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 0c922667398a..4b0af3c26176 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -308,13 +308,10 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
 			  struct drm_atomic_state *_state)
 {
 	struct intel_atomic_state *state = to_intel_atomic_state(_state);
-	struct drm_connector_state *new_conn_state =
-		drm_atomic_get_new_connector_state(&state->base, connector);
 	struct drm_connector_state *old_conn_state =
 		drm_atomic_get_old_connector_state(&state->base, connector);
 	struct intel_connector *intel_connector =
 		to_intel_connector(connector);
-	struct drm_crtc *new_crtc = new_conn_state->crtc;
 	struct drm_dp_mst_topology_mgr *mgr;
 	int ret;
 
@@ -326,27 +323,8 @@ intel_dp_mst_atomic_check(struct drm_connector *connector,
 	if (ret)
 		return ret;
 
-	if (!old_conn_state->crtc)
-		return 0;
-
-	/* We only want to free VCPI if this state disables the CRTC on this
-	 * connector
-	 */
-	if (new_crtc) {
-		struct intel_crtc *crtc = to_intel_crtc(new_crtc);
-		struct intel_crtc_state *crtc_state =
-			intel_atomic_get_new_crtc_state(state, crtc);
-
-		if (!crtc_state ||
-		    !drm_atomic_crtc_needs_modeset(&crtc_state->uapi) ||
-		    crtc_state->uapi.enable)
-			return 0;
-	}
-
 	mgr = &enc_to_mst(to_intel_encoder(old_conn_state->best_encoder))->primary->dp.mst_mgr;
-	ret = drm_dp_atomic_release_time_slots(&state->base, mgr, intel_connector->port);
-
-	return ret;
+	return drm_dp_atomic_release_time_slots(&state->base, mgr, intel_connector->port);
 }
 
 static void clear_act_sent(struct intel_encoder *encoder,
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 768312607fdb..461e5e3345f8 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1260,27 +1260,6 @@ nv50_mstc_atomic_check(struct drm_connector *connector,
 {
 	struct nv50_mstc *mstc = nv50_mstc(connector);
 	struct drm_dp_mst_topology_mgr *mgr = &mstc->mstm->mgr;
-	struct drm_connector_state *new_conn_state =
-		drm_atomic_get_new_connector_state(state, connector);
-	struct drm_connector_state *old_conn_state =
-		drm_atomic_get_old_connector_state(state, connector);
-	struct drm_crtc_state *crtc_state;
-	struct drm_crtc *new_crtc = new_conn_state->crtc;
-
-	if (!old_conn_state->crtc)
-		return 0;
-
-	/* We only want to free VCPI if this state disables the CRTC on this
-	 * connector
-	 */
-	if (new_crtc) {
-		crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
-
-		if (!crtc_state ||
-		    !drm_atomic_crtc_needs_modeset(crtc_state) ||
-		    crtc_state->enable)
-			return 0;
-	}
 
 	return drm_dp_atomic_release_time_slots(state, mgr, mstc->port);
 }
-- 
2.35.3

[Intel-gfx] [RESEND RFC 13/18] drm/display/dp_mst: Add helpers for serializing SST <-> MST transitions

[Lyude Paul]

There's another kind of situation where we could potentially race with
nonblocking modesets and MST, especially if we were to only use the locking
provided by atomic modesetting:

* Display 1 begins as enabled on DP-1 in SST mode
* Display 1 switches to MST mode, exposes one sink in MST mode
* Userspace does non-blocking modeset to disable the SST display
* Userspace does non-blocking modeset to enable the MST display with a
  different CRTC, but the SST display hasn't been fully taken down yet
* Execution order between the last two commits isn't guaranteed since they
  share no drm resources

We can fix this however, by ensuring that we always pull in the atomic
topology state whenever a connector capable of driving an MST display
performs its atomic check - and then tracking CRTC commits happening on the
SST connector in the MST topology state. So, let's add some simple helpers
for doing that and hook them up in various drivers.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  7 +++
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 59 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dp.c       |  9 +++
 drivers/gpu/drm/nouveau/dispnv50/disp.c       |  2 +-
 drivers/gpu/drm/nouveau/dispnv50/disp.h       |  2 +
 drivers/gpu/drm/nouveau/nouveau_connector.c   | 14 +++++
 include/drm/display/drm_dp_mst_helper.h       |  2 +
 7 files changed, 94 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index d9c7393ef151..ac8648e3c1c9 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7177,10 +7177,17 @@ amdgpu_dm_connector_atomic_check(struct drm_connector *conn,
 		drm_atomic_get_old_connector_state(state, conn);
 	struct drm_crtc *crtc = new_con_state->crtc;
 	struct drm_crtc_state *new_crtc_state;
+	struct amdgpu_dm_connector *aconn = to_amdgpu_dm_connector(conn);
 	int ret;
 
 	trace_amdgpu_dm_connector_atomic_check(new_con_state);
 
+	if (conn->connector_type == DRM_MODE_CONNECTOR_DisplayPort) {
+		ret = drm_dp_mst_root_conn_atomic_check(new_con_state, &aconn->mst_mgr);
+		if (ret < 0)
+			return ret;
+	}
+
 	if (!crtc)
 		return 0;
 
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index c5edcf2a26c8..a775f9437868 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -4608,6 +4608,65 @@ void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
 }
 EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
 
+/**
+ * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating
+ * in SST mode
+ * @new_conn_state: The new connector state of the &drm_connector
+ * @mgr: The MST topology manager for the &drm_connector
+ *
+ * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to
+ * serialize non-blocking commits happening on the real DP connector of an MST topology switching
+ * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's
+ * MST topology will never share the same &drm_encoder.
+ *
+ * This function takes care of this serialization issue, by checking a root MST connector's atomic
+ * state to determine if it is about to have a modeset - and then pulling in the MST topology state
+ * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask.
+ *
+ * Drivers implementing MST must call this function from the
+ * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of
+ * driving MST sinks.
+ *
+ * Returns:
+ * 0 on success, negative error code otherwise
+ */
+int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
+				      struct drm_dp_mst_topology_mgr *mgr)
+{
+	struct drm_atomic_state *state = new_conn_state->state;
+	struct drm_connector_state *old_conn_state =
+		drm_atomic_get_old_connector_state(state, new_conn_state->connector);
+	struct drm_crtc_state *crtc_state;
+	struct drm_dp_mst_topology_state *mst_state = NULL;
+
+	if (new_conn_state->crtc) {
+		crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
+		if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
+			mst_state = drm_atomic_get_mst_topology_state(state, mgr);
+			if (IS_ERR(mst_state))
+				return PTR_ERR(mst_state);
+
+			mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc);
+		}
+	}
+
+	if (old_conn_state->crtc) {
+		crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc);
+		if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
+			if (!mst_state) {
+				mst_state = drm_atomic_get_mst_topology_state(state, mgr);
+				if (IS_ERR(mst_state))
+					return PTR_ERR(mst_state);
+			}
+
+			mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check);
+
 /**
  * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
  * @mst_state: mst_state to update
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index b8e2d3cd4d68..943b7c0acc04 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4954,12 +4954,21 @@ static int intel_dp_connector_atomic_check(struct drm_connector *conn,
 {
 	struct drm_i915_private *dev_priv = to_i915(conn->dev);
 	struct intel_atomic_state *state = to_intel_atomic_state(_state);
+	struct drm_connector_state *conn_state = drm_atomic_get_new_connector_state(_state, conn);
+	struct intel_connector *intel_conn = to_intel_connector(conn);
+	struct intel_dp *intel_dp = enc_to_intel_dp(intel_conn->encoder);
 	int ret;
 
 	ret = intel_digital_connector_atomic_check(conn, &state->base);
 	if (ret)
 		return ret;
 
+	if (HAS_DP_MST(dev_priv) && !intel_dp_is_edp(intel_dp)) {
+		ret = drm_dp_mst_root_conn_atomic_check(conn_state, &intel_dp->mst_mgr);
+		if (ret)
+			return ret;
+	}
+
 	/*
 	 * We don't enable port sync on BDW due to missing w/as and
 	 * due to not having adjusted the modeset sequence appropriately.
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 834a5c5b77d5..57f74cfcdebf 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1815,7 +1815,7 @@ nv50_sor_func = {
 	.destroy = nv50_sor_destroy,
 };
 
-static bool nv50_has_mst(struct nouveau_drm *drm)
+bool nv50_has_mst(struct nouveau_drm *drm)
 {
 	struct nvkm_bios *bios = nvxx_bios(&drm->client.device);
 	u32 data;
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.h b/drivers/gpu/drm/nouveau/dispnv50/disp.h
index 38dec11e7dda..9d66c9c726c3 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.h
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.h
@@ -106,6 +106,8 @@ void nv50_dmac_destroy(struct nv50_dmac *);
  */
 struct nouveau_encoder *nv50_real_outp(struct drm_encoder *encoder);
 
+bool nv50_has_mst(struct nouveau_drm *drm);
+
 u32 *evo_wait(struct nv50_dmac *, int nr);
 void evo_kick(u32 *, struct nv50_dmac *);
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index ffbd8a9cf2af..1c8235f97737 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -1104,11 +1104,25 @@ nouveau_connector_best_encoder(struct drm_connector *connector)
 	return NULL;
 }
 
+static int
+nouveau_connector_atomic_check(struct drm_connector *connector, struct drm_atomic_state *state)
+{
+	struct nouveau_connector *nv_conn = nouveau_connector(connector);
+	struct drm_connector_state *conn_state =
+		drm_atomic_get_new_connector_state(state, connector);
+
+	if (!nv_conn->dp_encoder || !nv50_has_mst(nouveau_drm(connector->dev)))
+		return 0;
+
+	return drm_dp_mst_root_conn_atomic_check(conn_state, &nv_conn->dp_encoder->dp.mstm->mgr);
+}
+
 static const struct drm_connector_helper_funcs
 nouveau_connector_helper_funcs = {
 	.get_modes = nouveau_connector_get_modes,
 	.mode_valid = nouveau_connector_mode_valid,
 	.best_encoder = nouveau_connector_best_encoder,
+	.atomic_check = nouveau_connector_atomic_check,
 };
 
 static const struct drm_connector_funcs
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index dd74afcee888..690ebcabb51f 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -906,6 +906,8 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
 		struct drm_dp_mst_port *port,
 		struct drm_dp_query_stream_enc_status_ack_reply *status);
 int __must_check drm_dp_mst_atomic_check(struct drm_atomic_state *state);
+int __must_check drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
+						   struct drm_dp_mst_topology_mgr *mgr);
 
 void drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port);
 void drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port);
-- 
2.35.3

[Intel-gfx] [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into the atomic state

[Lyude Paul]

Now that we've finally gotten rid of the non-atomic MST users leftover in
the kernel, we can finally get rid of all of the legacy payload code we
have and move as much as possible into the MST atomic state structs. The
main purpose of this is to make the MST code a lot less confusing to work
on, as there's a lot of duplicated logic that doesn't really need to be
here. As well, this should make introducing features like fallback link
retraining and DSC support far easier.

Since the old payload code was pretty gnarly and there's a Lot of changes
here, I expect this might be a bit difficult to review. So to make things
as easy as possible for reviewers, I'll sum up how both the old and new
code worked here (it took me a while to figure this out too!).

The old MST code basically worked by maintaining two different payload
tables - proposed_vcpis, and payloads. proposed_vcpis would hold the
modified payload we wanted to push to the topology, while payloads held the
payload table that was currently programmed in hardware. Modifications to
proposed_vcpis would be handled through drm_dp_allocate_vcpi(),
drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then, they
would be pushed via drm_dp_mst_update_payload_step1() and
drm_dp_mst_update_payload_step2().

Furthermore, it's important to note how adding and removing VC payloads
actually worked with drm_dp_mst_update_payload_step1(). When a VC payload
is removed from the VC table, all VC payloads which come after the removed
VC payload's slots must have their time slots shifted towards the start of
the table. The old code handles this by looping through the entire payload
table and recomputing the start slot for every payload in the topology from
scratch. While very much overkill, this ends up doing the right thing
because we always order the VCPIs for payloads from first to last starting
timeslot.

It's important to also note that drm_dp_mst_update_payload_step2() isn't
actually limited to updating a single payload - the driver can use it to
queue up multiple payload changes so that as many of them can be sent as
possible before waiting for the ACT.

drm_dp_mst_update_payload_step2() is pretty self explanatory and basically
the same between the old and new code, save for the fact we don't have a
second step for deleting payloads anymore -and thus rename it to
drm_dp_mst_add_payload_step2().

The new payload code stores all of the current payload info within the MST
atomic state and computes as much of the state as possible ahead of time.
This has the one exception of the starting timeslots for payloads, which
can't be determined at atomic check time since the starting time slots will
vary depending on what order CRTCs are enabled in the atomic state - which
varies from driver to driver. These are still stored in the atomic MST
state, but are only copied from the old MST state during atomic commit
time. Likewise, this is when new start slots are determined.

Adding/removing payloads now works much more closely to how things are
described in the spec. When we delete a payload, we loop through the
current list of payloads and update the start slots for any payloads whose
time slots came after the payload we just deleted. Determining the starting
time slots for new payloads being added is done by simply keeping track of
where the end of the VC table is in
drm_dp_mst_topology_mgr->next_start_slot. Additionally, it's worth noting
that we no longer have a single update_payload() function. Instead, we now
have drm_dp_mst_add_payload_step1|2() and drm_dp_mst_remove_payload(). As
such, it's now left it up to the driver to figure out when to add or remove
payloads. The driver already knows when it's disabling/enabling CRTCs, so
it also already knows when payloads should be added or removed. And, this
doesn't interfere with the ability to queue up multiple payload changes
before waiting for the ACT.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Wayne Lin <Wayne.Lin@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <sean@poorly.run>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  56 +-
 .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 107 +--
 .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  85 +--
 .../amd/display/include/link_service_types.h  |   7 +
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 699 ++++++------------
 drivers/gpu/drm/i915/display/intel_dp_mst.c   |  64 +-
 drivers/gpu/drm/i915/display/intel_hdcp.c     |  24 +-
 drivers/gpu/drm/nouveau/dispnv50/disp.c       | 163 ++--
 include/drm/display/drm_dp_mst_helper.h       | 178 ++---
 9 files changed, 536 insertions(+), 847 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index ac8648e3c1c9..93d572ea3c48 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7378,6 +7378,7 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
 	const struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
 	struct drm_dp_mst_topology_mgr *mst_mgr;
 	struct drm_dp_mst_port *mst_port;
+	struct drm_dp_mst_topology_state *mst_state;
 	enum dc_color_depth color_depth;
 	int clock, bpp = 0;
 	bool is_y420 = false;
@@ -7391,6 +7392,13 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
 	if (!crtc_state->connectors_changed && !crtc_state->mode_changed)
 		return 0;
 
+	mst_state = drm_atomic_get_mst_topology_state(state, mst_mgr);
+	if (IS_ERR(mst_state))
+		return PTR_ERR(mst_state);
+
+	if (!mst_state->pbn_div)
+		mst_state->pbn_div = dm_mst_get_pbn_divider(aconnector->mst_port->dc_link);
+
 	if (!state->duplicated) {
 		int max_bpc = conn_state->max_requested_bpc;
 		is_y420 = drm_mode_is_420_also(&connector->display_info, adjusted_mode) &&
@@ -7402,11 +7410,10 @@ static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
 		clock = adjusted_mode->clock;
 		dm_new_connector_state->pbn = drm_dp_calc_pbn_mode(clock, bpp, false);
 	}
-	dm_new_connector_state->vcpi_slots = drm_dp_atomic_find_time_slots(state,
-									   mst_mgr,
-									   mst_port,
-									   dm_new_connector_state->pbn,
-									   dm_mst_get_pbn_divider(aconnector->dc_link));
+
+	dm_new_connector_state->vcpi_slots =
+		drm_dp_atomic_find_time_slots(state, mst_mgr, mst_port,
+					      dm_new_connector_state->pbn);
 	if (dm_new_connector_state->vcpi_slots < 0) {
 		DRM_DEBUG_ATOMIC("failed finding vcpi slots: %d\n", (int)dm_new_connector_state->vcpi_slots);
 		return dm_new_connector_state->vcpi_slots;
@@ -7476,18 +7483,12 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state,
 			dm_conn_state->pbn = pbn;
 			dm_conn_state->vcpi_slots = slot_num;
 
-			drm_dp_mst_atomic_enable_dsc(state,
-						     aconnector->port,
-						     dm_conn_state->pbn,
-						     0,
+			drm_dp_mst_atomic_enable_dsc(state, aconnector->port, dm_conn_state->pbn,
 						     false);
 			continue;
 		}
 
-		vcpi = drm_dp_mst_atomic_enable_dsc(state,
-						    aconnector->port,
-						    pbn, pbn_div,
-						    true);
+		vcpi = drm_dp_mst_atomic_enable_dsc(state, aconnector->port, pbn, true);
 		if (vcpi < 0)
 			return vcpi;
 
@@ -10943,8 +10944,6 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 	struct dm_crtc_state *dm_old_crtc_state, *dm_new_crtc_state;
 #if defined(CONFIG_DRM_AMD_DC_DCN)
 	struct dsc_mst_fairness_vars vars[MAX_PIPES];
-	struct drm_dp_mst_topology_state *mst_state;
-	struct drm_dp_mst_topology_mgr *mgr;
 #endif
 
 	trace_amdgpu_dm_atomic_check_begin(state);
@@ -11180,33 +11179,6 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 		lock_and_validation_needed = true;
 	}
 
-#if defined(CONFIG_DRM_AMD_DC_DCN)
-	/* set the slot info for each mst_state based on the link encoding format */
-	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
-		struct amdgpu_dm_connector *aconnector;
-		struct drm_connector *connector;
-		struct drm_connector_list_iter iter;
-		u8 link_coding_cap;
-
-		if (!mgr->mst_state )
-			continue;
-
-		drm_connector_list_iter_begin(dev, &iter);
-		drm_for_each_connector_iter(connector, &iter) {
-			int id = connector->index;
-
-			if (id == mst_state->mgr->conn_base_id) {
-				aconnector = to_amdgpu_dm_connector(connector);
-				link_coding_cap = dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link);
-				drm_dp_mst_update_slots(mst_state, link_coding_cap);
-
-				break;
-			}
-		}
-		drm_connector_list_iter_end(&iter);
-
-	}
-#endif
 	/**
 	 * Streams and planes are reset when there are changes that affect
 	 * bandwidth. Anything that affects bandwidth needs to go through
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 1eaacab0334b..f843fd86787f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -27,6 +27,7 @@
 #include <linux/acpi.h>
 #include <linux/i2c.h>
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/amdgpu_drm.h>
 #include <drm/drm_edid.h>
@@ -154,40 +155,32 @@ enum dc_edid_status dm_helpers_parse_edid_caps(
 }
 
 static void
-fill_dc_mst_payload_table_from_drm(struct amdgpu_dm_connector *aconnector,
-				   struct dc_dp_mst_stream_allocation_table *proposed_table)
+fill_dc_mst_payload_table_from_drm(struct drm_dp_mst_topology_state *mst_state,
+				   struct amdgpu_dm_connector *aconnector,
+				   struct dc_dp_mst_stream_allocation_table *table)
 {
+	struct dc_dp_mst_stream_allocation_table new_table = { 0 };
+	struct dc_dp_mst_stream_allocation *sa;
+	struct drm_dp_mst_atomic_payload *payload;
 	int i;
-	struct drm_dp_mst_topology_mgr *mst_mgr =
-			&aconnector->mst_port->mst_mgr;
 
-	mutex_lock(&mst_mgr->payload_lock);
-
-	proposed_table->stream_count = 0;
-
-	/* number of active streams */
-	for (i = 0; i < mst_mgr->max_payloads; i++) {
-		if (mst_mgr->payloads[i].num_slots == 0)
-			break; /* end of vcp_id table */
-
-		ASSERT(mst_mgr->payloads[i].payload_state !=
-				DP_PAYLOAD_DELETE_LOCAL);
-
-		if (mst_mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL ||
-			mst_mgr->payloads[i].payload_state ==
-					DP_PAYLOAD_REMOTE) {
-
-			struct dc_dp_mst_stream_allocation *sa =
-					&proposed_table->stream_allocations[
-						proposed_table->stream_count];
-
-			sa->slot_count = mst_mgr->payloads[i].num_slots;
-			sa->vcp_id = mst_mgr->proposed_vcpis[i]->vcpi;
-			proposed_table->stream_count++;
-		}
+	/* Copy over payloads */
+	list_for_each_entry(payload, &mst_state->payloads, next) {
+		if (payload->delete)
+			continue;
+
+		sa = &new_table.stream_allocations[new_table.stream_count];
+		sa->slot_count = payload->time_slots;
+		sa->vcp_id = payload->vcpi;
+		sa->port = payload->port;
+		drm_dp_mst_get_port_malloc(sa->port);
+		new_table.stream_count++;
 	}
 
-	mutex_unlock(&mst_mgr->payload_lock);
+	/* Release the old table, and copy over the new one */
+	for (i = 0; i < table->stream_count; i++)
+		drm_dp_mst_put_port_malloc(table->stream_allocations[i].port);
+	*table = new_table;
 }
 
 void dm_helpers_dp_update_branch_info(
@@ -205,11 +198,9 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
 		bool enable)
 {
 	struct amdgpu_dm_connector *aconnector;
-	struct dm_connector_state *dm_conn_state;
+	struct drm_dp_mst_topology_state *mst_state;
+	struct drm_dp_mst_atomic_payload *payload;
 	struct drm_dp_mst_topology_mgr *mst_mgr;
-	struct drm_dp_mst_port *mst_port;
-	bool ret;
-	u8 link_coding_cap = DP_8b_10b_ENCODING;
 
 	aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;
 	/* Accessing the connector state is required for vcpi_slots allocation
@@ -220,40 +211,21 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
 	if (!aconnector || !aconnector->mst_port)
 		return false;
 
-	dm_conn_state = to_dm_connector_state(aconnector->base.state);
-
 	mst_mgr = &aconnector->mst_port->mst_mgr;
-
-	if (!mst_mgr->mst_state)
-		return false;
-
-	mst_port = aconnector->port;
-
-#if defined(CONFIG_DRM_AMD_DC_DCN)
-	link_coding_cap = dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link);
-#endif
-
-	if (enable) {
-
-		ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port,
-					       dm_conn_state->pbn,
-					       dm_conn_state->vcpi_slots);
-		if (!ret)
-			return false;
-
-	} else {
-		drm_dp_mst_reset_vcpi_slots(mst_mgr, mst_port);
-	}
+	mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
 
 	/* It's OK for this to fail */
-	drm_dp_update_payload_part1(mst_mgr, (link_coding_cap == DP_CAP_ANSI_128B132B) ? 0:1);
+	payload = drm_atomic_get_mst_payload_state(mst_state, aconnector->port);
+	if (enable)
+		drm_dp_add_payload_part1(mst_mgr, mst_state, payload);
+	else
+		drm_dp_remove_payload(mst_mgr, mst_state, payload);
 
 	/* mst_mgr->->payloads are VC payload notify MST branch using DPCD or
 	 * AUX message. The sequence is slot 1-63 allocated sequence for each
 	 * stream. AMD ASIC stream slot allocation should follow the same
 	 * sequence. copy DRM MST allocation to dc */
-
-	fill_dc_mst_payload_table_from_drm(aconnector, proposed_table);
+	fill_dc_mst_payload_table_from_drm(mst_state, aconnector, proposed_table);
 
 	return true;
 }
@@ -310,26 +282,23 @@ bool dm_helpers_dp_mst_send_payload_allocation(
 		bool enable)
 {
 	struct amdgpu_dm_connector *aconnector;
+	struct drm_dp_mst_topology_state *mst_state;
 	struct drm_dp_mst_topology_mgr *mst_mgr;
-	struct drm_dp_mst_port *mst_port;
+	struct drm_dp_mst_atomic_payload *payload;
 
 	aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;
 
 	if (!aconnector || !aconnector->mst_port)
 		return false;
 
-	mst_port = aconnector->port;
-
 	mst_mgr = &aconnector->mst_port->mst_mgr;
-
-	if (!mst_mgr->mst_state)
-		return false;
+	mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
 
 	/* It's OK for this to fail */
-	drm_dp_update_payload_part2(mst_mgr);
-
-	if (!enable)
-		drm_dp_mst_deallocate_vcpi(mst_mgr, mst_port);
+	if (enable) {
+		payload = drm_atomic_get_mst_payload_state(mst_state, aconnector->port);
+		drm_dp_add_payload_part2(mst_mgr, mst_state->base.state, payload);
+	}
 
 	return true;
 }
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index b447c453b58d..18de4a98df40 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -501,15 +501,8 @@ void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
 
 	dc_link_dp_get_max_link_enc_cap(aconnector->dc_link, &max_link_enc_cap);
 	aconnector->mst_mgr.cbs = &dm_mst_cbs;
-	drm_dp_mst_topology_mgr_init(
-		&aconnector->mst_mgr,
-		adev_to_drm(dm->adev),
-		&aconnector->dm_dp_aux.aux,
-		16,
-		4,
-		max_link_enc_cap.lane_count,
-		drm_dp_bw_code_to_link_rate(max_link_enc_cap.link_rate),
-		aconnector->connector_id);
+	drm_dp_mst_topology_mgr_init(&aconnector->mst_mgr, adev_to_drm(dm->adev),
+				     &aconnector->dm_dp_aux.aux, 16, 4, aconnector->connector_id);
 
 	drm_connector_attach_dp_subconnector_property(&aconnector->base);
 }
@@ -614,6 +607,7 @@ static int bpp_x16_from_pbn(struct dsc_mst_fairness_params param, int pbn)
 }
 
 static void increase_dsc_bpp(struct drm_atomic_state *state,
+			     struct drm_dp_mst_topology_state *mst_state,
 			     struct dc_link *dc_link,
 			     struct dsc_mst_fairness_params *params,
 			     struct dsc_mst_fairness_vars *vars,
@@ -626,12 +620,9 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 	int min_initial_slack;
 	int next_index;
 	int remaining_to_increase = 0;
-	int pbn_per_timeslot;
 	int link_timeslots_used;
 	int fair_pbn_alloc;
 
-	pbn_per_timeslot = dm_mst_get_pbn_divider(dc_link);
-
 	for (i = 0; i < count; i++) {
 		if (vars[i + k].dsc_enabled) {
 			initial_slack[i] =
@@ -662,17 +653,17 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 		link_timeslots_used = 0;
 
 		for (i = 0; i < count; i++)
-			link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, pbn_per_timeslot);
+			link_timeslots_used += DIV_ROUND_UP(vars[i + k].pbn, mst_state->pbn_div);
 
-		fair_pbn_alloc = (63 - link_timeslots_used) / remaining_to_increase * pbn_per_timeslot;
+		fair_pbn_alloc =
+			(63 - link_timeslots_used) / remaining_to_increase * mst_state->pbn_div;
 
 		if (initial_slack[next_index] > fair_pbn_alloc) {
 			vars[next_index].pbn += fair_pbn_alloc;
 			if (drm_dp_atomic_find_time_slots(state,
 							  params[next_index].port->mgr,
 							  params[next_index].port,
-							  vars[next_index].pbn,
-							  pbn_per_timeslot) < 0)
+							  vars[next_index].pbn) < 0)
 				return;
 			if (!drm_dp_mst_atomic_check(state)) {
 				vars[next_index].bpp_x16 = bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
@@ -681,8 +672,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 				if (drm_dp_atomic_find_time_slots(state,
 								  params[next_index].port->mgr,
 								  params[next_index].port,
-								  vars[next_index].pbn,
-								  pbn_per_timeslot) < 0)
+								  vars[next_index].pbn) < 0)
 					return;
 			}
 		} else {
@@ -690,8 +680,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 			if (drm_dp_atomic_find_time_slots(state,
 							  params[next_index].port->mgr,
 							  params[next_index].port,
-							  vars[next_index].pbn,
-							  pbn_per_timeslot) < 0)
+							  vars[next_index].pbn) < 0)
 				return;
 			if (!drm_dp_mst_atomic_check(state)) {
 				vars[next_index].bpp_x16 = params[next_index].bw_range.max_target_bpp_x16;
@@ -700,8 +689,7 @@ static void increase_dsc_bpp(struct drm_atomic_state *state,
 				if (drm_dp_atomic_find_time_slots(state,
 								  params[next_index].port->mgr,
 								  params[next_index].port,
-								  vars[next_index].pbn,
-								  pbn_per_timeslot) < 0)
+								  vars[next_index].pbn) < 0)
 					return;
 			}
 		}
@@ -757,8 +745,7 @@ static void try_disable_dsc(struct drm_atomic_state *state,
 		if (drm_dp_atomic_find_time_slots(state,
 						  params[next_index].port->mgr,
 						  params[next_index].port,
-						  vars[next_index].pbn,
-						  dm_mst_get_pbn_divider(dc_link)) < 0)
+						  vars[next_index].pbn) < 0)
 			return;
 
 		if (!drm_dp_mst_atomic_check(state)) {
@@ -769,8 +756,7 @@ static void try_disable_dsc(struct drm_atomic_state *state,
 			if (drm_dp_atomic_find_time_slots(state,
 							  params[next_index].port->mgr,
 							  params[next_index].port,
-							  vars[next_index].pbn,
-							  dm_mst_get_pbn_divider(dc_link)) < 0)
+							  vars[next_index].pbn) < 0)
 				return;
 		}
 
@@ -783,17 +769,27 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 					     struct dc_state *dc_state,
 					     struct dc_link *dc_link,
 					     struct dsc_mst_fairness_vars *vars,
+					     struct drm_dp_mst_topology_mgr *mgr,
 					     int *link_vars_start_index)
 {
-	int i, k;
 	struct dc_stream_state *stream;
 	struct dsc_mst_fairness_params params[MAX_PIPES];
 	struct amdgpu_dm_connector *aconnector;
+	struct drm_dp_mst_topology_state *mst_state = drm_atomic_get_mst_topology_state(state, mgr);
 	int count = 0;
+	int i, k;
 	bool debugfs_overwrite = false;
 
 	memset(params, 0, sizeof(params));
 
+	if (IS_ERR(mst_state))
+		return false;
+
+	mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link);
+#if defined(CONFIG_DRM_AMD_DC_DCN)
+	drm_dp_mst_update_slots(mst_state, dc_link_dp_mst_decide_link_encoding_format(dc_link));
+#endif
+
 	/* Set up params */
 	for (i = 0; i < dc_state->stream_count; i++) {
 		struct dc_dsc_policy dsc_policy = {0};
@@ -852,11 +848,8 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 		vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
 		vars[i + k].dsc_enabled = false;
 		vars[i + k].bpp_x16 = 0;
-		if (drm_dp_atomic_find_time_slots(state,
-						  params[i].port->mgr,
-						  params[i].port,
-						  vars[i + k].pbn,
-						  dm_mst_get_pbn_divider(dc_link)) < 0)
+		if (drm_dp_atomic_find_time_slots(state, params[i].port->mgr, params[i].port,
+						  vars[i + k].pbn) < 0)
 			return false;
 	}
 	if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) {
@@ -870,21 +863,15 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 			vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps);
 			vars[i + k].dsc_enabled = true;
 			vars[i + k].bpp_x16 = params[i].bw_range.min_target_bpp_x16;
-			if (drm_dp_atomic_find_time_slots(state,
-							  params[i].port->mgr,
-							  params[i].port,
-							  vars[i + k].pbn,
-							  dm_mst_get_pbn_divider(dc_link)) < 0)
+			if (drm_dp_atomic_find_time_slots(state, params[i].port->mgr,
+							  params[i].port, vars[i + k].pbn) < 0)
 				return false;
 		} else {
 			vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
 			vars[i + k].dsc_enabled = false;
 			vars[i + k].bpp_x16 = 0;
-			if (drm_dp_atomic_find_time_slots(state,
-							  params[i].port->mgr,
-							  params[i].port,
-							  vars[i + k].pbn,
-							  dm_mst_get_pbn_divider(dc_link)) < 0)
+			if (drm_dp_atomic_find_time_slots(state, params[i].port->mgr,
+							  params[i].port, vars[i + k].pbn) < 0)
 				return false;
 		}
 	}
@@ -892,7 +879,7 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
 		return false;
 
 	/* Optimize degree of compression */
-	increase_dsc_bpp(state, dc_link, params, vars, count, k);
+	increase_dsc_bpp(state, mst_state, dc_link, params, vars, count, k);
 
 	try_disable_dsc(state, dc_link, params, vars, count, k);
 
@@ -1036,9 +1023,9 @@ bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
 			continue;
 
 		mutex_lock(&aconnector->mst_mgr.lock);
-		if (!compute_mst_dsc_configs_for_link(state, dc_state, stream->link,
-			vars, &link_vars_start_index)) {
-			mutex_unlock(&aconnector->mst_mgr.lock);
+		if (!compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars,
+						      &aconnector->mst_mgr,
+						      &link_vars_start_index)) {
 			return false;
 		}
 		mutex_unlock(&aconnector->mst_mgr.lock);
@@ -1095,10 +1082,8 @@ static bool
 			continue;
 
 		mutex_lock(&aconnector->mst_mgr.lock);
-		if (!compute_mst_dsc_configs_for_link(state,
-						      dc_state,
-						      stream->link,
-						      vars,
+		if (!compute_mst_dsc_configs_for_link(state, dc_state, stream->link, vars,
+						      &aconnector->mst_mgr,
 						      &link_vars_start_index)) {
 			mutex_unlock(&aconnector->mst_mgr.lock);
 			return false;
diff --git a/drivers/gpu/drm/amd/display/include/link_service_types.h b/drivers/gpu/drm/amd/display/include/link_service_types.h
index 91bffc5bf52c..143baab54b41 100644
--- a/drivers/gpu/drm/amd/display/include/link_service_types.h
+++ b/drivers/gpu/drm/amd/display/include/link_service_types.h
@@ -250,12 +250,19 @@ union dpcd_training_lane_set {
  * _ONLY_ be filled out from DM and then passed to DC, do NOT use these for _any_ kind of atomic
  * state calculations in DM, or you will break something.
  */
+
+struct drm_dp_mst_port;
+
 /* DP MST stream allocation (payload bandwidth number) */
 struct dc_dp_mst_stream_allocation {
 	uint8_t vcp_id;
 	/* number of slots required for the DP stream in
 	 * transport packet */
 	uint8_t slot_count;
+	/* The MST port this is on, this is used to associate DC MST payloads with their
+	 * respective DRM payloads allocations, and can be ignored on non-Linux.
+	 */
+	struct drm_dp_mst_port *port;
 };
 
 /* DP MST stream allocation table */
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 10d26a7e028c..d8e32269585b 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -67,8 +67,7 @@ static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
 
 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
-				     int id,
-				     struct drm_dp_payload *payload);
+				     int id, u8 start_slot, u8 num_slots);
 
 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port,
@@ -1234,57 +1233,6 @@ build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
 	return 0;
 }
 
-static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
-					struct drm_dp_vcpi *vcpi)
-{
-	int ret, vcpi_ret;
-
-	mutex_lock(&mgr->payload_lock);
-	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
-	if (ret > mgr->max_payloads) {
-		ret = -EINVAL;
-		drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
-		goto out_unlock;
-	}
-
-	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
-	if (vcpi_ret > mgr->max_payloads) {
-		ret = -EINVAL;
-		drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
-		goto out_unlock;
-	}
-
-	set_bit(ret, &mgr->payload_mask);
-	set_bit(vcpi_ret, &mgr->vcpi_mask);
-	vcpi->vcpi = vcpi_ret + 1;
-	mgr->proposed_vcpis[ret - 1] = vcpi;
-out_unlock:
-	mutex_unlock(&mgr->payload_lock);
-	return ret;
-}
-
-static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
-				      int vcpi)
-{
-	int i;
-
-	if (vcpi == 0)
-		return;
-
-	mutex_lock(&mgr->payload_lock);
-	drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
-	clear_bit(vcpi - 1, &mgr->vcpi_mask);
-
-	for (i = 0; i < mgr->max_payloads; i++) {
-		if (mgr->proposed_vcpis[i] &&
-		    mgr->proposed_vcpis[i]->vcpi == vcpi) {
-			mgr->proposed_vcpis[i] = NULL;
-			clear_bit(i + 1, &mgr->payload_mask);
-		}
-	}
-	mutex_unlock(&mgr->payload_lock);
-}
-
 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
 			      struct drm_dp_sideband_msg_tx *txmsg)
 {
@@ -1737,7 +1685,7 @@ drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
 #define save_port_topology_ref(port, type)
 #endif
 
-static struct drm_dp_mst_atomic_payload *
+struct drm_dp_mst_atomic_payload *
 drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
 				 struct drm_dp_mst_port *port)
 {
@@ -1749,6 +1697,7 @@ drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
 
 	return NULL;
 }
+EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
 
 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
 {
@@ -3272,6 +3221,8 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
 		struct drm_dp_mst_port *port,
 		struct drm_dp_query_stream_enc_status_ack_reply *status)
 {
+	struct drm_dp_mst_topology_state *state;
+	struct drm_dp_mst_atomic_payload *payload;
 	struct drm_dp_sideband_msg_tx *txmsg;
 	u8 nonce[7];
 	int ret;
@@ -3288,6 +3239,10 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
 
 	get_random_bytes(nonce, sizeof(nonce));
 
+	drm_modeset_lock(&mgr->base.lock, NULL);
+	state = to_drm_dp_mst_topology_state(mgr->base.state);
+	payload = drm_atomic_get_mst_payload_state(state, port);
+
 	/*
 	 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
 	 *  transaction at the MST Branch device directly connected to the
@@ -3295,7 +3250,7 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
 	 */
 	txmsg->dst = mgr->mst_primary;
 
-	build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
+	build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
 
 	drm_dp_queue_down_tx(mgr, txmsg);
 
@@ -3312,6 +3267,7 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
 	memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
 
 out:
+	drm_modeset_unlock(&mgr->base.lock);
 	drm_dp_mst_topology_put_port(port);
 out_get_port:
 	kfree(txmsg);
@@ -3320,219 +3276,161 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
 
 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
-				       int id,
-				       struct drm_dp_payload *payload)
+				       struct drm_dp_mst_atomic_payload *payload)
 {
-	int ret;
-
-	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
-	if (ret < 0) {
-		payload->payload_state = 0;
-		return ret;
-	}
-	payload->payload_state = DP_PAYLOAD_LOCAL;
-	return 0;
+	return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot,
+					 payload->time_slots);
 }
 
 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
-				       struct drm_dp_mst_port *port,
-				       int id,
-				       struct drm_dp_payload *payload)
+				       struct drm_dp_mst_atomic_payload *payload)
 {
 	int ret;
+	struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
 
-	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
-	if (ret < 0)
-		return ret;
-	payload->payload_state = DP_PAYLOAD_REMOTE;
+	if (!port)
+		return -EIO;
+
+	ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn);
+	drm_dp_mst_topology_put_port(port);
 	return ret;
 }
 
 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
-					struct drm_dp_mst_port *port,
-					int id,
-					struct drm_dp_payload *payload)
+					struct drm_dp_mst_topology_state *mst_state,
+					struct drm_dp_mst_atomic_payload *payload)
 {
+
 	drm_dbg_kms(mgr->dev, "\n");
-	/* it's okay for these to fail */
-	if (port) {
-		drm_dp_payload_send_msg(mgr, port, id, 0);
-	}
 
-	drm_dp_dpcd_write_payload(mgr, id, payload);
-	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
-	return 0;
-}
+	/* it's okay for these to fail */
+	drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
+	drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0);
 
-static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
-					int id,
-					struct drm_dp_payload *payload)
-{
-	payload->payload_state = 0;
 	return 0;
 }
 
 /**
- * drm_dp_update_payload_part1() - Execute payload update part 1
- * @mgr: manager to use.
- * @start_slot: this is the cur slot
+ * drm_dp_add_payload_part1() - Execute payload update part 1
+ * @mgr: Manager to use.
+ * @mst_state: The MST atomic state
+ * @payload: The payload to write
  *
- * NOTE: start_slot is a temporary workaround for non-atomic drivers,
- * this will be removed when non-atomic mst helpers are moved out of the helper
+ * Determines the starting time slot for the given payload, and programs the VCPI for this payload
+ * into hardware.
  *
- * This iterates over all proposed virtual channels, and tries to
- * allocate space in the link for them. For 0->slots transitions,
- * this step just writes the VCPI to the MST device. For slots->0
- * transitions, this writes the updated VCPIs and removes the
- * remote VC payloads.
+ * After calling this, the driver should generate ACT and payload packets. Note that the driver may
+ * generate ACT once per payload change, or only once after all new payloads in a given atomic state
+ * have been added.
  *
- * after calling this the driver should generate ACT and payload
- * packets.
+ * Returns: 0 on success, error code on failure. In the event that this fails,
+ * @payload.vc_start_slot will also be set to -1.
  */
-int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr, int start_slot)
+int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
+			     struct drm_dp_mst_topology_state *mst_state,
+			     struct drm_dp_mst_atomic_payload *payload)
 {
-	struct drm_dp_payload req_payload;
 	struct drm_dp_mst_port *port;
-	int i, j;
-	int cur_slots = start_slot;
-
-	mutex_lock(&mgr->payload_lock);
-	for (i = 0; i < mgr->max_payloads; i++) {
-		struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
-		struct drm_dp_payload *payload = &mgr->payloads[i];
-		bool put_port = false;
-
-		/* solve the current payloads - compare to the hw ones
-		   - update the hw view */
-		req_payload.start_slot = cur_slots;
-		if (vcpi) {
-			port = container_of(vcpi, struct drm_dp_mst_port,
-					    vcpi);
-
-			/* Validated ports don't matter if we're releasing
-			 * VCPI
-			 */
-			if (vcpi->num_slots) {
-				port = drm_dp_mst_topology_get_port_validated(
-				    mgr, port);
-				if (!port) {
-					if (vcpi->num_slots == payload->num_slots) {
-						cur_slots += vcpi->num_slots;
-						payload->start_slot = req_payload.start_slot;
-						continue;
-					} else {
-						drm_dbg_kms(mgr->dev,
-							    "Fail:set payload to invalid sink");
-						mutex_unlock(&mgr->payload_lock);
-						return -EINVAL;
-					}
-				}
-				put_port = true;
-			}
+	int ret;
 
-			req_payload.num_slots = vcpi->num_slots;
-			req_payload.vcpi = vcpi->vcpi;
-		} else {
-			port = NULL;
-			req_payload.num_slots = 0;
-		}
+	port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
+	if (!port)
+		return 0;
 
-		payload->start_slot = req_payload.start_slot;
-		/* work out what is required to happen with this payload */
-		if (payload->num_slots != req_payload.num_slots) {
-
-			/* need to push an update for this payload */
-			if (req_payload.num_slots) {
-				drm_dp_create_payload_step1(mgr, vcpi->vcpi,
-							    &req_payload);
-				payload->num_slots = req_payload.num_slots;
-				payload->vcpi = req_payload.vcpi;
-
-			} else if (payload->num_slots) {
-				payload->num_slots = 0;
-				drm_dp_destroy_payload_step1(mgr, port,
-							     payload->vcpi,
-							     payload);
-				req_payload.payload_state =
-					payload->payload_state;
-				payload->start_slot = 0;
-			}
-			payload->payload_state = req_payload.payload_state;
-		}
-		cur_slots += req_payload.num_slots;
+	if (mgr->payload_count == 0)
+		mgr->next_start_slot = mst_state->start_slot;
 
-		if (put_port)
-			drm_dp_mst_topology_put_port(port);
+	payload->vc_start_slot = mgr->next_start_slot;
+	ret = drm_dp_create_payload_step1(mgr, payload);
+	drm_dp_mst_topology_put_port(port);
+	if (ret < 0) {
+		drm_warn(mgr->dev, "Failed to create MST payload for port %p: %d\n",
+			 payload->port, ret);
+		payload->vc_start_slot = -1;
+		return ret;
 	}
 
-	for (i = 0; i < mgr->max_payloads; /* do nothing */) {
-		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
-			i++;
-			continue;
-		}
+	mgr->payload_count++;
+	mgr->next_start_slot += payload->time_slots;
 
-		drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
-		for (j = i; j < mgr->max_payloads - 1; j++) {
-			mgr->payloads[j] = mgr->payloads[j + 1];
-			mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_add_payload_part1);
 
-			if (mgr->proposed_vcpis[j] &&
-			    mgr->proposed_vcpis[j]->num_slots) {
-				set_bit(j + 1, &mgr->payload_mask);
-			} else {
-				clear_bit(j + 1, &mgr->payload_mask);
-			}
-		}
+/**
+ * drm_dp_remove_payload() - Remove an MST payload
+ * @mgr: Manager to use.
+ * @mst_state: The MST atomic state
+ * @payload: The payload to write
+ *
+ * Removes a payload from an MST topology if it was successfully assigned a start slot. Also updates
+ * the starting time slots of all other payloads which would have been shifted towards the start of
+ * the VC table as a result.
+ *
+ * After calling this, the driver should generate ACT and payload packets. Note that the driver may
+ * generate ACT once per payload change, or only once after all payloads for a given atomic state
+ * have been removed.
+ */
+void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
+			   struct drm_dp_mst_topology_state *mst_state,
+			   struct drm_dp_mst_atomic_payload *payload)
+{
+	struct drm_dp_mst_atomic_payload *pos;
 
-		memset(&mgr->payloads[mgr->max_payloads - 1], 0,
-		       sizeof(struct drm_dp_payload));
-		mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
-		clear_bit(mgr->max_payloads, &mgr->payload_mask);
+	/* We failed to make the payload, so nothing to do */
+	if (payload->vc_start_slot == -1)
+		return;
+
+	drm_dp_destroy_payload_step1(mgr, mst_state, payload);
+
+	list_for_each_entry(pos, &mst_state->payloads, next) {
+		if (pos != payload && pos->vc_start_slot > payload->vc_start_slot)
+			pos->vc_start_slot -= payload->time_slots;
 	}
-	mutex_unlock(&mgr->payload_lock);
+	payload->vc_start_slot = -1;
 
-	return 0;
+	mgr->payload_count--;
+	mgr->next_start_slot -= payload->time_slots;
 }
-EXPORT_SYMBOL(drm_dp_update_payload_part1);
+EXPORT_SYMBOL(drm_dp_remove_payload);
 
 /**
- * drm_dp_update_payload_part2() - Execute payload update part 2
- * @mgr: manager to use.
+ * drm_dp_add_payload_part2() - Execute payload update part 2
+ * @mgr: Manager to use.
+ * @state: The global atomic state
+ * @payload: The payload to update
+ *
+ * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this
+ * function will send the sideband messages to finish allocating this payload.
  *
- * This iterates over all proposed virtual channels, and tries to
- * allocate space in the link for them. For 0->slots transitions,
- * this step writes the remote VC payload commands. For slots->0
- * this just resets some internal state.
+ * Returns: 0 on success, negative error code on failure.
  */
-int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
+int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
+			     struct drm_atomic_state *state,
+			     struct drm_dp_mst_atomic_payload *payload)
 {
-	struct drm_dp_mst_port *port;
-	int i;
 	int ret = 0;
 
-	mutex_lock(&mgr->payload_lock);
-	for (i = 0; i < mgr->max_payloads; i++) {
-
-		if (!mgr->proposed_vcpis[i])
-			continue;
-
-		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
+	/* Skip failed payloads */
+	if (payload->vc_start_slot == -1) {
+		drm_dbg_kms(state->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
+			    payload->port->connector->name);
+		return -EIO;
+	}
 
-		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
-		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
-			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
-		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
-			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
-		}
-		if (ret) {
-			mutex_unlock(&mgr->payload_lock);
-			return ret;
-		}
+	ret = drm_dp_create_payload_step2(mgr, payload);
+	if (ret < 0) {
+		if (!payload->delete)
+			drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n",
+				payload->port, ret);
+		else
+			drm_dbg_kms(mgr->dev, "Step 2 of removing MST payload for %p failed: %d\n",
+				    payload->port, ret);
 	}
-	mutex_unlock(&mgr->payload_lock);
-	return 0;
+
+	return ret;
 }
-EXPORT_SYMBOL(drm_dp_update_payload_part2);
+EXPORT_SYMBOL(drm_dp_add_payload_part2);
 
 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port,
@@ -3712,7 +3610,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 	int ret = 0;
 	struct drm_dp_mst_branch *mstb = NULL;
 
-	mutex_lock(&mgr->payload_lock);
 	mutex_lock(&mgr->lock);
 	if (mst_state == mgr->mst_state)
 		goto out_unlock;
@@ -3720,10 +3617,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 	mgr->mst_state = mst_state;
 	/* set the device into MST mode */
 	if (mst_state) {
-		struct drm_dp_payload reset_pay;
-		int lane_count;
-		int link_rate;
-
 		WARN_ON(mgr->mst_primary);
 
 		/* get dpcd info */
@@ -3734,16 +3627,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 			goto out_unlock;
 		}
 
-		lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
-		link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
-		mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
-							link_rate,
-							lane_count);
-		if (mgr->pbn_div == 0) {
-			ret = -EINVAL;
-			goto out_unlock;
-		}
-
 		/* add initial branch device at LCT 1 */
 		mstb = drm_dp_add_mst_branch_device(1, NULL);
 		if (mstb == NULL) {
@@ -3763,9 +3646,8 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		if (ret < 0)
 			goto out_unlock;
 
-		reset_pay.start_slot = 0;
-		reset_pay.num_slots = 0x3f;
-		drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
+		/* Write reset payload */
+		drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
 
 		queue_work(system_long_wq, &mgr->work);
 
@@ -3777,19 +3659,11 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		/* this can fail if the device is gone */
 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
 		ret = 0;
-		memset(mgr->payloads, 0,
-		       mgr->max_payloads * sizeof(mgr->payloads[0]));
-		memset(mgr->proposed_vcpis, 0,
-		       mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
-		mgr->payload_mask = 0;
-		set_bit(0, &mgr->payload_mask);
-		mgr->vcpi_mask = 0;
 		mgr->payload_id_table_cleared = false;
 	}
 
 out_unlock:
 	mutex_unlock(&mgr->lock);
-	mutex_unlock(&mgr->payload_lock);
 	if (mstb)
 		drm_dp_mst_topology_put_mstb(mstb);
 	return ret;
@@ -4310,62 +4184,18 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_
 }
 EXPORT_SYMBOL(drm_dp_mst_get_edid);
 
-/**
- * drm_dp_find_vcpi_slots() - Find time slots for this PBN value
- * @mgr: manager to use
- * @pbn: payload bandwidth to convert into slots.
- *
- * Calculate the number of time slots that will be required for the given PBN
- * value. This function is deprecated, and should not be used in atomic
- * drivers.
- *
- * RETURNS:
- * The total slots required for this port, or error.
- */
-int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
-			   int pbn)
-{
-	int num_slots;
-
-	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
-
-	/* max. time slots - one slot for MTP header */
-	if (num_slots > 63)
-		return -ENOSPC;
-	return num_slots;
-}
-EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
-
-static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
-			    struct drm_dp_vcpi *vcpi, int pbn, int slots)
-{
-	int ret;
-
-	vcpi->pbn = pbn;
-	vcpi->aligned_pbn = slots * mgr->pbn_div;
-	vcpi->num_slots = slots;
-
-	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
-	if (ret < 0)
-		return ret;
-	return 0;
-}
-
 /**
  * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
  * @state: global atomic state
  * @mgr: MST topology manager for the port
  * @port: port to find time slots for
  * @pbn: bandwidth required for the mode in PBN
- * @pbn_div: divider for DSC mode that takes FEC into account
  *
- * Allocates time slots to @port, replacing any previous timeslot allocations it
- * may have had. Any atomic drivers which support MST must call this function
- * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
- * current timeslot allocation for the new state, but only when
- * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
- * to ensure compatibility with userspace applications that still use the
- * legacy modesetting UAPI.
+ * Allocates time slots to @port, replacing any previous time slot allocations it may
+ * have had. Any atomic drivers which support MST must call this function in
+ * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to
+ * change the current time slot allocation for the new state, and ensure the MST
+ * atomic state is added whenever the state of payloads in the topology changes.
  *
  * Allocations set by this function are not checked against the bandwidth
  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
@@ -4384,8 +4214,7 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
  */
 int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 				  struct drm_dp_mst_topology_mgr *mgr,
-				  struct drm_dp_mst_port *port, int pbn,
-				  int pbn_div)
+				  struct drm_dp_mst_port *port, int pbn)
 {
 	struct drm_dp_mst_topology_state *topology_state;
 	struct drm_dp_mst_atomic_payload *payload = NULL;
@@ -4418,10 +4247,7 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 		}
 	}
 
-	if (pbn_div <= 0)
-		pbn_div = mgr->pbn_div;
-
-	req_slots = DIV_ROUND_UP(pbn, pbn_div);
+	req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div);
 
 	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
 		       port->connector->base.id, port->connector->name,
@@ -4430,7 +4256,7 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 		       port->connector->base.id, port->connector->name,
 		       port, prev_bw, pbn);
 
-	/* Add the new allocation to the state */
+	/* Add the new allocation to the state, note the VCPI isn't assigned until the end */
 	if (!payload) {
 		payload = kzalloc(sizeof(*payload), GFP_KERNEL);
 		if (!payload)
@@ -4438,6 +4264,7 @@ int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 
 		drm_dp_mst_get_port_malloc(port);
 		payload->port = port;
+		payload->vc_start_slot = -1;
 		list_add(&payload->next, &topology_state->payloads);
 	}
 	payload->time_slots = req_slots;
@@ -4454,10 +4281,12 @@ EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
  * @port: The port to release the time slots from
  *
  * Releases any time slots that have been allocated to a port in the atomic
- * state. Any atomic drivers which support MST must call this function in
- * their &drm_connector_helper_funcs.atomic_check() callback when the
- * connector will no longer have VCPI allocated (e.g. because its CRTC was
- * removed) when it had VCPI allocated in the previous atomic state.
+ * state. Any atomic drivers which support MST must call this function
+ * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback.
+ * This helper will check whether time slots would be released by the new state and
+ * respond accordingly, along with ensuring the MST state is always added to the
+ * atomic state whenever a new state would modify the state of payloads on the
+ * topology.
  *
  * It is OK to call this even if @port has been removed from the system.
  * Additionally, it is OK to call this function multiple times on the same
@@ -4519,6 +4348,7 @@ int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
 		drm_dp_mst_put_port_malloc(port);
 		payload->pbn = 0;
 		payload->delete = true;
+		topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
 	}
 
 	return 0;
@@ -4569,7 +4399,8 @@ int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
 EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
 
 /**
- * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies
+ * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies,
+ * prepare new MST state for commit
  * @state: global atomic state
  *
  * Goes through any MST topologies in this atomic state, and waits for any pending commits which
@@ -4587,17 +4418,30 @@ EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
  */
 void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
 {
-	struct drm_dp_mst_topology_state *old_mst_state;
+	struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state;
 	struct drm_dp_mst_topology_mgr *mgr;
+	struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
 	int i, j, ret;
 
-	for_each_old_mst_mgr_in_state(state, mgr, old_mst_state, i) {
+	for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) {
 		for (j = 0; j < old_mst_state->num_commit_deps; j++) {
 			ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
 			if (ret < 0)
 				drm_err(state->dev, "Failed to wait for %s: %d\n",
 					old_mst_state->commit_deps[j]->crtc->name, ret);
 		}
+
+		/* Now that previous state is committed, it's safe to copy over the start slot
+		 * assignments
+		 */
+		list_for_each_entry(old_payload, &old_mst_state->payloads, next) {
+			if (old_payload->delete)
+				continue;
+
+			new_payload = drm_atomic_get_mst_payload_state(new_mst_state,
+								       old_payload->port);
+			new_payload->vc_start_slot = old_payload->vc_start_slot;
+		}
 	}
 }
 EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
@@ -4682,110 +4526,8 @@ void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_
 }
 EXPORT_SYMBOL(drm_dp_mst_update_slots);
 
-/**
- * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
- * @mgr: manager for this port
- * @port: port to allocate a virtual channel for.
- * @pbn: payload bandwidth number to request
- * @slots: returned number of slots for this PBN.
- */
-bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
-			      struct drm_dp_mst_port *port, int pbn, int slots)
-{
-	int ret;
-
-	if (slots < 0)
-		return false;
-
-	port = drm_dp_mst_topology_get_port_validated(mgr, port);
-	if (!port)
-		return false;
-
-	if (port->vcpi.vcpi > 0) {
-		drm_dbg_kms(mgr->dev,
-			    "payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
-			    port->vcpi.vcpi, port->vcpi.pbn, pbn);
-		if (pbn == port->vcpi.pbn) {
-			drm_dp_mst_topology_put_port(port);
-			return true;
-		}
-	}
-
-	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
-	if (ret) {
-		drm_dbg_kms(mgr->dev, "failed to init time slots=%d ret=%d\n",
-			    DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
-		drm_dp_mst_topology_put_port(port);
-		goto out;
-	}
-	drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn, port->vcpi.num_slots);
-
-	/* Keep port allocated until its payload has been removed */
-	drm_dp_mst_get_port_malloc(port);
-	drm_dp_mst_topology_put_port(port);
-	return true;
-out:
-	return false;
-}
-EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
-
-int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
-{
-	int slots = 0;
-
-	port = drm_dp_mst_topology_get_port_validated(mgr, port);
-	if (!port)
-		return slots;
-
-	slots = port->vcpi.num_slots;
-	drm_dp_mst_topology_put_port(port);
-	return slots;
-}
-EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
-
-/**
- * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
- * @mgr: manager for this port
- * @port: unverified pointer to a port.
- *
- * This just resets the number of slots for the ports VCPI for later programming.
- */
-void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
-{
-	/*
-	 * A port with VCPI will remain allocated until its VCPI is
-	 * released, no verified ref needed
-	 */
-
-	port->vcpi.num_slots = 0;
-}
-EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
-
-/**
- * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
- * @mgr: manager for this port
- * @port: port to deallocate vcpi for
- *
- * This can be called unconditionally, regardless of whether
- * drm_dp_mst_allocate_vcpi() succeeded or not.
- */
-void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
-				struct drm_dp_mst_port *port)
-{
-	if (!port->vcpi.vcpi)
-		return;
-
-	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
-	port->vcpi.num_slots = 0;
-	port->vcpi.pbn = 0;
-	port->vcpi.aligned_pbn = 0;
-	port->vcpi.vcpi = 0;
-	drm_dp_mst_put_port_malloc(port);
-}
-EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
-
 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
-				     int id, struct drm_dp_payload *payload)
+				     int id, u8 start_slot, u8 num_slots)
 {
 	u8 payload_alloc[3], status;
 	int ret;
@@ -4795,8 +4537,8 @@ static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
 			   DP_PAYLOAD_TABLE_UPDATED);
 
 	payload_alloc[0] = id;
-	payload_alloc[1] = payload->start_slot;
-	payload_alloc[2] = payload->num_slots;
+	payload_alloc[1] = start_slot;
+	payload_alloc[2] = num_slots;
 
 	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
 	if (ret != 3) {
@@ -5011,8 +4753,9 @@ static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
 void drm_dp_mst_dump_topology(struct seq_file *m,
 			      struct drm_dp_mst_topology_mgr *mgr)
 {
-	int i;
-	struct drm_dp_mst_port *port;
+	struct drm_dp_mst_topology_state *state;
+	struct drm_dp_mst_atomic_payload *payload;
+	int i, ret;
 
 	mutex_lock(&mgr->lock);
 	if (mgr->mst_primary)
@@ -5021,36 +4764,35 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
 	/* dump VCPIs */
 	mutex_unlock(&mgr->lock);
 
-	mutex_lock(&mgr->payload_lock);
-	seq_printf(m, "\n*** VCPI Info ***\n");
-	seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads: %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
+	ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
+	if (ret < 0)
+		return;
+
+	state = to_drm_dp_mst_topology_state(mgr->base.state);
+	seq_printf(m, "\n*** Atomic state info ***\n");
+	seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
+		   state->payload_mask, mgr->max_payloads, state->start_slot, state->pbn_div);
 
-	seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |     sink name     |\n");
+	seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc |     sink name     |\n");
 	for (i = 0; i < mgr->max_payloads; i++) {
-		if (mgr->proposed_vcpis[i]) {
+		list_for_each_entry(payload, &state->payloads, next) {
 			char name[14];
 
-			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
-			fetch_monitor_name(mgr, port, name, sizeof(name));
-			seq_printf(m, "%10d%10d%10d%10d%20s\n",
+			if (payload->vcpi != i || payload->delete)
+				continue;
+
+			fetch_monitor_name(mgr, payload->port, name, sizeof(name));
+			seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %19s\n",
 				   i,
-				   port->port_num,
-				   port->vcpi.vcpi,
-				   port->vcpi.num_slots,
+				   payload->port->port_num,
+				   payload->vcpi,
+				   payload->vc_start_slot,
+				   payload->vc_start_slot + payload->time_slots - 1,
+				   payload->pbn,
+				   payload->dsc_enabled ? "Y" : "N",
 				   (*name != 0) ? name : "Unknown");
-		} else
-			seq_printf(m, "%6d - Unused\n", i);
-	}
-	seq_printf(m, "\n*** Payload Info ***\n");
-	seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
-	for (i = 0; i < mgr->max_payloads; i++) {
-		seq_printf(m, "%10d%10d%15d%10d\n",
-			   i,
-			   mgr->payloads[i].payload_state,
-			   mgr->payloads[i].start_slot,
-			   mgr->payloads[i].num_slots);
+		}
 	}
-	mutex_unlock(&mgr->payload_lock);
 
 	seq_printf(m, "\n*** DPCD Info ***\n");
 	mutex_lock(&mgr->lock);
@@ -5097,7 +4839,7 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
 
 out:
 	mutex_unlock(&mgr->lock);
-
+	drm_modeset_unlock(&mgr->base.lock);
 }
 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
 
@@ -5418,9 +5160,22 @@ drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr
 				       mgr, mst_state, mgr->max_payloads);
 			return -EINVAL;
 		}
+
+		/* Assign a VCPI */
+		if (!payload->vcpi) {
+			payload->vcpi = ffz(mst_state->payload_mask) + 1;
+			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n",
+				       payload->port, payload->vcpi);
+			mst_state->payload_mask |= BIT(payload->vcpi - 1);
+		}
 	}
-	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU avail=%d used=%d\n",
-		       mgr, mst_state, avail_slots, mst_state->total_avail_slots - avail_slots);
+
+	if (!payload_count)
+		mst_state->pbn_div = 0;
+
+	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
+		       mgr, mst_state, mst_state->pbn_div, avail_slots,
+		       mst_state->total_avail_slots - avail_slots);
 
 	return 0;
 }
@@ -5491,7 +5246,6 @@ EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
  * @state: Pointer to the new drm_atomic_state
  * @port: Pointer to the affected MST Port
  * @pbn: Newly recalculated bw required for link with DSC enabled
- * @pbn_div: Divider to calculate correct number of pbn per slot
  * @enable: Boolean flag to enable or disable DSC on the port
  *
  * This function enables DSC on the given Port
@@ -5502,8 +5256,7 @@ EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
  */
 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 				 struct drm_dp_mst_port *port,
-				 int pbn, int pbn_div,
-				 bool enable)
+				 int pbn, bool enable)
 {
 	struct drm_dp_mst_topology_state *mst_state;
 	struct drm_dp_mst_atomic_payload *payload;
@@ -5529,7 +5282,7 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 	}
 
 	if (enable) {
-		time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn, pbn_div);
+		time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn);
 		drm_dbg_atomic(state->dev,
 			       "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
 			       port, time_slots);
@@ -5542,6 +5295,7 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 	return time_slots;
 }
 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
+
 /**
  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
  * atomic update is valid
@@ -5599,7 +5353,6 @@ EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
 
 /**
  * drm_atomic_get_mst_topology_state: get MST topology state
- *
  * @state: global atomic state
  * @mgr: MST topology manager, also the private object in this case
  *
@@ -5619,6 +5372,31 @@ struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_a
 }
 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
 
+/**
+ * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
+ * @state: global atomic state
+ * @mgr: MST topology manager, also the private object in this case
+ *
+ * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
+ * state vtable so that the private object state returned is that of a MST
+ * topology object.
+ *
+ * Returns:
+ *
+ * The MST topology state, or NULL if there's no topology state for this MST mgr
+ * in the global atomic state
+ */
+struct drm_dp_mst_topology_state *
+drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
+				      struct drm_dp_mst_topology_mgr *mgr)
+{
+	struct drm_private_state *priv_state =
+		drm_atomic_get_new_private_obj_state(state, &mgr->base);
+
+	return priv_state ? to_dp_mst_topology_state(priv_state) : NULL;
+}
+EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
+
 /**
  * drm_dp_mst_topology_mgr_init - initialise a topology manager
  * @mgr: manager struct to initialise
@@ -5626,8 +5404,6 @@ EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
  * @aux: DP helper aux channel to talk to this device
  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
  * @max_payloads: maximum number of payloads this GPU can source
- * @max_lane_count: maximum number of lanes this GPU supports
- * @max_link_rate: maximum link rate per lane this GPU supports in kHz
  * @conn_base_id: the connector object ID the MST device is connected to.
  *
  * Return 0 for success, or negative error code on failure
@@ -5635,14 +5411,12 @@ EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_device *dev, struct drm_dp_aux *aux,
 				 int max_dpcd_transaction_bytes, int max_payloads,
-				 int max_lane_count, int max_link_rate,
 				 int conn_base_id)
 {
 	struct drm_dp_mst_topology_state *mst_state;
 
 	mutex_init(&mgr->lock);
 	mutex_init(&mgr->qlock);
-	mutex_init(&mgr->payload_lock);
 	mutex_init(&mgr->delayed_destroy_lock);
 	mutex_init(&mgr->up_req_lock);
 	mutex_init(&mgr->probe_lock);
@@ -5672,19 +5446,7 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
 	mgr->aux = aux;
 	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
 	mgr->max_payloads = max_payloads;
-	mgr->max_lane_count = max_lane_count;
-	mgr->max_link_rate = max_link_rate;
 	mgr->conn_base_id = conn_base_id;
-	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
-	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
-		return -EINVAL;
-	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
-	if (!mgr->payloads)
-		return -ENOMEM;
-	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
-	if (!mgr->proposed_vcpis)
-		return -ENOMEM;
-	set_bit(0, &mgr->payload_mask);
 
 	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
 	if (mst_state == NULL)
@@ -5717,19 +5479,12 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
 		destroy_workqueue(mgr->delayed_destroy_wq);
 		mgr->delayed_destroy_wq = NULL;
 	}
-	mutex_lock(&mgr->payload_lock);
-	kfree(mgr->payloads);
-	mgr->payloads = NULL;
-	kfree(mgr->proposed_vcpis);
-	mgr->proposed_vcpis = NULL;
-	mutex_unlock(&mgr->payload_lock);
 	mgr->dev = NULL;
 	mgr->aux = NULL;
 	drm_atomic_private_obj_fini(&mgr->base);
 	mgr->funcs = NULL;
 
 	mutex_destroy(&mgr->delayed_destroy_lock);
-	mutex_destroy(&mgr->payload_lock);
 	mutex_destroy(&mgr->qlock);
 	mutex_destroy(&mgr->lock);
 	mutex_destroy(&mgr->up_req_lock);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 4b0af3c26176..ec389e3caf24 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -52,6 +52,7 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
 	struct drm_atomic_state *state = crtc_state->uapi.state;
 	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
 	struct intel_dp *intel_dp = &intel_mst->primary->dp;
+	struct drm_dp_mst_topology_state *mst_state;
 	struct intel_connector *connector =
 		to_intel_connector(conn_state->connector);
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
@@ -60,22 +61,28 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
 	bool constant_n = drm_dp_has_quirk(&intel_dp->desc, DP_DPCD_QUIRK_CONSTANT_N);
 	int bpp, slots = -EINVAL;
 
+	mst_state = drm_atomic_get_mst_topology_state(state, &intel_dp->mst_mgr);
+	if (IS_ERR(mst_state))
+		return PTR_ERR(mst_state);
+
 	crtc_state->lane_count = limits->max_lane_count;
 	crtc_state->port_clock = limits->max_rate;
 
+	// TODO: Handle pbn_div changes by adding a new MST helper
+	if (!mst_state->pbn_div) {
+		mst_state->pbn_div = drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
+							      limits->max_rate,
+							      limits->max_lane_count);
+	}
+
 	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
 		crtc_state->pipe_bpp = bpp;
 
 		crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
 						       crtc_state->pipe_bpp,
 						       false);
-
 		slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
-						      connector->port,
-						      crtc_state->pbn,
-						      drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
-									       crtc_state->port_clock,
-									       crtc_state->lane_count));
+						      connector->port, crtc_state->pbn);
 		if (slots == -EDEADLK)
 			return slots;
 		if (slots >= 0)
@@ -360,21 +367,17 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
 	struct intel_dp *intel_dp = &dig_port->dp;
 	struct intel_connector *connector =
 		to_intel_connector(old_conn_state->connector);
+	struct drm_dp_mst_topology_state *mst_state =
+		drm_atomic_get_mst_topology_state(&state->base, &intel_dp->mst_mgr);
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
-	int start_slot = intel_dp_is_uhbr(old_crtc_state) ? 0 : 1;
-	int ret;
 
 	drm_dbg_kms(&i915->drm, "active links %d\n",
 		    intel_dp->active_mst_links);
 
 	intel_hdcp_disable(intel_mst->connector);
 
-	drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, connector->port);
-
-	ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr, start_slot);
-	if (ret) {
-		drm_dbg_kms(&i915->drm, "failed to update payload %d\n", ret);
-	}
+	drm_dp_remove_payload(&intel_dp->mst_mgr, mst_state,
+			      drm_atomic_get_mst_payload_state(mst_state, connector->port));
 
 	intel_audio_codec_disable(encoder, old_crtc_state, old_conn_state);
 }
@@ -402,8 +405,6 @@ static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
 
 	intel_disable_transcoder(old_crtc_state);
 
-	drm_dp_update_payload_part2(&intel_dp->mst_mgr);
-
 	clear_act_sent(encoder, old_crtc_state);
 
 	intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(old_crtc_state->cpu_transcoder),
@@ -411,8 +412,6 @@ static void intel_mst_post_disable_dp(struct intel_atomic_state *state,
 
 	wait_for_act_sent(encoder, old_crtc_state);
 
-	drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, connector->port);
-
 	intel_ddi_disable_transcoder_func(old_crtc_state);
 
 	if (DISPLAY_VER(dev_priv) >= 9)
@@ -479,7 +478,8 @@ static void intel_mst_pre_enable_dp(struct intel_atomic_state *state,
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_connector *connector =
 		to_intel_connector(conn_state->connector);
-	int start_slot = intel_dp_is_uhbr(pipe_config) ? 0 : 1;
+	struct drm_dp_mst_topology_state *mst_state =
+		drm_atomic_get_new_mst_topology_state(&state->base, &intel_dp->mst_mgr);
 	int ret;
 	bool first_mst_stream;
 
@@ -505,16 +505,13 @@ static void intel_mst_pre_enable_dp(struct intel_atomic_state *state,
 		dig_port->base.pre_enable(state, &dig_port->base,
 						pipe_config, NULL);
 
-	ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
-				       connector->port,
-				       pipe_config->pbn,
-				       pipe_config->dp_m_n.tu);
-	if (!ret)
-		drm_err(&dev_priv->drm, "failed to allocate vcpi\n");
-
 	intel_dp->active_mst_links++;
 
-	ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr, start_slot);
+	ret = drm_dp_add_payload_part1(&intel_dp->mst_mgr, mst_state,
+				       drm_atomic_get_mst_payload_state(mst_state, connector->port));
+	if (ret < 0)
+		drm_err(&dev_priv->drm, "Failed to create MST payload for %s: %d\n",
+			connector->base.name, ret);
 
 	/*
 	 * Before Gen 12 this is not done as part of
@@ -537,7 +534,10 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
 	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
 	struct intel_digital_port *dig_port = intel_mst->primary;
 	struct intel_dp *intel_dp = &dig_port->dp;
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct drm_dp_mst_topology_state *mst_state =
+		drm_atomic_get_new_mst_topology_state(&state->base, &intel_dp->mst_mgr);
 	enum transcoder trans = pipe_config->cpu_transcoder;
 
 	drm_WARN_ON(&dev_priv->drm, pipe_config->has_pch_encoder);
@@ -565,7 +565,8 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
 
 	wait_for_act_sent(encoder, pipe_config);
 
-	drm_dp_update_payload_part2(&intel_dp->mst_mgr);
+	drm_dp_add_payload_part2(&intel_dp->mst_mgr, &state->base,
+				 drm_atomic_get_mst_payload_state(mst_state, connector->port));
 
 	if (DISPLAY_VER(dev_priv) >= 12 && pipe_config->fec_enable)
 		intel_de_rmw(dev_priv, CHICKEN_TRANS(trans), 0,
@@ -948,8 +949,6 @@ intel_dp_mst_encoder_init(struct intel_digital_port *dig_port, int conn_base_id)
 	struct intel_dp *intel_dp = &dig_port->dp;
 	enum port port = dig_port->base.port;
 	int ret;
-	int max_source_rate =
-		intel_dp->source_rates[intel_dp->num_source_rates - 1];
 
 	if (!HAS_DP_MST(i915) || intel_dp_is_edp(intel_dp))
 		return 0;
@@ -965,10 +964,7 @@ intel_dp_mst_encoder_init(struct intel_digital_port *dig_port, int conn_base_id)
 	/* create encoders */
 	intel_dp_create_fake_mst_encoders(dig_port);
 	ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, &i915->drm,
-					   &intel_dp->aux, 16, 3,
-					   dig_port->max_lanes,
-					   max_source_rate,
-					   conn_base_id);
+					   &intel_dp->aux, 16, 3, conn_base_id);
 	if (ret) {
 		intel_dp->mst_mgr.cbs = NULL;
 		return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 8ea66a2e1b09..7dbc9f0bb24f 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -30,8 +30,30 @@
 
 static int intel_conn_to_vcpi(struct intel_connector *connector)
 {
+	struct drm_dp_mst_topology_mgr *mgr;
+	struct drm_dp_mst_atomic_payload *payload;
+	struct drm_dp_mst_topology_state *mst_state;
+	int vcpi = 0;
+
 	/* For HDMI this is forced to be 0x0. For DP SST also this is 0x0. */
-	return connector->port	? connector->port->vcpi.vcpi : 0;
+	if (!connector->port)
+		return 0;
+	mgr = connector->port->mgr;
+
+	drm_modeset_lock(&mgr->base.lock, NULL);
+	mst_state = to_drm_dp_mst_topology_state(mgr->base.state);
+	payload = drm_atomic_get_mst_payload_state(mst_state, connector->port);
+	if (drm_WARN_ON(mgr->dev, !payload))
+		goto out;
+
+	vcpi = payload->vcpi;
+	if (drm_WARN_ON(mgr->dev, vcpi < 0)) {
+		vcpi = 0;
+		goto out;
+	}
+out:
+	drm_modeset_unlock(&mgr->base.lock);
+	return vcpi;
 }
 
 /*
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 57f74cfcdebf..e8f4c806fa39 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -937,6 +937,7 @@ struct nv50_msto {
 	struct nv50_head *head;
 	struct nv50_mstc *mstc;
 	bool disabled;
+	bool enabled;
 };
 
 struct nouveau_encoder *nv50_real_outp(struct drm_encoder *encoder)
@@ -952,57 +953,37 @@ struct nouveau_encoder *nv50_real_outp(struct drm_encoder *encoder)
 	return msto->mstc->mstm->outp;
 }
 
-static struct drm_dp_payload *
-nv50_msto_payload(struct nv50_msto *msto)
-{
-	struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
-	struct nv50_mstc *mstc = msto->mstc;
-	struct nv50_mstm *mstm = mstc->mstm;
-	int vcpi = mstc->port->vcpi.vcpi, i;
-
-	WARN_ON(!mutex_is_locked(&mstm->mgr.payload_lock));
-
-	NV_ATOMIC(drm, "%s: vcpi %d\n", msto->encoder.name, vcpi);
-	for (i = 0; i < mstm->mgr.max_payloads; i++) {
-		struct drm_dp_payload *payload = &mstm->mgr.payloads[i];
-		NV_ATOMIC(drm, "%s: %d: vcpi %d start 0x%02x slots 0x%02x\n",
-			  mstm->outp->base.base.name, i, payload->vcpi,
-			  payload->start_slot, payload->num_slots);
-	}
-
-	for (i = 0; i < mstm->mgr.max_payloads; i++) {
-		struct drm_dp_payload *payload = &mstm->mgr.payloads[i];
-		if (payload->vcpi == vcpi)
-			return payload;
-	}
-
-	return NULL;
-}
-
 static void
-nv50_msto_cleanup(struct nv50_msto *msto)
+nv50_msto_cleanup(struct drm_atomic_state *state,
+		  struct drm_dp_mst_topology_state *mst_state,
+		  struct drm_dp_mst_topology_mgr *mgr,
+		  struct nv50_msto *msto)
 {
 	struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
-	struct nv50_mstc *mstc = msto->mstc;
-	struct nv50_mstm *mstm = mstc->mstm;
-
-	if (!msto->disabled)
-		return;
+	struct drm_dp_mst_atomic_payload *payload =
+		drm_atomic_get_mst_payload_state(mst_state, msto->mstc->port);
 
 	NV_ATOMIC(drm, "%s: msto cleanup\n", msto->encoder.name);
 
-	drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port);
-
-	msto->mstc = NULL;
-	msto->disabled = false;
+	if (msto->disabled) {
+		msto->mstc = NULL;
+		msto->disabled = false;
+	} else if (msto->enabled) {
+		drm_dp_add_payload_part2(mgr, state, payload);
+		msto->enabled = false;
+	}
 }
 
 static void
-nv50_msto_prepare(struct nv50_msto *msto)
+nv50_msto_prepare(struct drm_atomic_state *state,
+		  struct drm_dp_mst_topology_state *mst_state,
+		  struct drm_dp_mst_topology_mgr *mgr,
+		  struct nv50_msto *msto)
 {
 	struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
 	struct nv50_mstc *mstc = msto->mstc;
 	struct nv50_mstm *mstm = mstc->mstm;
+	struct drm_dp_mst_atomic_payload *payload;
 	struct {
 		struct nv50_disp_mthd_v1 base;
 		struct nv50_disp_sor_dp_mst_vcpi_v0 vcpi;
@@ -1014,17 +995,21 @@ nv50_msto_prepare(struct nv50_msto *msto)
 			       (0x0100 << msto->head->base.index),
 	};
 
-	mutex_lock(&mstm->mgr.payload_lock);
-
 	NV_ATOMIC(drm, "%s: msto prepare\n", msto->encoder.name);
-	if (mstc->port->vcpi.vcpi > 0) {
-		struct drm_dp_payload *payload = nv50_msto_payload(msto);
-		if (payload) {
-			args.vcpi.start_slot = payload->start_slot;
-			args.vcpi.num_slots = payload->num_slots;
-			args.vcpi.pbn = mstc->port->vcpi.pbn;
-			args.vcpi.aligned_pbn = mstc->port->vcpi.aligned_pbn;
-		}
+
+	payload = drm_atomic_get_mst_payload_state(mst_state, mstc->port);
+
+	// TODO: Figure out if we want to do a better job of handling VCPI allocation failures here?
+	if (msto->disabled) {
+		drm_dp_remove_payload(mgr, mst_state, payload);
+	} else {
+		if (msto->enabled)
+			drm_dp_add_payload_part1(mgr, mst_state, payload);
+
+		args.vcpi.start_slot = payload->vc_start_slot;
+		args.vcpi.num_slots = payload->time_slots;
+		args.vcpi.pbn = payload->pbn;
+		args.vcpi.aligned_pbn = payload->time_slots * mst_state->pbn_div;
 	}
 
 	NV_ATOMIC(drm, "%s: %s: %02x %02x %04x %04x\n",
@@ -1033,7 +1018,6 @@ nv50_msto_prepare(struct nv50_msto *msto)
 		  args.vcpi.pbn, args.vcpi.aligned_pbn);
 
 	nvif_mthd(&drm->display->disp.object, 0, &args, sizeof(args));
-	mutex_unlock(&mstm->mgr.payload_lock);
 }
 
 static int
@@ -1043,6 +1027,7 @@ nv50_msto_atomic_check(struct drm_encoder *encoder,
 {
 	struct drm_atomic_state *state = crtc_state->state;
 	struct drm_connector *connector = conn_state->connector;
+	struct drm_dp_mst_topology_state *mst_state;
 	struct nv50_mstc *mstc = nv50_mstc(connector);
 	struct nv50_mstm *mstm = mstc->mstm;
 	struct nv50_head_atom *asyh = nv50_head_atom(crtc_state);
@@ -1070,8 +1055,18 @@ nv50_msto_atomic_check(struct drm_encoder *encoder,
 						    false);
 	}
 
-	slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc->port,
-					      asyh->dp.pbn, 0);
+	mst_state = drm_atomic_get_mst_topology_state(state, &mstm->mgr);
+	if (IS_ERR(mst_state))
+		return PTR_ERR(mst_state);
+
+	if (!mst_state->pbn_div) {
+		struct nouveau_encoder *outp = mstc->mstm->outp;
+
+		mst_state->pbn_div = drm_dp_get_vc_payload_bw(&mstm->mgr,
+							      outp->dp.link_bw, outp->dp.link_nr);
+	}
+
+	slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc->port, asyh->dp.pbn);
 	if (slots < 0)
 		return slots;
 
@@ -1103,7 +1098,6 @@ nv50_msto_atomic_enable(struct drm_encoder *encoder, struct drm_atomic_state *st
 	struct drm_connector *connector;
 	struct drm_connector_list_iter conn_iter;
 	u8 proto;
-	bool r;
 
 	drm_connector_list_iter_begin(encoder->dev, &conn_iter);
 	drm_for_each_connector_iter(connector, &conn_iter) {
@@ -1118,10 +1112,6 @@ nv50_msto_atomic_enable(struct drm_encoder *encoder, struct drm_atomic_state *st
 	if (WARN_ON(!mstc))
 		return;
 
-	r = drm_dp_mst_allocate_vcpi(&mstm->mgr, mstc->port, asyh->dp.pbn, asyh->dp.tu);
-	if (!r)
-		DRM_DEBUG_KMS("Failed to allocate VCPI\n");
-
 	if (!mstm->links++)
 		nv50_outp_acquire(mstm->outp, false /*XXX: MST audio.*/);
 
@@ -1134,6 +1124,7 @@ nv50_msto_atomic_enable(struct drm_encoder *encoder, struct drm_atomic_state *st
 			   nv50_dp_bpc_to_depth(asyh->or.bpc));
 
 	msto->mstc = mstc;
+	msto->enabled = true;
 	mstm->modified = true;
 }
 
@@ -1144,8 +1135,6 @@ nv50_msto_atomic_disable(struct drm_encoder *encoder, struct drm_atomic_state *s
 	struct nv50_mstc *mstc = msto->mstc;
 	struct nv50_mstm *mstm = mstc->mstm;
 
-	drm_dp_mst_reset_vcpi_slots(&mstm->mgr, mstc->port);
-
 	mstm->outp->update(mstm->outp, msto->head->base.index, NULL, 0, 0);
 	mstm->modified = true;
 	if (!--mstm->links)
@@ -1365,7 +1354,9 @@ nv50_mstc_new(struct nv50_mstm *mstm, struct drm_dp_mst_port *port,
 }
 
 static void
-nv50_mstm_cleanup(struct nv50_mstm *mstm)
+nv50_mstm_cleanup(struct drm_atomic_state *state,
+		  struct drm_dp_mst_topology_state *mst_state,
+		  struct nv50_mstm *mstm)
 {
 	struct nouveau_drm *drm = nouveau_drm(mstm->outp->base.base.dev);
 	struct drm_encoder *encoder;
@@ -1373,14 +1364,12 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
 	NV_ATOMIC(drm, "%s: mstm cleanup\n", mstm->outp->base.base.name);
 	drm_dp_check_act_status(&mstm->mgr);
 
-	drm_dp_update_payload_part2(&mstm->mgr);
-
 	drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
 		if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST) {
 			struct nv50_msto *msto = nv50_msto(encoder);
 			struct nv50_mstc *mstc = msto->mstc;
 			if (mstc && mstc->mstm == mstm)
-				nv50_msto_cleanup(msto);
+				nv50_msto_cleanup(state, mst_state, &mstm->mgr, msto);
 		}
 	}
 
@@ -1388,20 +1377,34 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
 }
 
 static void
-nv50_mstm_prepare(struct nv50_mstm *mstm)
+nv50_mstm_prepare(struct drm_atomic_state *state,
+		  struct drm_dp_mst_topology_state *mst_state,
+		  struct nv50_mstm *mstm)
 {
 	struct nouveau_drm *drm = nouveau_drm(mstm->outp->base.base.dev);
 	struct drm_encoder *encoder;
 
 	NV_ATOMIC(drm, "%s: mstm prepare\n", mstm->outp->base.base.name);
-	drm_dp_update_payload_part1(&mstm->mgr, 1);
 
+	/* Disable payloads first */
 	drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
 		if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST) {
 			struct nv50_msto *msto = nv50_msto(encoder);
 			struct nv50_mstc *mstc = msto->mstc;
-			if (mstc && mstc->mstm == mstm)
-				nv50_msto_prepare(msto);
+			if (mstc && mstc->mstm == mstm && msto->disabled)
+				nv50_msto_prepare(state, mst_state, &mstm->mgr, msto);
+		}
+	}
+
+	/* Add payloads for new heads, while also updating the start slots of any unmodified (but
+	 * active) heads that may have had their VC slots shifted left after the previous step
+	 */
+	drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
+		if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST) {
+			struct nv50_msto *msto = nv50_msto(encoder);
+			struct nv50_mstc *mstc = msto->mstc;
+			if (mstc && mstc->mstm == mstm && !msto->disabled)
+				nv50_msto_prepare(state, mst_state, &mstm->mgr, msto);
 		}
 	}
 
@@ -1598,9 +1601,7 @@ nv50_mstm_new(struct nouveau_encoder *outp, struct drm_dp_aux *aux, int aux_max,
 	mstm->mgr.cbs = &nv50_mstm;
 
 	ret = drm_dp_mst_topology_mgr_init(&mstm->mgr, dev, aux, aux_max,
-					   max_payloads, outp->dcb->dpconf.link_nr,
-					   drm_dp_bw_code_to_link_rate(outp->dcb->dpconf.link_bw),
-					   conn_base_id);
+					   max_payloads, conn_base_id);
 	if (ret)
 		return ret;
 
@@ -2045,20 +2046,20 @@ nv50_pior_create(struct drm_connector *connector, struct dcb_output *dcbe)
 static void
 nv50_disp_atomic_commit_core(struct drm_atomic_state *state, u32 *interlock)
 {
+	struct drm_dp_mst_topology_mgr *mgr;
+	struct drm_dp_mst_topology_state *mst_state;
 	struct nouveau_drm *drm = nouveau_drm(state->dev);
 	struct nv50_disp *disp = nv50_disp(drm->dev);
 	struct nv50_core *core = disp->core;
 	struct nv50_mstm *mstm;
-	struct drm_encoder *encoder;
+	int i;
 
 	NV_ATOMIC(drm, "commit core %08x\n", interlock[NV50_DISP_INTERLOCK_BASE]);
 
-	drm_for_each_encoder(encoder, drm->dev) {
-		if (encoder->encoder_type != DRM_MODE_ENCODER_DPMST) {
-			mstm = nouveau_encoder(encoder)->dp.mstm;
-			if (mstm && mstm->modified)
-				nv50_mstm_prepare(mstm);
-		}
+	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
+		mstm = nv50_mstm(mgr);
+		if (mstm->modified)
+			nv50_mstm_prepare(state, mst_state, mstm);
 	}
 
 	core->func->ntfy_init(disp->sync, NV50_DISP_CORE_NTFY);
@@ -2067,12 +2068,10 @@ nv50_disp_atomic_commit_core(struct drm_atomic_state *state, u32 *interlock)
 				       disp->core->chan.base.device))
 		NV_ERROR(drm, "core notifier timeout\n");
 
-	drm_for_each_encoder(encoder, drm->dev) {
-		if (encoder->encoder_type != DRM_MODE_ENCODER_DPMST) {
-			mstm = nouveau_encoder(encoder)->dp.mstm;
-			if (mstm && mstm->modified)
-				nv50_mstm_cleanup(mstm);
-		}
+	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
+		mstm = nv50_mstm(mgr);
+		if (mstm->modified)
+			nv50_mstm_cleanup(state, mst_state, mstm);
 	}
 }
 
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index ecd130028337..6317831705ab 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -48,20 +48,6 @@ struct drm_dp_mst_topology_ref_history {
 
 struct drm_dp_mst_branch;
 
-/**
- * struct drm_dp_vcpi - Virtual Channel Payload Identifier
- * @vcpi: Virtual channel ID.
- * @pbn: Payload Bandwidth Number for this channel
- * @aligned_pbn: PBN aligned with slot size
- * @num_slots: number of slots for this PBN
- */
-struct drm_dp_vcpi {
-	int vcpi;
-	int pbn;
-	int aligned_pbn;
-	int num_slots;
-};
-
 /**
  * struct drm_dp_mst_port - MST port
  * @port_num: port number
@@ -142,7 +128,6 @@ struct drm_dp_mst_port {
 	struct drm_dp_aux aux; /* i2c bus for this port? */
 	struct drm_dp_mst_branch *parent;
 
-	struct drm_dp_vcpi vcpi;
 	struct drm_connector *connector;
 	struct drm_dp_mst_topology_mgr *mgr;
 
@@ -527,19 +512,6 @@ struct drm_dp_mst_topology_cbs {
 	void (*poll_hpd_irq)(struct drm_dp_mst_topology_mgr *mgr);
 };
 
-#define DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
-
-#define DP_PAYLOAD_LOCAL 1
-#define DP_PAYLOAD_REMOTE 2
-#define DP_PAYLOAD_DELETE_LOCAL 3
-
-struct drm_dp_payload {
-	int payload_state;
-	int start_slot;
-	int num_slots;
-	int vcpi;
-};
-
 #define to_dp_mst_topology_state(x) container_of(x, struct drm_dp_mst_topology_state, base)
 
 /**
@@ -551,6 +523,35 @@ struct drm_dp_payload {
 struct drm_dp_mst_atomic_payload {
 	/** @port: The MST port assigned to this payload */
 	struct drm_dp_mst_port *port;
+
+	/**
+	 * @vc_start_slot: The time slot that this payload starts on. Because payload start slots
+	 * can't be determined ahead of time, the contents of this value are UNDEFINED at atomic
+	 * check time. This shouldn't usually matter, as the start slot should never be relevant for
+	 * atomic state computations.
+	 *
+	 * Since this value is determined at commit time instead of check time, this value is
+	 * protected by the MST helpers ensuring that async commits operating on the given topology
+	 * never run in parallel. In the event that a driver does need to read this value (e.g. to
+	 * inform hardware of the starting timeslot for a payload), the driver may either:
+	 *
+	 * * Read this field during the atomic commit after
+	 *   drm_dp_mst_atomic_wait_for_dependencies() has been called, which will ensure the
+	 *   previous MST states payload start slots have been copied over to the new state. Note
+	 *   that a new start slot won't be assigned/removed from this payload until
+	 *   drm_dp_add_payload_part1()/drm_dp_remove_payload() have been called.
+	 * * Acquire the MST modesetting lock, and then wait for any pending MST-related commits to
+	 *   get committed to hardware by calling drm_crtc_commit_wait() on each of the
+	 *   &drm_crtc_commit structs in &drm_dp_mst_topology_state.commit_deps.
+	 *
+	 * If neither of the two above solutions suffice (e.g. the driver needs to read the start
+	 * slot in the middle of an atomic commit without waiting for some reason), then drivers
+	 * should cache this value themselves after changing payloads.
+	 */
+	s8 vc_start_slot;
+
+	/** @vcpi: The Virtual Channel Payload Identifier */
+	u8 vcpi;
 	/** @time_slots: The number of timeslots allocated to this payload */
 	int time_slots;
 	/** @pbn: The payload bandwidth for this payload */
@@ -574,8 +575,6 @@ struct drm_dp_mst_topology_state {
 	/** @base: Base private state for atomic */
 	struct drm_private_state base;
 
-	/** @payloads: The list of payloads being created/destroyed in this state */
-	struct list_head payloads;
 	/** @mgr: The topology manager */
 	struct drm_dp_mst_topology_mgr *mgr;
 
@@ -592,10 +591,21 @@ struct drm_dp_mst_topology_state {
 	/** @num_commit_deps: The number of CRTC commits in @commit_deps */
 	size_t num_commit_deps;
 
+	/** @payload_mask: A bitmask of allocated VCPIs, used for VCPI assignments */
+	u32 payload_mask;
+	/** @payloads: The list of payloads being created/destroyed in this state */
+	struct list_head payloads;
+
 	/** @total_avail_slots: The total number of slots this topology can handle (63 or 64) */
 	u8 total_avail_slots;
 	/** @start_slot: The first usable time slot in this topology (1 or 0) */
 	u8 start_slot;
+
+	/**
+	 * @pbn_div: The current PBN divisor for this topology. The driver is expected to fill this
+	 * out itself.
+	 */
+	int pbn_div;
 };
 
 #define to_dp_mst_topology_mgr(x) container_of(x, struct drm_dp_mst_topology_mgr, base)
@@ -635,14 +645,6 @@ struct drm_dp_mst_topology_mgr {
 	 * @max_payloads: maximum number of payloads the GPU can generate.
 	 */
 	int max_payloads;
-	/**
-	 * @max_lane_count: maximum number of lanes the GPU can drive.
-	 */
-	int max_lane_count;
-	/**
-	 * @max_link_rate: maximum link rate per lane GPU can output, in kHz.
-	 */
-	int max_link_rate;
 	/**
 	 * @conn_base_id: DRM connector ID this mgr is connected to. Only used
 	 * to build the MST connector path value.
@@ -685,6 +687,20 @@ struct drm_dp_mst_topology_mgr {
 	 */
 	bool payload_id_table_cleared : 1;
 
+	/**
+	 * @payload_count: The number of currently active payloads in hardware. This value is only
+	 * intended to be used internally by MST helpers for payload tracking, and is only safe to
+	 * read/write from the atomic commit (not check) context.
+	 */
+	u8 payload_count;
+
+	/**
+	 * @next_start_slot: The starting timeslot to use for new VC payloads. This value is used
+	 * internally by MST helpers for payload tracking, and is only safe to read/write from the
+	 * atomic commit (not check) context.
+	 */
+	u8 next_start_slot;
+
 	/**
 	 * @mst_primary: Pointer to the primary/first branch device.
 	 */
@@ -698,10 +714,6 @@ struct drm_dp_mst_topology_mgr {
 	 * @sink_count: Sink count from DEVICE_SERVICE_IRQ_VECTOR_ESI0.
 	 */
 	u8 sink_count;
-	/**
-	 * @pbn_div: PBN to slots divisor.
-	 */
-	int pbn_div;
 
 	/**
 	 * @funcs: Atomic helper callbacks
@@ -718,32 +730,6 @@ struct drm_dp_mst_topology_mgr {
 	 */
 	struct list_head tx_msg_downq;
 
-	/**
-	 * @payload_lock: Protect payload information.
-	 */
-	struct mutex payload_lock;
-	/**
-	 * @proposed_vcpis: Array of pointers for the new VCPI allocation. The
-	 * VCPI structure itself is &drm_dp_mst_port.vcpi, and the size of
-	 * this array is determined by @max_payloads.
-	 */
-	struct drm_dp_vcpi **proposed_vcpis;
-	/**
-	 * @payloads: Array of payloads. The size of this array is determined
-	 * by @max_payloads.
-	 */
-	struct drm_dp_payload *payloads;
-	/**
-	 * @payload_mask: Elements of @payloads actually in use. Since
-	 * reallocation of active outputs isn't possible gaps can be created by
-	 * disabling outputs out of order compared to how they've been enabled.
-	 */
-	unsigned long payload_mask;
-	/**
-	 * @vcpi_mask: Similar to @payload_mask, but for @proposed_vcpis.
-	 */
-	unsigned long vcpi_mask;
-
 	/**
 	 * @tx_waitq: Wait to queue stall for the tx worker.
 	 */
@@ -815,9 +801,7 @@ struct drm_dp_mst_topology_mgr {
 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_device *dev, struct drm_dp_aux *aux,
 				 int max_dpcd_transaction_bytes,
-				 int max_payloads,
-				 int max_lane_count, int max_link_rate,
-				 int conn_base_id);
+				 int max_payloads, int conn_base_id);
 
 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
 
@@ -840,28 +824,17 @@ int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
 
 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc);
 
-bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
-			      struct drm_dp_mst_port *port, int pbn, int slots);
-
-int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
-
-
-void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
-
 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap);
 
-void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
-				struct drm_dp_mst_port *port);
-
-
-int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
-			   int pbn);
-
-
-int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr, int start_slot);
-
-
-int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr);
+int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
+			     struct drm_dp_mst_topology_state *mst_state,
+			     struct drm_dp_mst_atomic_payload *payload);
+int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
+			     struct drm_atomic_state *state,
+			     struct drm_dp_mst_atomic_payload *payload);
+void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
+			   struct drm_dp_mst_topology_state *mst_state,
+			   struct drm_dp_mst_atomic_payload *payload);
 
 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);
 
@@ -883,17 +856,22 @@ int drm_dp_mst_connector_late_register(struct drm_connector *connector,
 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
 					   struct drm_dp_mst_port *port);
 
-struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
-								    struct drm_dp_mst_topology_mgr *mgr);
+struct drm_dp_mst_topology_state *
+drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
+				  struct drm_dp_mst_topology_mgr *mgr);
+struct drm_dp_mst_topology_state *
+drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
+				      struct drm_dp_mst_topology_mgr *mgr);
+struct drm_dp_mst_atomic_payload *
+drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
+				 struct drm_dp_mst_port *port);
 int __must_check
 drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
 			      struct drm_dp_mst_topology_mgr *mgr,
-			      struct drm_dp_mst_port *port, int pbn,
-			      int pbn_div);
+			      struct drm_dp_mst_port *port, int pbn);
 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 				 struct drm_dp_mst_port *port,
-				 int pbn, int pbn_div,
-				 bool enable);
+				 int pbn, bool enable);
 int __must_check
 drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
 				  struct drm_dp_mst_topology_mgr *mgr);
@@ -917,6 +895,12 @@ void drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port);
 
 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port);
 
+static inline struct drm_dp_mst_topology_state *
+to_drm_dp_mst_topology_state(struct drm_private_state *state)
+{
+	return container_of(state, struct drm_dp_mst_topology_state, base);
+}
+
 extern const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs;
 
 /**
-- 
2.35.3

Re: [Intel-gfx] [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into the atomic state

[Lyude Paul]

On Tue, 2022-07-05 at 09:10 +0000, Lin, Wayne wrote:
> [Public]
> 
> 
> 
> > -----Original Message-----
> > From: Lyude Paul <lyude@redhat.com>
> > Sent: Wednesday, June 8, 2022 3:30 AM
> > To: dri-devel@lists.freedesktop.org; nouveau@lists.freedesktop.org; amd-
> > gfx@lists.freedesktop.org
> > Cc: Lin, Wayne <Wayne.Lin@amd.com>; Ville Syrjälä
> > <ville.syrjala@linux.intel.com>; Zuo, Jerry <Jerry.Zuo@amd.com>; Jani
> > Nikula
> > <jani.nikula@intel.com>; Imre Deak <imre.deak@intel.com>; Daniel Vetter
> > <daniel.vetter@ffwll.ch>; Sean Paul <sean@poorly.run>; Wentland, Harry
> > <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>;
> > Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander
> > <Alexander.Deucher@amd.com>; Koenig, Christian
> > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David
> > Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Jani Nikula
> > <jani.nikula@linux.intel.com>; Joonas Lahtinen
> > <joonas.lahtinen@linux.intel.com>; Rodrigo Vivi <rodrigo.vivi@intel.com>;
> > Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Ben Skeggs
> > <bskeggs@redhat.com>; Karol Herbst <kherbst@redhat.com>; Kazlauskas,
> > Nicholas <Nicholas.Kazlauskas@amd.com>; Li, Roman
> > <Roman.Li@amd.com>; Shih, Jude <Jude.Shih@amd.com>; Simon Ser
> > <contact@emersion.fr>; Lakha, Bhawanpreet
> > <Bhawanpreet.Lakha@amd.com>; Mikita Lipski <mikita.lipski@amd.com>;
> > Claudio Suarez <cssk@net-c.es>; Chen, Ian <Ian.Chen@amd.com>; Colin Ian
> > King <colin.king@intel.com>; Wu, Hersen <hersenxs.wu@amd.com>; Liu,
> > Wenjing <Wenjing.Liu@amd.com>; Lei, Jun <Jun.Lei@amd.com>; Strauss,
> > Michael <Michael.Strauss@amd.com>; Ma, Leo <Hanghong.Ma@amd.com>;
> > Thomas Zimmermann <tzimmermann@suse.de>; José Roberto de Souza
> > <jose.souza@intel.com>; He Ying <heying24@huawei.com>; Anshuman
> > Gupta <anshuman.gupta@intel.com>; Andi Shyti
> > <andi.shyti@linux.intel.com>; Ashutosh Dixit <ashutosh.dixit@intel.com>;
> > Juston Li <juston.li@intel.com>; Sean Paul <seanpaul@chromium.org>;
> > Fernando Ramos <greenfoo@u92.eu>; Luo Jiaxing
> > <luojiaxing@huawei.com>; Javier Martinez Canillas <javierm@redhat.com>;
> > open list <linux-kernel@vger.kernel.org>; open list:INTEL DRM DRIVERS
> > <intel-gfx@lists.freedesktop.org>
> > Subject: [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into
> > the atomic state
> > 
> > Now that we've finally gotten rid of the non-atomic MST users leftover in
> > the kernel, we can finally get rid of all of the legacy payload code we
> > have and move as much as possible into the MST atomic state structs. The
> > main purpose of this is to make the MST code a lot less confusing to work
> > on, as there's a lot of duplicated logic that doesn't really need to be
> > here. As well, this should make introducing features like fallback link
> > retraining and DSC support far easier.
> > 
> > Since the old payload code was pretty gnarly and there's a Lot of changes
> > here, I expect this might be a bit difficult to review. So to make things
> > as easy as possible for reviewers, I'll sum up how both the old and new
> > code worked here (it took me a while to figure this out too!).
> > 
> > The old MST code basically worked by maintaining two different payload
> > tables - proposed_vcpis, and payloads. proposed_vcpis would hold the
> > modified payload we wanted to push to the topology, while payloads held
> > the
> > payload table that was currently programmed in hardware. Modifications to
> > proposed_vcpis would be handled through drm_dp_allocate_vcpi(),
> > drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then,
> > they
> > would be pushed via drm_dp_mst_update_payload_step1() and
> > drm_dp_mst_update_payload_step2().
> > 
> > Furthermore, it's important to note how adding and removing VC payloads
> > actually worked with drm_dp_mst_update_payload_step1(). When a VC
> > payload
> > is removed from the VC table, all VC payloads which come after the removed
> > VC payload's slots must have their time slots shifted towards the start of
> > the table. The old code handles this by looping through the entire payload
> > table and recomputing the start slot for every payload in the topology
> > from
> > scratch. While very much overkill, this ends up doing the right thing
> > because we always order the VCPIs for payloads from first to last starting
> > timeslot.
> > 
> > It's important to also note that drm_dp_mst_update_payload_step2() isn't
> > actually limited to updating a single payload - the driver can use it to
> > queue up multiple payload changes so that as many of them can be sent as
> > possible before waiting for the ACT.
> 
> Hi Lyude,
> 
> I have concern for updating payload table multiple times for multiple
> payload
> changes before sending the ACT. Also consult with one branch vendor, they 
> say their fw will expect receiving one ALLOCATE_PAYLOAD after setting DPCD
> 002c0h bit 0 (VC payload ID table updated).

Ooooh, nice catch! Originally when I looked at amdgpu's MST stream updating
code I had thought that amdgpu was performing multiple updates per-ACT, but it
seems I must have misread something as upon reinspection that doesn't appear
to be the case.

FWIW nouveau does actually do this (iirc it's -technically- allowed in the
spec MST spec), but seeing as apparently not all hub vendors implement
supporting multiple payloads per-ACT correctly it sounds like we should
probably remove that behavior entirely. I wonder if we should also poke VESA
about this, so they know to mention that not all devices in the field will
work with this.

Anyway, thanks for the catch! I will definitely fix this up in the next
version of this series so we always do one ACT per payload update.

> 
> Thanks!
> > 
> > drm_dp_mst_update_payload_step2() is pretty self explanatory and
> > basically
> > the same between the old and new code, save for the fact we don't have a
> > second step for deleting payloads anymore -and thus rename it to
> > drm_dp_mst_add_payload_step2().
> > 
> > The new payload code stores all of the current payload info within the MST
> > atomic state and computes as much of the state as possible ahead of time.
> > This has the one exception of the starting timeslots for payloads, which
> > can't be determined at atomic check time since the starting time slots
> > will
> > vary depending on what order CRTCs are enabled in the atomic state - which
> > varies from driver to driver. These are still stored in the atomic MST
> > state, but are only copied from the old MST state during atomic commit
> > time. Likewise, this is when new start slots are determined.
> > 
> > Adding/removing payloads now works much more closely to how things are
> > described in the spec. When we delete a payload, we loop through the
> > current list of payloads and update the start slots for any payloads whose
> > time slots came after the payload we just deleted. Determining the
> > starting
> > time slots for new payloads being added is done by simply keeping track of
> > where the end of the VC table is in
> > drm_dp_mst_topology_mgr->next_start_slot. Additionally, it's worth noting
> > that we no longer have a single update_payload() function. Instead, we now
> > have drm_dp_mst_add_payload_step1|2() and
> > drm_dp_mst_remove_payload(). As
> > such, it's now left it up to the driver to figure out when to add or
> > remove
> > payloads. The driver already knows when it's disabling/enabling CRTCs, so
> > it also already knows when payloads should be added or removed. And, this
> > doesn't interfere with the ability to queue up multiple payload changes
> > before waiting for the ACT.
> > 
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > Cc: Wayne Lin <Wayne.Lin@amd.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Fangzhi Zuo <Jerry.Zuo@amd.com>
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Imre Deak <imre.deak@intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Sean Paul <sean@poorly.run>
> > ---
> >  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  56 +-
> >  .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 107 +--
> >  .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  85 +--
> >  .../amd/display/include/link_service_types.h  |   7 +
> >  drivers/gpu/drm/display/drm_dp_mst_topology.c | 699 ++++++------------
> >  drivers/gpu/drm/i915/display/intel_dp_mst.c   |  64 +-
> >  drivers/gpu/drm/i915/display/intel_hdcp.c     |  24 +-
> >  drivers/gpu/drm/nouveau/dispnv50/disp.c       | 163 ++--
> >  include/drm/display/drm_dp_mst_helper.h       | 178 ++---
> >  9 files changed, 536 insertions(+), 847 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index ac8648e3c1c9..93d572ea3c48 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -7378,6 +7378,7 @@ static int dm_encoder_helper_atomic_check(struct
> > drm_encoder *encoder,
> >         const struct drm_display_mode *adjusted_mode = &crtc_state-
> > > adjusted_mode;
> >         struct drm_dp_mst_topology_mgr *mst_mgr;
> >         struct drm_dp_mst_port *mst_port;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         enum dc_color_depth color_depth;
> >         int clock, bpp = 0;
> >         bool is_y420 = false;
> > @@ -7391,6 +7392,13 @@ static int
> > dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
> >         if (!crtc_state->connectors_changed && !crtc_state-
> > > mode_changed)
> >                 return 0;
> > 
> > +       mst_state = drm_atomic_get_mst_topology_state(state, mst_mgr);
> > +       if (IS_ERR(mst_state))
> > +               return PTR_ERR(mst_state);
> > +
> > +       if (!mst_state->pbn_div)
> > +               mst_state->pbn_div =
> > dm_mst_get_pbn_divider(aconnector->mst_port->dc_link);
> > +
> >         if (!state->duplicated) {
> >                 int max_bpc = conn_state->max_requested_bpc;
> >                 is_y420 = drm_mode_is_420_also(&connector->display_info,
> > adjusted_mode) &&
> > @@ -7402,11 +7410,10 @@ static int
> > dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
> >                 clock = adjusted_mode->clock;
> >                 dm_new_connector_state->pbn =
> > drm_dp_calc_pbn_mode(clock, bpp, false);
> >         }
> > -       dm_new_connector_state->vcpi_slots =
> > drm_dp_atomic_find_time_slots(state,
> > -
> > mst_mgr,
> > -
> > mst_port,
> > -
> > dm_new_connector_state->pbn,
> > -
> > dm_mst_get_pbn_divider(aconnector->dc_link));
> > +
> > +       dm_new_connector_state->vcpi_slots =
> > +               drm_dp_atomic_find_time_slots(state, mst_mgr, mst_port,
> > +                                             dm_new_connector_state-
> > >pbn);
> >         if (dm_new_connector_state->vcpi_slots < 0) {
> >                 DRM_DEBUG_ATOMIC("failed finding vcpi slots: %d\n",
> > (int)dm_new_connector_state->vcpi_slots);
> >                 return dm_new_connector_state->vcpi_slots;
> > @@ -7476,18 +7483,12 @@ static int
> > dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state,
> >                         dm_conn_state->pbn = pbn;
> >                         dm_conn_state->vcpi_slots = slot_num;
> > 
> > -                       drm_dp_mst_atomic_enable_dsc(state,
> > -                                                    aconnector->port,
> > -                                                    dm_conn_state->pbn,
> > -                                                    0,
> > +                       drm_dp_mst_atomic_enable_dsc(state, aconnector-
> > > port, dm_conn_state->pbn,
> >                                                      false);
> >                         continue;
> >                 }
> > 
> > -               vcpi = drm_dp_mst_atomic_enable_dsc(state,
> > -                                                   aconnector->port,
> > -                                                   pbn, pbn_div,
> > -                                                   true);
> > +               vcpi = drm_dp_mst_atomic_enable_dsc(state, aconnector-
> > > port, pbn, true);
> >                 if (vcpi < 0)
> >                         return vcpi;
> > 
> > @@ -10943,8 +10944,6 @@ static int amdgpu_dm_atomic_check(struct
> > drm_device *dev,
> >         struct dm_crtc_state *dm_old_crtc_state, *dm_new_crtc_state;
> >  #if defined(CONFIG_DRM_AMD_DC_DCN)
> >         struct dsc_mst_fairness_vars vars[MAX_PIPES];
> > -       struct drm_dp_mst_topology_state *mst_state;
> > -       struct drm_dp_mst_topology_mgr *mgr;
> >  #endif
> > 
> >         trace_amdgpu_dm_atomic_check_begin(state);
> > @@ -11180,33 +11179,6 @@ static int amdgpu_dm_atomic_check(struct
> > drm_device *dev,
> >                 lock_and_validation_needed = true;
> >         }
> > 
> > -#if defined(CONFIG_DRM_AMD_DC_DCN)
> > -       /* set the slot info for each mst_state based on the link encoding
> > format */
> > -       for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> > -               struct amdgpu_dm_connector *aconnector;
> > -               struct drm_connector *connector;
> > -               struct drm_connector_list_iter iter;
> > -               u8 link_coding_cap;
> > -
> > -               if (!mgr->mst_state )
> > -                       continue;
> > -
> > -               drm_connector_list_iter_begin(dev, &iter);
> > -               drm_for_each_connector_iter(connector, &iter) {
> > -                       int id = connector->index;
> > -
> > -                       if (id == mst_state->mgr->conn_base_id) {
> > -                               aconnector =
> > to_amdgpu_dm_connector(connector);
> > -                               link_coding_cap =
> > dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link);
> > -                               drm_dp_mst_update_slots(mst_state,
> > link_coding_cap);
> > -
> > -                               break;
> > -                       }
> > -               }
> > -               drm_connector_list_iter_end(&iter);
> > -
> > -       }
> > -#endif
> >         /**
> >          * Streams and planes are reset when there are changes that affect
> >          * bandwidth. Anything that affects bandwidth needs to go through
> > diff --git
> > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > index 1eaacab0334b..f843fd86787f 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > @@ -27,6 +27,7 @@
> >  #include <linux/acpi.h>
> >  #include <linux/i2c.h>
> > 
> > +#include <drm/drm_atomic.h>
> >  #include <drm/drm_probe_helper.h>
> >  #include <drm/amdgpu_drm.h>
> >  #include <drm/drm_edid.h>
> > @@ -154,40 +155,32 @@ enum dc_edid_status
> > dm_helpers_parse_edid_caps(
> >  }
> > 
> >  static void
> > -fill_dc_mst_payload_table_from_drm(struct amdgpu_dm_connector
> > *aconnector,
> > -                                  struct
> > dc_dp_mst_stream_allocation_table
> > *proposed_table)
> > +fill_dc_mst_payload_table_from_drm(struct drm_dp_mst_topology_state
> > *mst_state,
> > +                                  struct amdgpu_dm_connector *aconnector,
> > +                                  struct
> > dc_dp_mst_stream_allocation_table
> > *table)
> >  {
> > +       struct dc_dp_mst_stream_allocation_table new_table = { 0 };
> > +       struct dc_dp_mst_stream_allocation *sa;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         int i;
> > -       struct drm_dp_mst_topology_mgr *mst_mgr =
> > -                       &aconnector->mst_port->mst_mgr;
> > 
> > -       mutex_lock(&mst_mgr->payload_lock);
> > -
> > -       proposed_table->stream_count = 0;
> > -
> > -       /* number of active streams */
> > -       for (i = 0; i < mst_mgr->max_payloads; i++) {
> > -               if (mst_mgr->payloads[i].num_slots == 0)
> > -                       break; /* end of vcp_id table */
> > -
> > -               ASSERT(mst_mgr->payloads[i].payload_state !=
> > -                               DP_PAYLOAD_DELETE_LOCAL);
> > -
> > -               if (mst_mgr->payloads[i].payload_state ==
> > DP_PAYLOAD_LOCAL ||
> > -                       mst_mgr->payloads[i].payload_state ==
> > -                                       DP_PAYLOAD_REMOTE) {
> > -
> > -                       struct dc_dp_mst_stream_allocation *sa =
> > -                                       &proposed_table-
> > > stream_allocations[
> > -                                               proposed_table-
> > > stream_count];
> > -
> > -                       sa->slot_count = mst_mgr->payloads[i].num_slots;
> > -                       sa->vcp_id = mst_mgr->proposed_vcpis[i]->vcpi;
> > -                       proposed_table->stream_count++;
> > -               }
> > +       /* Copy over payloads */
> > +       list_for_each_entry(payload, &mst_state->payloads, next) {
> > +               if (payload->delete)
> > +                       continue;
> > +
> > +               sa =
> > &new_table.stream_allocations[new_table.stream_count];
> > +               sa->slot_count = payload->time_slots;
> > +               sa->vcp_id = payload->vcpi;
> > +               sa->port = payload->port;
> > +               drm_dp_mst_get_port_malloc(sa->port);
> > +               new_table.stream_count++;
> >         }
> > 
> > -       mutex_unlock(&mst_mgr->payload_lock);
> > +       /* Release the old table, and copy over the new one */
> > +       for (i = 0; i < table->stream_count; i++)
> > +               drm_dp_mst_put_port_malloc(table-
> > > stream_allocations[i].port);
> > +       *table = new_table;
> >  }
> > 
> >  void dm_helpers_dp_update_branch_info(
> > @@ -205,11 +198,9 @@ bool
> > dm_helpers_dp_mst_write_payload_allocation_table(
> >                 bool enable)
> >  {
> >         struct amdgpu_dm_connector *aconnector;
> > -       struct dm_connector_state *dm_conn_state;
> > +       struct drm_dp_mst_topology_state *mst_state;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         struct drm_dp_mst_topology_mgr *mst_mgr;
> > -       struct drm_dp_mst_port *mst_port;
> > -       bool ret;
> > -       u8 link_coding_cap = DP_8b_10b_ENCODING;
> > 
> >         aconnector = (struct amdgpu_dm_connector *)stream-
> > > dm_stream_context;
> >         /* Accessing the connector state is required for vcpi_slots
> > allocation
> > @@ -220,40 +211,21 @@ bool
> > dm_helpers_dp_mst_write_payload_allocation_table(
> >         if (!aconnector || !aconnector->mst_port)
> >                 return false;
> > 
> > -       dm_conn_state = to_dm_connector_state(aconnector->base.state);
> > -
> >         mst_mgr = &aconnector->mst_port->mst_mgr;
> > -
> > -       if (!mst_mgr->mst_state)
> > -               return false;
> > -
> > -       mst_port = aconnector->port;
> > -
> > -#if defined(CONFIG_DRM_AMD_DC_DCN)
> > -       link_coding_cap =
> > dc_link_dp_mst_decide_link_encoding_format(aconnector->dc_link);
> > -#endif
> > -
> > -       if (enable) {
> > -
> > -               ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port,
> > -                                              dm_conn_state->pbn,
> > -                                              dm_conn_state->vcpi_slots);
> > -               if (!ret)
> > -                       return false;
> > -
> > -       } else {
> > -               drm_dp_mst_reset_vcpi_slots(mst_mgr, mst_port);
> > -       }
> > +       mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
> > 
> >         /* It's OK for this to fail */
> > -       drm_dp_update_payload_part1(mst_mgr, (link_coding_cap ==
> > DP_CAP_ANSI_128B132B) ? 0:1);
> > +       payload = drm_atomic_get_mst_payload_state(mst_state,
> > aconnector->port);
> > +       if (enable)
> > +               drm_dp_add_payload_part1(mst_mgr, mst_state, payload);
> > +       else
> > +               drm_dp_remove_payload(mst_mgr, mst_state, payload);
> > 
> >         /* mst_mgr->->payloads are VC payload notify MST branch using
> > DPCD or
> >          * AUX message. The sequence is slot 1-63 allocated sequence for
> > each
> >          * stream. AMD ASIC stream slot allocation should follow the same
> >          * sequence. copy DRM MST allocation to dc */
> > -
> > -       fill_dc_mst_payload_table_from_drm(aconnector, proposed_table);
> > +       fill_dc_mst_payload_table_from_drm(mst_state, aconnector,
> > proposed_table);
> > 
> >         return true;
> >  }
> > @@ -310,26 +282,23 @@ bool
> > dm_helpers_dp_mst_send_payload_allocation(
> >                 bool enable)
> >  {
> >         struct amdgpu_dm_connector *aconnector;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct drm_dp_mst_topology_mgr *mst_mgr;
> > -       struct drm_dp_mst_port *mst_port;
> > +       struct drm_dp_mst_atomic_payload *payload;
> > 
> >         aconnector = (struct amdgpu_dm_connector *)stream-
> > > dm_stream_context;
> > 
> >         if (!aconnector || !aconnector->mst_port)
> >                 return false;
> > 
> > -       mst_port = aconnector->port;
> > -
> >         mst_mgr = &aconnector->mst_port->mst_mgr;
> > -
> > -       if (!mst_mgr->mst_state)
> > -               return false;
> > +       mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
> > 
> >         /* It's OK for this to fail */
> > -       drm_dp_update_payload_part2(mst_mgr);
> > -
> > -       if (!enable)
> > -               drm_dp_mst_deallocate_vcpi(mst_mgr, mst_port);
> > +       if (enable) {
> > +               payload = drm_atomic_get_mst_payload_state(mst_state,
> > aconnector->port);
> > +               drm_dp_add_payload_part2(mst_mgr, mst_state-
> > > base.state, payload);
> > +       }
> > 
> >         return true;
> >  }
> > diff --git
> > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > index b447c453b58d..18de4a98df40 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > +++
> > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> > @@ -501,15 +501,8 @@ void amdgpu_dm_initialize_dp_connector(struct
> > amdgpu_display_manager *dm,
> > 
> >         dc_link_dp_get_max_link_enc_cap(aconnector->dc_link,
> > &max_link_enc_cap);
> >         aconnector->mst_mgr.cbs = &dm_mst_cbs;
> > -       drm_dp_mst_topology_mgr_init(
> > -               &aconnector->mst_mgr,
> > -               adev_to_drm(dm->adev),
> > -               &aconnector->dm_dp_aux.aux,
> > -               16,
> > -               4,
> > -               max_link_enc_cap.lane_count,
> > -
> >         drm_dp_bw_code_to_link_rate(max_link_enc_cap.link_rate),
> > -               aconnector->connector_id);
> > +       drm_dp_mst_topology_mgr_init(&aconnector->mst_mgr,
> > adev_to_drm(dm->adev),
> > +                                    &aconnector->dm_dp_aux.aux, 16, 4,
> > aconnector->connector_id);
> > 
> >         drm_connector_attach_dp_subconnector_property(&aconnector-
> > > base);
> >  }
> > @@ -614,6 +607,7 @@ static int bpp_x16_from_pbn(struct
> > dsc_mst_fairness_params param, int pbn)
> >  }
> > 
> >  static void increase_dsc_bpp(struct drm_atomic_state *state,
> > +                            struct drm_dp_mst_topology_state *mst_state,
> >                              struct dc_link *dc_link,
> >                              struct dsc_mst_fairness_params *params,
> >                              struct dsc_mst_fairness_vars *vars,
> > @@ -626,12 +620,9 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >         int min_initial_slack;
> >         int next_index;
> >         int remaining_to_increase = 0;
> > -       int pbn_per_timeslot;
> >         int link_timeslots_used;
> >         int fair_pbn_alloc;
> > 
> > -       pbn_per_timeslot = dm_mst_get_pbn_divider(dc_link);
> > -
> >         for (i = 0; i < count; i++) {
> >                 if (vars[i + k].dsc_enabled) {
> >                         initial_slack[i] =
> > @@ -662,17 +653,17 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                 link_timeslots_used = 0;
> > 
> >                 for (i = 0; i < count; i++)
> > -                       link_timeslots_used += DIV_ROUND_UP(vars[i +
> > k].pbn, pbn_per_timeslot);
> > +                       link_timeslots_used += DIV_ROUND_UP(vars[i +
> > k].pbn, mst_state->pbn_div);
> > 
> > -               fair_pbn_alloc = (63 - link_timeslots_used) /
> > remaining_to_increase * pbn_per_timeslot;
> > +               fair_pbn_alloc =
> > +                       (63 - link_timeslots_used) / remaining_to_increase
> > *
> > mst_state->pbn_div;
> > 
> >                 if (initial_slack[next_index] > fair_pbn_alloc) {
> >                         vars[next_index].pbn += fair_pbn_alloc;
> >                         if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -                                                        
> > pbn_per_timeslot) <
> > 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                 return;
> >                         if (!drm_dp_mst_atomic_check(state)) {
> >                                 vars[next_index].bpp_x16 =
> > bpp_x16_from_pbn(params[next_index], vars[next_index].pbn);
> > @@ -681,8 +672,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                                 if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -
> > pbn_per_timeslot) < 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                         return;
> >                         }
> >                 } else {
> > @@ -690,8 +680,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                         if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -                                                        
> > pbn_per_timeslot) <
> > 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                 return;
> >                         if (!drm_dp_mst_atomic_check(state)) {
> >                                 vars[next_index].bpp_x16 =
> > params[next_index].bw_range.max_target_bpp_x16;
> > @@ -700,8 +689,7 @@ static void increase_dsc_bpp(struct
> > drm_atomic_state *state,
> >                                 if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -
> > pbn_per_timeslot) < 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                         return;
> >                         }
> >                 }
> > @@ -757,8 +745,7 @@ static void try_disable_dsc(struct drm_atomic_state
> > *state,
> >                 if (drm_dp_atomic_find_time_slots(state,
> >                                                   params[next_index].port-
> > > mgr,
> >                                                   params[next_index].port,
> > -                                                 vars[next_index].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +                                                 vars[next_index].pbn) <
> > 0)
> >                         return;
> > 
> >                 if (!drm_dp_mst_atomic_check(state)) {
> > @@ -769,8 +756,7 @@ static void try_disable_dsc(struct drm_atomic_state
> > *state,
> >                         if (drm_dp_atomic_find_time_slots(state,
> > 
> > params[next_index].port->mgr,
> > 
> > params[next_index].port,
> > -
> > vars[next_index].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +
> > vars[next_index].pbn) < 0)
> >                                 return;
> >                 }
> > 
> > @@ -783,17 +769,27 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                                              struct dc_state *dc_state,
> >                                              struct dc_link *dc_link,
> >                                              struct dsc_mst_fairness_vars
> > *vars,
> > +                                            struct
> > drm_dp_mst_topology_mgr
> > *mgr,
> >                                              int *link_vars_start_index)
> >  {
> > -       int i, k;
> >         struct dc_stream_state *stream;
> >         struct dsc_mst_fairness_params params[MAX_PIPES];
> >         struct amdgpu_dm_connector *aconnector;
> > +       struct drm_dp_mst_topology_state *mst_state =
> > drm_atomic_get_mst_topology_state(state, mgr);
> >         int count = 0;
> > +       int i, k;
> >         bool debugfs_overwrite = false;
> > 
> >         memset(params, 0, sizeof(params));
> > 
> > +       if (IS_ERR(mst_state))
> > +               return false;
> > +
> > +       mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link);
> > +#if defined(CONFIG_DRM_AMD_DC_DCN)
> > +       drm_dp_mst_update_slots(mst_state,
> > dc_link_dp_mst_decide_link_encoding_format(dc_link));
> > +#endif
> > +
> >         /* Set up params */
> >         for (i = 0; i < dc_state->stream_count; i++) {
> >                 struct dc_dsc_policy dsc_policy = {0};
> > @@ -852,11 +848,8 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                 vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> >                 vars[i + k].dsc_enabled = false;
> >                 vars[i + k].bpp_x16 = 0;
> > -               if (drm_dp_atomic_find_time_slots(state,
> > -                                                 params[i].port->mgr,
> > -                                                 params[i].port,
> > -                                                 vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +               if (drm_dp_atomic_find_time_slots(state, params[i].port-
> > > mgr, params[i].port,
> > +                                                 vars[i + k].pbn) < 0)
> >                         return false;
> >         }
> >         if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) {
> > @@ -870,21 +863,15 @@ static bool
> > compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
> >                         vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.min_kbps);
> >                         vars[i + k].dsc_enabled = true;
> >                         vars[i + k].bpp_x16 =
> > params[i].bw_range.min_target_bpp_x16;
> > -                       if (drm_dp_atomic_find_time_slots(state,
> > -                                                         params[i].port-
> > >mgr,
> > -                                                         params[i].port,
> > -                                                         vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > params[i].port->mgr,
> > +                                                         params[i].port,
> > vars[i
> > + k].pbn) < 0)
> >                                 return false;
> >                 } else {
> >                         vars[i + k].pbn =
> > kbps_to_peak_pbn(params[i].bw_range.stream_kbps);
> >                         vars[i + k].dsc_enabled = false;
> >                         vars[i + k].bpp_x16 = 0;
> > -                       if (drm_dp_atomic_find_time_slots(state,
> > -                                                         params[i].port-
> > >mgr,
> > -                                                         params[i].port,
> > -                                                         vars[i + k].pbn,
> > -
> > dm_mst_get_pbn_divider(dc_link)) < 0)
> > +                       if (drm_dp_atomic_find_time_slots(state,
> > params[i].port->mgr,
> > +                                                         params[i].port,
> > vars[i
> > + k].pbn) < 0)
> >                                 return false;
> >                 }
> >         }
> > @@ -892,7 +879,7 @@ static bool compute_mst_dsc_configs_for_link(struct
> > drm_atomic_state *state,
> >                 return false;
> > 
> >         /* Optimize degree of compression */
> > -       increase_dsc_bpp(state, dc_link, params, vars, count, k);
> > +       increase_dsc_bpp(state, mst_state, dc_link, params, vars, count,
> > k);
> > 
> >         try_disable_dsc(state, dc_link, params, vars, count, k);
> > 
> > @@ -1036,9 +1023,9 @@ bool compute_mst_dsc_configs_for_state(struct
> > drm_atomic_state *state,
> >                         continue;
> > 
> >                 mutex_lock(&aconnector->mst_mgr.lock);
> > -               if (!compute_mst_dsc_configs_for_link(state, dc_state,
> > stream->link,
> > -                       vars, &link_vars_start_index)) {
> > -                       mutex_unlock(&aconnector->mst_mgr.lock);
> > +               if (!compute_mst_dsc_configs_for_link(state, dc_state,
> > stream->link, vars,
> > +                                                     &aconnector-
> > >mst_mgr,
> > +                                                    
> > &link_vars_start_index)) {
> 
> Should still keep "mutex_unlock(&aconnector->mst_mgr.lock);" here.
> 
> >                         return false;
> >                 }
> >                 mutex_unlock(&aconnector->mst_mgr.lock);
> > @@ -1095,10 +1082,8 @@ static bool
> >                         continue;
> > 
> >                 mutex_lock(&aconnector->mst_mgr.lock);
> > -               if (!compute_mst_dsc_configs_for_link(state,
> > -                                                     dc_state,
> > -                                                     stream->link,
> > -                                                     vars,
> > +               if (!compute_mst_dsc_configs_for_link(state, dc_state,
> > stream->link, vars,
> > +                                                     &aconnector-
> > >mst_mgr,
> >                                                      
> > &link_vars_start_index)) {
> >                         mutex_unlock(&aconnector->mst_mgr.lock);
> >                         return false;
> > diff --git a/drivers/gpu/drm/amd/display/include/link_service_types.h
> > b/drivers/gpu/drm/amd/display/include/link_service_types.h
> > index 91bffc5bf52c..143baab54b41 100644
> > --- a/drivers/gpu/drm/amd/display/include/link_service_types.h
> > +++ b/drivers/gpu/drm/amd/display/include/link_service_types.h
> > @@ -250,12 +250,19 @@ union dpcd_training_lane_set {
> >   * _ONLY_ be filled out from DM and then passed to DC, do NOT use these
> > for _any_ kind of atomic
> >   * state calculations in DM, or you will break something.
> >   */
> > +
> > +struct drm_dp_mst_port;
> > +
> >  /* DP MST stream allocation (payload bandwidth number) */
> >  struct dc_dp_mst_stream_allocation {
> >         uint8_t vcp_id;
> >         /* number of slots required for the DP stream in
> >          * transport packet */
> >         uint8_t slot_count;
> > +       /* The MST port this is on, this is used to associate DC MST
> > payloads
> > with their
> > +        * respective DRM payloads allocations, and can be ignored on non-
> > Linux.
> > +        */
> 
> Is it necessary for adding this new member? Since this is for setting the DC
> HW and not relating to drm.
> 
> > +       struct drm_dp_mst_port *port;
> >  };
> > 
> >  /* DP MST stream allocation table */
> > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > index 10d26a7e028c..d8e32269585b 100644
> > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > @@ -67,8 +67,7 @@ static bool dump_dp_payload_table(struct
> > drm_dp_mst_topology_mgr *mgr,
> >  static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port
> > *port);
> > 
> >  static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                    int id,
> > -                                    struct drm_dp_payload *payload);
> > +                                    int id, u8 start_slot, u8 num_slots);
> > 
> >  static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> >                                  struct drm_dp_mst_port *port,
> > @@ -1234,57 +1233,6 @@ build_query_stream_enc_status(struct
> > drm_dp_sideband_msg_tx *msg, u8 stream_id,
> >         return 0;
> >  }
> > 
> > -static int drm_dp_mst_assign_payload_id(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                       struct drm_dp_vcpi *vcpi)
> > -{
> > -       int ret, vcpi_ret;
> > -
> > -       mutex_lock(&mgr->payload_lock);
> > -       ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads
> > + 1);
> > -       if (ret > mgr->max_payloads) {
> > -               ret = -EINVAL;
> > -               drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
> > -               goto out_unlock;
> > -       }
> > -
> > -       vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr-
> > > max_payloads + 1);
> > -       if (vcpi_ret > mgr->max_payloads) {
> > -               ret = -EINVAL;
> > -               drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
> > -               goto out_unlock;
> > -       }
> > -
> > -       set_bit(ret, &mgr->payload_mask);
> > -       set_bit(vcpi_ret, &mgr->vcpi_mask);
> > -       vcpi->vcpi = vcpi_ret + 1;
> > -       mgr->proposed_vcpis[ret - 1] = vcpi;
> > -out_unlock:
> > -       mutex_unlock(&mgr->payload_lock);
> > -       return ret;
> > -}
> > -
> > -static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                     int vcpi)
> > -{
> > -       int i;
> > -
> > -       if (vcpi == 0)
> > -               return;
> > -
> > -       mutex_lock(&mgr->payload_lock);
> > -       drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
> > -       clear_bit(vcpi - 1, &mgr->vcpi_mask);
> > -
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -               if (mgr->proposed_vcpis[i] &&
> > -                   mgr->proposed_vcpis[i]->vcpi == vcpi) {
> > -                       mgr->proposed_vcpis[i] = NULL;
> > -                       clear_bit(i + 1, &mgr->payload_mask);
> > -               }
> > -       }
> > -       mutex_unlock(&mgr->payload_lock);
> > -}
> > -
> >  static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
> >                               struct drm_dp_sideband_msg_tx *txmsg)
> >  {
> > @@ -1737,7 +1685,7 @@ drm_dp_mst_dump_port_topology_history(struct
> > drm_dp_mst_port *port) {}
> >  #define save_port_topology_ref(port, type)
> >  #endif
> > 
> > -static struct drm_dp_mst_atomic_payload *
> > +struct drm_dp_mst_atomic_payload *
> >  drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state
> > *state,
> >                                  struct drm_dp_mst_port *port)
> >  {
> > @@ -1749,6 +1697,7 @@ drm_atomic_get_mst_payload_state(struct
> > drm_dp_mst_topology_state *state,
> > 
> >         return NULL;
> >  }
> > +EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
> > 
> >  static void drm_dp_destroy_mst_branch_device(struct kref *kref)
> >  {
> > @@ -3272,6 +3221,8 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >                 struct drm_dp_mst_port *port,
> >                 struct drm_dp_query_stream_enc_status_ack_reply *status)
> >  {
> > +       struct drm_dp_mst_topology_state *state;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         struct drm_dp_sideband_msg_tx *txmsg;
> >         u8 nonce[7];
> >         int ret;
> > @@ -3288,6 +3239,10 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> > 
> >         get_random_bytes(nonce, sizeof(nonce));
> > 
> > +       drm_modeset_lock(&mgr->base.lock, NULL);
> > +       state = to_drm_dp_mst_topology_state(mgr->base.state);
> > +       payload = drm_atomic_get_mst_payload_state(state, port);
> > +
> >         /*
> >          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS
> > message
> >          *  transaction at the MST Branch device directly connected to the
> > @@ -3295,7 +3250,7 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >          */
> >         txmsg->dst = mgr->mst_primary;
> > 
> > -       build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
> > +       build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
> > 
> >         drm_dp_queue_down_tx(mgr, txmsg);
> > 
> > @@ -3312,6 +3267,7 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
> > 
> >  out:
> > +       drm_modeset_unlock(&mgr->base.lock);
> >         drm_dp_mst_topology_put_port(port);
> >  out_get_port:
> >         kfree(txmsg);
> > @@ -3320,219 +3276,161 @@ int
> > drm_dp_send_query_stream_enc_status(struct
> > drm_dp_mst_topology_mgr *mgr,
> >  EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
> > 
> >  static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                      int id,
> > -                                      struct drm_dp_payload *payload)
> > +                                      struct drm_dp_mst_atomic_payload
> > *payload)
> >  {
> > -       int ret;
> > -
> > -       ret = drm_dp_dpcd_write_payload(mgr, id, payload);
> > -       if (ret < 0) {
> > -               payload->payload_state = 0;
> > -               return ret;
> > -       }
> > -       payload->payload_state = DP_PAYLOAD_LOCAL;
> > -       return 0;
> > +       return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload-
> > > vc_start_slot,
> > +                                        payload->time_slots);
> >  }
> > 
> >  static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                      struct drm_dp_mst_port *port,
> > -                                      int id,
> > -                                      struct drm_dp_payload *payload)
> > +                                      struct drm_dp_mst_atomic_payload
> > *payload)
> >  {
> >         int ret;
> > +       struct drm_dp_mst_port *port =
> > drm_dp_mst_topology_get_port_validated(mgr, payload->port);
> > 
> > -       ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
> > -       if (ret < 0)
> > -               return ret;
> > -       payload->payload_state = DP_PAYLOAD_REMOTE;
> > +       if (!port)
> > +               return -EIO;
> > +
> > +       ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload-
> > > pbn);
> > +       drm_dp_mst_topology_put_port(port);
> >         return ret;
> >  }
> > 
> >  static int drm_dp_destroy_payload_step1(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                       struct drm_dp_mst_port *port,
> > -                                       int id,
> > -                                       struct drm_dp_payload *payload)
> > +                                       struct drm_dp_mst_topology_state
> > *mst_state,
> > +                                       struct drm_dp_mst_atomic_payload
> > *payload)
> >  {
> > +
> >         drm_dbg_kms(mgr->dev, "\n");
> > -       /* it's okay for these to fail */
> > -       if (port) {
> > -               drm_dp_payload_send_msg(mgr, port, id, 0);
> > -       }
> > 
> > -       drm_dp_dpcd_write_payload(mgr, id, payload);
> > -       payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
> > -       return 0;
> > -}
> > +       /* it's okay for these to fail */
> > +       drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
> > +       drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload-
> > > vc_start_slot, 0);
> > 
> > -static int drm_dp_destroy_payload_step2(struct
> > drm_dp_mst_topology_mgr *mgr,
> > -                                       int id,
> > -                                       struct drm_dp_payload *payload)
> > -{
> > -       payload->payload_state = 0;
> >         return 0;
> >  }
> > 
> >  /**
> > - * drm_dp_update_payload_part1() - Execute payload update part 1
> > - * @mgr: manager to use.
> > - * @start_slot: this is the cur slot
> > + * drm_dp_add_payload_part1() - Execute payload update part 1
> > + * @mgr: Manager to use.
> > + * @mst_state: The MST atomic state
> > + * @payload: The payload to write
> >   *
> > - * NOTE: start_slot is a temporary workaround for non-atomic drivers,
> > - * this will be removed when non-atomic mst helpers are moved out of the
> > helper
> > + * Determines the starting time slot for the given payload, and programs
> > the
> > VCPI for this payload
> > + * into hardware.
> >   *
> > - * This iterates over all proposed virtual channels, and tries to
> > - * allocate space in the link for them. For 0->slots transitions,
> > - * this step just writes the VCPI to the MST device. For slots->0
> > - * transitions, this writes the updated VCPIs and removes the
> > - * remote VC payloads.
> > + * After calling this, the driver should generate ACT and payload
> > packets.
> > Note that the driver may
> > + * generate ACT once per payload change, or only once after all new
> > payloads in a given atomic state
> > + * have been added.
> >   *
> > - * after calling this the driver should generate ACT and payload
> > - * packets.
> > + * Returns: 0 on success, error code on failure. In the event that this
> > fails,
> > + * @payload.vc_start_slot will also be set to -1.
> >   */
> > -int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr
> > *mgr, int start_slot)
> > +int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_dp_mst_topology_state *mst_state,
> > +                            struct drm_dp_mst_atomic_payload *payload)
> >  {
> > -       struct drm_dp_payload req_payload;
> >         struct drm_dp_mst_port *port;
> > -       int i, j;
> > -       int cur_slots = start_slot;
> > -
> > -       mutex_lock(&mgr->payload_lock);
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -               struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> > -               struct drm_dp_payload *payload = &mgr->payloads[i];
> > -               bool put_port = false;
> > -
> > -               /* solve the current payloads - compare to the hw ones
> > -                  - update the hw view */
> > -               req_payload.start_slot = cur_slots;
> > -               if (vcpi) {
> > -                       port = container_of(vcpi, struct drm_dp_mst_port,
> > -                                           vcpi);
> > -
> > -                       /* Validated ports don't matter if we're releasing
> > -                        * VCPI
> > -                        */
> > -                       if (vcpi->num_slots) {
> > -                               port =
> > drm_dp_mst_topology_get_port_validated(
> > -                                   mgr, port);
> > -                               if (!port) {
> > -                                       if (vcpi->num_slots == payload-
> > > num_slots) {
> > -                                               cur_slots += vcpi-
> > >num_slots;
> > -                                               payload->start_slot =
> > req_payload.start_slot;
> > -                                               continue;
> > -                                       } else {
> > -                                               drm_dbg_kms(mgr->dev,
> > -                                                           "Fail:set
> > payload to
> > invalid sink");
> > -                                               mutex_unlock(&mgr-
> > > payload_lock);
> > -                                               return -EINVAL;
> > -                                       }
> > -                               }
> > -                               put_port = true;
> > -                       }
> > +       int ret;
> > 
> > -                       req_payload.num_slots = vcpi->num_slots;
> > -                       req_payload.vcpi = vcpi->vcpi;
> > -               } else {
> > -                       port = NULL;
> > -                       req_payload.num_slots = 0;
> > -               }
> > +       port = drm_dp_mst_topology_get_port_validated(mgr, payload-
> > > port);
> > +       if (!port)
> > +               return 0;
> > 
> > -               payload->start_slot = req_payload.start_slot;
> > -               /* work out what is required to happen with this payload
> > */
> > -               if (payload->num_slots != req_payload.num_slots) {
> > -
> > -                       /* need to push an update for this payload */
> > -                       if (req_payload.num_slots) {
> > -                               drm_dp_create_payload_step1(mgr, vcpi-
> > > vcpi,
> > -                                                           &req_payload);
> > -                               payload->num_slots =
> > req_payload.num_slots;
> > -                               payload->vcpi = req_payload.vcpi;
> > -
> > -                       } else if (payload->num_slots) {
> > -                               payload->num_slots = 0;
> > -                               drm_dp_destroy_payload_step1(mgr, port,
> > -                                                            payload-
> > >vcpi,
> > -                                                            payload);
> > -                               req_payload.payload_state =
> > -                                       payload->payload_state;
> > -                               payload->start_slot = 0;
> > -                       }
> > -                       payload->payload_state =
> > req_payload.payload_state;
> > -               }
> > -               cur_slots += req_payload.num_slots;
> > +       if (mgr->payload_count == 0)
> > +               mgr->next_start_slot = mst_state->start_slot;
> > 
> > -               if (put_port)
> > -                       drm_dp_mst_topology_put_port(port);
> > +       payload->vc_start_slot = mgr->next_start_slot;
> > +       ret = drm_dp_create_payload_step1(mgr, payload);
> > +       drm_dp_mst_topology_put_port(port);
> > +       if (ret < 0) {
> > +               drm_warn(mgr->dev, "Failed to create MST payload for port
> > %p: %d\n",
> > +                        payload->port, ret);
> > +               payload->vc_start_slot = -1;
> > +               return ret;
> >         }
> > 
> > -       for (i = 0; i < mgr->max_payloads; /* do nothing */) {
> > -               if (mgr->payloads[i].payload_state !=
> > DP_PAYLOAD_DELETE_LOCAL) {
> > -                       i++;
> > -                       continue;
> > -               }
> > +       mgr->payload_count++;
> > +       mgr->next_start_slot += payload->time_slots;
> > 
> > -               drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
> > -               for (j = i; j < mgr->max_payloads - 1; j++) {
> > -                       mgr->payloads[j] = mgr->payloads[j + 1];
> > -                       mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j +
> > 1];
> > +       return 0;
> > +}
> > +EXPORT_SYMBOL(drm_dp_add_payload_part1);
> > 
> > -                       if (mgr->proposed_vcpis[j] &&
> > -                           mgr->proposed_vcpis[j]->num_slots) {
> > -                               set_bit(j + 1, &mgr->payload_mask);
> > -                       } else {
> > -                               clear_bit(j + 1, &mgr->payload_mask);
> > -                       }
> > -               }
> > +/**
> > + * drm_dp_remove_payload() - Remove an MST payload
> > + * @mgr: Manager to use.
> > + * @mst_state: The MST atomic state
> > + * @payload: The payload to write
> > + *
> > + * Removes a payload from an MST topology if it was successfully assigned
> > a
> > start slot. Also updates
> > + * the starting time slots of all other payloads which would have been
> > shifted towards the start of
> > + * the VC table as a result.
> > + *
> > + * After calling this, the driver should generate ACT and payload
> > packets.
> > Note that the driver may
> > + * generate ACT once per payload change, or only once after all payloads
> > for
> > a given atomic state
> > + * have been removed.
> > + */
> > +void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
> > +                          struct drm_dp_mst_topology_state *mst_state,
> > +                          struct drm_dp_mst_atomic_payload *payload)
> > +{
> > +       struct drm_dp_mst_atomic_payload *pos;
> > 
> > -               memset(&mgr->payloads[mgr->max_payloads - 1], 0,
> > -                      sizeof(struct drm_dp_payload));
> > -               mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
> > -               clear_bit(mgr->max_payloads, &mgr->payload_mask);
> > +       /* We failed to make the payload, so nothing to do */
> > +       if (payload->vc_start_slot == -1)
> > +               return;
> > +
> > +       drm_dp_destroy_payload_step1(mgr, mst_state, payload);
> > +
> > +       list_for_each_entry(pos, &mst_state->payloads, next) {
> > +               if (pos != payload && pos->vc_start_slot > payload-
> > > vc_start_slot)
> > +                       pos->vc_start_slot -= payload->time_slots;
> >         }
> > -       mutex_unlock(&mgr->payload_lock);
> > +       payload->vc_start_slot = -1;
> > 
> > -       return 0;
> > +       mgr->payload_count--;
> > +       mgr->next_start_slot -= payload->time_slots;
> >  }
> > -EXPORT_SYMBOL(drm_dp_update_payload_part1);
> > +EXPORT_SYMBOL(drm_dp_remove_payload);
> > 
> >  /**
> > - * drm_dp_update_payload_part2() - Execute payload update part 2
> > - * @mgr: manager to use.
> > + * drm_dp_add_payload_part2() - Execute payload update part 2
> > + * @mgr: Manager to use.
> > + * @state: The global atomic state
> > + * @payload: The payload to update
> > + *
> > + * If @payload was successfully assigned a starting time slot by
> > drm_dp_add_payload_part1(), this
> > + * function will send the sideband messages to finish allocating this
> > payload.
> >   *
> > - * This iterates over all proposed virtual channels, and tries to
> > - * allocate space in the link for them. For 0->slots transitions,
> > - * this step writes the remote VC payload commands. For slots->0
> > - * this just resets some internal state.
> > + * Returns: 0 on success, negative error code on failure.
> >   */
> > -int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr
> > *mgr)
> > +int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_atomic_state *state,
> > +                            struct drm_dp_mst_atomic_payload *payload)
> >  {
> > -       struct drm_dp_mst_port *port;
> > -       int i;
> >         int ret = 0;
> > 
> > -       mutex_lock(&mgr->payload_lock);
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -
> > -               if (!mgr->proposed_vcpis[i])
> > -                       continue;
> > -
> > -               port = container_of(mgr->proposed_vcpis[i], struct
> > drm_dp_mst_port, vcpi);
> > +       /* Skip failed payloads */
> > +       if (payload->vc_start_slot == -1) {
> > +               drm_dbg_kms(state->dev, "Part 1 of payload creation for %s
> > failed, skipping part 2\n",
> > +                           payload->port->connector->name);
> > +               return -EIO;
> > +       }
> > 
> > -               drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr-
> > > payloads[i].payload_state);
> > -               if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL)
> > {
> > -                       ret = drm_dp_create_payload_step2(mgr, port, mgr-
> > > proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
> > -               } else if (mgr->payloads[i].payload_state ==
> > DP_PAYLOAD_DELETE_LOCAL) {
> > -                       ret = drm_dp_destroy_payload_step2(mgr, mgr-
> > > proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
> > -               }
> > -               if (ret) {
> > -                       mutex_unlock(&mgr->payload_lock);
> > -                       return ret;
> > -               }
> > +       ret = drm_dp_create_payload_step2(mgr, payload);
> > +       if (ret < 0) {
> > +               if (!payload->delete)
> > +                       drm_err(mgr->dev, "Step 2 of creating MST payload
> > for %p failed: %d\n",
> > +                               payload->port, ret);
> > +               else
> > +                       drm_dbg_kms(mgr->dev, "Step 2 of removing MST
> > payload for %p failed: %d\n",
> > +                                   payload->port, ret);
> >         }
> > -       mutex_unlock(&mgr->payload_lock);
> > -       return 0;
> > +
> > +       return ret;
> >  }
> > -EXPORT_SYMBOL(drm_dp_update_payload_part2);
> > +EXPORT_SYMBOL(drm_dp_add_payload_part2);
> > 
> >  static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> >                                  struct drm_dp_mst_port *port,
> > @@ -3712,7 +3610,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >         int ret = 0;
> >         struct drm_dp_mst_branch *mstb = NULL;
> > 
> > -       mutex_lock(&mgr->payload_lock);
> >         mutex_lock(&mgr->lock);
> >         if (mst_state == mgr->mst_state)
> >                 goto out_unlock;
> > @@ -3720,10 +3617,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >         mgr->mst_state = mst_state;
> >         /* set the device into MST mode */
> >         if (mst_state) {
> > -               struct drm_dp_payload reset_pay;
> > -               int lane_count;
> > -               int link_rate;
> > -
> >                 WARN_ON(mgr->mst_primary);
> > 
> >                 /* get dpcd info */
> > @@ -3734,16 +3627,6 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >                         goto out_unlock;
> >                 }
> > 
> > -               lane_count = min_t(int, mgr->dpcd[2] &
> > DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
> > -               link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr-
> > > dpcd[1]), mgr->max_link_rate);
> > -               mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
> > -                                                       link_rate,
> > -                                                       lane_count);
> > -               if (mgr->pbn_div == 0) {
> > -                       ret = -EINVAL;
> > -                       goto out_unlock;
> > -               }
> > -
> >                 /* add initial branch device at LCT 1 */
> >                 mstb = drm_dp_add_mst_branch_device(1, NULL);
> >                 if (mstb == NULL) {
> > @@ -3763,9 +3646,8 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >                 if (ret < 0)
> >                         goto out_unlock;
> > 
> > -               reset_pay.start_slot = 0;
> > -               reset_pay.num_slots = 0x3f;
> > -               drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
> > +               /* Write reset payload */
> > +               drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
> > 
> >                 queue_work(system_long_wq, &mgr->work);
> > 
> > @@ -3777,19 +3659,11 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> > drm_dp_mst_topology_mgr *mgr, bool ms
> >                 /* this can fail if the device is gone */
> >                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
> >                 ret = 0;
> > -               memset(mgr->payloads, 0,
> > -                      mgr->max_payloads * sizeof(mgr->payloads[0]));
> > -               memset(mgr->proposed_vcpis, 0,
> > -                      mgr->max_payloads * sizeof(mgr-
> > >proposed_vcpis[0]));
> > -               mgr->payload_mask = 0;
> > -               set_bit(0, &mgr->payload_mask);
> > -               mgr->vcpi_mask = 0;
> >                 mgr->payload_id_table_cleared = false;
> >         }
> > 
> >  out_unlock:
> >         mutex_unlock(&mgr->lock);
> > -       mutex_unlock(&mgr->payload_lock);
> >         if (mstb)
> >                 drm_dp_mst_topology_put_mstb(mstb);
> >         return ret;
> > @@ -4310,62 +4184,18 @@ struct edid *drm_dp_mst_get_edid(struct
> > drm_connector *connector, struct drm_dp_
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_get_edid);
> > 
> > -/**
> > - * drm_dp_find_vcpi_slots() - Find time slots for this PBN value
> > - * @mgr: manager to use
> > - * @pbn: payload bandwidth to convert into slots.
> > - *
> > - * Calculate the number of time slots that will be required for the given
> > PBN
> > - * value. This function is deprecated, and should not be used in atomic
> > - * drivers.
> > - *
> > - * RETURNS:
> > - * The total slots required for this port, or error.
> > - */
> > -int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > -                          int pbn)
> > -{
> > -       int num_slots;
> > -
> > -       num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
> > -
> > -       /* max. time slots - one slot for MTP header */
> > -       if (num_slots > 63)
> > -               return -ENOSPC;
> > -       return num_slots;
> > -}
> > -EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
> > -
> > -static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                           struct drm_dp_vcpi *vcpi, int pbn, int slots)
> > -{
> > -       int ret;
> > -
> > -       vcpi->pbn = pbn;
> > -       vcpi->aligned_pbn = slots * mgr->pbn_div;
> > -       vcpi->num_slots = slots;
> > -
> > -       ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
> > -       if (ret < 0)
> > -               return ret;
> > -       return 0;
> > -}
> > -
> >  /**
> >   * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
> >   * @state: global atomic state
> >   * @mgr: MST topology manager for the port
> >   * @port: port to find time slots for
> >   * @pbn: bandwidth required for the mode in PBN
> > - * @pbn_div: divider for DSC mode that takes FEC into account
> >   *
> > - * Allocates time slots to @port, replacing any previous timeslot
> > allocations it
> > - * may have had. Any atomic drivers which support MST must call this
> > function
> > - * in their &drm_encoder_helper_funcs.atomic_check() callback to change
> > the
> > - * current timeslot allocation for the new state, but only when
> > - * &drm_crtc_state.mode_changed or
> > &drm_crtc_state.connectors_changed is set
> > - * to ensure compatibility with userspace applications that still use the
> > - * legacy modesetting UAPI.
> > + * Allocates time slots to @port, replacing any previous time slot
> > allocations
> > it may
> > + * have had. Any atomic drivers which support MST must call this function
> > in
> > + * their &drm_encoder_helper_funcs.atomic_check() callback
> > unconditionally to
> > + * change the current time slot allocation for the new state, and ensure
> > the
> > MST
> > + * atomic state is added whenever the state of payloads in the topology
> > changes.
> >   *
> >   * Allocations set by this function are not checked against the bandwidth
> >   * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
> > @@ -4384,8 +4214,7 @@ static int drm_dp_init_vcpi(struct
> > drm_dp_mst_topology_mgr *mgr,
> >   */
> >  int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> >                                   struct drm_dp_mst_topology_mgr *mgr,
> > -                                 struct drm_dp_mst_port *port, int pbn,
> > -                                 int pbn_div)
> > +                                 struct drm_dp_mst_port *port, int pbn)
> >  {
> >         struct drm_dp_mst_topology_state *topology_state;
> >         struct drm_dp_mst_atomic_payload *payload = NULL;
> > @@ -4418,10 +4247,7 @@ int drm_dp_atomic_find_time_slots(struct
> > drm_atomic_state *state,
> >                 }
> >         }
> > 
> > -       if (pbn_div <= 0)
> > -               pbn_div = mgr->pbn_div;
> > -
> > -       req_slots = DIV_ROUND_UP(pbn, pbn_div);
> > +       req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div);
> > 
> >         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p]
> > TU %d -> %d\n",
> >                        port->connector->base.id, port->connector->name,
> > @@ -4430,7 +4256,7 @@ int drm_dp_atomic_find_time_slots(struct
> > drm_atomic_state *state,
> >                        port->connector->base.id, port->connector->name,
> >                        port, prev_bw, pbn);
> > 
> > -       /* Add the new allocation to the state */
> > +       /* Add the new allocation to the state, note the VCPI isn't
> > assigned
> > until the end */
> >         if (!payload) {
> >                 payload = kzalloc(sizeof(*payload), GFP_KERNEL);
> >                 if (!payload)
> > @@ -4438,6 +4264,7 @@ int drm_dp_atomic_find_time_slots(struct
> > drm_atomic_state *state,
> > 
> >                 drm_dp_mst_get_port_malloc(port);
> >                 payload->port = port;
> > +               payload->vc_start_slot = -1;
> >                 list_add(&payload->next, &topology_state->payloads);
> >         }
> >         payload->time_slots = req_slots;
> > @@ -4454,10 +4281,12 @@
> > EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
> >   * @port: The port to release the time slots from
> >   *
> >   * Releases any time slots that have been allocated to a port in the
> > atomic
> > - * state. Any atomic drivers which support MST must call this function in
> > - * their &drm_connector_helper_funcs.atomic_check() callback when the
> > - * connector will no longer have VCPI allocated (e.g. because its CRTC
> > was
> > - * removed) when it had VCPI allocated in the previous atomic state.
> > + * state. Any atomic drivers which support MST must call this function
> > + * unconditionally in their &drm_connector_helper_funcs.atomic_check()
> > callback.
> > + * This helper will check whether time slots would be released by the new
> > state and
> > + * respond accordingly, along with ensuring the MST state is always added
> > to the
> > + * atomic state whenever a new state would modify the state of payloads
> > on the
> > + * topology.
> >   *
> >   * It is OK to call this even if @port has been removed from the system.
> >   * Additionally, it is OK to call this function multiple times on the
> > same
> > @@ -4519,6 +4348,7 @@ int drm_dp_atomic_release_time_slots(struct
> > drm_atomic_state *state,
> >                 drm_dp_mst_put_port_malloc(port);
> >                 payload->pbn = 0;
> >                 payload->delete = true;
> > +               topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
> >         }
> > 
> >         return 0;
> > @@ -4569,7 +4399,8 @@ int drm_dp_mst_atomic_setup_commit(struct
> > drm_atomic_state *state)
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
> > 
> >  /**
> > - * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending
> > commits on MST topologies
> > + * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending
> > commits on MST topologies,
> > + * prepare new MST state for commit
> >   * @state: global atomic state
> >   *
> >   * Goes through any MST topologies in this atomic state, and waits for
> > any
> > pending commits which
> > @@ -4587,17 +4418,30 @@
> > EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
> >   */
> >  void drm_dp_mst_atomic_wait_for_dependencies(struct
> > drm_atomic_state *state)
> >  {
> > -       struct drm_dp_mst_topology_state *old_mst_state;
> > +       struct drm_dp_mst_topology_state *old_mst_state,
> > *new_mst_state;
> >         struct drm_dp_mst_topology_mgr *mgr;
> > +       struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
> >         int i, j, ret;
> > 
> > -       for_each_old_mst_mgr_in_state(state, mgr, old_mst_state, i) {
> > +       for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state,
> > new_mst_state, i) {
> >                 for (j = 0; j < old_mst_state->num_commit_deps; j++) {
> >                         ret = drm_crtc_commit_wait(old_mst_state-
> > > commit_deps[j]);
> >                         if (ret < 0)
> >                                 drm_err(state->dev, "Failed to wait for
> > %s:
> > %d\n",
> >                                         old_mst_state->commit_deps[j]-
> > > crtc->name, ret);
> >                 }
> > +
> > +               /* Now that previous state is committed, it's safe to copy
> > over the start slot
> > +                * assignments
> > +                */
> > +               list_for_each_entry(old_payload, &old_mst_state->payloads,
> > next) {
> > +                       if (old_payload->delete)
> > +                               continue;
> > +
> > +                       new_payload =
> > drm_atomic_get_mst_payload_state(new_mst_state,
> > +
> > old_payload->port);
> > +                       new_payload->vc_start_slot = old_payload-
> > > vc_start_slot;
> > +               }
> >         }
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
> > @@ -4682,110 +4526,8 @@ void drm_dp_mst_update_slots(struct
> > drm_dp_mst_topology_state *mst_state, uint8_
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_update_slots);
> > 
> > -/**
> > - * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
> > - * @mgr: manager for this port
> > - * @port: port to allocate a virtual channel for.
> > - * @pbn: payload bandwidth number to request
> > - * @slots: returned number of slots for this PBN.
> > - */
> > -bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                             struct drm_dp_mst_port *port, int pbn, int
> > slots)
> > -{
> > -       int ret;
> > -
> > -       if (slots < 0)
> > -               return false;
> > -
> > -       port = drm_dp_mst_topology_get_port_validated(mgr, port);
> > -       if (!port)
> > -               return false;
> > -
> > -       if (port->vcpi.vcpi > 0) {
> > -               drm_dbg_kms(mgr->dev,
> > -                           "payload: vcpi %d already allocated for pbn %d
> > -
> > requested pbn %d\n",
> > -                           port->vcpi.vcpi, port->vcpi.pbn, pbn);
> > -               if (pbn == port->vcpi.pbn) {
> > -                       drm_dp_mst_topology_put_port(port);
> > -                       return true;
> > -               }
> > -       }
> > -
> > -       ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
> > -       if (ret) {
> > -               drm_dbg_kms(mgr->dev, "failed to init time slots=%d
> > ret=%d\n",
> > -                           DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
> > -               drm_dp_mst_topology_put_port(port);
> > -               goto out;
> > -       }
> > -       drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn,
> > port->vcpi.num_slots);
> > -
> > -       /* Keep port allocated until its payload has been removed */
> > -       drm_dp_mst_get_port_malloc(port);
> > -       drm_dp_mst_topology_put_port(port);
> > -       return true;
> > -out:
> > -       return false;
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
> > -
> > -int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > struct drm_dp_mst_port *port)
> > -{
> > -       int slots = 0;
> > -
> > -       port = drm_dp_mst_topology_get_port_validated(mgr, port);
> > -       if (!port)
> > -               return slots;
> > -
> > -       slots = port->vcpi.num_slots;
> > -       drm_dp_mst_topology_put_port(port);
> > -       return slots;
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
> > -
> > -/**
> > - * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
> > - * @mgr: manager for this port
> > - * @port: unverified pointer to a port.
> > - *
> > - * This just resets the number of slots for the ports VCPI for later
> > programming.
> > - */
> > -void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr
> > *mgr, struct drm_dp_mst_port *port)
> > -{
> > -       /*
> > -        * A port with VCPI will remain allocated until its VCPI is
> > -        * released, no verified ref needed
> > -        */
> > -
> > -       port->vcpi.num_slots = 0;
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
> > -
> > -/**
> > - * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
> > - * @mgr: manager for this port
> > - * @port: port to deallocate vcpi for
> > - *
> > - * This can be called unconditionally, regardless of whether
> > - * drm_dp_mst_allocate_vcpi() succeeded or not.
> > - */
> > -void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                               struct drm_dp_mst_port *port)
> > -{
> > -       if (!port->vcpi.vcpi)
> > -               return;
> > -
> > -       drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
> > -       port->vcpi.num_slots = 0;
> > -       port->vcpi.pbn = 0;
> > -       port->vcpi.aligned_pbn = 0;
> > -       port->vcpi.vcpi = 0;
> > -       drm_dp_mst_put_port_malloc(port);
> > -}
> > -EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
> > -
> >  static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                    int id, struct drm_dp_payload
> > *payload)
> > +                                    int id, u8 start_slot, u8 num_slots)
> >  {
> >         u8 payload_alloc[3], status;
> >         int ret;
> > @@ -4795,8 +4537,8 @@ static int drm_dp_dpcd_write_payload(struct
> > drm_dp_mst_topology_mgr *mgr,
> >                            DP_PAYLOAD_TABLE_UPDATED);
> > 
> >         payload_alloc[0] = id;
> > -       payload_alloc[1] = payload->start_slot;
> > -       payload_alloc[2] = payload->num_slots;
> > +       payload_alloc[1] = start_slot;
> > +       payload_alloc[2] = num_slots;
> > 
> >         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET,
> > payload_alloc, 3);
> >         if (ret != 3) {
> > @@ -5011,8 +4753,9 @@ static void fetch_monitor_name(struct
> > drm_dp_mst_topology_mgr *mgr,
> >  void drm_dp_mst_dump_topology(struct seq_file *m,
> >                               struct drm_dp_mst_topology_mgr *mgr)
> >  {
> > -       int i;
> > -       struct drm_dp_mst_port *port;
> > +       struct drm_dp_mst_topology_state *state;
> > +       struct drm_dp_mst_atomic_payload *payload;
> > +       int i, ret;
> > 
> >         mutex_lock(&mgr->lock);
> >         if (mgr->mst_primary)
> > @@ -5021,36 +4764,35 @@ void drm_dp_mst_dump_topology(struct
> > seq_file *m,
> >         /* dump VCPIs */
> >         mutex_unlock(&mgr->lock);
> > 
> > -       mutex_lock(&mgr->payload_lock);
> > -       seq_printf(m, "\n*** VCPI Info ***\n");
> > -       seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads:
> > %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
> > +       ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
> > +       if (ret < 0)
> > +               return;
> > +
> > +       state = to_drm_dp_mst_topology_state(mgr->base.state);
> > +       seq_printf(m, "\n*** Atomic state info ***\n");
> > +       seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u,
> > pbn_div: %d\n",
> > +                  state->payload_mask, mgr->max_payloads, state-
> > > start_slot, state->pbn_div);
> > 
> > -       seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |    
> > sink name
> > > \n");
> > +       seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc |    
> > sink name
> > > \n");
> >         for (i = 0; i < mgr->max_payloads; i++) {
> > -               if (mgr->proposed_vcpis[i]) {
> > +               list_for_each_entry(payload, &state->payloads, next) {
> >                         char name[14];
> > 
> > -                       port = container_of(mgr->proposed_vcpis[i], struct
> > drm_dp_mst_port, vcpi);
> > -                       fetch_monitor_name(mgr, port, name,
> > sizeof(name));
> > -                       seq_printf(m, "%10d%10d%10d%10d%20s\n",
> > +                       if (payload->vcpi != i || payload->delete)
> > +                               continue;
> > +
> > +                       fetch_monitor_name(mgr, payload->port, name,
> > sizeof(name));
> > +                       seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s
> > %19s\n",
> >                                    i,
> > -                                  port->port_num,
> > -                                  port->vcpi.vcpi,
> > -                                  port->vcpi.num_slots,
> > +                                  payload->port->port_num,
> > +                                  payload->vcpi,
> > +                                  payload->vc_start_slot,
> > +                                  payload->vc_start_slot + payload-
> > > time_slots - 1,
> > +                                  payload->pbn,
> > +                                  payload->dsc_enabled ? "Y" : "N",
> >                                    (*name != 0) ? name : "Unknown");
> > -               } else
> > -                       seq_printf(m, "%6d - Unused\n", i);
> > -       }
> > -       seq_printf(m, "\n*** Payload Info ***\n");
> > -       seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
> > -       for (i = 0; i < mgr->max_payloads; i++) {
> > -               seq_printf(m, "%10d%10d%15d%10d\n",
> > -                          i,
> > -                          mgr->payloads[i].payload_state,
> > -                          mgr->payloads[i].start_slot,
> > -                          mgr->payloads[i].num_slots);
> > +               }
> >         }
> > -       mutex_unlock(&mgr->payload_lock);
> > 
> >         seq_printf(m, "\n*** DPCD Info ***\n");
> >         mutex_lock(&mgr->lock);
> > @@ -5097,7 +4839,7 @@ void drm_dp_mst_dump_topology(struct seq_file
> > *m,
> > 
> >  out:
> >         mutex_unlock(&mgr->lock);
> > -
> > +       drm_modeset_unlock(&mgr->base.lock);
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_dump_topology);
> > 
> > @@ -5418,9 +5160,22 @@
> > drm_dp_mst_atomic_check_payload_alloc_limits(struct
> > drm_dp_mst_topology_mgr *mgr
> >                                        mgr, mst_state, mgr->max_payloads);
> >                         return -EINVAL;
> >                 }
> > +
> > +               /* Assign a VCPI */
> > +               if (!payload->vcpi) {
> > +                       payload->vcpi = ffz(mst_state->payload_mask) + 1;
> > +                       drm_dbg_atomic(mgr->dev, "[MST PORT:%p]
> > assigned VCPI #%d\n",
> > +                                      payload->port, payload->vcpi);
> > +                       mst_state->payload_mask |= BIT(payload->vcpi - 1);
> > +               }
> >         }
> > -       drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU
> > avail=%d used=%d\n",
> > -                      mgr, mst_state, avail_slots, mst_state-
> > >total_avail_slots -
> > avail_slots);
> > +
> > +       if (!payload_count)
> > +               mst_state->pbn_div = 0;
> > +
> > +       drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU
> > pbn_div=%d avail=%d used=%d\n",
> > +                      mgr, mst_state, mst_state->pbn_div, avail_slots,
> > +                      mst_state->total_avail_slots - avail_slots);
> > 
> >         return 0;
> >  }
> > @@ -5491,7 +5246,6 @@
> > EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
> >   * @state: Pointer to the new drm_atomic_state
> >   * @port: Pointer to the affected MST Port
> >   * @pbn: Newly recalculated bw required for link with DSC enabled
> > - * @pbn_div: Divider to calculate correct number of pbn per slot
> >   * @enable: Boolean flag to enable or disable DSC on the port
> >   *
> >   * This function enables DSC on the given Port
> > @@ -5502,8 +5256,7 @@
> > EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
> >   */
> >  int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
> >                                  struct drm_dp_mst_port *port,
> > -                                int pbn, int pbn_div,
> > -                                bool enable)
> > +                                int pbn, bool enable)
> >  {
> >         struct drm_dp_mst_topology_state *mst_state;
> >         struct drm_dp_mst_atomic_payload *payload;
> > @@ -5529,7 +5282,7 @@ int drm_dp_mst_atomic_enable_dsc(struct
> > drm_atomic_state *state,
> >         }
> > 
> >         if (enable) {
> > -               time_slots = drm_dp_atomic_find_time_slots(state, port-
> > > mgr, port, pbn, pbn_div);
> > +               time_slots = drm_dp_atomic_find_time_slots(state, port-
> > > mgr, port, pbn);
> >                 drm_dbg_atomic(state->dev,
> >                                "[MST PORT:%p] Enabling DSC flag,
> > reallocating
> > %d time slots on the port\n",
> >                                port, time_slots);
> > @@ -5542,6 +5295,7 @@ int drm_dp_mst_atomic_enable_dsc(struct
> > drm_atomic_state *state,
> >         return time_slots;
> >  }
> >  EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
> > +
> >  /**
> >   * drm_dp_mst_atomic_check - Check that the new state of an MST
> > topology in an
> >   * atomic update is valid
> > @@ -5599,7 +5353,6 @@
> > EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
> > 
> >  /**
> >   * drm_atomic_get_mst_topology_state: get MST topology state
> > - *
> >   * @state: global atomic state
> >   * @mgr: MST topology manager, also the private object in this case
> >   *
> > @@ -5619,6 +5372,31 @@ struct drm_dp_mst_topology_state
> > *drm_atomic_get_mst_topology_state(struct drm_a
> >  }
> >  EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> > 
> > +/**
> > + * drm_atomic_get_new_mst_topology_state: get new MST topology state
> > in atomic state, if any
> > + * @state: global atomic state
> > + * @mgr: MST topology manager, also the private object in this case
> > + *
> > + * This function wraps drm_atomic_get_priv_obj_state() passing in the MST
> > atomic
> > + * state vtable so that the private object state returned is that of a
> > MST
> > + * topology object.
> > + *
> > + * Returns:
> > + *
> > + * The MST topology state, or NULL if there's no topology state for this
> > MST
> > mgr
> > + * in the global atomic state
> > + */
> > +struct drm_dp_mst_topology_state *
> > +drm_atomic_get_new_mst_topology_state(struct drm_atomic_state
> > *state,
> > +                                     struct drm_dp_mst_topology_mgr *mgr)
> > +{
> > +       struct drm_private_state *priv_state =
> > +               drm_atomic_get_new_private_obj_state(state, &mgr-
> > > base);
> > +
> > +       return priv_state ? to_dp_mst_topology_state(priv_state) : NULL;
> > +}
> > +EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
> > +
> >  /**
> >   * drm_dp_mst_topology_mgr_init - initialise a topology manager
> >   * @mgr: manager struct to initialise
> > @@ -5626,8 +5404,6 @@
> > EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> >   * @aux: DP helper aux channel to talk to this device
> >   * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
> >   * @max_payloads: maximum number of payloads this GPU can source
> > - * @max_lane_count: maximum number of lanes this GPU supports
> > - * @max_link_rate: maximum link rate per lane this GPU supports in kHz
> >   * @conn_base_id: the connector object ID the MST device is connected to.
> >   *
> >   * Return 0 for success, or negative error code on failure
> > @@ -5635,14 +5411,12 @@
> > EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> >  int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr
> > *mgr,
> >                                  struct drm_device *dev, struct drm_dp_aux
> > *aux,
> >                                  int max_dpcd_transaction_bytes, int
> > max_payloads,
> > -                                int max_lane_count, int max_link_rate,
> >                                  int conn_base_id)
> >  {
> >         struct drm_dp_mst_topology_state *mst_state;
> > 
> >         mutex_init(&mgr->lock);
> >         mutex_init(&mgr->qlock);
> > -       mutex_init(&mgr->payload_lock);
> >         mutex_init(&mgr->delayed_destroy_lock);
> >         mutex_init(&mgr->up_req_lock);
> >         mutex_init(&mgr->probe_lock);
> > @@ -5672,19 +5446,7 @@ int drm_dp_mst_topology_mgr_init(struct
> > drm_dp_mst_topology_mgr *mgr,
> >         mgr->aux = aux;
> >         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
> >         mgr->max_payloads = max_payloads;
> > -       mgr->max_lane_count = max_lane_count;
> > -       mgr->max_link_rate = max_link_rate;
> >         mgr->conn_base_id = conn_base_id;
> > -       if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
> > -           max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
> > -               return -EINVAL;
> > -       mgr->payloads = kcalloc(max_payloads, sizeof(struct
> > drm_dp_payload), GFP_KERNEL);
> > -       if (!mgr->payloads)
> > -               return -ENOMEM;
> > -       mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct
> > drm_dp_vcpi *), GFP_KERNEL);
> > -       if (!mgr->proposed_vcpis)
> > -               return -ENOMEM;
> > -       set_bit(0, &mgr->payload_mask);
> > 
> >         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
> >         if (mst_state == NULL)
> > @@ -5717,19 +5479,12 @@ void drm_dp_mst_topology_mgr_destroy(struct
> > drm_dp_mst_topology_mgr *mgr)
> >                 destroy_workqueue(mgr->delayed_destroy_wq);
> >                 mgr->delayed_destroy_wq = NULL;
> >         }
> > -       mutex_lock(&mgr->payload_lock);
> > -       kfree(mgr->payloads);
> > -       mgr->payloads = NULL;
> > -       kfree(mgr->proposed_vcpis);
> > -       mgr->proposed_vcpis = NULL;
> > -       mutex_unlock(&mgr->payload_lock);
> >         mgr->dev = NULL;
> >         mgr->aux = NULL;
> >         drm_atomic_private_obj_fini(&mgr->base);
> >         mgr->funcs = NULL;
> > 
> >         mutex_destroy(&mgr->delayed_destroy_lock);
> > -       mutex_destroy(&mgr->payload_lock);
> >         mutex_destroy(&mgr->qlock);
> >         mutex_destroy(&mgr->lock);
> >         mutex_destroy(&mgr->up_req_lock);
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 4b0af3c26176..ec389e3caf24 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -52,6 +52,7 @@ static int intel_dp_mst_compute_link_config(struct
> > intel_encoder *encoder,
> >         struct drm_atomic_state *state = crtc_state->uapi.state;
> >         struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> >         struct intel_dp *intel_dp = &intel_mst->primary->dp;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct intel_connector *connector =
> >                 to_intel_connector(conn_state->connector);
> >         struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > @@ -60,22 +61,28 @@ static int intel_dp_mst_compute_link_config(struct
> > intel_encoder *encoder,
> >         bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> > DP_DPCD_QUIRK_CONSTANT_N);
> >         int bpp, slots = -EINVAL;
> > 
> > +       mst_state = drm_atomic_get_mst_topology_state(state, &intel_dp-
> > > mst_mgr);
> > +       if (IS_ERR(mst_state))
> > +               return PTR_ERR(mst_state);
> > +
> >         crtc_state->lane_count = limits->max_lane_count;
> >         crtc_state->port_clock = limits->max_rate;
> > 
> > +       // TODO: Handle pbn_div changes by adding a new MST helper
> > +       if (!mst_state->pbn_div) {
> > +               mst_state->pbn_div =
> > drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
> > +                                                             limits-
> > >max_rate,
> > +                                                             limits-
> > > max_lane_count);
> > +       }
> > +
> >         for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3)
> > {
> >                 crtc_state->pipe_bpp = bpp;
> > 
> >                 crtc_state->pbn =
> > drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
> >                                                        crtc_state-
> > >pipe_bpp,
> >                                                        false);
> > -
> >                 slots = drm_dp_atomic_find_time_slots(state, &intel_dp-
> > > mst_mgr,
> > -                                                     connector->port,
> > -                                                     crtc_state->pbn,
> > -
> > drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
> > -
> > crtc_state->port_clock,
> > -
> > crtc_state->lane_count));
> > +                                                     connector->port,
> > crtc_state->pbn);
> >                 if (slots == -EDEADLK)
> >                         return slots;
> >                 if (slots >= 0)
> > @@ -360,21 +367,17 @@ static void intel_mst_disable_dp(struct
> > intel_atomic_state *state,
> >         struct intel_dp *intel_dp = &dig_port->dp;
> >         struct intel_connector *connector =
> >                 to_intel_connector(old_conn_state->connector);
> > +       struct drm_dp_mst_topology_state *mst_state =
> > +               drm_atomic_get_mst_topology_state(&state->base,
> > &intel_dp->mst_mgr);
> >         struct drm_i915_private *i915 = to_i915(connector->base.dev);
> > -       int start_slot = intel_dp_is_uhbr(old_crtc_state) ? 0 : 1;
> > -       int ret;
> > 
> >         drm_dbg_kms(&i915->drm, "active links %d\n",
> >                     intel_dp->active_mst_links);
> > 
> >         intel_hdcp_disable(intel_mst->connector);
> > 
> > -       drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, connector-
> > > port);
> > -
> > -       ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr,
> > start_slot);
> > -       if (ret) {
> > -               drm_dbg_kms(&i915->drm, "failed to update payload %d\n",
> > ret);
> > -       }
> > +       drm_dp_remove_payload(&intel_dp->mst_mgr, mst_state,
> > +                             drm_atomic_get_mst_payload_state(mst_state,
> > connector->port));
> > 
> >         intel_audio_codec_disable(encoder, old_crtc_state,
> > old_conn_state);
> >  }
> > @@ -402,8 +405,6 @@ static void intel_mst_post_disable_dp(struct
> > intel_atomic_state *state,
> > 
> >         intel_disable_transcoder(old_crtc_state);
> > 
> > -       drm_dp_update_payload_part2(&intel_dp->mst_mgr);
> > -
> >         clear_act_sent(encoder, old_crtc_state);
> > 
> >         intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(old_crtc_state-
> > > cpu_transcoder),
> > @@ -411,8 +412,6 @@ static void intel_mst_post_disable_dp(struct
> > intel_atomic_state *state,
> > 
> >         wait_for_act_sent(encoder, old_crtc_state);
> > 
> > -       drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, connector-
> > > port);
> > -
> >         intel_ddi_disable_transcoder_func(old_crtc_state);
> > 
> >         if (DISPLAY_VER(dev_priv) >= 9)
> > @@ -479,7 +478,8 @@ static void intel_mst_pre_enable_dp(struct
> > intel_atomic_state *state,
> >         struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >         struct intel_connector *connector =
> >                 to_intel_connector(conn_state->connector);
> > -       int start_slot = intel_dp_is_uhbr(pipe_config) ? 0 : 1;
> > +       struct drm_dp_mst_topology_state *mst_state =
> > +               drm_atomic_get_new_mst_topology_state(&state->base,
> > &intel_dp->mst_mgr);
> >         int ret;
> >         bool first_mst_stream;
> > 
> > @@ -505,16 +505,13 @@ static void intel_mst_pre_enable_dp(struct
> > intel_atomic_state *state,
> >                 dig_port->base.pre_enable(state, &dig_port->base,
> >                                                 pipe_config, NULL);
> > 
> > -       ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
> > -                                      connector->port,
> > -                                      pipe_config->pbn,
> > -                                      pipe_config->dp_m_n.tu);
> > -       if (!ret)
> > -               drm_err(&dev_priv->drm, "failed to allocate vcpi\n");
> > -
> >         intel_dp->active_mst_links++;
> > 
> > -       ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr,
> > start_slot);
> > +       ret = drm_dp_add_payload_part1(&intel_dp->mst_mgr, mst_state,
> > +
> > drm_atomic_get_mst_payload_state(mst_state, connector->port));
> > +       if (ret < 0)
> > +               drm_err(&dev_priv->drm, "Failed to create MST payload for
> > %s: %d\n",
> > +                       connector->base.name, ret);
> > 
> >         /*
> >          * Before Gen 12 this is not done as part of
> > @@ -537,7 +534,10 @@ static void intel_mst_enable_dp(struct
> > intel_atomic_state *state,
> >         struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
> >         struct intel_digital_port *dig_port = intel_mst->primary;
> >         struct intel_dp *intel_dp = &dig_port->dp;
> > +       struct intel_connector *connector = to_intel_connector(conn_state-
> > > connector);
> >         struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > +       struct drm_dp_mst_topology_state *mst_state =
> > +               drm_atomic_get_new_mst_topology_state(&state->base,
> > &intel_dp->mst_mgr);
> >         enum transcoder trans = pipe_config->cpu_transcoder;
> > 
> >         drm_WARN_ON(&dev_priv->drm, pipe_config->has_pch_encoder);
> > @@ -565,7 +565,8 @@ static void intel_mst_enable_dp(struct
> > intel_atomic_state *state,
> > 
> >         wait_for_act_sent(encoder, pipe_config);
> > 
> > -       drm_dp_update_payload_part2(&intel_dp->mst_mgr);
> > +       drm_dp_add_payload_part2(&intel_dp->mst_mgr, &state->base,
> > +
> > drm_atomic_get_mst_payload_state(mst_state, connector->port));
> > 
> >         if (DISPLAY_VER(dev_priv) >= 12 && pipe_config->fec_enable)
> >                 intel_de_rmw(dev_priv, CHICKEN_TRANS(trans), 0,
> > @@ -948,8 +949,6 @@ intel_dp_mst_encoder_init(struct intel_digital_port
> > *dig_port, int conn_base_id)
> >         struct intel_dp *intel_dp = &dig_port->dp;
> >         enum port port = dig_port->base.port;
> >         int ret;
> > -       int max_source_rate =
> > -               intel_dp->source_rates[intel_dp->num_source_rates - 1];
> > 
> >         if (!HAS_DP_MST(i915) || intel_dp_is_edp(intel_dp))
> >                 return 0;
> > @@ -965,10 +964,7 @@ intel_dp_mst_encoder_init(struct intel_digital_port
> > *dig_port, int conn_base_id)
> >         /* create encoders */
> >         intel_dp_create_fake_mst_encoders(dig_port);
> >         ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, &i915-
> > > drm,
> > -                                          &intel_dp->aux, 16, 3,
> > -                                          dig_port->max_lanes,
> > -                                          max_source_rate,
> > -                                          conn_base_id);
> > +                                          &intel_dp->aux, 16, 3,
> > conn_base_id);
> >         if (ret) {
> >                 intel_dp->mst_mgr.cbs = NULL;
> >                 return ret;
> > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c
> > b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > index 8ea66a2e1b09..7dbc9f0bb24f 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > @@ -30,8 +30,30 @@
> > 
> >  static int intel_conn_to_vcpi(struct intel_connector *connector)
> >  {
> > +       struct drm_dp_mst_topology_mgr *mgr;
> > +       struct drm_dp_mst_atomic_payload *payload;
> > +       struct drm_dp_mst_topology_state *mst_state;
> > +       int vcpi = 0;
> > +
> >         /* For HDMI this is forced to be 0x0. For DP SST also this is 0x0.
> > */
> > -       return connector->port  ? connector->port->vcpi.vcpi : 0;
> > +       if (!connector->port)
> > +               return 0;
> > +       mgr = connector->port->mgr;
> > +
> > +       drm_modeset_lock(&mgr->base.lock, NULL);
> > +       mst_state = to_drm_dp_mst_topology_state(mgr->base.state);
> > +       payload = drm_atomic_get_mst_payload_state(mst_state,
> > connector->port);
> > +       if (drm_WARN_ON(mgr->dev, !payload))
> > +               goto out;
> > +
> > +       vcpi = payload->vcpi;
> > +       if (drm_WARN_ON(mgr->dev, vcpi < 0)) {
> > +               vcpi = 0;
> > +               goto out;
> > +       }
> > +out:
> > +       drm_modeset_unlock(&mgr->base.lock);
> > +       return vcpi;
> >  }
> > 
> >  /*
> > diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > index 57f74cfcdebf..e8f4c806fa39 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > @@ -937,6 +937,7 @@ struct nv50_msto {
> >         struct nv50_head *head;
> >         struct nv50_mstc *mstc;
> >         bool disabled;
> > +       bool enabled;
> >  };
> > 
> >  struct nouveau_encoder *nv50_real_outp(struct drm_encoder *encoder)
> > @@ -952,57 +953,37 @@ struct nouveau_encoder *nv50_real_outp(struct
> > drm_encoder *encoder)
> >         return msto->mstc->mstm->outp;
> >  }
> > 
> > -static struct drm_dp_payload *
> > -nv50_msto_payload(struct nv50_msto *msto)
> > -{
> > -       struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
> > -       struct nv50_mstc *mstc = msto->mstc;
> > -       struct nv50_mstm *mstm = mstc->mstm;
> > -       int vcpi = mstc->port->vcpi.vcpi, i;
> > -
> > -       WARN_ON(!mutex_is_locked(&mstm->mgr.payload_lock));
> > -
> > -       NV_ATOMIC(drm, "%s: vcpi %d\n", msto->encoder.name, vcpi);
> > -       for (i = 0; i < mstm->mgr.max_payloads; i++) {
> > -               struct drm_dp_payload *payload = &mstm->mgr.payloads[i];
> > -               NV_ATOMIC(drm, "%s: %d: vcpi %d start 0x%02x slots
> > 0x%02x\n",
> > -                         mstm->outp->base.base.name, i, payload->vcpi,
> > -                         payload->start_slot, payload->num_slots);
> > -       }
> > -
> > -       for (i = 0; i < mstm->mgr.max_payloads; i++) {
> > -               struct drm_dp_payload *payload = &mstm->mgr.payloads[i];
> > -               if (payload->vcpi == vcpi)
> > -                       return payload;
> > -       }
> > -
> > -       return NULL;
> > -}
> > -
> >  static void
> > -nv50_msto_cleanup(struct nv50_msto *msto)
> > +nv50_msto_cleanup(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct drm_dp_mst_topology_mgr *mgr,
> > +                 struct nv50_msto *msto)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
> > -       struct nv50_mstc *mstc = msto->mstc;
> > -       struct nv50_mstm *mstm = mstc->mstm;
> > -
> > -       if (!msto->disabled)
> > -               return;
> > +       struct drm_dp_mst_atomic_payload *payload =
> > +               drm_atomic_get_mst_payload_state(mst_state, msto-
> > > mstc->port);
> > 
> >         NV_ATOMIC(drm, "%s: msto cleanup\n", msto->encoder.name);
> > 
> > -       drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port);
> > -
> > -       msto->mstc = NULL;
> > -       msto->disabled = false;
> > +       if (msto->disabled) {
> > +               msto->mstc = NULL;
> > +               msto->disabled = false;
> > +       } else if (msto->enabled) {
> > +               drm_dp_add_payload_part2(mgr, state, payload);
> > +               msto->enabled = false;
> > +       }
> >  }
> > 
> >  static void
> > -nv50_msto_prepare(struct nv50_msto *msto)
> > +nv50_msto_prepare(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct drm_dp_mst_topology_mgr *mgr,
> > +                 struct nv50_msto *msto)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(msto->encoder.dev);
> >         struct nv50_mstc *mstc = msto->mstc;
> >         struct nv50_mstm *mstm = mstc->mstm;
> > +       struct drm_dp_mst_atomic_payload *payload;
> >         struct {
> >                 struct nv50_disp_mthd_v1 base;
> >                 struct nv50_disp_sor_dp_mst_vcpi_v0 vcpi;
> > @@ -1014,17 +995,21 @@ nv50_msto_prepare(struct nv50_msto *msto)
> >                                (0x0100 << msto->head->base.index),
> >         };
> > 
> > -       mutex_lock(&mstm->mgr.payload_lock);
> > -
> >         NV_ATOMIC(drm, "%s: msto prepare\n", msto->encoder.name);
> > -       if (mstc->port->vcpi.vcpi > 0) {
> > -               struct drm_dp_payload *payload =
> > nv50_msto_payload(msto);
> > -               if (payload) {
> > -                       args.vcpi.start_slot = payload->start_slot;
> > -                       args.vcpi.num_slots = payload->num_slots;
> > -                       args.vcpi.pbn = mstc->port->vcpi.pbn;
> > -                       args.vcpi.aligned_pbn = mstc->port-
> > > vcpi.aligned_pbn;
> > -               }
> > +
> > +       payload = drm_atomic_get_mst_payload_state(mst_state, mstc-
> > > port);
> > +
> > +       // TODO: Figure out if we want to do a better job of handling VCPI
> > allocation failures here?
> > +       if (msto->disabled) {
> > +               drm_dp_remove_payload(mgr, mst_state, payload);
> > +       } else {
> > +               if (msto->enabled)
> > +                       drm_dp_add_payload_part1(mgr, mst_state,
> > payload);
> > +
> > +               args.vcpi.start_slot = payload->vc_start_slot;
> > +               args.vcpi.num_slots = payload->time_slots;
> > +               args.vcpi.pbn = payload->pbn;
> > +               args.vcpi.aligned_pbn = payload->time_slots * mst_state-
> > > pbn_div;
> >         }
> > 
> >         NV_ATOMIC(drm, "%s: %s: %02x %02x %04x %04x\n",
> > @@ -1033,7 +1018,6 @@ nv50_msto_prepare(struct nv50_msto *msto)
> >                   args.vcpi.pbn, args.vcpi.aligned_pbn);
> > 
> >         nvif_mthd(&drm->display->disp.object, 0, &args, sizeof(args));
> > -       mutex_unlock(&mstm->mgr.payload_lock);
> >  }
> > 
> >  static int
> > @@ -1043,6 +1027,7 @@ nv50_msto_atomic_check(struct drm_encoder
> > *encoder,
> >  {
> >         struct drm_atomic_state *state = crtc_state->state;
> >         struct drm_connector *connector = conn_state->connector;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct nv50_mstc *mstc = nv50_mstc(connector);
> >         struct nv50_mstm *mstm = mstc->mstm;
> >         struct nv50_head_atom *asyh = nv50_head_atom(crtc_state);
> > @@ -1070,8 +1055,18 @@ nv50_msto_atomic_check(struct drm_encoder
> > *encoder,
> >                                                     false);
> >         }
> > 
> > -       slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc-
> > > port,
> > -                                             asyh->dp.pbn, 0);
> > +       mst_state = drm_atomic_get_mst_topology_state(state, &mstm-
> > > mgr);
> > +       if (IS_ERR(mst_state))
> > +               return PTR_ERR(mst_state);
> > +
> > +       if (!mst_state->pbn_div) {
> > +               struct nouveau_encoder *outp = mstc->mstm->outp;
> > +
> > +               mst_state->pbn_div =
> > drm_dp_get_vc_payload_bw(&mstm->mgr,
> > +                                                             outp-
> > >dp.link_bw,
> > outp->dp.link_nr);
> > +       }
> > +
> > +       slots = drm_dp_atomic_find_time_slots(state, &mstm->mgr, mstc-
> > > port, asyh->dp.pbn);
> >         if (slots < 0)
> >                 return slots;
> > 
> > @@ -1103,7 +1098,6 @@ nv50_msto_atomic_enable(struct drm_encoder
> > *encoder, struct drm_atomic_state *st
> >         struct drm_connector *connector;
> >         struct drm_connector_list_iter conn_iter;
> >         u8 proto;
> > -       bool r;
> > 
> >         drm_connector_list_iter_begin(encoder->dev, &conn_iter);
> >         drm_for_each_connector_iter(connector, &conn_iter) {
> > @@ -1118,10 +1112,6 @@ nv50_msto_atomic_enable(struct drm_encoder
> > *encoder, struct drm_atomic_state *st
> >         if (WARN_ON(!mstc))
> >                 return;
> > 
> > -       r = drm_dp_mst_allocate_vcpi(&mstm->mgr, mstc->port, asyh-
> > > dp.pbn, asyh->dp.tu);
> > -       if (!r)
> > -               DRM_DEBUG_KMS("Failed to allocate VCPI\n");
> > -
> >         if (!mstm->links++)
> >                 nv50_outp_acquire(mstm->outp, false /*XXX: MST audio.*/);
> > 
> > @@ -1134,6 +1124,7 @@ nv50_msto_atomic_enable(struct drm_encoder
> > *encoder, struct drm_atomic_state *st
> >                            nv50_dp_bpc_to_depth(asyh->or.bpc));
> > 
> >         msto->mstc = mstc;
> > +       msto->enabled = true;
> >         mstm->modified = true;
> >  }
> > 
> > @@ -1144,8 +1135,6 @@ nv50_msto_atomic_disable(struct drm_encoder
> > *encoder, struct drm_atomic_state *s
> >         struct nv50_mstc *mstc = msto->mstc;
> >         struct nv50_mstm *mstm = mstc->mstm;
> > 
> > -       drm_dp_mst_reset_vcpi_slots(&mstm->mgr, mstc->port);
> > -
> >         mstm->outp->update(mstm->outp, msto->head->base.index, NULL,
> > 0, 0);
> >         mstm->modified = true;
> >         if (!--mstm->links)
> > @@ -1365,7 +1354,9 @@ nv50_mstc_new(struct nv50_mstm *mstm, struct
> > drm_dp_mst_port *port,
> >  }
> > 
> >  static void
> > -nv50_mstm_cleanup(struct nv50_mstm *mstm)
> > +nv50_mstm_cleanup(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct nv50_mstm *mstm)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(mstm->outp-
> > > base.base.dev);
> >         struct drm_encoder *encoder;
> > @@ -1373,14 +1364,12 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
> >         NV_ATOMIC(drm, "%s: mstm cleanup\n", mstm->outp-
> > > base.base.name);
> >         drm_dp_check_act_status(&mstm->mgr);
> > 
> > -       drm_dp_update_payload_part2(&mstm->mgr);
> > -
> >         drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> >                 if (encoder->encoder_type ==
> > DRM_MODE_ENCODER_DPMST) {
> >                         struct nv50_msto *msto = nv50_msto(encoder);
> >                         struct nv50_mstc *mstc = msto->mstc;
> >                         if (mstc && mstc->mstm == mstm)
> > -                               nv50_msto_cleanup(msto);
> > +                               nv50_msto_cleanup(state, mst_state,
> > &mstm->mgr, msto);
> >                 }
> >         }
> > 
> > @@ -1388,20 +1377,34 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
> >  }
> > 
> >  static void
> > -nv50_mstm_prepare(struct nv50_mstm *mstm)
> > +nv50_mstm_prepare(struct drm_atomic_state *state,
> > +                 struct drm_dp_mst_topology_state *mst_state,
> > +                 struct nv50_mstm *mstm)
> >  {
> >         struct nouveau_drm *drm = nouveau_drm(mstm->outp-
> > > base.base.dev);
> >         struct drm_encoder *encoder;
> > 
> >         NV_ATOMIC(drm, "%s: mstm prepare\n", mstm->outp-
> > > base.base.name);
> > -       drm_dp_update_payload_part1(&mstm->mgr, 1);
> > 
> > +       /* Disable payloads first */
> >         drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> >                 if (encoder->encoder_type ==
> > DRM_MODE_ENCODER_DPMST) {
> >                         struct nv50_msto *msto = nv50_msto(encoder);
> >                         struct nv50_mstc *mstc = msto->mstc;
> > -                       if (mstc && mstc->mstm == mstm)
> > -                               nv50_msto_prepare(msto);
> > +                       if (mstc && mstc->mstm == mstm && msto->disabled)
> > +                               nv50_msto_prepare(state, mst_state,
> > &mstm->mgr, msto);
> > +               }
> > +       }
> > +
> > +       /* Add payloads for new heads, while also updating the start slots
> > of
> > any unmodified (but
> > +        * active) heads that may have had their VC slots shifted left
> > after the
> > previous step
> > +        */
> > +       drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> > +               if (encoder->encoder_type ==
> > DRM_MODE_ENCODER_DPMST) {
> > +                       struct nv50_msto *msto = nv50_msto(encoder);
> > +                       struct nv50_mstc *mstc = msto->mstc;
> > +                       if (mstc && mstc->mstm == mstm && !msto-
> > > disabled)
> > +                               nv50_msto_prepare(state, mst_state,
> > &mstm->mgr, msto);
> >                 }
> >         }
> > 
> > @@ -1598,9 +1601,7 @@ nv50_mstm_new(struct nouveau_encoder *outp,
> > struct drm_dp_aux *aux, int aux_max,
> >         mstm->mgr.cbs = &nv50_mstm;
> > 
> >         ret = drm_dp_mst_topology_mgr_init(&mstm->mgr, dev, aux,
> > aux_max,
> > -                                          max_payloads, outp->dcb-
> > > dpconf.link_nr,
> > -
> > drm_dp_bw_code_to_link_rate(outp->dcb->dpconf.link_bw),
> > -                                          conn_base_id);
> > +                                          max_payloads, conn_base_id);
> >         if (ret)
> >                 return ret;
> > 
> > @@ -2045,20 +2046,20 @@ nv50_pior_create(struct drm_connector
> > *connector, struct dcb_output *dcbe)
> >  static void
> >  nv50_disp_atomic_commit_core(struct drm_atomic_state *state, u32
> > *interlock)
> >  {
> > +       struct drm_dp_mst_topology_mgr *mgr;
> > +       struct drm_dp_mst_topology_state *mst_state;
> >         struct nouveau_drm *drm = nouveau_drm(state->dev);
> >         struct nv50_disp *disp = nv50_disp(drm->dev);
> >         struct nv50_core *core = disp->core;
> >         struct nv50_mstm *mstm;
> > -       struct drm_encoder *encoder;
> > +       int i;
> > 
> >         NV_ATOMIC(drm, "commit core %08x\n",
> > interlock[NV50_DISP_INTERLOCK_BASE]);
> > 
> > -       drm_for_each_encoder(encoder, drm->dev) {
> > -               if (encoder->encoder_type !=
> > DRM_MODE_ENCODER_DPMST) {
> > -                       mstm = nouveau_encoder(encoder)->dp.mstm;
> > -                       if (mstm && mstm->modified)
> > -                               nv50_mstm_prepare(mstm);
> > -               }
> > +       for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> > +               mstm = nv50_mstm(mgr);
> > +               if (mstm->modified)
> > +                       nv50_mstm_prepare(state, mst_state, mstm);
> >         }
> > 
> >         core->func->ntfy_init(disp->sync, NV50_DISP_CORE_NTFY);
> > @@ -2067,12 +2068,10 @@ nv50_disp_atomic_commit_core(struct
> > drm_atomic_state *state, u32 *interlock)
> >                                        disp->core->chan.base.device))
> >                 NV_ERROR(drm, "core notifier timeout\n");
> > 
> > -       drm_for_each_encoder(encoder, drm->dev) {
> > -               if (encoder->encoder_type !=
> > DRM_MODE_ENCODER_DPMST) {
> > -                       mstm = nouveau_encoder(encoder)->dp.mstm;
> > -                       if (mstm && mstm->modified)
> > -                               nv50_mstm_cleanup(mstm);
> > -               }
> > +       for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
> > +               mstm = nv50_mstm(mgr);
> > +               if (mstm->modified)
> > +                       nv50_mstm_cleanup(state, mst_state, mstm);
> >         }
> >  }
> > 
> > diff --git a/include/drm/display/drm_dp_mst_helper.h
> > b/include/drm/display/drm_dp_mst_helper.h
> > index ecd130028337..6317831705ab 100644
> > --- a/include/drm/display/drm_dp_mst_helper.h
> > +++ b/include/drm/display/drm_dp_mst_helper.h
> > @@ -48,20 +48,6 @@ struct drm_dp_mst_topology_ref_history {
> > 
> >  struct drm_dp_mst_branch;
> > 
> > -/**
> > - * struct drm_dp_vcpi - Virtual Channel Payload Identifier
> > - * @vcpi: Virtual channel ID.
> > - * @pbn: Payload Bandwidth Number for this channel
> > - * @aligned_pbn: PBN aligned with slot size
> > - * @num_slots: number of slots for this PBN
> > - */
> > -struct drm_dp_vcpi {
> > -       int vcpi;
> > -       int pbn;
> > -       int aligned_pbn;
> > -       int num_slots;
> > -};
> > -
> >  /**
> >   * struct drm_dp_mst_port - MST port
> >   * @port_num: port number
> > @@ -142,7 +128,6 @@ struct drm_dp_mst_port {
> >         struct drm_dp_aux aux; /* i2c bus for this port? */
> >         struct drm_dp_mst_branch *parent;
> > 
> > -       struct drm_dp_vcpi vcpi;
> >         struct drm_connector *connector;
> >         struct drm_dp_mst_topology_mgr *mgr;
> > 
> > @@ -527,19 +512,6 @@ struct drm_dp_mst_topology_cbs {
> >         void (*poll_hpd_irq)(struct drm_dp_mst_topology_mgr *mgr);
> >  };
> > 
> > -#define DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
> > -
> > -#define DP_PAYLOAD_LOCAL 1
> > -#define DP_PAYLOAD_REMOTE 2
> > -#define DP_PAYLOAD_DELETE_LOCAL 3
> > -
> > -struct drm_dp_payload {
> > -       int payload_state;
> > -       int start_slot;
> > -       int num_slots;
> > -       int vcpi;
> > -};
> > -
> >  #define to_dp_mst_topology_state(x) container_of(x, struct
> > drm_dp_mst_topology_state, base)
> > 
> >  /**
> > @@ -551,6 +523,35 @@ struct drm_dp_payload {
> >  struct drm_dp_mst_atomic_payload {
> >         /** @port: The MST port assigned to this payload */
> >         struct drm_dp_mst_port *port;
> > +
> > +       /**
> > +        * @vc_start_slot: The time slot that this payload starts on.
> > Because
> > payload start slots
> > +        * can't be determined ahead of time, the contents of this value
> > are
> > UNDEFINED at atomic
> > +        * check time. This shouldn't usually matter, as the start slot
> > should
> > never be relevant for
> > +        * atomic state computations.
> > +        *
> > +        * Since this value is determined at commit time instead of check
> > time, this value is
> > +        * protected by the MST helpers ensuring that async commits
> > operating on the given topology
> > +        * never run in parallel. In the event that a driver does need to
> > read
> > this value (e.g. to
> > +        * inform hardware of the starting timeslot for a payload), the
> > driver
> > may either:
> > +        *
> > +        * * Read this field during the atomic commit after
> > +        *   drm_dp_mst_atomic_wait_for_dependencies() has been called,
> > which will ensure the
> > +        *   previous MST states payload start slots have been copied over
> > to
> > the new state. Note
> > +        *   that a new start slot won't be assigned/removed from this
> > payload until
> > +        *   drm_dp_add_payload_part1()/drm_dp_remove_payload() have
> > been called.
> > +        * * Acquire the MST modesetting lock, and then wait for any
> > pending MST-related commits to
> > +        *   get committed to hardware by calling drm_crtc_commit_wait()
> > on
> > each of the
> > +        *   &drm_crtc_commit structs in
> > &drm_dp_mst_topology_state.commit_deps.
> > +        *
> > +        * If neither of the two above solutions suffice (e.g. the driver
> > needs
> > to read the start
> > +        * slot in the middle of an atomic commit without waiting for some
> > reason), then drivers
> > +        * should cache this value themselves after changing payloads.
> > +        */
> > +       s8 vc_start_slot;
> > +
> > +       /** @vcpi: The Virtual Channel Payload Identifier */
> > +       u8 vcpi;
> >         /** @time_slots: The number of timeslots allocated to this payload
> > */
> >         int time_slots;
> >         /** @pbn: The payload bandwidth for this payload */
> > @@ -574,8 +575,6 @@ struct drm_dp_mst_topology_state {
> >         /** @base: Base private state for atomic */
> >         struct drm_private_state base;
> > 
> > -       /** @payloads: The list of payloads being created/destroyed in
> > this
> > state */
> > -       struct list_head payloads;
> >         /** @mgr: The topology manager */
> >         struct drm_dp_mst_topology_mgr *mgr;
> > 
> > @@ -592,10 +591,21 @@ struct drm_dp_mst_topology_state {
> >         /** @num_commit_deps: The number of CRTC commits in
> > @commit_deps */
> >         size_t num_commit_deps;
> > 
> > +       /** @payload_mask: A bitmask of allocated VCPIs, used for VCPI
> > assignments */
> > +       u32 payload_mask;
> > +       /** @payloads: The list of payloads being created/destroyed in
> > this
> > state */
> > +       struct list_head payloads;
> > +
> >         /** @total_avail_slots: The total number of slots this topology
> > can
> > handle (63 or 64) */
> >         u8 total_avail_slots;
> >         /** @start_slot: The first usable time slot in this topology (1 or
> > 0) */
> >         u8 start_slot;
> > +
> > +       /**
> > +        * @pbn_div: The current PBN divisor for this topology. The driver
> > is
> > expected to fill this
> > +        * out itself.
> > +        */
> > +       int pbn_div;
> >  };
> > 
> >  #define to_dp_mst_topology_mgr(x) container_of(x, struct
> > drm_dp_mst_topology_mgr, base)
> > @@ -635,14 +645,6 @@ struct drm_dp_mst_topology_mgr {
> >          * @max_payloads: maximum number of payloads the GPU can
> > generate.
> >          */
> >         int max_payloads;
> > -       /**
> > -        * @max_lane_count: maximum number of lanes the GPU can drive.
> > -        */
> > -       int max_lane_count;
> > -       /**
> > -        * @max_link_rate: maximum link rate per lane GPU can output, in
> > kHz.
> > -        */
> > -       int max_link_rate;
> >         /**
> >          * @conn_base_id: DRM connector ID this mgr is connected to. Only
> > used
> >          * to build the MST connector path value.
> > @@ -685,6 +687,20 @@ struct drm_dp_mst_topology_mgr {
> >          */
> >         bool payload_id_table_cleared : 1;
> > 
> > +       /**
> > +        * @payload_count: The number of currently active payloads in
> > hardware. This value is only
> > +        * intended to be used internally by MST helpers for payload
> > tracking,
> > and is only safe to
> > +        * read/write from the atomic commit (not check) context.
> > +        */
> > +       u8 payload_count;
> > +
> > +       /**
> > +        * @next_start_slot: The starting timeslot to use for new VC
> > payloads.
> > This value is used
> > +        * internally by MST helpers for payload tracking, and is only
> > safe to
> > read/write from the
> > +        * atomic commit (not check) context.
> > +        */
> > +       u8 next_start_slot;
> > +
> >         /**
> >          * @mst_primary: Pointer to the primary/first branch device.
> >          */
> > @@ -698,10 +714,6 @@ struct drm_dp_mst_topology_mgr {
> >          * @sink_count: Sink count from DEVICE_SERVICE_IRQ_VECTOR_ESI0.
> >          */
> >         u8 sink_count;
> > -       /**
> > -        * @pbn_div: PBN to slots divisor.
> > -        */
> > -       int pbn_div;
> > 
> >         /**
> >          * @funcs: Atomic helper callbacks
> > @@ -718,32 +730,6 @@ struct drm_dp_mst_topology_mgr {
> >          */
> >         struct list_head tx_msg_downq;
> > 
> > -       /**
> > -        * @payload_lock: Protect payload information.
> > -        */
> > -       struct mutex payload_lock;
> > -       /**
> > -        * @proposed_vcpis: Array of pointers for the new VCPI allocation.
> > The
> > -        * VCPI structure itself is &drm_dp_mst_port.vcpi, and the size of
> > -        * this array is determined by @max_payloads.
> > -        */
> > -       struct drm_dp_vcpi **proposed_vcpis;
> > -       /**
> > -        * @payloads: Array of payloads. The size of this array is
> > determined
> > -        * by @max_payloads.
> > -        */
> > -       struct drm_dp_payload *payloads;
> > -       /**
> > -        * @payload_mask: Elements of @payloads actually in use. Since
> > -        * reallocation of active outputs isn't possible gaps can be
> > created by
> > -        * disabling outputs out of order compared to how they've been
> > enabled.
> > -        */
> > -       unsigned long payload_mask;
> > -       /**
> > -        * @vcpi_mask: Similar to @payload_mask, but for @proposed_vcpis.
> > -        */
> > -       unsigned long vcpi_mask;
> > -
> >         /**
> >          * @tx_waitq: Wait to queue stall for the tx worker.
> >          */
> > @@ -815,9 +801,7 @@ struct drm_dp_mst_topology_mgr {
> >  int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr
> > *mgr,
> >                                  struct drm_device *dev, struct drm_dp_aux
> > *aux,
> >                                  int max_dpcd_transaction_bytes,
> > -                                int max_payloads,
> > -                                int max_lane_count, int max_link_rate,
> > -                                int conn_base_id);
> > +                                int max_payloads, int conn_base_id);
> > 
> >  void drm_dp_mst_topology_mgr_destroy(struct
> > drm_dp_mst_topology_mgr *mgr);
> > 
> > @@ -840,28 +824,17 @@ int drm_dp_get_vc_payload_bw(const struct
> > drm_dp_mst_topology_mgr *mgr,
> > 
> >  int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc);
> > 
> > -bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                             struct drm_dp_mst_port *port, int pbn, int
> > slots);
> > -
> > -int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > struct drm_dp_mst_port *port);
> > -
> > -
> > -void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr
> > *mgr, struct drm_dp_mst_port *port);
> > -
> >  void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state
> > *mst_state, uint8_t link_encoding_cap);
> > 
> > -void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> > -                               struct drm_dp_mst_port *port);
> > -
> > -
> > -int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> > -                          int pbn);
> > -
> > -
> > -int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr
> > *mgr, int start_slot);
> > -
> > -
> > -int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr
> > *mgr);
> > +int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_dp_mst_topology_state *mst_state,
> > +                            struct drm_dp_mst_atomic_payload *payload);
> > +int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
> > +                            struct drm_atomic_state *state,
> > +                            struct drm_dp_mst_atomic_payload *payload);
> > +void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr,
> > +                          struct drm_dp_mst_topology_state *mst_state,
> > +                          struct drm_dp_mst_atomic_payload *payload);
> > 
> >  int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);
> > 
> > @@ -883,17 +856,22 @@ int drm_dp_mst_connector_late_register(struct
> > drm_connector *connector,
> >  void drm_dp_mst_connector_early_unregister(struct drm_connector
> > *connector,
> >                                            struct drm_dp_mst_port *port);
> > 
> > -struct drm_dp_mst_topology_state
> > *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> > -                                                                   struct
> > drm_dp_mst_topology_mgr *mgr);
> > +struct drm_dp_mst_topology_state *
> > +drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> > +                                 struct drm_dp_mst_topology_mgr *mgr);
> > +struct drm_dp_mst_topology_state *
> > +drm_atomic_get_new_mst_topology_state(struct drm_atomic_state
> > *state,
> > +                                     struct drm_dp_mst_topology_mgr
> > *mgr);
> > +struct drm_dp_mst_atomic_payload *
> > +drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state
> > *state,
> > +                                struct drm_dp_mst_port *port);
> >  int __must_check
> >  drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
> >                               struct drm_dp_mst_topology_mgr *mgr,
> > -                             struct drm_dp_mst_port *port, int pbn,
> > -                             int pbn_div);
> > +                             struct drm_dp_mst_port *port, int pbn);
> >  int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
> >                                  struct drm_dp_mst_port *port,
> > -                                int pbn, int pbn_div,
> > -                                bool enable);
> > +                                int pbn, bool enable);
> >  int __must_check
> >  drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
> >                                   struct drm_dp_mst_topology_mgr *mgr);
> > @@ -917,6 +895,12 @@ void drm_dp_mst_put_port_malloc(struct
> > drm_dp_mst_port *port);
> > 
> >  struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct
> > drm_dp_mst_port *port);
> > 
> > +static inline struct drm_dp_mst_topology_state *
> > +to_drm_dp_mst_topology_state(struct drm_private_state *state)
> > +{
> > +       return container_of(state, struct drm_dp_mst_topology_state,
> > base);
> > +}
> > +
> >  extern const struct drm_private_state_funcs
> > drm_dp_mst_topology_state_funcs;
> > 
> >  /**
> > --
> > 2.35.3
> 
> --
> Regards,
> Wayne Lin

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat

Re: [Intel-gfx] [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into the atomic state

[Lyude Paul]

On Tue, 2022-07-05 at 09:10 +0000, Lin, Wayne wrote:
> > +struct drm_dp_mst_port;
> > +
> >   /* DP MST stream allocation (payload bandwidth number) */
> >   struct dc_dp_mst_stream_allocation {
> >    uint8_t vcp_id;
> >    /* number of slots required for the DP stream in
> >    * transport packet */
> >    uint8_t slot_count;
> > + /* The MST port this is on, this is used to associate DC MST payloads
> > with their
> > + * respective DRM payloads allocations, and can be ignored on non-
> > Linux.
> > + */
> 
> Is it necessary for adding this new member? Since this is for setting the DC
> HW and not relating to drm.

I don't entirely know, honestly. The reasons I did it:

 * Mapping things from DRM to DC and from DC to DRM is really confusing for
   outside contributors like myself, so it wasn't even really clear to me if
   there was another way to reconstruct the DRM context from the spots where
   we call from DC up to DM (not a typo, see next point).
 * These DC structs for MST are already layer mixing as far as I can tell,
   just not in an immediately obvious way. While this struct itself is for DC,
   there's multiple spots where we pass the DC payload structs down from DM to
   DC, then pass them back up from DC to DM and have to figure out how to
   reconstruct the DRM context that we actually need to use the MST helpers
   from that. So, that kind of further complicates the confusion of where
   layers should be separated.
 * As far as I'm aware with C there shouldn't be any issue with adding a
   pointer to a struct whose contents are undefined. IMHO, this is also
   preferable to just using void* because then at least you get some hint as
   to the actual type of the data and avoid the possibility of casting it to
   the wrong type. So tl;dr, on any platform even outside of Linux with a
   reasonably compliant compiler this should still build just fine. It'll even
   give you the added bonus of warning people if they try to access the
   contents of this member in DC on non-Linux platforms. If void* is preferred
   though I'm fine with switching it to that.

-- 
Cheers, Lyude Paul (she/her) Software Engineer at Red Hat

Re: [Intel-gfx] [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into the atomic state

[Lin, Wayne]

[Public]



> -----Original Message-----
> From: Lyude Paul <lyude@redhat.com>
> Sent: Thursday, August 4, 2022 4:28 AM
> To: Lin, Wayne <Wayne.Lin@amd.com>; dri-devel@lists.freedesktop.org;
> nouveau@lists.freedesktop.org; amd-gfx@lists.freedesktop.org
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>; Zuo, Jerry
> <Jerry.Zuo@amd.com>; Jani Nikula <jani.nikula@intel.com>; Imre Deak
> <imre.deak@intel.com>; Daniel Vetter <daniel.vetter@ffwll.ch>; Sean Paul
> <sean@poorly.run>; Wentland, Harry <Harry.Wentland@amd.com>; Li, Sun
> peng (Leo) <Sunpeng.Li@amd.com>; Siqueira, Rodrigo
> <Rodrigo.Siqueira@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Koenig, Christian
> <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David
> Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Jani Nikula
> <jani.nikula@linux.intel.com>; Joonas Lahtinen
> <joonas.lahtinen@linux.intel.com>; Rodrigo Vivi <rodrigo.vivi@intel.com>;
> Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Ben Skeggs
> <bskeggs@redhat.com>; Karol Herbst <kherbst@redhat.com>; Kazlauskas,
> Nicholas <Nicholas.Kazlauskas@amd.com>; Li, Roman
> <Roman.Li@amd.com>; Shih, Jude <Jude.Shih@amd.com>; Simon Ser
> <contact@emersion.fr>; Lakha, Bhawanpreet
> <Bhawanpreet.Lakha@amd.com>; Mikita Lipski <mikita.lipski@amd.com>;
> Claudio Suarez <cssk@net-c.es>; Chen, Ian <Ian.Chen@amd.com>; Colin Ian
> King <colin.king@intel.com>; Wu, Hersen <hersenxs.wu@amd.com>; Liu,
> Wenjing <Wenjing.Liu@amd.com>; Lei, Jun <Jun.Lei@amd.com>; Strauss,
> Michael <Michael.Strauss@amd.com>; Ma, Leo <Hanghong.Ma@amd.com>;
> Thomas Zimmermann <tzimmermann@suse.de>; José Roberto de Souza
> <jose.souza@intel.com>; He Ying <heying24@huawei.com>; Anshuman
> Gupta <anshuman.gupta@intel.com>; Andi Shyti
> <andi.shyti@linux.intel.com>; Ashutosh Dixit <ashutosh.dixit@intel.com>;
> Juston Li <juston.li@intel.com>; Sean Paul <seanpaul@chromium.org>;
> Fernando Ramos <greenfoo@u92.eu>; Luo Jiaxing
> <luojiaxing@huawei.com>; Javier Martinez Canillas <javierm@redhat.com>;
> open list <linux-kernel@vger.kernel.org>; open list:INTEL DRM DRIVERS
> <intel-gfx@lists.freedesktop.org>
> Subject: Re: [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info
> into the atomic state
> 
> On Tue, 2022-07-05 at 09:10 +0000, Lin, Wayne wrote:
> > > +struct drm_dp_mst_port;
> > > +
> > >   /* DP MST stream allocation (payload bandwidth number) */
> > >   struct dc_dp_mst_stream_allocation {
> > >    uint8_t vcp_id;
> > >    /* number of slots required for the DP stream in
> > >    * transport packet */
> > >    uint8_t slot_count;
> > > + /* The MST port this is on, this is used to associate DC MST
> > > + payloads
> > > with their
> > > + * respective DRM payloads allocations, and can be ignored on non-
> > > Linux.
> > > + */
> >
> > Is it necessary for adding this new member? Since this is for setting
> > the DC HW and not relating to drm.
> 
> I don't entirely know, honestly. The reasons I did it:
> 
>  * Mapping things from DRM to DC and from DC to DRM is really confusing for
>    outside contributors like myself, so it wasn't even really clear to me if
>    there was another way to reconstruct the DRM context from the spots
> where
>    we call from DC up to DM (not a typo, see next point).
>  * These DC structs for MST are already layer mixing as far as I can tell,
>    just not in an immediately obvious way. While this struct itself is for DC,
>    there's multiple spots where we pass the DC payload structs down from
> DM to
>    DC, then pass them back up from DC to DM and have to figure out how to
>    reconstruct the DRM context that we actually need to use the MST helpers
>    from that. So, that kind of further complicates the confusion of where
>    layers should be separated.
>  * As far as I'm aware with C there shouldn't be any issue with adding a
>    pointer to a struct whose contents are undefined. IMHO, this is also
>    preferable to just using void* because then at least you get some hint as
>    to the actual type of the data and avoid the possibility of casting it to
>    the wrong type. So tl;dr, on any platform even outside of Linux with a
>    reasonably compliant compiler this should still build just fine. It'll even
>    give you the added bonus of warning people if they try to access the
>    contents of this member in DC on non-Linux platforms. If void* is preferred
>    though I'm fine with switching it to that.
> 
> --
> Cheers, Lyude Paul (she/her) Software Engineer at Red Hat

Hi Lyude,

Thanks for your time!
I was thinking that our DC just mainly takes care of HW related programming. 
Struct dc_dp_mst_stream_allocation is only used to construct a copy of the virtual 
channel payload ID and slots count of payload allocation table determined by
dm/drm. ID and slots are only things required for programming HW registers.
I think there shouldn't be any spots to try to construct the DRM context from
this dc struct since there is no such concept in HW level. Our HW should only 
take care of local DP link and it doesn't have overall topology info.

Thanks!

Regards,
Wayne

Re: [Intel-gfx] [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info into the atomic state

[Lyude Paul]

On Mon, 2022-08-08 at 10:02 +0000, Lin, Wayne wrote:
> [Public]
> 
> 
> 
> > -----Original Message-----
> > From: Lyude Paul <lyude@redhat.com>
> > Sent: Thursday, August 4, 2022 4:28 AM
> > To: Lin, Wayne <Wayne.Lin@amd.com>; dri-devel@lists.freedesktop.org;
> > nouveau@lists.freedesktop.org; amd-gfx@lists.freedesktop.org
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>; Zuo, Jerry
> > <Jerry.Zuo@amd.com>; Jani Nikula <jani.nikula@intel.com>; Imre Deak
> > <imre.deak@intel.com>; Daniel Vetter <daniel.vetter@ffwll.ch>; Sean Paul
> > <sean@poorly.run>; Wentland, Harry <Harry.Wentland@amd.com>; Li, Sun
> > peng (Leo) <Sunpeng.Li@amd.com>; Siqueira, Rodrigo
> > <Rodrigo.Siqueira@amd.com>; Deucher, Alexander
> > <Alexander.Deucher@amd.com>; Koenig, Christian
> > <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David
> > Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Jani Nikula
> > <jani.nikula@linux.intel.com>; Joonas Lahtinen
> > <joonas.lahtinen@linux.intel.com>; Rodrigo Vivi <rodrigo.vivi@intel.com>;
> > Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Ben Skeggs
> > <bskeggs@redhat.com>; Karol Herbst <kherbst@redhat.com>; Kazlauskas,
> > Nicholas <Nicholas.Kazlauskas@amd.com>; Li, Roman
> > <Roman.Li@amd.com>; Shih, Jude <Jude.Shih@amd.com>; Simon Ser
> > <contact@emersion.fr>; Lakha, Bhawanpreet
> > <Bhawanpreet.Lakha@amd.com>; Mikita Lipski <mikita.lipski@amd.com>;
> > Claudio Suarez <cssk@net-c.es>; Chen, Ian <Ian.Chen@amd.com>; Colin Ian
> > King <colin.king@intel.com>; Wu, Hersen <hersenxs.wu@amd.com>; Liu,
> > Wenjing <Wenjing.Liu@amd.com>; Lei, Jun <Jun.Lei@amd.com>; Strauss,
> > Michael <Michael.Strauss@amd.com>; Ma, Leo <Hanghong.Ma@amd.com>;
> > Thomas Zimmermann <tzimmermann@suse.de>; José Roberto de Souza
> > <jose.souza@intel.com>; He Ying <heying24@huawei.com>; Anshuman
> > Gupta <anshuman.gupta@intel.com>; Andi Shyti
> > <andi.shyti@linux.intel.com>; Ashutosh Dixit <ashutosh.dixit@intel.com>;
> > Juston Li <juston.li@intel.com>; Sean Paul <seanpaul@chromium.org>;
> > Fernando Ramos <greenfoo@u92.eu>; Luo Jiaxing
> > <luojiaxing@huawei.com>; Javier Martinez Canillas <javierm@redhat.com>;
> > open list <linux-kernel@vger.kernel.org>; open list:INTEL DRM DRIVERS
> > <intel-gfx@lists.freedesktop.org>
> > Subject: Re: [RESEND RFC 18/18] drm/display/dp_mst: Move all payload info
> > into the atomic state
> > 
> > On Tue, 2022-07-05 at 09:10 +0000, Lin, Wayne wrote:
> > > > +struct drm_dp_mst_port;
> > > > +
> > > >   /* DP MST stream allocation (payload bandwidth number) */
> > > >   struct dc_dp_mst_stream_allocation {
> > > >    uint8_t vcp_id;
> > > >    /* number of slots required for the DP stream in
> > > >    * transport packet */
> > > >    uint8_t slot_count;
> > > > + /* The MST port this is on, this is used to associate DC MST
> > > > + payloads
> > > > with their
> > > > + * respective DRM payloads allocations, and can be ignored on non-
> > > > Linux.
> > > > + */
> > > 
> > > Is it necessary for adding this new member? Since this is for setting
> > > the DC HW and not relating to drm.
> > 
> > I don't entirely know, honestly. The reasons I did it:
> > 
> >  * Mapping things from DRM to DC and from DC to DRM is really confusing for
> >    outside contributors like myself, so it wasn't even really clear to me if
> >    there was another way to reconstruct the DRM context from the spots
> > where
> >    we call from DC up to DM (not a typo, see next point).
> >  * These DC structs for MST are already layer mixing as far as I can tell,
> >    just not in an immediately obvious way. While this struct itself is for DC,
> >    there's multiple spots where we pass the DC payload structs down from
> > DM to
> >    DC, then pass them back up from DC to DM and have to figure out how to
> >    reconstruct the DRM context that we actually need to use the MST helpers
> >    from that. So, that kind of further complicates the confusion of where
> >    layers should be separated.
> >  * As far as I'm aware with C there shouldn't be any issue with adding a
> >    pointer to a struct whose contents are undefined. IMHO, this is also
> >    preferable to just using void* because then at least you get some hint as
> >    to the actual type of the data and avoid the possibility of casting it to
> >    the wrong type. So tl;dr, on any platform even outside of Linux with a
> >    reasonably compliant compiler this should still build just fine. It'll even
> >    give you the added bonus of warning people if they try to access the
> >    contents of this member in DC on non-Linux platforms. If void* is preferred
> >    though I'm fine with switching it to that.
> > 
> > --
> > Cheers, Lyude Paul (she/her) Software Engineer at Red Hat
> 
> Hi Lyude,
> 
> Thanks for your time!
> I was thinking that our DC just mainly takes care of HW related programming. 
> Struct dc_dp_mst_stream_allocation is only used to construct a copy of the virtual 
> channel payload ID and slots count of payload allocation table determined by
> dm/drm. ID and slots are only things required for programming HW registers.
> I think there shouldn't be any spots to try to construct the DRM context from
> this dc struct since there is no such concept in HW level. Our HW should only 
> take care of local DP link and it doesn't have overall topology info.

Looking at the code I wrote again and realizing I slightly misspoke, looking
at the code again I think I probably can drop this. It's likely I just got
totally lost with the DC codebase and thought this was necessary when it
wasn't. Will drop in the respin

> 
> Thanks!
> 
> Regards,
> Wayne

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat