[Intel-gfx] [PATCH v3] drm/i915/mst: update slot information for 128b/132b

Jani Nikula
2022-02-08T15:23:28Z

128b/132b supports using 64 slots starting from 0, while 8b/10b reserves
slot 0 for metadata.

Commit d6c6a76f80a1 ("drm: Update MST First Link Slot Information Based
on Encoding Format") added support for updating the topology state
accordingly, and commit 41724ea273cd ("drm/amd/display: Add DP 2.0 MST
DM Support") started using it in the amd driver.

This feels more than a little cumbersome, especially updating the
information in atomic check. For i915, add the update to MST connector
.compute_config hook rather than iterating over all MST managers and
connectors in global mode config .atomic_check. Fingers crossed.

v3:
- Propagate errors from intel_dp_mst_update_slots() (Ville)

v2:
- Update in .compute_config() not .atomic_check (Ville)

Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
drivers/gpu/drm/i915/display/intel_dp_mst.c | 33 +++++++++++++++++++--
1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 6b6eab507d30..e30e698aa684 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -99,6 +99,29 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
return 0;
}

+static int intel_dp_mst_update_slots(struct intel_encoder *encoder,
+ struct intel_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state)
+{
+ struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+ 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_mgr *mgr = &intel_dp->mst_mgr;
+ struct drm_dp_mst_topology_state *topology_state;
+ u8 link_coding_cap = intel_dp_is_uhbr(crtc_state) ?
+ DP_CAP_ANSI_128B132B : DP_CAP_ANSI_8B10B;
+
+ topology_state = drm_atomic_get_mst_topology_state(conn_state->state, mgr);
+ if (IS_ERR(topology_state)) {
+ drm_dbg_kms(&i915->drm, "slot update failed\n");
+ return PTR_ERR(topology_state);
+ }
+
+ drm_dp_mst_update_slots(topology_state, link_coding_cap);
+
+ return 0;
+}
+
static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
struct intel_crtc_state *pipe_config,
struct drm_connector_state *conn_state)
@@ -155,6 +178,10 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
if (ret)
return ret;

+ ret = intel_dp_mst_update_slots(encoder, pipe_config, conn_state);
+ if (ret)
+ return ret;
+
pipe_config->limited_color_range =
intel_dp_limited_color_range(pipe_config, conn_state);

@@ -357,6 +384,7 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
struct intel_connector *connector =
to_intel_connector(old_conn_state->connector);
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",
@@ -366,7 +394,7 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,

drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, connector->port);

- ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr, 1);
+ 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);
}
@@ -475,6 +503,7 @@ 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;
int ret;
bool first_mst_stream;

@@ -509,7 +538,7 @@ static void intel_mst_pre_enable_dp(struct intel_atomic_state *state,

intel_dp->active_mst_links++;

- ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr, 1);
+ ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr, start_slot);

/*
* Before Gen 12 this is not done as part of
--
2.30.2