[PATCH v1 0/3] drm/amd/display: passive VRR

[PATCH v1 0/3] drm/amd/display: passive VRR

[Fangzhi Zuo]

Passive VRR keeps a sink in its variable-refresh state during fixed-refresh
(desktop) use, avoiding the blanking/brightness flicker that HDMI sinks
without seamless VRR transitions show on VRR entry/exit. It is opt-out
(enabled by default where the connector advertises passive_vrr_capable) and
is not useful for DP/eDP, where seamless VRR transitions are mandated by the
standard.

Patch 1 adds the DRM core plumbing: the PASSIVE_VRR_DISABLED atomic CRTC
property and the immutable passive_vrr_capable connector property, with the
attach/set helpers.

Patch 2 wires these into amdgpu via the existing DC
stream->freesync_on_desktop path.

Patch 3 fixes the MCCS FreeSync fallback so that HDMI-Forum VRR (HF-VSDB)
sinks keep freesync_capable; without it passive VRR never engages on the
very TMDS HF-VSDB sinks it targets.


Fangzhi Zuo (1):
  drm/amd/display: Keep FreeSync for HF-VSDB VRR sinks in MCCS fallback

Tomasz Pakuła (2):
  drm: Add passive_vrr properties for passive/desktop VRR
  drm/amd/display: Use passive_vrr properties in amdgpu

 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  1 +
 .../display/amdgpu_dm/amdgpu_dm_connector.c   | 13 +++-
 .../display/amdgpu_dm/amdgpu_dm_freesync.c    |  7 ++
 drivers/gpu/drm/drm_atomic_uapi.c             |  4 +
 drivers/gpu/drm/drm_connector.c               | 73 +++++++++++++++++++
 drivers/gpu/drm/drm_crtc.c                    |  2 +
 drivers/gpu/drm/drm_mode_config.c             |  6 ++
 include/drm/drm_connector.h                   | 15 ++++
 include/drm/drm_crtc.h                        |  9 +++
 include/drm/drm_mode_config.h                 |  6 ++
 10 files changed, 134 insertions(+), 2 deletions(-)


base-commit: 8c77d618886a143de5cd87a35963b4993075802a
-- 
2.53.0

[PATCH v1 1/3] drm: Add passive_vrr properties for passive/desktop VRR

[Fangzhi Zuo]

From: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>

Backport of upstream (Tomasz Pakula) amd-gfx v4 series patches 23/27 and
24/27, squashed into the drm-core change required for passive_vrr_capable.

Add the PASSIVE_VRR_DISABLED atomic CRTC property (drm_crtc_state.
passive_vrr_disabled) and the immutable passive_vrr_capable connector
property, together with drm_connector_attach_passive_vrr_capable_property()
and drm_connector_set_passive_vrr_capable_property() helpers.

Passive VRR keeps a sink in its variable-refresh state during fixed
refresh (desktop) use, avoiding blanking/flicker on VRR entry/exit for
HDMI sinks that lack seamless VRR transitions. The property is opt-out
(default enabled where the connector advertises passive_vrr_capable);
lacking hardware support is not treated as failure. Not useful for
DP/eDP where seamless VRR transitions are enforced by the standard.

Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
---
 drivers/gpu/drm/drm_atomic_uapi.c |  4 ++
 drivers/gpu/drm/drm_connector.c   | 73 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_crtc.c        |  2 +
 drivers/gpu/drm/drm_mode_config.c |  6 +++
 include/drm/drm_connector.h       | 15 +++++++
 include/drm/drm_crtc.h            |  9 ++++
 include/drm/drm_mode_config.h     |  6 +++
 7 files changed, 115 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index e997917819e8..c50c83360ba2 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -420,6 +420,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 		return ret;
 	} else if (property == config->prop_vrr_enabled) {
 		state->vrr_enabled = val;
+	} else if (property == config->prop_passive_vrr_disabled) {
+		state->passive_vrr_disabled = val;
 	} else if (property == config->degamma_lut_property) {
 		const size_t elem_size = sizeof(struct drm_color_lut);
 		u64 lut_size;
@@ -505,6 +507,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
 		*val = (state->mode_blob) ? state->mode_blob->base.id : 0;
 	else if (property == config->prop_vrr_enabled)
 		*val = state->vrr_enabled;
+	else if (property == config->prop_passive_vrr_disabled)
+		*val = state->passive_vrr_disabled;
 	else if (property == config->degamma_lut_property)
 		*val = (state->degamma_lut) ? state->degamma_lut->base.id : 0;
 	else if (property == config->ctm_property)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 9d820a2a87ce..c429105172b0 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -2368,6 +2368,16 @@ EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
  *
  *	Absence of the property should indicate absence of support.
  *
+ * "passive_vrr_capable":
+ *	Optional &drm_connector boolean property that drivers should attach
+ *	with drm_connector_attach_passive_vrr_capable_property() on
+ *	connectors that could support keeping variable refresh rate signalling
+ *	in fixed-refresh rate scenarios like desktop work. Drivers should update
+ *	the property value by calling
+ *	drm_connector_set_passive_vrr_capable_property().
+ *
+ *	Absence of the property should indicate absence of support.
+ *
  * "VRR_ENABLED":
  *	Default &drm_crtc boolean property that notifies the driver that the
  *	content on the CRTC is suitable for variable refresh rate presentation.
@@ -2386,6 +2396,17 @@ EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
  *
  *	The driver may place further restrictions within these minimum
  *	and maximum bounds.
+ *
+ * "PASSIVE_VRR_DISABLED":
+ *	Default &drm_crtc boolean property that notifies the driver that the
+ *	VRR singalling should be disabled in fixed refresh rate scenarios.
+ *	Functionally, psssive vrr works the same as VRR_ENABLED == false
+ *	but works around displays blanking (mainly HDMI) that do not support
+ *	seamless VRR transitions. Also helps with brightness flickering during
+ *	VRR transitions.
+ *
+ *	Passive VRR mode is not that useful for DP/eDP sinks where seamless VRR
+ *	transitions are enforced by the standard.
  */
 
 /**
@@ -2419,6 +2440,37 @@ int drm_connector_attach_vrr_capable_property(
 }
 EXPORT_SYMBOL(drm_connector_attach_vrr_capable_property);
 
+/**
+ * drm_connector_attach_passive_vrr_capable_property - creates the
+ * passive_vrr_capable property
+ * @connector: connector to create the passive_vrr_capable property on.
+ *
+ * This is used by atomic drivers to add support for querying
+ * variable refresh rate on desktop capability for a connector.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_connector_attach_passive_vrr_capable_property(
+	struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_property *prop;
+
+	if (!connector->passive_vrr_capable_property) {
+		prop = drm_property_create_bool(dev, DRM_MODE_PROP_IMMUTABLE,
+			"passive_vrr_capable");
+		if (!prop)
+			return -ENOMEM;
+
+		connector->passive_vrr_capable_property = prop;
+		drm_object_attach_property(&connector->base, prop, 0);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_connector_attach_passive_vrr_capable_property);
+
 /**
  * drm_connector_attach_scaling_mode_property - attach atomic scaling mode property
  * @connector: connector to attach scaling mode property on.
@@ -2985,6 +3037,27 @@ void drm_connector_set_vrr_capable_property(
 }
 EXPORT_SYMBOL(drm_connector_set_vrr_capable_property);
 
+/**
+ * drm_connector_set_passive_vrr_capable_property - sets the variable refresh
+ * rate on desktop capable property for a connector
+ * @connector: drm connector
+ * @capable: True if the connector is variable refresh rate on desktop capable
+ *
+ * Should be used by atomic drivers to update the indicated support for
+ * variable refresh rate on desktop over a connector.
+ */
+void drm_connector_set_passive_vrr_capable_property(
+		struct drm_connector *connector, bool capable)
+{
+	if (!connector->passive_vrr_capable_property)
+		return;
+
+	drm_object_property_set_value(&connector->base,
+				      connector->passive_vrr_capable_property,
+				      capable);
+}
+EXPORT_SYMBOL(drm_connector_set_passive_vrr_capable_property);
+
 /**
  * drm_connector_set_panel_orientation - sets the connector's panel_orientation
  * @connector: connector for which to set the panel-orientation property.
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 63ead8ba6756..bd666dbc30f2 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -322,6 +322,8 @@ static int __drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *
 					   config->prop_out_fence_ptr, 0);
 		drm_object_attach_property(&crtc->base,
 					   config->prop_vrr_enabled, 0);
+		drm_object_attach_property(&crtc->base,
+					   config->prop_passive_vrr_disabled, 0);
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 66f7dc37b597..dc1ca08655ca 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -345,6 +345,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.prop_vrr_enabled = prop;
 
+	prop = drm_property_create_bool(dev, 0,
+			"PASSIVE_VRR_DISABLED");
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.prop_passive_vrr_disabled = prop;
+
 	prop = drm_property_create(dev,
 			DRM_MODE_PROP_BLOB,
 			"DEGAMMA_LUT", 0);
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 9f8f109c2dd1..fd370ecfc6a2 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2212,6 +2212,17 @@ struct drm_connector {
 	 */
 	struct drm_property *vrr_capable_property;
 
+	/**
+	 * @passive_vrr_capable_property: Optional property to help userspace
+	 * query hardware support for passive variable refresh rate on a
+	 * connector. Drivers can add the property to a connector by
+	 * calling drm_connector_attach_passive_vrr_capable_property().
+	 *
+	 * This should be updated only by calling
+	 * drm_connector_set_passive_vrr_capable_property().
+	 */
+	struct drm_property *passive_vrr_capable_property;
+
 	/**
 	 * @colorspace_property: Connector property to set the suitable
 	 * colorspace supported by the sink.
@@ -2606,6 +2617,8 @@ int drm_connector_attach_scaling_mode_property(struct drm_connector *connector,
 					       u32 scaling_mode_mask);
 int drm_connector_attach_vrr_capable_property(
 		struct drm_connector *connector);
+int drm_connector_attach_passive_vrr_capable_property(
+		struct drm_connector *connector);
 void drm_connector_attach_panel_type_property(struct drm_connector *connector);
 int drm_connector_attach_broadcast_rgb_property(struct drm_connector *connector);
 int drm_connector_attach_colorspace_property(struct drm_connector *connector);
@@ -2629,6 +2642,8 @@ void drm_connector_set_link_status_property(struct drm_connector *connector,
 					    uint64_t link_status);
 void drm_connector_set_vrr_capable_property(
 		struct drm_connector *connector, bool capable);
+void drm_connector_set_passive_vrr_capable_property(
+		struct drm_connector *connector, bool capable);
 int drm_connector_set_panel_orientation(
 	struct drm_connector *connector,
 	enum drm_panel_orientation panel_orientation);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c6dbe8b7db9e..642a374f403e 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -311,6 +311,15 @@ struct drm_crtc_state {
 	 */
 	bool vrr_enabled;
 
+	/**
+	 * @passive_vrr_disabled:
+	 *
+	 * Indicates if variable refresh rate on desktop should be enabled for
+	 * the CRTC. Support for the requested state will depend on driver and
+	 * hardware capabiltiy - lacking support is not treated as failure.
+	 */
+	bool passive_vrr_disabled;
+
 	/**
 	 * @self_refresh_active:
 	 *
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index e584652ddf67..e312e6ae4d7e 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -701,6 +701,12 @@ struct drm_mode_config {
 	 * whether variable refresh rate should be enabled on the CRTC.
 	 */
 	struct drm_property *prop_vrr_enabled;
+	/**
+	 * @prop_passive_vrr_disabled: Default atomic CRTC property to indicate
+	 * whether passive variable refresh rate should be disabled
+	 * on the CRTC.
+	 */
+	struct drm_property *prop_passive_vrr_disabled;
 
 	/**
 	 * @dvi_i_subconnector_property: Optional DVI-I property to
-- 
2.53.0

[PATCH v1 2/3] drm/amd/display: Use passive_vrr properties in amdgpu

[Fangzhi Zuo]

From: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>

Backport of upstream (Tomasz Pakula) amd-gfx v4 27-patch series patch
26/27, adapted to the split amdgpu_dm sources on amd-staging-drm-next.

Wire the passive_vrr DRM properties into amdgpu for HDMI/DP/eDP sinks:
- Add dm_connector_state.freesync_on_desktop_capable and copy it in
  amdgpu_dm_connector_atomic_duplicate_state().
- Attach the passive_vrr_capable connector property alongside
  vrr_capable for non-MST connectors.
- In amdgpu_dm_update_freesync_caps(), record freesync_on_desktop_capable
  and update the passive_vrr_capable property from freesync_capable.
- In amdgpu_dm_get_freesync_config_for_crtc(), drive
  stream->freesync_on_desktop from the inverse of passive_vrr_disabled
  when capable, hooking into the existing DC freesync_on_desktop logic
  that keeps the FreeSync-Active bit set during fixed-refresh (desktop)
  use.

Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h    |  1 +
 .../drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c  | 12 ++++++++++--
 .../drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c   |  7 +++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 089741ba0619..0b0ab7b2aa43 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -1064,6 +1064,7 @@ struct dm_connector_state {
 	uint8_t underscan_hborder;
 	bool underscan_enable;
 	bool freesync_capable;
+	bool freesync_on_desktop_capable;
 	bool update_hdcp;
 	bool abm_sysfs_forbidden;
 	uint8_t abm_level;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
index 0e71ba498e8a..8b2eec1a683d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
@@ -1982,6 +1982,7 @@ amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector *connector)
 	__drm_atomic_helper_connector_duplicate_state(connector, &new_state->base);
 
 	new_state->freesync_capable = state->freesync_capable;
+	new_state->freesync_on_desktop_capable = state->freesync_on_desktop_capable;
 	new_state->abm_level = state->abm_level;
 	new_state->scaling = state->scaling;
 	new_state->underscan_enable = state->underscan_enable;
@@ -3241,8 +3242,10 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
 	    connector_type == DRM_MODE_CONNECTOR_eDP) {
 		drm_connector_attach_hdr_output_metadata_property(&aconnector->base);
 
-		if (!aconnector->mst_root)
+		if (!aconnector->mst_root) {
 			drm_connector_attach_vrr_capable_property(&aconnector->base);
+			drm_connector_attach_passive_vrr_capable_property(&aconnector->base);
+		}
 
 
 		if (adev->dm.hdcp_workqueue)
@@ -3978,8 +3981,10 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
 		dm_helpers_mccs_vcp_set(adev->dm.dc->ctx, amdgpu_dm_connector->dc_link, sink);
 
 update:
-	if (dm_con_state)
+	if (dm_con_state) {
 		dm_con_state->freesync_capable = freesync_capable;
+		dm_con_state->freesync_on_desktop_capable = freesync_capable;
+	}
 
 	drm_dbg_driver(adev_to_drm(adev),
 		       "VRR: caps result: freesync_capable=%d min_vfreq=%d max_vfreq=%d\n",
@@ -3995,4 +4000,7 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
 	if (connector->vrr_capable_property)
 		drm_connector_set_vrr_capable_property(connector,
 						       freesync_capable);
+
+	if (connector->passive_vrr_capable_property)
+		drm_connector_set_passive_vrr_capable_property(connector, freesync_capable);
 }
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c
index 281c6cec9f4b..903d5ab387d4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c
@@ -138,6 +138,12 @@ void amdgpu_dm_get_freesync_config_for_crtc(
 		config.vsif_supported = true;
 		config.btr = true;
 
+		if (new_con_state->freesync_on_desktop_capable)
+			new_crtc_state->stream->freesync_on_desktop =
+				!new_crtc_state->base.passive_vrr_disabled;
+		else
+			new_crtc_state->stream->freesync_on_desktop = false;
+
 		if (fs_vid_mode) {
 			config.state = VRR_STATE_ACTIVE_FIXED;
 			config.fixed_refresh_in_uhz = new_crtc_state->freesync_config.fixed_refresh_in_uhz;
@@ -149,6 +155,7 @@ void amdgpu_dm_get_freesync_config_for_crtc(
 		}
 	} else {
 		config.state = VRR_STATE_UNSUPPORTED;
+		new_crtc_state->stream->freesync_on_desktop = false;
 	}
 out:
 	new_crtc_state->freesync_config = config;
-- 
2.53.0

[PATCH v1 3/3] drm/amd/display: Keep FreeSync for HF-VSDB VRR sinks in MCCS fallback

[Fangzhi Zuo]

From: Fangzhi Zuo <Jerry.Zuo@amd.com>

amdgpu_dm_update_freesync_caps() clears freesync_capable for any
SIGNAL_TYPE_HDMI_TYPE_A sink that lacks an AMD FreeSync MCCS VCP code.
HDMI-Forum VRR (HF-VSDB) sinks advertise VRR without such a VCP code, so
the HF-VSDB fallback that set freesync_capable was immediately undone,
leaving VRR and passive VRR disabled on those sinks.

Skip the MCCS clear when the sink reports HF-VSDB VRR capability, so
freesync_capable survives for HDMI-Forum VRR sinks.

Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
index 8b2eec1a683d..e4b53086f312 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
@@ -3973,6 +3973,7 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
 
 	if ((sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A ||
 		as_type == FREESYNC_TYPE_PCON_IN_WHITELIST) &&
+		!connector->display_info.hdmi.vrr_cap.supported &&
 		(!sink->edid_caps.freesync_vcp_code ||
 		(sink->edid_caps.freesync_vcp_code && !sink->mccs_caps.freesync_supported)))
 		freesync_capable = false;
-- 
2.53.0

Re: [PATCH v1 1/3] drm: Add passive_vrr properties for passive/desktop VRR

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Contradictory kerneldoc for `passive_vrr_disabled` in `struct drm_crtc_state` and multiple spelling errors in comments.
--

commit 870f0fcb955a90bd32f228b223d6193abfa63290
Author: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Subject: drm: Add passive_vrr properties for passive/desktop VRR

This commit adds atomic CRTC and immutable connector properties to support
passive VRR for desktop usage on HDMI sinks. This aims to avoid blanking or
flickering on VRR entry and exit by keeping the sink in a variable-refresh
state during fixed refresh use.

> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 9d820a2a87ce4..c429105172b0d 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
[ ... ]
> @@ -2386,6 +2396,17 @@ EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
>   *
>   *	The driver may place further restrictions within these minimum
>   *	and maximum bounds.
> + *
> + * "PASSIVE_VRR_DISABLED":
> + *	Default &drm_crtc boolean property that notifies the driver that the
> + *	VRR singalling should be disabled in fixed refresh rate scenarios.
> + *	Functionally, psssive vrr works the same as VRR_ENABLED == false

[Severity: Low]
This isn't a bug, but there are a couple of spelling errors in the uAPI
documentation here: "singalling" should be "signalling", and "psssive"
should be "passive".

> + *	but works around displays blanking (mainly HDMI) that do not support
> + *	seamless VRR transitions. Also helps with brightness flickering during
> + *	VRR transitions.
> + *
> + *	Passive VRR mode is not that useful for DP/eDP sinks where seamless VRR
> + *	transitions are enforced by the standard.
>   */
[ ... ]
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index c6dbe8b7db9ee..642a374f403e6 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -311,6 +311,15 @@ struct drm_crtc_state {
>  	 */
>  	bool vrr_enabled;
>  
> +	/**
> +	 * @passive_vrr_disabled:
> +	 *
> +	 * Indicates if variable refresh rate on desktop should be enabled for
> +	 * the CRTC. Support for the requested state will depend on driver and
> +	 * hardware capabiltiy - lacking support is not treated as failure.
> +	 */
> +	bool passive_vrr_disabled;
> +

[Severity: Low]
This isn't a bug, but the documentation states this field "Indicates if
variable refresh rate on desktop should be enabled", which contradicts the
variable name passive_vrr_disabled. Should this description read "disabled"
instead?

Also, there is a spelling error in "capabiltiy" (capability).

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901191251.2653684-1-jerry.zuo@amd.com?part=1

Re: [PATCH v1 1/3] drm: Add passive_vrr properties for passive/desktop VRR

[Tomasz Pakuła]

On Tue, 2026-09-01 at 15:12 -0400, Fangzhi Zuo wrote:
> Add the PASSIVE_VRR_DISABLED atomic CRTC property

Michel Dänzer already commented on this:
https://lore.kernel.org/amd-gfx/c6a852ae-4edf-4336-9f2a-448c296cc045@mailbox.org/

"Having a negation term like "disabled" in the property name can be
confusing (as it involves double negation when the property value is 0)
and is better avoided."

To this day, I'm not sure how to better handle this, without the driver
just forcing VRR on it's own. Consequently, this will enforce ALLM so
probably there is a benefit to leaving this configurable and somehow
default for HDMI.

IDK, smarter people can probably deal with this, just wanted to forward
the comments I received previously.

On windows, AMD driver just doesn't care and forces VRR signaling all
the time, without a way to disable it.

Re: [PATCH v1 2/3] drm/amd/display: Use passive_vrr properties in amdgpu

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] Missing `passive_vrr_disabled` check in atomic check prevents hardware update.
- [High] In-place mutation of shared `dc_stream_state` during atomic check.
- [Medium] Missing `passive_vrr_capable` property on MST endpoints, but the feature is silently enabled.
--

commit b13d5b0a2a71643131cf661b1a6d126b390f1d96
Author: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>

drm/amd/display: Use passive_vrr properties in amdgpu

This commit wires the passive_vrr DRM properties into amdgpu for HDMI, DP,
and eDP sinks. It attaches the passive_vrr_capable property alongside
vrr_capable for non-MST connectors, records the freesync_on_desktop
capability, and sets the stream freesync_on_desktop state based on the
passive_vrr_disabled property.

> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> index 0e71ba498e8aa..8b2eec1a683d4 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
[ ... ]
> @@ -3241,8 +3242,10 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
>  	    connector_type == DRM_MODE_CONNECTOR_eDP) {
>  		drm_connector_attach_hdr_output_metadata_property(&aconnector->base);
>  
> -		if (!aconnector->mst_root)
> +		if (!aconnector->mst_root) {
>  			drm_connector_attach_vrr_capable_property(&aconnector->base);
> +			drm_connector_attach_passive_vrr_capable_property(&aconnector->base);
> +		}

[Severity: Medium]
Will this result in passive VRR being silently enabled for MST endpoints
without exposing the capability property to userspace?

The passive_vrr_capable property is explicitly restricted to non-MST
endpoints here. However, the logic in amdgpu_dm_update_freesync_caps() and
amdgpu_dm_get_freesync_config_for_crtc() appears to unconditionally activate
freesync_on_desktop if the display is FreeSync capable.

Because the capability property isn't cloned to dynamic MST endpoints, those
endpoints will have the feature activated by default (since the
passive_vrr_disabled property defaults to false) without userspace being
able to discover the capability.

[ ... ]
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c
> index 281c6cec9f4bc..903d5ab387d4b 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_freesync.c
> @@ -138,6 +138,12 @@ void amdgpu_dm_get_freesync_config_for_crtc(
>  		config.vsif_supported = true;
>  		config.btr = true;
>  
> +		if (new_con_state->freesync_on_desktop_capable)
> +			new_crtc_state->stream->freesync_on_desktop =
> +				!new_crtc_state->base.passive_vrr_disabled;
> +		else
> +			new_crtc_state->stream->freesync_on_desktop = false;
> +

[Severity: High]
If userspace only toggles the passive_vrr_disabled property without
triggering a modeset, will the hardware actually get updated?

It appears that amdgpu_dm_atomic_check() in amdgpu_dm.c skips adding
affected planes if only passive_vrr_disabled changes. Its fast-return path
checks for color_mgmt_changed, vrr_enabled, and dsc_force_changed, but
misses a check for passive_vrr_disabled.

If planes aren't added to the atomic state, the subsequent commit will skip
updating the stream and VRR state entirely, leaving hardware and software
out of sync.

[Severity: High]
Does this assignment mutate the active stream state during a TEST_ONLY
atomic commit?

In amdgpu_dm_get_freesync_config_for_crtc(), new_crtc_state->stream points
to a shared, refcounted dc_stream_state object that represents the current
hardware state. It is not deep-copied during state duplication.

If userspace performs a DRM_MODE_ATOMIC_TEST_ONLY commit, writing directly
to stream->freesync_on_desktop permanently alters the running state and
breaks atomic test-only invariants.

>  		if (fs_vid_mode) {
>  			config.state = VRR_STATE_ACTIVE_FIXED;
>  			config.fixed_refresh_in_uhz = new_crtc_state->freesync_config.fixed_refresh_in_uhz;
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901191251.2653684-1-jerry.zuo@amd.com?part=2

Re: [PATCH v1 0/3] drm/amd/display: passive VRR

[Adolfo]

I tested these patches in conjunction with the HDMI 2.1 VRR ones on 
kernel 7.3-rc1, and VRR still does not engage while on the desktop, only 
in-game.


On 01/09/2026 20:12, Fangzhi Zuo wrote:

> Passive VRR keeps a sink in its variable-refresh state during fixed-refresh
> (desktop) use, avoiding the blanking/brightness flicker that HDMI sinks
> without seamless VRR transitions show on VRR entry/exit. It is opt-out
> (enabled by default where the connector advertises passive_vrr_capable) and
> is not useful for DP/eDP, where seamless VRR transitions are mandated by the
> standard.
>
> Patch 1 adds the DRM core plumbing: the PASSIVE_VRR_DISABLED atomic CRTC
> property and the immutable passive_vrr_capable connector property, with the
> attach/set helpers.
>
> Patch 2 wires these into amdgpu via the existing DC
> stream->freesync_on_desktop path.
>
> Patch 3 fixes the MCCS FreeSync fallback so that HDMI-Forum VRR (HF-VSDB)
> sinks keep freesync_capable; without it passive VRR never engages on the
> very TMDS HF-VSDB sinks it targets.
>
>
> Fangzhi Zuo (1):
>    drm/amd/display: Keep FreeSync for HF-VSDB VRR sinks in MCCS fallback
>
> Tomasz Pakuła (2):
>    drm: Add passive_vrr properties for passive/desktop VRR
>    drm/amd/display: Use passive_vrr properties in amdgpu
>
>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  1 +
>   .../display/amdgpu_dm/amdgpu_dm_connector.c   | 13 +++-
>   .../display/amdgpu_dm/amdgpu_dm_freesync.c    |  7 ++
>   drivers/gpu/drm/drm_atomic_uapi.c             |  4 +
>   drivers/gpu/drm/drm_connector.c               | 73 +++++++++++++++++++
>   drivers/gpu/drm/drm_crtc.c                    |  2 +
>   drivers/gpu/drm/drm_mode_config.c             |  6 ++
>   include/drm/drm_connector.h                   | 15 ++++
>   include/drm/drm_crtc.h                        |  9 +++
>   include/drm/drm_mode_config.h                 |  6 ++
>   10 files changed, 134 insertions(+), 2 deletions(-)
>
>
> base-commit: 8c77d618886a143de5cd87a35963b4993075802a