drm: Add vrr_enabled property to drm CRTC

This patch introduces the 'vrr_enabled' CRTC property to allow
dynamic control over variable refresh rate support for a CRTC.

This property should be treated like a content hint to the driver -
if the hardware or driver is not capable of driving variable refresh
timings then this is not considered an error.

Capability for variable refresh rate support should be determined
by querying the vrr_capable drm connector property.

It is worth noting that while the property is intended for atomic use
it isn't filtered from legacy userspace queries. This allows for Xorg
userspace drivers to implement support.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index d5b7f31..eec396a 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -433,6 +433,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
                ret = drm_atomic_set_mode_prop_for_crtc(state, mode);
                drm_property_blob_put(mode);
                return ret;
+       } else if (property == config->prop_vrr_enabled) {
+               state->vrr_enabled = val;
        } else if (property == config->degamma_lut_property) {
                ret = drm_atomic_replace_property_blob_from_id(dev,
                                        &state->degamma_lut,
@@ -491,6 +493,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
                *val = state->active;
        else if (property == config->prop_mode_id)
                *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->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_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 268a182..6f8ddfc 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -340,6 +340,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
                drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
                drm_object_attach_property(&crtc->base,
                                           config->prop_out_fence_ptr, 0);
+               drm_object_attach_property(&crtc->base,
+                                          config->prop_vrr_enabled, 0);
        }
 
        return 0;

diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index ee80788..5670c67 100644 (file)
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -310,6 +310,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
                return -ENOMEM;
        dev->mode_config.prop_mode_id = prop;
 
+       prop = drm_property_create_bool(dev, 0,
+                       "VRR_ENABLED");
+       if (!prop)
+               return -ENOMEM;
+       dev->mode_config.prop_vrr_enabled = prop;
+
        prop = drm_property_create(dev,
                        DRM_MODE_PROP_BLOB,
                        "DEGAMMA_LUT", 0);

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index b21437b..39c3900 100644 (file)
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -291,6 +291,15 @@ struct drm_crtc_state {
        u32 pageflip_flags;
 
        /**
+        * @vrr_enabled:
+        *
+        * Indicates if variable refresh rate should be enabled for the CRTC.
+        * Support for the requested vrr state will depend on driver and
+        * hardware capabiltiy - lacking support is not treated as failure.
+        */
+       bool vrr_enabled;
+
+       /**
         * @event:
         *
         * Optional pointer to a DRM event to signal upon completion of the

diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 5dbeabd..9db59a1 100644 (file)
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -645,6 +645,11 @@ struct drm_mode_config {
         * connectors must be of and active must be set to disabled, too.
         */
        struct drm_property *prop_mode_id;
+       /**
+        * @prop_vrr_enabled: Default atomic CRTC property to indicate
+        * whether variable refresh rate should be enabled on the CRTC.
+        */
+       struct drm_property *prop_vrr_enabled;
 
        /**
         * @dvi_i_subconnector_property: Optional DVI-I property to