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authorDave Airlie <airlied@redhat.com>2018-12-06 06:28:19 +0300
committerDave Airlie <airlied@redhat.com>2018-12-06 06:29:09 +0300
commit513126ae00ba897cac1ab07f61edf062093d4dcb (patch)
treea6c8bf7e52609a4d3d42954eb4492f01113eaafc /drivers/gpu/drm/drm_connector.c
parent467e8a516dcf922d1ea343cebb0e751f81f0dca3 (diff)
parent2c486cc4c2774df684d8a43ca7a20670c67ccd76 (diff)
downloadlinux-513126ae00ba897cac1ab07f61edf062093d4dcb.tar.xz
Merge branch 'drm-next-4.21' of git://people.freedesktop.org/~agd5f/linux into drm-next
amdgpu and amdkfd: - Freesync support - ABM support in DC - KFD support for vega12 and polaris12 - Add sdma paging queue support for vega - Use ACPI to query backlight range on supported platforms - Clean up doorbell handling - KFD fix for pasid handling under non-HWS - Misc cleanups and fixes scheduler: - Revert "fix timeout handling v2" radeon: - Fix possible overflow on 32 bit ttm: - Fix for LRU handling for ghost objects Signed-off-by: Dave Airlie <airlied@redhat.com> From: Alex Deucher <alexdeucher@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181130192505.2946-1-alexander.deucher@amd.com
Diffstat (limited to 'drivers/gpu/drm/drm_connector.c')
-rw-r--r--drivers/gpu/drm/drm_connector.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index fa9baacc863b..da8ae80c2750 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1279,6 +1279,105 @@ int drm_mode_create_scaling_mode_property(struct drm_device *dev)
EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
/**
+ * DOC: Variable refresh properties
+ *
+ * Variable refresh rate capable displays can dynamically adjust their
+ * refresh rate by extending the duration of their vertical front porch
+ * until page flip or timeout occurs. This can reduce or remove stuttering
+ * and latency in scenarios where the page flip does not align with the
+ * vblank interval.
+ *
+ * An example scenario would be an application flipping at a constant rate
+ * of 48Hz on a 60Hz display. The page flip will frequently miss the vblank
+ * interval and the same contents will be displayed twice. This can be
+ * observed as stuttering for content with motion.
+ *
+ * If variable refresh rate was active on a display that supported a
+ * variable refresh range from 35Hz to 60Hz no stuttering would be observable
+ * for the example scenario. The minimum supported variable refresh rate of
+ * 35Hz is below the page flip frequency and the vertical front porch can
+ * be extended until the page flip occurs. The vblank interval will be
+ * directly aligned to the page flip rate.
+ *
+ * Not all userspace content is suitable for use with variable refresh rate.
+ * Large and frequent changes in vertical front porch duration may worsen
+ * perceived stuttering for input sensitive applications.
+ *
+ * Panel brightness will also vary with vertical front porch duration. Some
+ * panels may have noticeable differences in brightness between the minimum
+ * vertical front porch duration and the maximum vertical front porch duration.
+ * Large and frequent changes in vertical front porch duration may produce
+ * observable flickering for such panels.
+ *
+ * Userspace control for variable refresh rate is supported via properties
+ * on the &drm_connector and &drm_crtc objects.
+ *
+ * "vrr_capable":
+ * Optional &drm_connector boolean property that drivers should attach
+ * with drm_connector_attach_vrr_capable_property() on connectors that
+ * could support variable refresh rates. Drivers should update the
+ * property value by calling drm_connector_set_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.
+ * The driver will take this property as a hint to enable variable
+ * refresh rate support if the receiver supports it, ie. if the
+ * "vrr_capable" property is true on the &drm_connector object. The
+ * vertical front porch duration will be extended until page-flip or
+ * timeout when enabled.
+ *
+ * The minimum vertical front porch duration is defined as the vertical
+ * front porch duration for the current mode.
+ *
+ * The maximum vertical front porch duration is greater than or equal to
+ * the minimum vertical front porch duration. The duration is derived
+ * from the minimum supported variable refresh rate for the connector.
+ *
+ * The driver may place further restrictions within these minimum
+ * and maximum bounds.
+ *
+ * The semantics for the vertical blank timestamp differ when
+ * variable refresh rate is active. The vertical blank timestamp
+ * is defined to be an estimate using the current mode's fixed
+ * refresh rate timings. The semantics for the page-flip event
+ * timestamp remain the same.
+ */
+
+/**
+ * drm_connector_attach_vrr_capable_property - creates the
+ * vrr_capable property
+ * @connector: connector to create the vrr_capable property on.
+ *
+ * This is used by atomic drivers to add support for querying
+ * variable refresh rate capability for a connector.
+ *
+ * Returns:
+ * Zero on success, negative errono on failure.
+ */
+int drm_connector_attach_vrr_capable_property(
+ struct drm_connector *connector)
+{
+ struct drm_device *dev = connector->dev;
+ struct drm_property *prop;
+
+ if (!connector->vrr_capable_property) {
+ prop = drm_property_create_bool(dev, DRM_MODE_PROP_IMMUTABLE,
+ "vrr_capable");
+ if (!prop)
+ return -ENOMEM;
+
+ connector->vrr_capable_property = prop;
+ drm_object_attach_property(&connector->base, prop, 0);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_connector_attach_vrr_capable_property);
+
+/**
* drm_connector_attach_scaling_mode_property - attach atomic scaling mode property
* @connector: connector to attach scaling mode property on.
* @scaling_mode_mask: or'ed mask of BIT(%DRM_MODE_SCALE_\*).
@@ -1641,6 +1740,24 @@ int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
EXPORT_SYMBOL(drm_connector_attach_max_bpc_property);
/**
+ * drm_connector_set_vrr_capable_property - sets the variable refresh rate
+ * capable property for a connector
+ * @connector: drm connector
+ * @capable: True if the connector is variable refresh rate capable
+ *
+ * Should be used by atomic drivers to update the indicated support for
+ * variable refresh rate over a connector.
+ */
+void drm_connector_set_vrr_capable_property(
+ struct drm_connector *connector, bool capable)
+{
+ drm_object_property_set_value(&connector->base,
+ connector->vrr_capable_property,
+ capable);
+}
+EXPORT_SYMBOL(drm_connector_set_vrr_capable_property);
+
+/**
* drm_connector_init_panel_orientation_property -
* initialize the connecters panel_orientation property
* @connector: connector for which to init the panel-orientation property.