kms/connector: Add support for the Broadcast RGB property

It can be used to force a specific RGB range. Some monitors don't follow
the specification and expect a signal different from what we send. This
property allows to force a mode which hopefully then works correctly for
the sink.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3535>

src/backends/meta-output.h

@@ -40,6 +40,14 @@ typedef enum
   META_OUTPUT_HDR_METADATA_EOTF_HLG,
 } MetaOutputHdrMetadataEOTF;
 
+typedef enum _MetaOutputRGBRange
+{
+  META_OUTPUT_RGB_RANGE_UNKNOWN = 0,
+  META_OUTPUT_RGB_RANGE_AUTO,
+  META_OUTPUT_RGB_RANGE_FULL,
+  META_OUTPUT_RGB_RANGE_LIMITED,
+} MetaOutputRGBRange;
+
 typedef struct _MetaOutputHdrMetadata
 {
   gboolean active;

src/backends/native/meta-kms-connector-private.h

@@ -39,6 +39,7 @@ typedef enum _MetaKmsConnectorProp
   META_KMS_CONNECTOR_PROP_MAX_BPC,
   META_KMS_CONNECTOR_PROP_COLORSPACE,
   META_KMS_CONNECTOR_PROP_HDR_OUTPUT_METADATA,
+  META_KMS_CONNECTOR_PROP_BROADCAST_RGB,
   META_KMS_CONNECTOR_N_PROPS
 } MetaKmsConnectorProp;
 
@@ -113,6 +114,15 @@ typedef enum _MetaKmsConnectorColorspace
   META_KMS_CONNECTOR_COLORSPACE_UNKNOWN,
 } MetaKmsConnectorColorspace;
 
+typedef enum _MetaKmsConnectorBroadcastRGB
+{
+  META_KMS_CONNECTOR_BROADCAST_RGB_AUTOMATIC = 0,
+  META_KMS_CONNECTOR_BROADCAST_RGB_FULL,
+  META_KMS_CONNECTOR_BROADCAST_RGB_LIMITED_16_235,
+  META_KMS_CONNECTOR_BROADCAST_RGB_N_PROPS,
+  META_KMS_CONNECTOR_BROADCAST_RGB_UNKNOWN,
+} MetaKmsConnectorBroadcastRGB;
+
 uint32_t meta_kms_connector_get_prop_id (MetaKmsConnector     *connector,
                                          MetaKmsConnectorProp  prop);
 
@@ -141,6 +151,8 @@ gboolean meta_kms_connector_is_same_as (MetaKmsConnector *connector,
 
 uint64_t meta_output_color_space_to_drm_color_space (MetaOutputColorspace color_space);
 
+uint64_t meta_output_rgb_range_to_drm_broadcast_rgb (MetaOutputRGBRange rgb_range);
+
 META_EXPORT_TEST
 void meta_set_drm_hdr_metadata (MetaOutputHdrMetadata      *metadata,
                                 struct hdr_output_metadata *drm_metadata);

src/backends/native/meta-kms-connector.c

@@ -56,6 +56,7 @@ typedef struct _MetaKmsConnectorPropTable
   MetaKmsEnum scaling_mode_enum[META_KMS_CONNECTOR_SCALING_MODE_N_PROPS];
   MetaKmsEnum panel_orientation_enum[META_KMS_CONNECTOR_PANEL_ORIENTATION_N_PROPS];
   MetaKmsEnum colorspace_enum[META_KMS_CONNECTOR_COLORSPACE_N_PROPS];
+  MetaKmsEnum broadcast_rgb_enum[META_KMS_CONNECTOR_BROADCAST_RGB_N_PROPS];
 } MetaKmsConnectorPropTable;
 
 struct _MetaKmsConnector
@@ -253,6 +254,13 @@ meta_kms_connector_is_hdr_metadata_supported (MetaKmsConnector *connector)
   return connector->current_state->hdr.supported;
 }
 
+gboolean
+meta_kms_connector_is_broadcast_rgb_supported (MetaKmsConnector   *connector,
+                                               MetaOutputRGBRange  broadcast_rgb)
+{
+  return !!(connector->current_state->broadcast_rgb.supported & (1 << broadcast_rgb));
+}
+
 static void
 set_panel_orientation (MetaKmsConnectorState *state,
                        MetaKmsProp           *panel_orientation)
@@ -355,6 +363,53 @@ meta_output_color_space_to_drm_color_space (MetaOutputColorspace color_space)
     }
 }
 
+static MetaOutputRGBRange
+drm_broadcast_rgb_to_output_rgb_range (uint64_t drm_broadcast_rgb)
+{
+  switch (drm_broadcast_rgb)
+    {
+    case META_KMS_CONNECTOR_BROADCAST_RGB_AUTOMATIC:
+      return META_OUTPUT_RGB_RANGE_AUTO;
+    case META_KMS_CONNECTOR_BROADCAST_RGB_FULL:
+      return META_OUTPUT_RGB_RANGE_FULL;
+    case META_KMS_CONNECTOR_BROADCAST_RGB_LIMITED_16_235:
+      return META_OUTPUT_RGB_RANGE_LIMITED;
+    default:
+      return META_OUTPUT_RGB_RANGE_UNKNOWN;
+    }
+}
+
+static uint64_t
+supported_drm_broadcast_rgb_to_output_rgb_range (uint64_t drm_support)
+{
+  uint64_t supported = 0;
+
+  if (drm_support & (1 << META_KMS_CONNECTOR_BROADCAST_RGB_AUTOMATIC))
+    supported |= (1 << META_OUTPUT_RGB_RANGE_AUTO);
+  if (drm_support & (1 << META_KMS_CONNECTOR_BROADCAST_RGB_FULL))
+    supported |= (1 << META_OUTPUT_RGB_RANGE_FULL);
+  if (drm_support & (1 << META_KMS_CONNECTOR_BROADCAST_RGB_LIMITED_16_235))
+    supported |= (1 << META_OUTPUT_RGB_RANGE_LIMITED);
+
+  return supported;
+}
+
+uint64_t
+meta_output_rgb_range_to_drm_broadcast_rgb (MetaOutputRGBRange rgb_range)
+{
+  switch (rgb_range)
+    {
+    case META_OUTPUT_RGB_RANGE_FULL:
+      return META_KMS_CONNECTOR_BROADCAST_RGB_FULL;
+    case META_OUTPUT_RGB_RANGE_LIMITED:
+      return META_KMS_CONNECTOR_BROADCAST_RGB_LIMITED_16_235;
+    case META_OUTPUT_RGB_RANGE_UNKNOWN:
+    case META_OUTPUT_RGB_RANGE_AUTO:
+    default:
+      return META_KMS_CONNECTOR_BROADCAST_RGB_AUTOMATIC;
+    }
+}
+
 static void
 state_set_properties (MetaKmsConnectorState *state,
                       MetaKmsImplDevice     *impl_device,
@@ -408,6 +463,15 @@ state_set_properties (MetaKmsConnectorState *state,
       state->colorspace.supported =
         supported_drm_color_spaces_to_output_color_spaces (prop->supported_variants);
     }
+
+  prop = &props[META_KMS_CONNECTOR_PROP_BROADCAST_RGB];
+  if (prop->prop_id)
+    {
+      state->broadcast_rgb.value =
+        drm_broadcast_rgb_to_output_rgb_range (prop->value);
+      state->broadcast_rgb.supported =
+        supported_drm_broadcast_rgb_to_output_rgb_range (prop->supported_variants);
+    }
 }
 
 static CoglSubpixelOrder
@@ -1013,6 +1077,10 @@ meta_kms_connector_state_changes (MetaKmsConnectorState *state,
       !hdr_metadata_equal (&state->hdr.value, &new_state->hdr.value))
     return META_KMS_RESOURCE_CHANGE_FULL;
 
+  if (state->broadcast_rgb.value != new_state->broadcast_rgb.value ||
+      state->broadcast_rgb.supported != new_state->broadcast_rgb.supported)
+    return META_KMS_RESOURCE_CHANGE_FULL;
+
   if (state->privacy_screen_state != new_state->privacy_screen_state)
     return META_KMS_RESOURCE_CHANGE_PRIVACY_SCREEN;
 
@@ -1224,6 +1292,14 @@ meta_kms_connector_predict_state_in_impl (MetaKmsConnector *connector,
                           connector));
           current_state->hdr.value = connector_update->hdr.value;
         }
+
+      if (connector_update->broadcast_rgb.has_update)
+        {
+          g_warn_if_fail (meta_kms_connector_is_broadcast_rgb_supported (
+                          connector,
+                          connector_update->broadcast_rgb.value));
+          current_state->broadcast_rgb.value = connector_update->broadcast_rgb.value;
+        }
     }
 
   sync_fd_held (connector, connector->impl_device);
@@ -1350,6 +1426,14 @@ init_properties (MetaKmsConnector  *connector,
           .name = "HDR_OUTPUT_METADATA",
           .type = DRM_MODE_PROP_BLOB,
         },
+      [META_KMS_CONNECTOR_PROP_BROADCAST_RGB] =
+        {
+          .name = "Broadcast RGB",
+          .type = DRM_MODE_PROP_ENUM,
+          .enum_values = prop_table->broadcast_rgb_enum,
+          .num_enum_values = META_KMS_CONNECTOR_BROADCAST_RGB_N_PROPS,
+          .default_value = META_KMS_CONNECTOR_BROADCAST_RGB_UNKNOWN,
+        },
     },
     .dpms_enum = {
       [META_KMS_CONNECTOR_DPMS_ON] =
@@ -1521,6 +1605,20 @@ init_properties (MetaKmsConnector  *connector,
           .name = "DCI-P3_RGB_Theater",
         },
     },
+    .broadcast_rgb_enum = {
+      [META_KMS_CONNECTOR_BROADCAST_RGB_AUTOMATIC] =
+        {
+          .name = "Automatic",
+        },
+      [META_KMS_CONNECTOR_BROADCAST_RGB_FULL] =
+        {
+          .name = "Full",
+        },
+      [META_KMS_CONNECTOR_BROADCAST_RGB_LIMITED_16_235] =
+        {
+          .name = "Limited 16:235",
+        }
+    },
   };
 }
 

src/backends/native/meta-kms-connector.h

@@ -69,6 +69,11 @@ typedef struct _MetaKmsConnectorState
     gboolean supported;
     gboolean unknown;
   } hdr;
+
+  struct {
+    MetaOutputRGBRange value;
+    uint64_t supported;
+  } broadcast_rgb;
 } MetaKmsConnectorState;
 
 META_EXPORT_TEST
@@ -98,4 +103,7 @@ const MetaKmsRange * meta_kms_connector_get_max_bpc (MetaKmsConnector *connector
 gboolean meta_kms_connector_is_color_space_supported (MetaKmsConnector     *connector,
                                                       MetaOutputColorspace  color_space);
 
+gboolean meta_kms_connector_is_broadcast_rgb_supported (MetaKmsConnector   *connector,
+                                                        MetaOutputRGBRange  broadcast_rgb);
+
 gboolean meta_kms_connector_is_hdr_metadata_supported (MetaKmsConnector *connector);

src/backends/native/meta-kms-impl-device-atomic.c

@@ -292,6 +292,25 @@ process_connector_update (MetaKmsImplDevice  *impl_device,
         return FALSE;
     }
 
+  if (connector_update->broadcast_rgb.has_update)
+    {
+      MetaOutputRGBRange rgb_range = connector_update->broadcast_rgb.value;
+      uint64_t value = meta_output_rgb_range_to_drm_broadcast_rgb (rgb_range);
+
+      meta_topic (META_DEBUG_KMS,
+                  "[atomic] Setting Broadcast RGB to %u on connector %u (%s)",
+                  rgb_range,
+                  meta_kms_connector_get_id (connector),
+                  meta_kms_impl_device_get_path (impl_device));
+
+      if (!add_connector_property (impl_device,
+                                   connector, req,
+                                   META_KMS_CONNECTOR_PROP_BROADCAST_RGB,
+                                   value,
+                                   error))
+        return FALSE;
+    }
+
   return TRUE;
 }
 

src/backends/native/meta-kms-update-private.h

@@ -110,6 +110,11 @@ typedef struct _MetaKmsConnectorUpdate
     gboolean has_update;
     MetaOutputHdrMetadata value;
   } hdr;
+
+  struct {
+    gboolean has_update;
+    MetaOutputRGBRange value;
+  } broadcast_rgb;
 } MetaKmsConnectorUpdate;
 
 typedef struct _MetaKmsPageFlipListener

src/backends/native/meta-kms-update.c

@@ -444,8 +444,6 @@ meta_kms_update_set_color_space (MetaKmsUpdate        *update,
   MetaKmsConnectorUpdate *connector_update;
 
   g_assert (meta_kms_connector_get_device (connector) == update->device);
-  g_return_if_fail (meta_kms_connector_is_color_space_supported (connector,
-                                                                 color_space));
 
   connector_update = ensure_connector_update (update, connector);
   connector_update->colorspace.has_update = TRUE;
@@ -470,6 +468,22 @@ meta_kms_update_set_hdr_metadata (MetaKmsUpdate         *update,
   update->needs_modeset = TRUE;
 }
 
+void
+meta_kms_update_set_broadcast_rgb (MetaKmsUpdate      *update,
+                                   MetaKmsConnector   *connector,
+                                   MetaOutputRGBRange  rgb_range)
+{
+  MetaKmsConnectorUpdate *connector_update;
+
+  g_assert (meta_kms_connector_get_device (connector) == update->device);
+  g_return_if_fail (meta_kms_connector_is_broadcast_rgb_supported (connector,
+                                                                   rgb_range));
+
+  connector_update = ensure_connector_update (update, connector);
+  connector_update->broadcast_rgb.has_update = TRUE;
+  connector_update->broadcast_rgb.value = rgb_range;
+}
+
 static MetaKmsCrtcColorUpdate *
 ensure_color_update (MetaKmsUpdate *update,
                      MetaKmsCrtc   *crtc)

src/backends/native/meta-kms-update.h

@@ -134,6 +134,10 @@ void meta_kms_update_set_hdr_metadata (MetaKmsUpdate         *update,
                                        MetaKmsConnector      *connector,
                                        MetaOutputHdrMetadata *metadata);
 
+void meta_kms_update_set_broadcast_rgb (MetaKmsUpdate      *update,
+                                        MetaKmsConnector   *connector,
+                                        MetaOutputRGBRange  rgb_range);
+
 META_EXPORT_TEST
 void meta_kms_update_set_power_save (MetaKmsUpdate *update);