On Fri, 18 Jun 2021 11:11:08 +0200 Werner Sembach wrote: > Add a new general drm property "active color range" which can be used by > graphic drivers to report the used color range back to userspace. > > There was no way to check which color range got actually used on a given > monitor. To surely predict this, one must know the exact capabilities of > the monitor and what the default behaviour of the used driver is. This > property helps eliminating the guessing at this point. > > In the future, automatic color calibration for screens might also depend on > this information being available. > > Signed-off-by: Werner Sembach > --- > drivers/gpu/drm/drm_connector.c | 59 +++++++++++++++++++++++++++++++++ > include/drm/drm_connector.h | 27 +++++++++++++++ > 2 files changed, 86 insertions(+) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index 684d7abdf0eb..818de58d972f 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -897,6 +897,12 @@ static const struct drm_prop_enum_list drm_active_color_format_enum_list[] = { > { DRM_COLOR_FORMAT_YCRCB420, "ycbcr420" }, > }; > > +static const struct drm_prop_enum_list drm_active_color_range_enum_list[] = { > + { DRM_MODE_COLOR_RANGE_UNSET, "Unknown" }, > + { DRM_MODE_COLOR_RANGE_FULL, "Full" }, > + { DRM_MODE_COLOR_RANGE_LIMITED_16_235, "Limited 16:235" }, Doesn't "limited" mean different numbers on RGB vs. Y vs. CbCr? I have a vague recollection that at least one of them was different from the others. Documenting DRM_MODE_COLOR_RANGE_UNSET as "unspecified/default" while the string for it is "Unknown" seems inconsistent to me. I would recommend to avoid the word "default" because "reset to defaults" might become a thing one day, and that probably is not the same default as here. Is there actually a case for "unknown"? How can it be not known? Or does it mean "not applicable"? Otherwise looks good to me. Thanks, pq > +}; > + > DRM_ENUM_NAME_FN(drm_get_dp_subconnector_name, > drm_dp_subconnector_enum_list) > > @@ -1221,6 +1227,14 @@ static const struct drm_prop_enum_list dp_colorspaces[] = { > * drm_connector_attach_active_color_format_property() to install this > * property. > * > + * active color range: > + * This read-only property tells userspace the color range actually used by > + * the hardware display engine on "the cable" on a connector. The chosen > + * value depends on hardware capabilities of the monitor and the used color > + * format. Drivers shall use > + * drm_connector_attach_active_color_range_property() to install this > + * property. > + * > * Connectors also have one standardized atomic property: > * > * CRTC_ID: > @@ -2264,6 +2278,51 @@ void drm_connector_set_active_color_format_property(struct drm_connector *connec > } > EXPORT_SYMBOL(drm_connector_set_active_color_format_property); > > +/** > + * drm_connector_attach_active_color_range_property - attach "active color range" property > + * @connector: connector to attach active color range property on. > + * > + * This is used to check the applied color range on a connector. > + * > + * Returns: > + * Zero on success, negative errno on failure. > + */ > +int drm_connector_attach_active_color_range_property(struct drm_connector *connector) > +{ > + struct drm_device *dev = connector->dev; > + struct drm_property *prop; > + > + if (!connector->active_color_range_property) { > + prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE, "active color range", > + drm_active_color_range_enum_list, > + ARRAY_SIZE(drm_active_color_range_enum_list)); > + if (!prop) > + return -ENOMEM; > + > + connector->active_color_range_property = prop; > + drm_object_attach_property(&connector->base, prop, DRM_MODE_COLOR_RANGE_UNSET); > + } > + > + return 0; > +} > +EXPORT_SYMBOL(drm_connector_attach_active_color_range_property); > + > +/** > + * drm_connector_set_active_color_range_property - sets the active color range property for a > + * connector > + * @connector: drm connector > + * @active_color_range: color range for the connector currently active on "the cable" > + * > + * Should be used by atomic drivers to update the active color range over a connector. > + */ > +void drm_connector_set_active_color_range_property(struct drm_connector *connector, > + enum drm_mode_color_range active_color_range) > +{ > + drm_object_property_set_value(&connector->base, connector->active_color_range_property, > + active_color_range); > +} > +EXPORT_SYMBOL(drm_connector_set_active_color_range_property); > + > /** > * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property > * @connector: connector to attach the property on. > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > index 8a5197f14e87..9fb7119b7a02 100644 > --- a/include/drm/drm_connector.h > +++ b/include/drm/drm_connector.h > @@ -648,6 +648,24 @@ struct drm_tv_connector_state { > unsigned int hue; > }; > > +/** > + * enum drm_mode_color_range - color_range info for &drm_connector > + * > + * This enum is used to represent full or limited color range on the display > + * connector signal. > + * > + * @DRM_MODE_COLOR_RANGE_UNSET: Color range is unspecified/default. > + * @DRM_MODE_COLOR_RANGE_FULL: Color range is full range, 0-255 for > + * 8-Bit color depth. > + * DRM_MODE_COLOR_RANGE_LIMITED_16_235: Color range is limited range, 16-235 for > + * 8-Bit color depth. > + */ > +enum drm_mode_color_range { > + DRM_MODE_COLOR_RANGE_UNSET, > + DRM_MODE_COLOR_RANGE_FULL, > + DRM_MODE_COLOR_RANGE_LIMITED_16_235, > +}; > + > /** > * struct drm_connector_state - mutable connector state > */ > @@ -1392,6 +1410,12 @@ struct drm_connector { > */ > struct drm_property *active_color_format_property; > > + /** > + * @active_color_range_property: Default connector property for the > + * active color range to be driven out of the connector. > + */ > + struct drm_property *active_color_range_property; > + > #define DRM_CONNECTOR_POLL_HPD (1 << 0) > #define DRM_CONNECTOR_POLL_CONNECT (1 << 1) > #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2) > @@ -1719,6 +1743,9 @@ void drm_connector_set_active_bpc_property(struct drm_connector *connector, int > int drm_connector_attach_active_color_format_property(struct drm_connector *connector); > void drm_connector_set_active_color_format_property(struct drm_connector *connector, > u32 active_color_format); > +int drm_connector_attach_active_color_range_property(struct drm_connector *connector); > +void drm_connector_set_active_color_range_property(struct drm_connector *connector, > + enum drm_mode_color_range active_color_range); > > /** > * struct drm_tile_group - Tile group metadata