On Tue, Mar 24, 2026 at 05:01:07PM +0100, Nicolas Frattaroli wrote:
> +enum drm_connector_color_format {
> + /**
> + * @DRM_CONNECTOR_COLOR_FORMAT_AUTO: The driver or display protocol
> + * helpers should pick a suitable color format. All implementations of a
> + * specific display protocol must behave the same way with "AUTO", but
> + * different display protocols do not necessarily have the same "AUTO"
> + * semantics.
> + *
> + * For HDMI, "AUTO" picks RGB, but falls back to YCbCr 4:2:0 if the
> + * bandwidth required for full-scale RGB is not available, or the mode
> + * is YCbCr 4:2:0-only, as long as the mode and output both support
> + * YCbCr 4:2:0.
> + *
> + * For display protocols other than HDMI, the recursive bridge chain
> + * format selection picks the first chain of bridge formats that works,
> + * as has already been the case before the introduction of the "color
> + * format" property. Non-HDMI bridges should therefore either sort their
> + * bus output formats by preference, or agree on a unified auto format
> + * selection logic that's implemented in a common state helper (like
> + * how HDMI does it).
> + */
> + DRM_CONNECTOR_COLOR_FORMAT_AUTO = 0,
> +
> + /**
> + * @DRM_CONNECTOR_COLOR_FORMAT_RGB444: RGB output format
> + */
> + DRM_CONNECTOR_COLOR_FORMAT_RGB444,
> +
> + /**
> + * @DRM_CONNECTOR_COLOR_FORMAT_YCBCR444: YCbCr 4:4:4 output format (ie.
> + * not subsampled)
> + */
> + DRM_CONNECTOR_COLOR_FORMAT_YCBCR444,
> +
> + /**
> + * @DRM_CONNECTOR_COLOR_FORMAT_YCBCR422: YCbCr 4:2:2 output format (ie.
> + * with horizontal subsampling)
> + */
> + DRM_CONNECTOR_COLOR_FORMAT_YCBCR422,
> +
> + /**
> + * @DRM_CONNECTOR_COLOR_FORMAT_YCBCR420: YCbCr 4:2:0 output format (ie.
> + * with horizontal and vertical subsampling)
> + */
> + DRM_CONNECTOR_COLOR_FORMAT_YCBCR420,
Seems like this should document what the quantization range
should be for each format.
> +
> + /**
> + * @DRM_CONNECTOR_COLOR_FORMAT_COUNT: Number of valid connector color
> + * format values in this enum
> + */
> + DRM_CONNECTOR_COLOR_FORMAT_COUNT,
> +};
> +
> +/**
> + * drm_connector_color_format_valid - Validate drm_connector_color_format
> value
> + * @fmt: value to check against all values of &enum
> drm_connector_color_format
> + *
> + * Checks whether the passed in value of @fmt is one of the allowable values
> in
> + * &enum drm_connector_color_format.
> + *
> + * Returns: %true if it's a valid value for the enum, %false otherwise.
> + */
> +static inline bool __pure
> +drm_connector_color_format_valid(enum drm_connector_color_format fmt)
> +{
> + switch (fmt) {
> + case DRM_CONNECTOR_COLOR_FORMAT_AUTO:
> + case DRM_CONNECTOR_COLOR_FORMAT_RGB444:
> + case DRM_CONNECTOR_COLOR_FORMAT_YCBCR444:
> + case DRM_CONNECTOR_COLOR_FORMAT_YCBCR422:
> + case DRM_CONNECTOR_COLOR_FORMAT_YCBCR420:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> const char *
> drm_hdmi_connector_get_output_format_name(enum drm_output_color_format fmt);
>
> @@ -1129,6 +1217,13 @@ struct drm_connector_state {
> */
> enum drm_colorspace colorspace;
>
> + /**
> + * @color_format: State variable for Connector property to request
> + * color format change on Sink. This is most commonly used to switch
> + * between RGB to YUV and vice-versa.
> + */
> + enum drm_connector_color_format color_format;
> +
> /**
> * @writeback_job: Writeback job for writeback connectors
> *
> @@ -2127,6 +2222,12 @@ struct drm_connector {
> */
> struct drm_property *colorspace_property;
>
> + /**
> + * @color_format_property: Connector property to set the suitable
> + * color format supported by the sink.
> + */
> + struct drm_property *color_format_property;
> +
> /**
> * @path_blob_ptr:
> *
> @@ -2610,6 +2711,9 @@ bool drm_connector_has_possible_encoder(struct
> drm_connector *connector,
> struct drm_encoder *encoder);
> const char *drm_get_colorspace_name(enum drm_colorspace colorspace);
>
> +int drm_connector_attach_color_format_property(struct drm_connector
> *connector,
> + unsigned long
> supported_color_formats);
> +
> /**
> * drm_for_each_connector_iter - connector_list iterator macro
> * @connector: &struct drm_connector pointer used as cursor
>
> --
> 2.53.0
--
Ville Syrjälä
Intel
