Re: [PATCH 01/14] drm/connector: Introduce drm_output_color_format enum

Maxime Ripard
2026-02-27T08:38:16Z

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Hi Philipp

On Thu, Feb 26, 2026 at 10:12:02AM +0100, Philipp Zabel wrote:
> On Di, 2026-02-24 at 11:58 +0100, Maxime Ripard wrote:
> > The EDID parsing code initially introduced the DRM_COLOR_FORMAT_*
> > defines to represent the sink capabilities. Since a given sink could
> > support multiple formats, it was first defined as a bitmask.
> >
> > However, the core and drivers have since leveraged those defines to
> > represent both the supported formats but also the current format being
> > used.
> >
> > Considering the latter case, the more natural, and consistent, thing to
> > do would be to create an enum of all the possible formats, and then list
> > the supported formats using a bitmask of the individual enum values.
> >
> > Let's create a new enum following that pattern, drm_output_color_format,
> > while maintaining the DRM_COLOR_FORMAT_* compatibility to make the
> > transition easier.
> >
> > Signed-off-by: Maxime Ripard <mripard@kernel.org>
> > ---
> > include/drm/drm_connector.h | 42 ++++++++++++++++++++++++++++++++++--------
> > 1 file changed, 34 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > index 7eaec37ae1c735334afa7dad15a38cf0c8b761b8..c67539708f636ae3905bb8424c63799bd1811f28 100644
> > --- a/include/drm/drm_connector.h
> > +++ b/include/drm/drm_connector.h
> > @@ -554,10 +554,35 @@ enum drm_colorspace {
> > DRM_MODE_COLORIMETRY_RGB_WIDE_FLOAT = 14,
> > DRM_MODE_COLORIMETRY_BT601_YCC = 15,
> > DRM_MODE_COLORIMETRY_COUNT
> > };
> >
> > +/**
> > + * enum drm_output_color_format - Output Color Format
> > + *
> > + * This enum is a consolidated color format list supported by
> > + * connectors. It's only ever really been used for HDMI and DP so far,
> > + * so it's not exhaustive and can be extended to represent other formats
> > + * in the future.
> > + *
> > + *
> > + * @DRM_OUTPUT_COLOR_FORMAT_RGB444:
> > + * RGB output format
> > + * @DRM_OUTPUT_COLOR_FORMAT_YCBCR444:
> > + * YCbCr 4:4:4 output format (ie. not subsampled)
> > + * @DRM_OUTPUT_COLOR_FORMAT_YCBCR422:
> > + * YCbCr 4:2:2 output format (ie. with horizontal subsampling)
> > + * @DRM_OUTPUT_COLOR_FORMAT_YCBCR420:
> > + * YCbCr 4:2:0 output format (ie. with horizontal and vertical subsampling)
> > + */
> > +enum drm_output_color_format {
> > + DRM_OUTPUT_COLOR_FORMAT_RGB444 = 0,
> > + DRM_OUTPUT_COLOR_FORMAT_YCBCR444,
> > + DRM_OUTPUT_COLOR_FORMAT_YCBCR422,
> > + DRM_OUTPUT_COLOR_FORMAT_YCBCR420,
> > +};
> > +
> > /**
> > * enum drm_bus_flags - bus_flags info for &drm_display_info
> > *
> > * This enum defines signal polarities and clock edge information for signals on
> > * a bus as bitmask flags.
> > @@ -697,14 +722,14 @@ struct drm_display_info {
> > /**
> > * @subpixel_order: Subpixel order of LCD panels.
> > */
> > enum subpixel_order subpixel_order;
> >
> > -#define DRM_COLOR_FORMAT_RGB444 (1<<0)
> > -#define DRM_COLOR_FORMAT_YCBCR444 (1<<1)
> > -#define DRM_COLOR_FORMAT_YCBCR422 (1<<2)
> > -#define DRM_COLOR_FORMAT_YCBCR420 (1<<3)
> > +#define DRM_COLOR_FORMAT_RGB444 (1 << DRM_OUTPUT_COLOR_FORMAT_RGB444)
> > +#define DRM_COLOR_FORMAT_YCBCR444 (1 << DRM_OUTPUT_COLOR_FORMAT_YCBCR444)
> > +#define DRM_COLOR_FORMAT_YCBCR422 (1 << DRM_OUTPUT_COLOR_FORMAT_YCBCR422)
> > +#define DRM_COLOR_FORMAT_YCBCR420 (1 << DRM_OUTPUT_COLOR_FORMAT_YCBCR420)
>
> Can we move this? Either up, directly after drm_output_color_format, or
> down, directly before color_formats.
>
> I think 8d70f395e6cb ("drm: Add support for a panel-orientation
> connector property, v6") didn't separate the two on purpose.

I'm not sure it's worth it, the last patch in this series will remove
these so it's not going to stick around either.

> > /**
> > * @panel_orientation: Read only connector property for built-in panels,
> > * indicating the orientation of the panel vs the device's casing.
> > * drm_connector_init() sets this to DRM_MODE_PANEL_ORIENTATION_UNKNOWN.
> > @@ -712,14 +737,15 @@ struct drm_display_info {
> > * fb to compensate and gets exported as prop to userspace.
> > */
> > int panel_orientation;
> >
> > /**
> > - * @color_formats: HDMI Color formats, selects between RGB and YCrCb
> > - * modes. Used DRM_COLOR_FORMAT\_ defines, which are _not_ the same ones
> > - * as used to describe the pixel format in framebuffers, and also don't
> > - * match the formats in @bus_formats which are shared with v4l.
> > + * @color_formats: HDMI Color formats, selects between RGB and
> > + * YCrCb modes. Uses a bitmask of DRM_OUTPUT_COLOR_FORMAT\_
>
> Maybe s/YCrCb/YCbCr/ for consistency?

Yep, definitely. I'll update it.

Maxime

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