Hi Tomi, Thank you for the patch.
On Mon, Dec 01, 2025 at 02:18:45PM +0200, Tomi Valkeinen wrote: > Add greyscale Y8 format. I would explain here why we need a new format and can't just use DRM_FORMAT_R8. You don't need to convince me, but I think it's important to summarize the rationale should someone later wonder why we introduced this. > Acked-by: Dmitry Baryshkov <[email protected]> > Reviewed-by: Pekka Paalanen <[email protected]> > Reviewed-by: Vishal Sagar <[email protected]> > Signed-off-by: Tomi Valkeinen <[email protected]> > --- > drivers/gpu/drm/drm_fourcc.c | 1 + > include/uapi/drm/drm_fourcc.h | 10 ++++++++++ > 2 files changed, 11 insertions(+) > > diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c > index b22ef86428a1..a39b9d7a5b62 100644 > --- a/drivers/gpu/drm/drm_fourcc.c > +++ b/drivers/gpu/drm/drm_fourcc.c > @@ -275,6 +275,7 @@ const struct drm_format_info *__drm_format_info(u32 > format) > { .format = DRM_FORMAT_YVU422, .depth = 0, > .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 2, .vsub = 1, .is_yuv = true }, > { .format = DRM_FORMAT_YUV444, .depth = 0, > .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 1, .vsub = 1, .is_yuv = true }, > { .format = DRM_FORMAT_YVU444, .depth = 0, > .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 1, .vsub = 1, .is_yuv = true }, > + { .format = DRM_FORMAT_Y8, .depth = 8, > .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true }, > { .format = DRM_FORMAT_NV12, .depth = 0, > .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 2, .is_yuv = true }, > { .format = DRM_FORMAT_NV21, .depth = 0, > .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 2, .is_yuv = true }, > { .format = DRM_FORMAT_NV16, .depth = 0, > .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true }, > diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h > index 6c786701238e..5cfc188c4e72 100644 > --- a/include/uapi/drm/drm_fourcc.h > +++ b/include/uapi/drm/drm_fourcc.h > @@ -459,6 +459,16 @@ extern "C" { > #define DRM_FORMAT_YUV444 fourcc_code('Y', 'U', '2', '4') /* > non-subsampled Cb (1) and Cr (2) planes */ > #define DRM_FORMAT_YVU444 fourcc_code('Y', 'V', '2', '4') /* > non-subsampled Cr (1) and Cb (2) planes */ > > +/* > + * Y-only (greyscale) formats > + * > + * The Y-only formats are handled similarly to the YCbCr formats in the > display > + * pipeline, with the Cb and Cr implicitly neutral (0.0 in nominal values). > This > + * also means that COLOR_RANGE property applies to the Y-only formats. > + * Extra blank line. > + */ > + > +#define DRM_FORMAT_Y8 fourcc_code('G', 'R', 'E', 'Y') /* > 8-bit Y-only */ I would have gone for 'Y', '8', ' ', ' ' > > /* > * Format Modifiers: -- Regards, Laurent Pinchart
