Re: [PATCH v10 03/11] drm/fourcc: Add DRM_FORMAT_Y8

[Simon Ser]

On Thursday, April 23rd, 2026 at 16:22, Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx> wrote:

> However, adding DRM_FORMAT_Y8 makes sense, we can mark it as 'is_yuv' in
> the drm_format_info, and this can help the drivers handle e.g.
> full/limited range. This will distinguish two single-channel formats:
> R8, which is a RGB format with the same value for all components, and
> Y8, which is a Y-only YCbCr format, with Cb and Cr being neutral.

I've been wondering on IRC whether we really need yet another 1-channel
format, since Y8 isn't that different from Y8. Pekka said:

- R8 doesn't necessarily expand to G an B channels. The Vulkan spec
  states that R8 expands to (R, 0, 0).
- Y8 is semantically more correct than R8 to represent grayscale
  formats.

I wonder if we would've added R8 at all if had Y8 from the start… 

Acked-by: Simon Ser <contact@xxxxxxxxxxx>