Re: [PATCH v2 03/10] drm/fourcc: Add DRM_FORMAT_Y8

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

Hi,

On 15/01/2025 12:30, Geert Uytterhoeven wrote:
> Hi Tomi,
> 
> On Wed, Jan 15, 2025 at 10:04 AM Tomi Valkeinen
> <tomi.valkeinen@ideasonboard.com> wrote:
>> Add greyscale Y8 format.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> 
> Thanks for your patch!
> 
>> --- a/include/uapi/drm/drm_fourcc.h
>> +++ b/include/uapi/drm/drm_fourcc.h
>> @@ -405,6 +405,9 @@ 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 */
>>
>> +/* Greyscale formats */
>> +
>> +#define DRM_FORMAT_Y8          fourcc_code('G', 'R', 'E', 'Y')  /* 8-bit Y-only */
> 
> I don't think you need this. We already have:
> 
>      /* 8 bpp Red (direct relationship between channel value and brightness) */
>      #define DRM_FORMAT_R8           fourcc_code('R', '8', ' ', ' ') /*
> [7:0] R */
> 
> See also commit 8aba4d30520ed656 ("drm/fourcc: Clarify the meaning of
> single-channel "red"").

Yes, I discuss this topic in the cover letter.

  Tomi