Re: [PATCH v9 02/11] drm/fourcc: Add DRM_FORMAT_XV20

[Simon Ser]

On Wednesday, March 25th, 2026 at 15:02, Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx> wrote:

> XV20 is 2 plane 10 bit per component YCbCr 2x1 subsampled format. XV20
> is similar to the already existing P030 format, which is 2x2 subsampled.

I don't know for sure the multi-planar YCbCr format name scheme we're
using, but here are my observations looking at P, Q and S formats:

- The first digit indicates sub-sampling. 0 for 2x2, 2 for 2x1, 4 for none.
- The two other digits indicate bits for the Y channel, one of 10, 12, 16.
  One exception: Q401 indicates reverse order for Cb and Cr planes when compared
  to Q410.

P030 is a bit of an outlier here since it's the only one with multiple
Y samples. NV formats are also multi-planar but seem to use a completely
separate scheme.

Given the above I'd say what would make most sense to me is to use P230:
keep the last two digits and change the first one to indicate that the
only difference is the sub-sampling. Does that make sense to you?

Simon