Re: [PATCH 0/5] drm/vkms: support more formats and fix RGB565 regression

[Sidharth Saha]

Hi Matheus,

I tested this series on top of drm-misc-next (7.3.0-rc4) with vkms in
a VirtualBox VM, running IGT with and without the series applied.

kms_writeback: writeback-pixel-formats, writeback-invalid-parameters,
writeback-fb-id and writeback-check-output pass both with and without
the series (writeback-check-output passed 4/4 runs on each), so I see
no regression in the existing writeback path.

kms_plane: pixel-format-linear-modifier fails both with and without
the series, on the assertion in capture_crc() (crc->frame != vblank),
before it reaches the new formats. This looks like the existing
kms_plane CRC issue listed in the vkms TODO rather than anything in
this series.

I wasn't able to exercise the RGB332/BGR233 read paths or BGR565
writeback with these tests, so no Tested-by for the series as a whole.
I did test the RGB565 rounding fix with a KUnit test, and I'll reply
to patch 1/5 with the details.

Thanks,
Sidharth

On 9/27/2026 5:52 PM, Matheus Alves de Almeida wrote:
> Hi,
>
> This series adds support for RGB332, BGR233 and BGR565 writeback. This
> is done with new helpers added to make conversion easier. It also fixes
> a regression in the RGB565 write conversion.