Re: [PATCH 2/2] drm/tegra: Support YVU420

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] drm/tegra: DRM_FORMAT_YVU420 missing from tegra20_overlay_formats
--

commit f3a502c3f44845d367e8abc769d6a35f5bac0739
Author: Aaron Kling <webgeek1234@gmail.com>

drm/tegra: Support YVU420

This commit adds support for the YVU420 video format. It updates the format
lists for tegra114, tegra124, and shared planes, and adds logic to handle
UV swapping in the plane format configuration.

> diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
> index 76d3841a17b8b..57146c41c0972 100644
> --- a/drivers/gpu/drm/tegra/dc.c
> +++ b/drivers/gpu/drm/tegra/dc.c
> @@ -1312,6 +1312,7 @@ static const u32 tegra114_overlay_formats[] = {
>  	DRM_FORMAT_YUYV,
>  	DRM_FORMAT_YUV420,
>  	DRM_FORMAT_YUV422,
> +	DRM_FORMAT_YVU420,

[Severity: Medium]
Should this format also be added to tegra20_overlay_formats?

The commit adds DRM_FORMAT_YVU420 to tegra114_overlay_formats,
tegra124_overlay_formats, and tegra_shared_plane_formats, but it appears
to be omitted from tegra20_overlay_formats in the same file.

Since YVU420 support relies purely on software configuration by setting
swap_uv = true, which directs the driver to swap the pointers programmed
into the U and V hardware registers in tegra_dc_setup_window() and
tegra_shared_plane_atomic_update(), is it fully compatible with
Tegra20/30 platforms since they already support DRM_FORMAT_YUV420?

If so, does omitting it unnecessarily block Tegra20/30 platforms from
advertising YVU420 support to userspace, causing fallbacks to software
composition for video playback?

For context, tegra20_overlay_formats currently only includes:

static const u32 tegra20_overlay_formats[] = {
...
	DRM_FORMAT_UYVY,
	DRM_FORMAT_YUYV,
	DRM_FORMAT_YUV420,
	DRM_FORMAT_YUV422,
};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261008-tegra-drm-yvu420-v1-0-dc1c443c00f3@gmail.com?part=2