Re: [PATCH v1 2/4] drm/amdgpu: Add DRIVER_PLANE_COLOR_PIPELINE driver feature

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unconditional advertisement of DRIVER_PLANE_COLOR_PIPELINE breaks legacy YUV-to-RGB conversion on pre-DCN 3.0 hardware.
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commit 0f146a9591dc47b975ea73aa0e04b2950fb4ede5
Author: Robert Mader <robert.mader@collabora.com>

drm/amdgpu: Add DRIVER_PLANE_COLOR_PIPELINE driver feature

Adds the DRIVER_PLANE_COLOR_PIPELINE feature to the AMDGPU kms driver
structure to satisfy requirements for DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE.

> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -3092,7 +3092,7 @@ static const struct drm_driver amdgpu_kms_driver = {
>  	    DRIVER_ATOMIC |
>  	    DRIVER_GEM |
>  	    DRIVER_RENDER | DRIVER_MODESET | DRIVER_SYNCOBJ |
> -	    DRIVER_SYNCOBJ_TIMELINE,
> +	    DRIVER_SYNCOBJ_TIMELINE | DRIVER_PLANE_COLOR_PIPELINE,

[Severity: High]
Does advertising this feature unconditionally break legacy YUV-to-RGB conversion
on pre-DCN 3.0 hardware?

When a DRM client enables DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE based on this
flag, the DRM core hides the legacy COLOR_ENCODING and COLOR_RANGE properties.

However, looking at dm_plane_init_colorops(), the actual COLOR_PIPELINE
property is only initialized for newer hardware:

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c:dm_plane_init_colorops()
    ...
    if (dc->ctx->dce_version >= DCN_VERSION_3_0) {
        ret = amdgpu_dm_initialize_default_pipeline(plane, &pipelines[len]);
    ...

If the replacement COLOR_PIPELINE property is not attached on older hardware
(like Polaris or Vega), and the legacy properties are hidden, userspace will
have no way to configure YUV-to-RGB conversion. 

Should this capability only be exposed when the underlying hardware actually
supports and attaches the new pipeline properties?

>  	.open = amdgpu_driver_open_kms,
>  	.postclose = amdgpu_driver_postclose_kms,
>  	.ioctls = amdgpu_ioctls_kms,

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Sashiko AI review · https://sashiko.dev/#/patchset/20260630084229.529682-1-robert.mader@collabora.com?part=2