Re: [RFC PATCH v2 3/9] drm/vkms: Add CSC FF colorop to color pipeline

[Alex Hung <alex.hung@amd.com>]

Reviewed-by: Alex Hung <alex.hung@amd.com>

On 3/30/26 09:34, Harry Wentland wrote:
> Insert a CSC Fixed-Function colorop as the first operation in the
> VKMS color pipeline, before the existing 1D curve. This allows
> userspace to select YUV-to-RGB conversion via the color pipeline
> for YCbCr framebuffers.
> 
> The CSC FF colorop advertises support for all six YUV-to-RGB
> conversion presets:
>    - YUV601/709/2020 full-range to RGB
>    - YUV601/709/2020 limited-range to RGB
> 
> Bump MAX_COLOR_PIPELINE_OPS from 4 to 5 to accommodate the new op.
> 
> Assisted-by Claude:claude-opus-4.6
> 
> Signed-off-by: Harry Wentland <harry.wentland@amd.com>
> ---
>   drivers/gpu/drm/vkms/vkms_colorop.c | 66 ++++++++++++++++++++---------
>   1 file changed, 46 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_colorop.c b/drivers/gpu/drm/vkms/vkms_colorop.c
> index 071f3a8d2e7c..fa78ac7be36e 100644
> --- a/drivers/gpu/drm/vkms/vkms_colorop.c
> +++ b/drivers/gpu/drm/vkms/vkms_colorop.c
> @@ -12,11 +12,19 @@ static const u64 supported_tfs =
>   	BIT(DRM_COLOROP_1D_CURVE_SRGB_EOTF) |
>   	BIT(DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF);
>   
> +static const u64 supported_csc_ff =
> +	BIT(DRM_COLOROP_CSC_FF_YUV601_RGB601) |
> +	BIT(DRM_COLOROP_CSC_FF_YUV601_LIMITED_RGB601) |
> +	BIT(DRM_COLOROP_CSC_FF_YUV709_RGB709) |
> +	BIT(DRM_COLOROP_CSC_FF_YUV709_LIMITED_RGB709) |
> +	BIT(DRM_COLOROP_CSC_FF_YUV2020_RGB2020) |
> +	BIT(DRM_COLOROP_CSC_FF_YUV2020_LIMITED_RGB2020);
> +
>   static const struct drm_colorop_funcs vkms_colorop_funcs = {
>   	.destroy = drm_colorop_destroy,
>   };
>   
> -#define MAX_COLOR_PIPELINE_OPS 4
> +#define MAX_COLOR_PIPELINE_OPS 5
>   
>   static int vkms_initialize_color_pipeline(struct drm_plane *plane, struct drm_prop_enum_list *list)
>   {
> @@ -27,7 +35,25 @@ static int vkms_initialize_color_pipeline(struct drm_plane *plane, struct drm_pr
>   
>   	memset(ops, 0, sizeof(ops));
>   
> -	/* 1st op: 1d curve */
> +	/* 1st op: CSC Fixed-Function (YUV to RGB) */
> +	ops[i] = kzalloc_obj(*ops[i]);
> +	if (!ops[i]) {
> +		drm_err(dev, "KMS: Failed to allocate colorop\n");
> +		ret = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	ret = drm_plane_colorop_csc_ff_init(dev, ops[i], plane, &vkms_colorop_funcs,
> +					    supported_csc_ff,
> +					    DRM_COLOROP_FLAG_ALLOW_BYPASS);
> +	if (ret)
> +		goto cleanup;
> +
> +	list->type = ops[i]->base.id;
> +
> +	i++;
> +
> +	/* 2nd op: 1d curve */
>   	ops[i] = kzalloc_obj(*ops[i]);
>   	if (!ops[i]) {
>   		drm_err(dev, "KMS: Failed to allocate colorop\n");
> @@ -41,23 +67,6 @@ static int vkms_initialize_color_pipeline(struct drm_plane *plane, struct drm_pr
>   	if (ret)
>   		goto cleanup;
>   
> -	list->type = ops[i]->base.id;
> -
> -	i++;
> -
> -	/* 2nd op: 3x4 matrix */
> -	ops[i] = kzalloc_obj(*ops[i]);
> -	if (!ops[i]) {
> -		drm_err(dev, "KMS: Failed to allocate colorop\n");
> -		ret = -ENOMEM;
> -		goto cleanup;
> -	}
> -
> -	ret = drm_plane_colorop_ctm_3x4_init(dev, ops[i], plane, &vkms_colorop_funcs,
> -					     DRM_COLOROP_FLAG_ALLOW_BYPASS);
> -	if (ret)
> -		goto cleanup;
> -
>   	drm_colorop_set_next_property(ops[i - 1], ops[i]);
>   
>   	i++;
> @@ -79,7 +88,24 @@ static int vkms_initialize_color_pipeline(struct drm_plane *plane, struct drm_pr
>   
>   	i++;
>   
> -	/* 4th op: 1d curve */
> +	/* 4th op: 3x4 matrix */
> +	ops[i] = kzalloc_obj(*ops[i]);
> +	if (!ops[i]) {
> +		drm_err(dev, "KMS: Failed to allocate colorop\n");
> +		ret = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	ret = drm_plane_colorop_ctm_3x4_init(dev, ops[i], plane, &vkms_colorop_funcs,
> +					     DRM_COLOROP_FLAG_ALLOW_BYPASS);
> +	if (ret)
> +		goto cleanup;
> +
> +	drm_colorop_set_next_property(ops[i - 1], ops[i]);
> +
> +	i++;
> +
> +	/* 5th op: 1d curve */
>   	ops[i] = kzalloc_obj(*ops[i]);
>   	if (!ops[i]) {
>   		drm_err(dev, "KMS: Failed to allocate colorop\n");