Re: [PATCH v3 10/11] drm/amd/display: Set COLOR_SPACE_SRGB when fixed matrix colorop is bypassed

[Robert Mader <robert.mader@collabora.com>]

Hi,

On 23.06.26 18:48, Harry Wentland wrote:
> When the fixed matrix colorop is bypassed, the color_space was set to
> COLOR_SPACE_UNKNOWN (0). In DC's DPP setup (dpp1_cnv_setup), the logic
> 'input_color_space ? input_color_space : color_space' treats 0 as
> 'not provided', causing it to fall back to the format-based default of
> COLOR_SPACE_YCBCR709 for YUV framebuffers. This results in an implicit
> YUV-to-RGB conversion via ICSC even when a color pipeline is active and
> the fixed matrix is bypassed.

shouldn't a commit with YUV framebuffer and fixed matrix set to bypass 
always fail, like it does in the VKMS implementation?

If this commit is only needed for RGB formats, somehow getting a 
YUV-to-RGB conversion applied to them otherwise, then I think the commit 
message should be clarified accordingly, no?

>
> Fix this by setting COLOR_SPACE_SRGB (1) instead. This is non-zero, so
> it overrides the format default. The SRGB entry in dpp_input_csc_matrix
> is an identity matrix, so ICSC performs no actual conversion, which is
> the correct behavior when the fixed matrix colorop is bypassed.
>
> Cc: stable@vger.kernel.org
> Fixes: 93d922f4833b ("drm/amd/display: Implement fixed matrix colorop color space mapping")
> Assisted-by: Copilot:claude-opus-4.6
> Signed-off-by: Harry Wentland <harry.wentland@amd.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> index 561ee9a2e749..984bbfcf23f0 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> @@ -1534,7 +1534,7 @@ __set_dm_plane_colorop_fixed_matrix(struct drm_plane_state *plane_state,
>   		return -EINVAL;
>   
>   	if (colorop_state->bypass) {
> -		dc_plane_state->color_space = COLOR_SPACE_UNKNOWN;
> +		dc_plane_state->color_space = COLOR_SPACE_SRGB;
>   		return 0;
>   	}
>   

-- 
Robert Mader
Consultant Software Developer

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