Re: [PATCH V10 46/46] drm/amd/display: Disable CRTC degamma when color pipeline is enabled

[Melissa Wen <mwen@igalia.com>]

On 17/06/2025 00:17, Alex Hung wrote:
> The degamma is to be handled by Color pipeline API.
>
> Signed-off-by: Alex Hung <alex.hung@amd.com>
> ---
> V10:
>   - Disable CRTC degamma when color pipeline is enabled (Melissa Wen)
>
>   .../drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c    | 15 ++++++++++-----
>   1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> index 87058271b00c..62bb4855306d 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> @@ -685,7 +685,7 @@ int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm,
>   {
>   	struct amdgpu_crtc *acrtc = NULL;
>   	struct drm_plane *cursor_plane;
> -	bool is_dcn;
> +	bool has_degamma;
>   	int res = -ENOMEM;
>   
>   	cursor_plane = kzalloc(sizeof(*cursor_plane), GFP_KERNEL);
> @@ -724,11 +724,16 @@ int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm,
>   
>   	dm->adev->mode_info.crtcs[crtc_index] = acrtc;
>   
> -	/* Don't enable DRM CRTC degamma property for DCE since it doesn't
> -	 * support programmable degamma anywhere.
> +	/* Don't enable DRM CRTC degamma property for
> +	 * 1. Degamma is replaced by color pipeline.
> +	 * 2. DCE since it doesn't support programmable degamma anywhere.
>   	 */
> -	is_dcn = dm->adev->dm.dc->caps.color.dpp.dcn_arch;
> -	drm_crtc_enable_color_mgmt(&acrtc->base, is_dcn ? MAX_COLOR_LUT_ENTRIES : 0,
> +	if (plane->color_pipeline_property)
> +		has_degamma = false;
> +	else
> +		has_degamma = dm->adev->dm.dc->caps.color.dpp.dcn_arch;

Just a reminder to take into account this patch (if applied) for DCN401 
when rebasing:
https://lore.kernel.org/amd-gfx/20250511213847.61930-1-mwen@igalia.com/

> +
> +	drm_crtc_enable_color_mgmt(&acrtc->base, has_degamma ? MAX_COLOR_LUT_ENTRIES : 0,
>   				   true, MAX_COLOR_LUT_ENTRIES);
>   
>   	drm_mode_crtc_set_gamma_size(&acrtc->base, MAX_COLOR_LEGACY_LUT_ENTRIES);