Re: [PATCH V13 49/51] drm/amd/display: Disable CRTC degamma when color pipeline is enabled

["Michel Dänzer" <michel.daenzer@mailbox.org>]

On 11/15/25 01:02, Alex Hung wrote:
> 
> 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 38f9ea313dcb..697e232acebf 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
> @@ -736,7 +736,7 @@ 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);
> +	if (plane->color_pipeline_property)
> +		has_degamma = false;

AFAICT this doesn't create the DEGAMMA properties at all for CRTCs where the primary plane has the COLOR_PIPELINE property, right?

That's unfortunate, since it means existing user space which uses the DEGAMMA properties can no longer work. I'd suggest something like this instead:

* DEGAMMA properties are created even if the primary plane has the COLOR_PIPELINE property.
* User space can use either the DEGAMMA properties or the COLOR_PIPELINE property. An atomic commit which attempts to enable both is rejected.


-- 
Earthling Michel Dänzer       \        GNOME / Xwayland / Mesa developer
https://redhat.com             \               Libre software enthusiast