Re: [PATCH] drm/colorop: Mark interpolation properties as immutable and atomic

[Pekka Paalanen <pekka.paalanen@collabora.com>]

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On Wed, 1 Apr 2026 18:53:56 -0600
Alex Hung <alex.hung@amd.com> wrote:

> On 3/31/26 06:19, Pekka Paalanen wrote:
> > On Mon, 30 Mar 2026 09:33:53 -0300
> > Melissa Wen <mwen@igalia.com> wrote:
> >   
> >> On 26/03/2026 21:39, Alex Hung wrote:  
> >>> LUT1D_INTERPOLATION and LUT3D_INTERPOLATION are read-only properties but
> >>> were missing DRM_MODE_PROP_IMMUTABLE and DRM_MODE_PROP_ATOMIC flags.  
> >> + Xaver
> >>
> >> So, I double checked previous conversation about these two interpolation
> >> properties.
> >> AFAIU, we agreed (?) on not making it immutable because it could become
> >> mutable if a HW allows it.
> >> -
> >> https://lore.kernel.org/dri-devel/CAFZQkGyj7=N2UcbBnjv7Az3oHSD2LXaAx5wzccpSt_UEhH3NZw@mail.gmail.com/  
> > 
> > Simon's rationale there makes sense to me.  
> 
> Yes this makes sense and I forgot that we discussed it before. Thanks 
> Melissa and pekka
> 
> >   
> >> So, what's the best approach to inform userspace that they cannot change
> >> this property?
> >> Perhaps the driver has to reject if in the end the property is immutable (?)  
> > 
> > If the enum is exposed with a single value only, then obviously
> > userspace cannot program any other value.
> > 
> > Each driver needs to customize every enum for what they actually
> > support, anyway.  
> 
> As Melissa pointed out in the other thread, the doc said these 
> properties are "Read-only" when they are not. Should we update the 
> documents, such as below, to avoid confusion?

Yes, please!


Thanks,
pq


> diff --git include/drm/drm_colorop.h include/drm/drm_colorop.h
> index a3a32f9f918c..86d75babe30d 100644
> --- include/drm/drm_colorop.h
> +++ include/drm/drm_colorop.h
> @@ -312,7 +312,7 @@ struct drm_colorop {
>   	/**
>   	 * @lut1d_interpolation_property:
>   	 *
> -	 * Read-only property for DRM_COLOROP_1D_LUT interpolation
> +	 * Property for DRM_COLOROP_1D_LUT interpolation
>   	 */
>   	struct drm_property *lut1d_interpolation_property;
> 
> @@ -340,7 +340,7 @@ struct drm_colorop {
>   	/**
>   	 * @lut3d_interpolation_property:
>   	 *
> -	 * Read-only property for DRM_COLOROP_3D_LUT interpolation
> +	 * Property for DRM_COLOROP_3D_LUT interpolation
>   	 */
>   	struct drm_property *lut3d_interpolation_property;
> 

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