[RFC PATCH 4/5] drm/drm_color_mgmt: add 3D LUT to color mgmt properties

[Ville Syrjälä]

On Sun, Jun 19, 2022 at 09:31:03PM -0100, Melissa Wen wrote:
> Add 3D LUT for gammar correction using a 3D lookup table.  The position
> in the color correction pipeline where 3D LUT is applied depends on hw
> design, being after CTM or gamma. If just after CTM, a shaper lut must
> be set to shape the content for a non-linear space. That details should
> be handled by the driver according to its color capabilities.

I also cooked up a WIP 3D LUT support some time ago for Intel hw:
https://github.com/vsyrjala/linux/commits/3dlut
But that dried up due to having no userspace for it.

I also cooked up some basic igts for it:
https://patchwork.freedesktop.org/series/90165/

<snip>
> + * “LUT3D”:
> + *	Blob property to set the 3D LUT mapping pixel data after the color
> + *	transformation matrix and before gamma 1D lut correction.

On Intel hw the 3DLUT is after the gamma LUT in the pipeline, which is
where I placed it in my branch.

There is now some discussion happening about exposing some
kind of color pipeline description/configuration properties:
https://gitlab.freedesktop.org/pq/color-and-hdr/-/issues/11

-- 
Ville Syrjälä
Intel