It's unclear to me why there's no color palette/correction table exposed in libdrm/KMS at the kernel. It should just be part of the video mode, maybe with a bit to indicate when the driver/hardware doesn't support changing it. But always be able to read it out, make it linear nonsense when the support isn't there - that won't be worse than what we have now.

Then the layers up the stack like Wayland/X/GNOME/KDE are just messengers to/from the bottom @ drm.

We also need floating point frame buffers to be first-class citizens at the KMS level. I don't want to be forced into OpenGL/Vulkan just to be able to have the hardware apply gamma correction on a software-rendered frame buffer, and if I have the hardware do color correction, it kind of needs the HDR of floats - not uchars, which I don't think libdrm supports with dumb buffers of today. If not floats, at least more bits than 8 per color component.

Programs like Plymouth or other embedded style applications running directly on libdrm should be able to have color-corrected output without needing bespoke software implementations and their own calibration tables. I should be able to tell the kernel the correction table, maybe compile it in, or another payload on the boot parameters cmdline.

Hell there are fairly well-known simple algorithms for generating approximate color tables from a single gamma value. If I only want to make things look "better" in my linux kiosk, and care not about absolute color correctness, let me stick a drm.gamma=.55 field on the kernel commandline to generate the correction table in lieu of a full calibrated table.