HDR support in Wayland/Weston

Michel Dänzer michel at daenzer.net
Thu Mar 7 10:11:12 UTC 2019

On 2019-03-07 5:38 a.m., Graeme Gill wrote:
> Michel Dänzer wrote:
>> As of xserver 1.19, if the Xorg driver calls xf86HandleColormaps(), all
>> relevant mappings (colormap, global gamma, xf86VidMode per-X-screen
>> ramp, RandR per-CRTC ramp) are composed, and the result is applied to
>> the hardware LUT for all CRTCs.
> Hmm. Yuk from a color management point of view. So when
> I load up an ICC display profile I really need to reset
> all of that to be certain the screen is color calibrated!

Yep. The alternative is that the different mechanisms clobber the
hardware LUT from each other, which sucks from a user POV. Welcome to
the wonderful world of "colour management" in X, please pick your
poison. I guess you can see why Wayland has a different design. :)

Earthling Michel Dänzer               |              https://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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