30-bit X session and programs requiring 24-bit depth

Marek Szuba scriptkiddie at wp.pl
Fri Feb 14 11:53:53 UTC 2020


I do quite a lot of photo editing on my box and with both my monitors
and my graphics card (amdgpu) supporting 10-bit colour channels, I tend
to run X at colour depth 30. Unfortunately some software, most notably
programs using OpenGL it seems, refuse to run in this mode - presumably
(I have seen this mentioned as the reason of problems with 30-bit mode
under Windows when the first cards supporting it came out) because the
software assumes 8-bit alpha channel but with the frame buffer still
being only 32-bit it is only 2-bit. Seeing as there seem to be no way of
switching colour depth on the fly, the best I have been able to come up
with is two separate X sessions - one at depth 30 and one at 24.

Is there, or perhaps will there be some way in the near future, to work
around this problem - either by increasing framebuffer BPP (tried it a
while ago but it didn't seem to accept anything more than 32), using a
virtual X server (tried using Xephyr but it complained about there being
no matching screen), or some other way I haven't thought of?

Thank you in advance for your comments.


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