[Solved] Adjusting contrast on AMD GPU

[RomainOnDebian]

Hi everybody,
I have an issue with the external display of my laptop (HP EliteBook 655 G10). The screen plugged (BenQ GW2470) is displaying very bad colors. Especially the greys that become nearly white.
This make the use very complicated, because I cannot see the selected item, or some buttons are not visible.



The problem is the same with Windows, and I fixed it by adjusting the contrast value on that display with the ADM driver software.


I have spent a lot of time to set the contrast on my Debian, but I haven't found any solution (neither in the admgpu parameter, neither by importing the ICC profile of the windows).

• Do you have any idea to set the contrast ?
• Is it a missing feature of the AMD GPU driver ?

I'm using Debian 12, wayland (even I have also tested Xorg).
The GPU is a graphic car include in the AMD Ryzen 7730 U.

modinfo amdgpu |grep filename
filename:       /lib/modules/6.1.0-18-amd64/kernel/drivers/gpu/drm/amd/amdgpu/amdgpu.ko

[CwF]

Don't neglect to try the adjustments on the monitor itself.

[RomainOnDebian]

Don't neglect to try the adjustments on the monitor itself.

I made another full review of the monitor settings and found one settings that fix it.
It's called "HDMI RGB PC Range", if I force it to RGB (16~235) the problem is solved. If I choose again Auto-detect problem is back.

Thank you so much for the clue!

[CwF]

If I choose again Auto-detect problem is back.

Yes, I almost took the time to explain the 'bitness' issue, somewhere on here I have explained 'color gamut'. I'm pleased you found it. My newer replacement displays also no longer save settings properly either, or I haven't figured it out yet...

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