Brightness is reset to max after Xorg dpms screen blank
Brief summary of the problem:
Brightness is restored to max after coming back from DPMS screen turn off/standby.
I looked a bit into the code and digged a bit with igt-gpu-tools as far as I can see the brigthness written into the DPCD registers is reset to max (400000 millinits) when the screen turns on, so maybe this is expected behavior?
Hardware description:
Only amdgpu is listed in sysfs as backlight device.
- CPU: AMD Ryzen 7 5800H with Radeon Graphics
- GPU:
- 04:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Cezanne [Radeon Vega Series / Radeon Vega Mobile Series] [1002:1638] (rev c5)
- 01:00.0 3D controller [0302]: NVIDIA Corporation GA107M [GeForce RTX 3050 Mobile] [10de:25a2] (rev a1)
- System Memory: 16GB
- Display(s): 1920 x 1080 OLED HDR | 60Hz refresh rate (though I haven't configured anything HDR related)
- Type of Display Connection: eDP
System information:
- Distro name and Version: Artix Linux
- Kernel version: Linux elias-PC 6.6.7-artix1-1 #1 (closed) SMP PREEMPT_DYNAMIC Thu, 14 Dec 2023 10:09:41 +0000 x86_64 GNU/Linux
- Custom kernel: Tried latest rc, same issue
- AMD official driver version: N/A
How to reproduce the issue:
Set any brightness other than max and wait for DPMS to turn the screen off (or xset dpms force off), the screen returns to max brightness after turning back on.