Fix fullscreen in Arch Linux

I had an issue when going full screen while watching a video as the sound continued playing but the picture froze. In addition, I could no longer use my keyboard or mouse and I had to restart my laptop. This was happening intermittently.

When checking the logs using journalctl I could see a call trace related to amdgpu:

archlinux kernel: WARNING: CPU: 13 PID: 227 at drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:221 dmub_psr_enable+0xfd/0x110 [amdgpu]

Fortunately, the archlinux forum is really good and I was able to find how to disable PSR to resolve this. The solution was to modify the kernel parameters by appending the .conf file in /boot/loader/entries/ with:

amdgpu.dcdebugmask=0x10

After a reboot I didn’t have problems anymore going full screen. I could now waste time watching youtube again.

But what is PSR? According to Intel - “Panel self refresh can save power by allowing the panel to refresh independently”. I didn’t notice any differences in power consumption after disabling it.