Created attachment 293729 [details] dmesg Following: https://github.com/systemd/systemd/issues/17645 If I set kernel boot option "quiet", systemd fails to restore brightness level with error Failed to start Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0. At boot. full journal output is: journalctl -b -1 -u systemd-backlight@backlight:amdgpu_bl0.service -- Logs begin at Thu 2020-09-17 08:15:00 CEST, end at Tue 2020-11-17 14:19:18 CET. -- Nov 17 14:15:15 frigg systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0... Nov 17 14:15:15 frigg systemd-backlight[325]: amdgpu_bl0: Failed to write system 'brightness' attribute: No such device or address Nov 17 14:15:15 frigg systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Main process exited, code=exited, status=1/FAILURE Nov 17 14:15:15 frigg systemd[1]: systemd-backlight@backlight:amdgpu_bl0.service: Failed with result 'exit-code'. Nov 17 14:15:15 frigg systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0. This is an AMD Renoir system, with AMD Ryzen 5 4500U APU, This happens only, if I set 'quiet' as boot option. If I remove it, brightness restore works fine. If I boot with quiet set, after login I can do systemctl start systemd-backlight@backlight:amdgpu_bl0.service And it will successfully restore my brightness level.
Can confirm this with a Ryzen 7 4800H. Any news on this?
I just found out that this Issue does NOT occur when you additionally add the fbcon=nodefer kernel parameter.
(In reply to ninelore from comment #2) > I just found out that this Issue does NOT occur when you additionally add > the fbcon=nodefer kernel parameter. This workaround works for me too.
Workaround works for me too, on a Lenovo Ideapad 530S-14ARR with an AMD Ryzen 2500U. I also set acpi_backlight=vendor to fix the same error message for backlight:acpi_video1. (No idea why it tries to restore backlight brightness twice)
As of Kernel 5.15, I don't need fbcon=nodefer anymore. By default the backlight works and is set on start. I still get from time to time an boot-error by systemd, but that can be also worked around by loading amdgpu early. Can someone confirm this?
@Fabian I have the same experience. I was running kernel 5.13 on Ubuntu 21.10 and when I upgraded to mainline kernel 5.15.13 (using https://github.com/pimlie/ubuntu-mainline-kernel.sh), the service "systemd-backlight@backlight:amdgpu_bl0.service" starts as expected and backlight seems to be restored. With kernel 5.13 it failed: "Failed to start Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0" and I was not able to start it manually.
Related fix for resume from suspend in kernel 5.15 explained here: https://www.phoronix.com/scan.php?page=news_item&px=AMD-S2idle-Fix-Linux-5.15 The say it could also fix an issue with brightness.
(In reply to Fabian from comment #5) > As of Kernel 5.15, I don't need fbcon=nodefer anymore. By default the > backlight works and is set on start. I still get from time to time an > boot-error by systemd, but that can be also worked around by loading amdgpu > early. > > Can someone confirm this? (In reply to jaromir.obr from comment #6) > @Fabian > I have the same experience. I was running kernel 5.13 on Ubuntu 21.10 and > when I upgraded to mainline kernel 5.15.13 (using > https://github.com/pimlie/ubuntu-mainline-kernel.sh), the service > "systemd-backlight@backlight:amdgpu_bl0.service" starts as expected and > backlight seems to be restored. > > With kernel 5.13 it failed: "Failed to start Load/Save Screen Backlight > Brightness of backlight:amdgpu_bl0" and I was not able to start it manually. Can confirm this bug is fixed with 5.15