3

As what title shows, I see this message at the screen of booting system.

[ OK ] Created slice system-systemd\x2dbacklight.slice.
       Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0
       Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0
[FAILED] Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0
See 'systemctl status systemd-backlight@backlight:acpi_video0.service' for details.

and my screen brightness always reset to max value after reboot. (I just added echo 80 > /sys/class/backlight/amdgpu_bl0/brightness to temporarily solve this before)

after booting i just run sudo systemctl status systemd-backlight@backlight:acpi_video0.service and get a output:

● systemd-backlight@backlight:acpi_video0.service - Load/Save Screen Backlight Brightness of backlight:acpi_video0
     Loaded: loaded (/lib/systemd/system/systemd-backlight@.service; static; vendor preset: enabled)
     Active: failed (Result: exit-code) since Wed 2021-02-10 14:17:56 CST; 1min 15s ago
       Docs: man:systemd-backlight@.service(8)
    Process: 822 ExecStart=/lib/systemd/systemd-backlight load backlight:acpi_video0 (code=exited, status=1/FAILURE)
   Main PID: 822 (code=exited, status=1/FAILURE)

Feb 10 14:17:56 q-laptop systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
Feb 10 14:17:56 q-laptop systemd-backlight[822]: Failed to get backlight or LED device 'backlight:acpi_video0': No such device
Feb 10 14:17:56 q-laptop systemd[1]: systemd-backlight@backlight:acpi_video0.service: Main process exited, code=exited, status=1/FAILURE
Feb 10 14:17:56 q-laptop systemd[1]: systemd-backlight@backlight:acpi_video0.service: Failed with result 'exit-code'.
Feb 10 14:17:56 q-laptop systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0.

after that i run sudo systemctl status systemd-backlight@backlight:amdgpu_bl0 then i get output:

● systemd-backlight@backlight:amdgpu_bl0.service - Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0
     Loaded: loaded (/lib/systemd/system/systemd-backlight@.service; static; vendor preset: enabled)
     Active: active (exited) since Wed 2021-02-10 14:17:56 CST; 7min ago
       Docs: man:systemd-backlight@.service(8)
    Process: 824 ExecStart=/lib/systemd/systemd-backlight load backlight:amdgpu_bl0 (code=exited, status=0/SUCCESS)
   Main PID: 824 (code=exited, status=0/SUCCESS)

Feb 10 14:17:56 q-laptop systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0...
Feb 10 14:17:56 q-laptop systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0.

I'm new in Linux. I want to know what happened while my system booting. Does it has relation between the failed message and my screen brightness which always be reset after system rebooted? How to remove this error message?

My system is Ubuntu 20.04LTS.

thanks in advance.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.