Arch Linux

Captain Rage

Member

Registered: 2012-02-02

Posts: 45

'Failed to start' ... 'Backlight Brightness of backlight:acpi_video0.'

Heey,

This suddenly appeared after a recent update (maybe the kernel getting upgraded to 4.1.8-1-lts?):

myuser@Computer ~]$ systemctl status systemd-backlight@backlight:acpi_video0.service
● systemd-backlight@backlight:acpi_video0.service - Load/Save Screen Backlight Brightness of backlight:acpi_video0
   Loaded: loaded (/usr/lib/systemd/system/systemd-backlight@.service; static; vendor preset: disabled)
   Active: failed (Result: exit-code) since fre 2015-09-25 14:33:56 CEST; 12min ago
     Docs: man:systemd-backlight@.service(8)
  Process: 1199 ExecStart=/usr/lib/systemd/systemd-backlight load %i (code=exited, status=1/FAILURE)
 Main PID: 1199 (code=exited, status=1/FAILURE)

sep 25 14:33:56 Computer systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
sep 25 14:33:56 Computer systemd[1]: systemd-backlight@backlight:acpi_video0.service: Main process exited, code=exited, status=1/FAILURE
sep 25 14:33:56 Computer systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0.
sep 25 14:33:56 Computer systemd[1]: systemd-backlight@backlight:acpi_video0.service: Unit entered failed state.
sep 25 14:33:56 Computer systemd[1]: systemd-backlight@backlight:acpi_video0.service: Failed with result 'exit-code'.

And the brightness cannot be adjusted using the laptop shortcuts (the dimming key works, however).
Also:

[myuser@Computer ~]$ journalctl -xe
sep 25 22:09:53 Computer systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
-- Subject: Unit systemd-backlight@backlight:acpi_video0.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit systemd-backlight@backlight:acpi_video0.service has begun starting up.
sep 25 22:09:53 Computer systemd-backlight[5208]: Failed to get backlight or LED device 'backlight:acpi_video0': No such device
sep 25 22:09:53 Computer systemd[1]: systemd-backlight@backlight:acpi_video0.service: Main process exited, code=exited, status=1/FAILURE
sep 25 22:09:53 Computer systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0.
-- Subject: Unit systemd-backlight@backlight:acpi_video0.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit systemd-backlight@backlight:acpi_video0.service has failed.
-- 
-- The result is failed.
sep 25 22:09:53 Computer systemd[1]: systemd-backlight@backlight:acpi_video0.service: Unit entered failed state.
sep 25 22:09:53 Computer systemd[1]: systemd-backlight@backlight:acpi_video0.service: Failed with result 'exit-code'.
sep 25 22:09:53 Computer polkitd[347]: Unregistered Authentication Agent for unix-process:5201:2765978 (system bus name :1.46, object path /org/freedeskto

Is anybody else getting this?

I remember that this issue haunted my machine on the vanilla kernal, so I switched to the lts kernal and it remedied the problem (this was many months ago). Now it seems to have reappeared.

kalsan

Member

Registered: 2011-10-10

Posts: 119

Re: 'Failed to start' ... 'Backlight Brightness of backlight:acpi_video0.'

Hi,
I just ran across your problem googling the same error. It occurs on my system as well.
On i3, my brightness controls didn't work by default either, so I looked and found light. It can be installed from the aur and works fine for me.
Not sure if you can disable the faulty service.
Cheers,
Kalsan

aliasdeep

Member

Registered: 2016-07-26

Posts: 1

Re: 'Failed to start' ... 'Backlight Brightness of backlight:acpi_video0.'

Mask unit(s):

# systemctl mask systemd-backlight@backlight:acpi_video0