Manpages - systemd-backlight@.service.8

systemd-backlight@.service, systemd-backlight - Load and save the display backlight brightness at boot and shutdown

systemd-backlight@.service

/usr/lib/systemd/systemd-backlight save [backlight|leds]:DEVICE

/usr/lib/systemd/systemd-backlight load [backlight|leds]:DEVICE

systemd-backlight@.service is a service that restores the display backlight brightness at early boot and saves it at shutdown. On disk, the backlight brightness is stored in var/lib/systemd/backlight. During loading, if the udev property ID_BACKLIGHT_CLAMP is not set to false, the brightness is clamped to a value of at least 1 or 5% of maximum brightness, whichever is greater. This restriction will be removed when the kernel allows user space to reliably set a brightness value which does not turn off the display.

systemd-backlight understands the following kernel command line parameter:

systemd.restore_state=

Takes a boolean argument. Defaults to “1”. If “0”, does not restore the backlight settings on boot. However, settings will still be stored on shutdown.

*systemd*(1)