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.
KERNEL COMMAND LINE
systemd-backlight understands the following kernel command line
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 229 SYSTEMD-BACKLIGHT@.SERVICE(8)
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2019
All Rights Reserved.