---
name: "systemd-backlight"
section: "8"
platform: "linux"
package: "systemd"
version: "257.13-1~deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/systemd-backlight@.service"
---

# systemd-backlight(8)

Load and save the display backlight brightness at boot and shutdown

Part of [systemd-backlight@.service(8)](/systemd-backlight@.service/8.md).

## NAME

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

## SYNOPSIS

systemd-backlight@.service

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

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

## DESCRIPTION

systemd-backlight@.service is a service that restores the brightness of a display backlight or LED (e.g. keyboard backlight) device at early boot, and saves it at shutdown. The brightness is stored in /var/lib/systemd/backlight/.

On restoring brightness of a display backlight device, **systemd-backlight** reads *ID\_BACKLIGHT\_CLAMP* udev property, that takes a boolean value or a percentage (needs to be suffixed with "%", e.g. "30%"). When a percentage is specified, the saved brightness is clamped to a value of at least 1 or the specified percentage of the maximum brightness, whichever is greater. When unset or set to true, the brightness is clamped in the same way with percentage 5%. When false, the saved brightness will not be clamped, and loaded as is.

On restoring brightness of a LED device, **systemd-backlight** reads *ID\_LEDS\_CLAMP* udev property, that also takes a boolean value or a percentage. When a percentage is specified, the saved brightness is clamped to the specified percentage of the maximum brightness. When set to true, the brightness is clamped in the same way with percentage 5%. When unset or set to false, the saved brightness will not be clamped, and loaded as is.

## KERNEL COMMAND LINE

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.

Added in version 209.

## SEE ALSO

[**systemd**(1)](/systemd/1.md)