mirror of
https://github.com/systemd/systemd.git
synced 2024-11-01 00:51:24 +03:00
71 lines
2.5 KiB
XML
71 lines
2.5 KiB
XML
<?xml version="1.0"?>
|
|
<!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
|
|
<refentry id="systemd-backlight@.service" conditional='ENABLE_BACKLIGHT'>
|
|
|
|
<refentryinfo>
|
|
<title>systemd-backlight@.service</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>systemd-backlight@.service</refentrytitle>
|
|
<manvolnum>8</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>systemd-backlight@.service</refname>
|
|
<refname>systemd-backlight</refname>
|
|
<refpurpose>Load and save the display backlight brightness at boot and shutdown</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>systemd-backlight@.service</filename></para>
|
|
<para><filename>/usr/lib/systemd/systemd-backlight</filename> save [backlight|leds]:DEVICE</para>
|
|
<para><filename>/usr/lib/systemd/systemd-backlight</filename> load [backlight|leds]:DEVICE</para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para><filename>systemd-backlight@.service</filename> 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 <filename>/var/lib/systemd/backlight/</filename>. During
|
|
loading, if the udev property <option>ID_BACKLIGHT_CLAMP</option> 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.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Kernel Command Line</title>
|
|
|
|
<para><filename>systemd-backlight</filename> understands the
|
|
following kernel command line parameter:</para>
|
|
|
|
<variablelist class='kernel-commandline-options'>
|
|
<varlistentry>
|
|
<term><varname>systemd.restore_state=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean argument. Defaults to
|
|
<literal>1</literal>. If <literal>0</literal>, does not
|
|
restore the backlight settings on boot. However, settings will
|
|
still be stored on shutdown. </para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|