mirror of
https://github.com/systemd/systemd.git
synced 2024-11-28 12:53:36 +08:00
95 lines
3.2 KiB
XML
95 lines
3.2 KiB
XML
<?xml version="1.0"?>
|
|
<!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<!--
|
|
This file is part of systemd.
|
|
|
|
Copyright 2013 Lennart Poettering
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
-->
|
|
<refentry id="systemd-backlight@.service" conditional='ENABLE_BACKLIGHT'>
|
|
|
|
<refentryinfo>
|
|
<title>systemd-backlight@.service</title>
|
|
<productname>systemd</productname>
|
|
|
|
<authorgroup>
|
|
<author>
|
|
<contrib>Developer</contrib>
|
|
<firstname>Lennart</firstname>
|
|
<surname>Poettering</surname>
|
|
<email>lennart@poettering.net</email>
|
|
</author>
|
|
</authorgroup>
|
|
</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></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>
|