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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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  This file is part of systemd.

  Copyright 2013 Lennart Poettering

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<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>.</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>
