Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 70 insertions, 0 deletions

diff --git a/man/systemd-backlight@.service.xml b/man/systemd-backlight@.service.xml
new file mode 100644
index 0000000..431b27b
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+++ b/man/systemd-backlight@.service.xml
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+<?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'
+          xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <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. The percentage can be adjusted by specifying a
+    percentage (needs to be suffixed with <literal>%</literal>, e.g. <literal>30%</literal>) to the property
+    <option>ID_BACKLIGHT_CLAMP</option>.</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>
+
+        <xi:include href="version-info.xml" xpointer="v209"/></listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>