systemd/man/systemd-backlight@.service.html
2015-02-17 11:22:16 +01:00

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<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="systemd-backlight@.service"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>systemd-backlight@.service, systemd-backlight — Load and save the display backlight brightness at boot and shutdown</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><p><code class="filename">systemd-backlight@.service</code></p><p><code class="filename">/usr/lib/systemd/systemd-backlight</code></p></div><div class="refsect1"><a name="idm139645729052800"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description"></a></h2><p><code class="filename">systemd-backlight@.service</code> 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 <code class="filename">/var/lib/systemd/backlight/</code>. During
loading, if udev property <code class="option">ID_BACKLIGHT_CLAMP</code> is
not set to false value, 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.</p></div><div class="refsect1"><a name="idm139645729094416"></a><h2 id="Kernel Command Line">Kernel Command Line<a class="headerlink" title="Permalink to this headline" href="#Kernel%20Command%20Line"></a></h2><p><code class="filename">systemd-backlight</code> understands the
following kernel command line parameter:</p><div class="variablelist"><dl class="variablelist"><dt id="systemd.restore_state="><span class="term"><code class="varname">systemd.restore_state=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.restore_state="></a></dt><dd><p>Takes a boolean argument. Defaults to
"<code class="literal">1</code>". If "<code class="literal">0</code>", does not
restore the backlight settings on boot. However, settings will
still be stored on shutdown. </p></dd></dl></div></div><div class="refsect1"><a name="idm139645730342896"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>
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