systemd/man/systemd-suspend.service.xml

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<refentry id="systemd-suspend.service">

        <refentryinfo>
                <title>systemd-suspend.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-suspend.service</refentrytitle>
                <manvolnum>8</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>systemd-suspend.service</refname>
                <refname>systemd-hibernate.service</refname>
                <refname>systemd-hybrid-sleep.service</refname>
                <refname>systemd-sleep</refname>
                <refpurpose>System sleep state logic</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <para><filename>systemd-suspend.service</filename></para>
                <para><filename>systemd-hibernate.service</filename></para>
                <para><filename>systemd-hybrid-sleep.service</filename></para>
                <para><filename>/usr/lib/systemd/systemd-sleep</filename></para>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para><filename>systemd-suspend.service</filename> is
                a system service that is pulled in by
                <filename>suspend.target</filename> and is responsible
                for the actual system suspend. Similar,
                <filename>systemd-hibernate.service</filename> is
                pulled in by <filename>hibernate.target</filename> to
                execute the actual hibernation. Finally,
                <filename>systemd-hybrid-sleep.service</filename> is
                pulled in by <filename>hybrid-sleep.target</filename>
                to execute hybrid hibernation with system
                suspend.</para>

                <para>Immediately before entering system suspend
                and/or hibernation
                <filename>systemd-suspend.service</filename> (and the
                other mentioned units, respectively) will run all
                executables in
                <filename>/usr/lib/systemd/system-sleep/</filename>
                and pass two arguments to them. The first argument
                will be "<literal>pre</literal>", the second either
                "<literal>suspend</literal>",
                "<literal>hibernate</literal>", or
                "<literal>hybrid-sleep</literal>" depending on the
                chosen action. Immediately after leaving system
                suspend and/or hibernation the same executables are run,
                but the first argument is now
                "<literal>post</literal>". All executables in this
                directory are executed in parallel, and execution of
                the action is not continued before all executables
                finished.</para>

                <para>Note that scripts or binaries dropped in
                <filename>/usr/lib/systemd/system-sleep/</filename>
                are intended for local use only and should be
                considered hacks. If applications want to be notified
                of system suspend/hibernation and resume there are
                much nicer interfaces available.</para>

                <para>Note that
                <filename>systemd-suspend.service</filename>,
                <filename>systemd-hibernate.service</filename> and
                <filename>systemd-hybrid-sleep.service</filename>
                should never be executed directly. Instead, trigger
                system sleep states with a command such as
                "<literal>systemctl suspend</literal>" or
                similar.</para>

                <para>Internally, this service will echo a string like
                <literal>mem</literal> into
                <filename>/sys/power/state</filename>, to trigger the
                actual system suspend.</para>
        </refsect1>

        <refsect1>
                <title>See Also</title>
                <para>
                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemd-halt.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                </para>
        </refsect1>

</refentry>