chiark / gitweb /
man: fix references to systemctl man page which is now in section 1
[elogind.git] / man / systemd.device.xml
index 141d72e..557f15f 100644 (file)
         </refnamediv>
 
         <refsynopsisdiv>
-                <para><filename>systemd.device</filename></para>
+                <para><filename><replaceable>device</replaceable>.device</filename></para>
         </refsynopsisdiv>
 
         <refsect1>
                 <title>Description</title>
 
                 <para>A unit configuration file whose name ends in
-                <filename>.device</filename> encodes information about
+                <literal>.device</literal> encodes information about
                 a device unit as exposed in the
                 sysfs/<citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                 device tree.</para>
                 since no device-specific options may be
                 configured.</para>
 
-                <para>systemd will automatically create dynamic device
-                units for all kernel devices that are marked with the
-                "systemd" udev tag (by default all block and network
-                devices, and a few others). This may be used to define
-                dependencies between devices and other
-                units.</para>
+                <para>systemd will dynamically create device units for
+                all kernel devices that are marked with the "systemd"
+                udev tag (by default all block and network devices,
+                and a few others). This may be used to define
+                dependencies between devices and other units. To tag a
+                udev device, use <literal>TAG+="systemd"</literal> in
+                the udev rules file, see
+                <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+                for details.</para>
 
                 <para>Device units are named after the
                 <filename>/sys</filename> and
                 <filename>/dev</filename> paths they control. Example:
-                the device <filename>/dev/sda5</filename> is exposed
+                the device <filename noindex='true'>/dev/sda5</filename> is exposed
                 in systemd as <filename>dev-sda5.device</filename>. For
                 details about the escaping logic used to convert a
                 file system path to a unit name see
 
                 <para>The settings of device units may either be
                 configured via unit files, or directly from the udev
-                database (which is recommended). The following udev
+                database (which is recommended). The following udev device
                 properties are understood by systemd:</para>
 
                 <variablelist class='udev-directives'>
                         <varlistentry>
                                 <term><varname>SYSTEMD_WANTS=</varname></term>
+                                <term><varname>SYSTEMD_USER_WANTS=</varname></term>
                                 <listitem><para>Adds dependencies of
-                                type <varname>Wants</varname> from
-                                this unit to all listed units. This
-                                may be used to activate arbitrary
-                                units, when a specific device becomes
-                                available. Note that this and the
+                                type <varname>Wants</varname> from the
+                                device unit to all listed units. The
+                                first form is used by the system
+                                systemd instance, the second by user
+                                systemd instances. Those settings may
+                                be used to activate arbitrary units
+                                when a specific device becomes
+                                available.</para>
+
+                                <para>Note that this and the
                                 other tags are not taken into account
                                 unless the device is tagged with the
-                                "<literal>systemd</literal>" string in
+                                <literal>systemd</literal> string in
                                 the udev database, because otherwise
-                                the device is not exposed as systemd
-                                unit.</para></listitem>
+                                the device is not exposed as a systemd
+                                unit (see above).</para>
+
+                                <para>Note that systemd will only act
+                                on <varname>Wants</varname>
+                                dependencies when a device first
+                                becomes active. It will not act on
+                                them if they are added to devices that
+                                are already active. Use
+                                <varname>SYSTEMD_READY=</varname> (see
+                                below) to influence on which udev
+                                event to trigger the dependencies.
+                                </para></listitem>
                         </varlistentry>
 
                         <varlistentry>
 
                         <varlistentry>
                                 <term><varname>SYSTEMD_READY=</varname></term>
-                                <listitem><para>If set to 0 systemd
+                                <listitem><para>If set to 0, systemd
                                 will consider this device unplugged
                                 even if it shows up in the udev
                                 tree. If this property is unset or set
-                                to 1 the device will be considered
-                                plugged the moment it shows up in the
+                                to 1, the device will be considered
+                                plugged if it is visible in the
                                 udev tree. This property has no
                                 influence on the behavior when a
                                 device disappears from the udev
-                                tree. This option is useful to support
+                                tree.</para>
+
+                                <para>This option is useful to support
                                 devices that initially show up in an
-                                uninitialized state in the tree, and for
-                                which a changed event is generated the
-                                moment they are fully set
-                                up.</para></listitem>
+                                uninitialized state in the tree, and
+                                for which a <literal>changed</literal>
+                                event is generated the moment they are
+                                fully set up. Note that
+                                <varname>SYSTEMD_WANTS=</varname> (see
+                                above) is not acted on as long as
+                                <varname>SYSTEMD_READY=0</varname> is
+                                set for a device.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                   <title>See Also</title>
                   <para>
                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
-                          <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-                          <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+                          <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                   </para>
         </refsect1>