man: document the new Ctrl-Alt-Del magic

diff --git a/man/systemd.xml b/man/systemd.xml
index e0e8d37a90ade54c1788838a6cbc0f796db2b9b3..d020582b539cb1ea38f2d4a2e493b208fa3d142b 100644 (file)
--- a/man/systemd.xml
+++ b/man/systemd.xml
@@ -627,10 +627,19 @@
                                 <listitem><para>Upon receiving this
                                 signal the systemd system manager will
                                 start the
-                                <filename>ctrl-alt-del.target</filename> unit. This
-                                is mostly equivalent to
+                                <filename>ctrl-alt-del.target</filename>
+                                unit. This is mostly equivalent to
                                 <command>systemctl start
-                                ctl-alt-del.target</command>.</para>
+                                ctl-alt-del.target</command>. If this
+                                signal is received more often than 7
+                                times per 2s an immediate reboot is
+                                triggered. Note that pressing
+                                Ctrl-Alt-Del on the console will
+                                trigger this signal. Hence, if a
+                                reboot is hanging pressing
+                                Ctrl-Alt-Del more than 7 times in 2s
+                                is a relatively safe way to trigger an
+                                immediate reboot.</para>
 
                                 <para>systemd user managers
                                 treat this signal the same way as