Add a note describing how to enable DPMS.

PR:		35140
Submitted by:	Erik Greenwald <erik@smluc.org>

en_US.ISO8859-1/books/handbook/x11/chapter.sgml

@@ -407,6 +407,15 @@ EndSection</programlisting>
 	keyword.  In the example above the target monitor's rates where
 	entered.</para>
 
+      <para>X allows DPMS (Energy Star) features to be used with capable
+        monitors. The 'xset' program controls the time-outs and can force
+        standby, suspend, or off modes.  If you wish to enable DPMS features
+        for your monitor, you must add the following line to the monitor
+        section.</para>
+     
+      <programlisting>
+        Option       "DPMS"</programlisting>
+
       <indexterm>
         <primary><command>XF86Config</command></primary>
       </indexterm>