diff --git a/src/core/monitor.c b/src/core/monitor.c
index e3e81ab0c..c6b46496c 100644
--- a/src/core/monitor.c
+++ b/src/core/monitor.c
@@ -1228,7 +1228,7 @@ meta_monitor_manager_handle_change_backlight  (MetaDBusDisplayConfig *skeleton,
 
   META_MONITOR_MANAGER_GET_CLASS (manager)->change_backlight (manager, output, value);
 
-  meta_dbus_display_config_complete_change_backlight (skeleton, invocation);
+  meta_dbus_display_config_complete_change_backlight (skeleton, invocation, output->backlight);
   return TRUE;
 }
 
diff --git a/src/xrandr.xml b/src/xrandr.xml
index d8574ad7c..06449c36a 100644
--- a/src/xrandr.xml
+++ b/src/xrandr.xml
@@ -205,11 +205,14 @@
 
 	Changes the backlight of @output to @value, which is
 	expressed as a percentage and rounded to the HW limits.
+
+        Returns the new value after rounding.
     -->
     <method name="ChangeBacklight">
       <arg name="serial" direction="in" type="u" />
       <arg name="output" direction="in" type="u" />
       <arg name="value" direction="in" type="i" />
+      <arg name="new_value" direction="out" type="i" />
     </method>
 
     <!--