[gnome-desktop] GnomeRR: read the backlight value after asking mutter to change it

[Giovanni Campagna <gcampagna src gnome org>]

commit b1503715e81b44ff4089ca2581fd95dfd8ac3631
Author: Giovanni Campagna <gcampagn redhat com>
Date:   Mon Aug 26 17:29:26 2013 +0200

    GnomeRR: read the backlight value after asking mutter to change it
    
    Mutter now returns the new backlight value after a successfull call
    to ChangeBacklight, so we need to read it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706729

 libgnome-desktop/gnome-rr.c |    1 +
 libgnome-desktop/xrandr.xml |    3 +++
 2 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/libgnome-desktop/gnome-rr.c b/libgnome-desktop/gnome-rr.c
index 5b56ff4..88c87b5 100644
--- a/libgnome-desktop/gnome-rr.c
+++ b/libgnome-desktop/gnome-rr.c
@@ -1429,6 +1429,7 @@ gnome_rr_output_set_backlight (GnomeRROutput *output, gint value, GError **error
     return meta_dbus_display_config_call_change_backlight_sync (output->info->screen->priv->proxy,
                                                                output->info->serial,
                                                                output->id, value,
+                                                               &output->backlight,
                                                                NULL, error);
 }
 
diff --git a/libgnome-desktop/xrandr.xml b/libgnome-desktop/xrandr.xml
index d8574ad..06449c3 100644
--- a/libgnome-desktop/xrandr.xml
+++ b/libgnome-desktop/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>
 
     <!--