[gnome-desktop] gnome-rr: Don't print an error for no backlight

[Bastien Nocera <hadess src gnome org>]

commit 26efa98897aea50fb0d81b7733dd0deeba975e25
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Sep 12 17:50:51 2011 +0100

    gnome-rr: Don't print an error for no backlight
    
    If there's no support for the backlight property, don't
    throw a warning about it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=658844

 libgnome-desktop/gnome-rr.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/libgnome-desktop/gnome-rr.c b/libgnome-desktop/gnome-rr.c
index 8c5e9c9..d5f0590 100644
--- a/libgnome-desktop/gnome-rr.c
+++ b/libgnome-desktop/gnome-rr.c
@@ -1538,10 +1538,11 @@ update_brightness_limits (GnomeRROutput *output)
     atom = XInternAtom (DISPLAY (output), "BACKLIGHT", FALSE);
     info = XRRQueryOutputProperty (DISPLAY (output), output->id, atom);
     rc = gdk_error_trap_pop ();
-    if (rc != 0)
+    if (rc != Success)
     {
-        g_warning ("could not get output property for %s, rc: %i",
-		   output->name, rc);
+        if (rc != BadName)
+          g_warning ("could not get output property for %s, rc: %i",
+		     output->name, rc);
         goto out;
     }
     if (info == NULL)