[mutter] xrandr: ignore hotplug_mode_update value

[Jonathon Jongsma <jjongsma src gnome org>]

commit e72c6916aa90b182036362eb87b26d57352e2b6e
Author: Jonathon Jongsma <jjongsma redhat com>
Date:   Wed Nov 5 11:42:15 2014 -0600

    xrandr: ignore hotplug_mode_update value
    
    The important thing is whether this property exists or not, but the value
    doesn't matter.

 src/backends/x11/meta-monitor-manager-xrandr.c |   26 +++++++++++++++++++++++-
 1 files changed, 25 insertions(+), 1 deletions(-)
---
diff --git a/src/backends/x11/meta-monitor-manager-xrandr.c b/src/backends/x11/meta-monitor-manager-xrandr.c
index d492958..3fdfca2 100644
--- a/src/backends/x11/meta-monitor-manager-xrandr.c
+++ b/src/backends/x11/meta-monitor-manager-xrandr.c
@@ -140,6 +140,30 @@ meta_monitor_transform_from_xrandr_all (Rotation rotation)
 }
 
 static gboolean
+output_get_property_exists (MetaMonitorManagerXrandr *manager_xrandr,
+                            MetaOutput *output, const char *propname)
+{
+  gboolean exists = FALSE;
+  Atom atom, actual_type;
+  int actual_format;
+  unsigned long nitems, bytes_after;
+  unsigned char *buffer;
+
+  atom = XInternAtom (manager_xrandr->xdisplay, propname, False);
+  XRRGetOutputProperty (manager_xrandr->xdisplay,
+                        (XID)output->winsys_id,
+                        atom,
+                        0, G_MAXLONG, False, False, AnyPropertyType,
+                        &actual_type, &actual_format,
+                        &nitems, &bytes_after, &buffer);
+
+  exists = (actual_type != None);
+
+  XFree (buffer);
+  return exists;
+}
+
+static gboolean
 output_get_boolean_property (MetaMonitorManagerXrandr *manager_xrandr,
                              MetaOutput *output, const char *propname)
 {
@@ -329,7 +353,7 @@ static gboolean
 output_get_hotplug_mode_update (MetaMonitorManagerXrandr *manager_xrandr,
                                 MetaOutput               *output)
 {
-  return output_get_boolean_property (manager_xrandr, output, "hotplug_mode_update");
+  return output_get_property_exists (manager_xrandr, output, "hotplug_mode_update");
 }
 
 static char *