Comment 4 for bug 197153

A backtrace :

--- stack trace ---
#0 rw_output_by_id (info=0x0, id=77) at randrwrap.c:122
 output = <value optimized out>
#1 0xb6dc9990 in screen_info_new (screen=<value optimized out>) at randrwrap.c:606
 info = (ScreenInfo *) 0x80a4e50
#2 0xb6dc9f3b in rw_screen_new (gdk_screen=0x806e0b0, callback=0xb6e05340 <on_randr_event>, data=0x0) at randrwrap.c:391
 screen = (RWScreen *) 0x80a4c10
 dpy = (Display *) 0x8062878
 event_base = 98
 ignore = 173
#3 0xb6e05410 in gsd_xrandr_manager_start (manager=0x8078080, error=0xbf901500) at gsd-xrandr-manager.c:114
 rw_screen = <value optimized out>
#4 0xb6e0520f in impl_activate (plugin=0x80892c8) at gsd-xrandr-plugin.c:78
 res = <value optimized out>
 error = (GError *) 0x0
#5 0x0804b86e in gnome_settings_plugins_engine_activate_plugin (info=0x8087688) at gnome-settings-plugins-engine.c:533
 __PRETTY_FUNCTION__ = "gnome_settings_plugins_engine_activate_plugin"
#6 0x0804bb98 in activate_plugin (info=0x8087688, user_data=0x0) at gnome-settings-plugins-engine.c:244
 res = <value optimized out>
#7 0xb76af041 in IA__g_slist_foreach (list=0x8080fd0, func=0x804bb80 <activate_plugin>, user_data=0x0)
    at /build/buildd/glib2.0-2.15.6/glib/gslist.c:468
 next = (GSList *) 0x8080fe0
#8 0x0804beba in gnome_settings_plugins_engine_init (gconf_prefix=0x8082820 "/apps/gnome_settings_daemon/plugins")
    at gnome-settings-plugins-engine.c:346
 __PRETTY_FUNCTION__ = "gnome_settings_plugins_engine_init"
#9 0x0804acd3 in gnome_settings_manager_start (manager=0x8077f48, error=0xbf901634) at gnome-settings-manager.c:106
No locals.
#10 0x0804aa5a in main (argc=134712472, argv=0x2) at main.c:221
 manager = (GnomeSettingsManager *) 0x8077f48
 program = (GnomeProgram *) 0x80732b8
 res = <value optimized out>
 error = (GError *) 0x0
--- thread stack trace ---
.
Thread 2 (process 19530):
#0 0xb7fc6410 in __kernel_vsyscall ()
#1 0xb764d99b in read () from /lib/tls/i686/cmov/libpthread.so.0
#2 0xb7691cba in child_watch_helper_thread (data=0x0) at /build/buildd/glib2.0-2.15.6/glib/gmain.c:3910
 b = "\n\236d�(s��*\017u�\001\000\000\000\230K\b\b"
 list = (GSList *) 0x8084b98
#3 0xb76b8fef in g_thread_create_proxy (data=0x8084b98) at /build/buildd/glib2.0-2.15.6/glib/gthread.c:635
 __PRETTY_FUNCTION__ = "g_thread_create_proxy"
#4 0xb76464fb in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#5 0xb75c88ee in clone () from /lib/tls/i686/cmov/libc.so.6
.
Thread 1 (process 19528):
#0 rw_output_by_id (info=0x0, id=77) at randrwrap.c:122
 output = <value optimized out>
#1 0xb6dc9990 in screen_info_new (screen=<value optimized out>) at randrwrap.c:606
 info = (ScreenInfo *) 0x80a4e50
#2 0xb6dc9f3b in rw_screen_new (gdk_screen=0x806e0b0, callback=0xb6e05340 <on_randr_event>, data=0x0) at randrwrap.c:391
 screen = (RWScreen *) 0x80a4c10
 dpy = (Display *) 0x8062878
 event_base = 98
 ignore = 173
#3 0xb6e05410 in gsd_xrandr_manager_start (manager=0x8078080, error=0xbf901500) at gsd-xrandr-manager.c:114
 rw_screen = <value optimized out>
#4 0xb6e0520f in impl_activate (plugin=0x80892c8) at gsd-xrandr-plugin.c:78
 res = <value optimized out>
 error = (GError *) 0x0
#5 0x0804b86e in gnome_settings_plugins_engine_activate_plugin (info=0x8087688) at gnome-settings-plugins-engine.c:533
 __PRETTY_FUNCTION__ = "gnome_settings_plugins_engine_activate_plugin"
#6 0x0804bb98 in activate_plugin (info=0x8087688, user_data=0x0) at gnome-settings-plugins-engine.c:244
 res = <value optimized out>
#7 0xb76af041 in IA__g_slist_foreach (list=0x8080fd0, func=0x804bb80 <activate_plugin>, user_data=0x0)
    at /build/buildd/glib2.0-2.15.6/glib/gslist.c:468
 next = (GSList *) 0x8080fe0
#8 0x0804beba in gnome_settings_plugins_engine_init (gconf_prefix=0x8082820 "/apps/gnome_settings_daemon/plugins")
    at gnome-settings-plugins-engine.c:346
 __PRETTY_FUNCTION__ = "gnome_settings_plugins_engine_init"
#9 0x0804acd3 in gnome_settings_manager_start (manager=0x8077f48, error=0xbf901634) at gnome-settings-manager.c:106
No locals.
#10 0x0804aa5a in main (argc=134712472, argv=0x2) at main.c:221
 manager = (GnomeSettingsManager *) 0x8077f48
 program = (GnomeProgram *) 0x80732b8
 res = <value optimized out>
 error = (GError *) 0x0

It seams the problem is in gnome-desktop