diff --git a/ChangeLog b/ChangeLog
index 1b8a913d2d..4c07c6b43a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2007-03-01  Sebastian Dröge  <slomo@circular-chaos.org>
+
+	* ext/hal/gsthalaudiosink.c: (do_toggle_element):
+	* ext/hal/gsthalaudiosrc.c: (do_toggle_element):
+	  Check if the device UDI is set before trying to query HAL
+	  about it and give a useful error message if it wasn't set.
+	* ext/hal/hal.c: (gst_hal_get_string):
+	  Don't query HAL for NULL UDIs. Passing NULL as UDI to HAL
+	  gives an assertion failure in D-Bus when running with
+	  DBUS_FATAL_WARNINGS=1.
+
 2007-02-28  Thomas Vander Stichele  <thomas at apestaart dot org>
 
 	* configure.ac:
diff --git a/common b/common
index 54c2a701c2..9a56e28fc1 160000
--- a/common
+++ b/common
@@ -1 +1 @@
-Subproject commit 54c2a701c28dcddaf051abf09a360223acd096c9
+Subproject commit 9a56e28fc15440eb6852411321c46312e1d1bb73
diff --git a/ext/hal/gsthalaudiosink.c b/ext/hal/gsthalaudiosink.c
index ea3c406663..1b941aa0c5 100644
--- a/ext/hal/gsthalaudiosink.c
+++ b/ext/hal/gsthalaudiosink.c
@@ -162,7 +162,11 @@ do_toggle_element (GstHalAudioSink * sink)
   }
 
   GST_DEBUG_OBJECT (sink, "Creating new kid");
-  if (!(sink->kid = gst_hal_get_audio_sink (sink->udi))) {
+  if (!sink->udi) {
+    GST_ELEMENT_ERROR (sink, LIBRARY, SETTINGS, (NULL),
+        ("No UDI set for device"));
+    return FALSE;
+  } else if (!(sink->kid = gst_hal_get_audio_sink (sink->udi))) {
     GST_ELEMENT_ERROR (sink, LIBRARY, SETTINGS, (NULL),
         ("Failed to render audio sink from Hal"));
     return FALSE;
diff --git a/ext/hal/gsthalaudiosrc.c b/ext/hal/gsthalaudiosrc.c
index f57e963eb5..ed8875443d 100644
--- a/ext/hal/gsthalaudiosrc.c
+++ b/ext/hal/gsthalaudiosrc.c
@@ -164,7 +164,11 @@ do_toggle_element (GstHalAudioSrc * src)
   }
 
   GST_DEBUG_OBJECT (src, "Creating new kid");
-  if (!(src->kid = gst_hal_get_audio_src (src->udi))) {
+  if (!src->udi) {
+    GST_ELEMENT_ERROR (src, LIBRARY, SETTINGS, (NULL),
+        ("No UDI set for device"));
+    return FALSE;
+  } else if (!(src->kid = gst_hal_get_audio_src (src->udi))) {
     GST_ELEMENT_ERROR (src, LIBRARY, SETTINGS, (NULL),
         ("Failed to render audio source from Hal"));
     return FALSE;
diff --git a/ext/hal/hal.c b/ext/hal/hal.c
index 519258d6d2..57da8425ec 100644
--- a/ext/hal/hal.c
+++ b/ext/hal/hal.c
@@ -50,6 +50,12 @@ gst_hal_get_string (const gchar * udi)
   LibHalContext *ctx;
   char *string;
 
+  /* Don't query HAL for NULL UDIs. Passing NULL as UDI to HAL gives
+   * an assertion failure in D-Bus when running with
+   * DBUS_FATAL_WARNINGS=1. */
+  if (!udi)
+    return NULL;
+
   dbus_error_init (&error);
 
   connection = dbus_bus_get (DBUS_BUS_SYSTEM, &error);