diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index 6e3b70b66..0fb880fab 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -965,7 +965,7 @@ meta_backend_class_init (MetaBackendClass *klass)
   /**
    * MetaBackend::gpu-added: (skip)
    * @backend: the #MetaBackend
-   * @gpu: the #MetaGpu
+   * @gpu: (type gpointer): the #MetaGpu
    */
   signals[GPU_ADDED] =
     g_signal_new ("gpu-added",
diff --git a/src/x11/group.c b/src/x11/group.c
index cddf85608..870c26fa5 100644
--- a/src/x11/group.c
+++ b/src/x11/group.c
@@ -206,7 +206,7 @@ meta_group_get_startup_id (MetaGroup *group)
 /**
  * meta_group_property_notify: (skip)
  * @group: a #MetaGroup
- * @event: a X event
+ * @event: (type xlib.XEvent): a X event
  *
  */
 gboolean