diff --git a/src/backends/x11/meta-backend-x11.c b/src/backends/x11/meta-backend-x11.c
index 0fd7e7767..0306232e0 100644
--- a/src/backends/x11/meta-backend-x11.c
+++ b/src/backends/x11/meta-backend-x11.c
@@ -605,6 +605,12 @@ meta_backend_x11_class_init (MetaBackendX11Class *klass)
 static void
 meta_backend_x11_init (MetaBackendX11 *x11)
 {
+  /* XInitThreads() is needed to use the "threaded swap wait" functionality
+   * in Cogl - see meta_renderer_x11_create_cogl_renderer(). We call it here
+   * to hopefully call it before any other use of XLib.
+   */
+  XInitThreads();
+
   clutter_x11_request_reset_on_video_memory_purge ();
 
   /* We do X11 event retrieval ourselves */
diff --git a/src/backends/x11/meta-renderer-x11.c b/src/backends/x11/meta-renderer-x11.c
index 7d2080d3a..8560baab2 100644
--- a/src/backends/x11/meta-renderer-x11.c
+++ b/src/backends/x11/meta-renderer-x11.c
@@ -66,6 +66,14 @@ meta_renderer_x11_create_cogl_renderer (MetaRenderer *renderer)
   cogl_renderer_set_custom_winsys (cogl_renderer, get_x11_cogl_winsys_vtable);
   cogl_xlib_renderer_set_foreign_display (cogl_renderer, xdisplay);
 
+  /* Set up things so that if the INTEL_swap_event extension is not present,
+   * but the driver is known to have good thread support, we use an extra
+   * thread and call glXWaitVideoSync() in the thread. This allows idles
+   * to work properly, even when Mutter is constantly redrawing new frames;
+   * otherwise, without INTEL_swap_event, we'll just block in glXSwapBuffers().
+   */
+  cogl_xlib_renderer_set_threaded_swap_wait_enabled (cogl_renderer, TRUE);
+
   return cogl_renderer;
 }