--- old/src/xcb_xlib.c	2007-11-22 14:48:26.544068901 +0100
+++ new/src/xcb_xlib.c	2007-11-22 14:52:45.474129821 +0100
@@ -70,18 +70,22 @@
 void xcb_xlib_lock(xcb_connection_t *c)
 {
     _xcb_lock_io(c);
-    xcb_assert(c, !c->xlib.lock);
-    c->xlib.lock = 1;
-    c->xlib.thread = pthread_self();
+    if (c->xlib.lock) {
+        xcb_assert(c, !c->xlib.lock);
+        c->xlib.lock = 1;
+        c->xlib.thread = pthread_self();
+    }
     _xcb_unlock_io(c);
 }
 
 void xcb_xlib_unlock(xcb_connection_t *c)
 {
     _xcb_lock_io(c);
-    xcb_assert(c, c->xlib.lock);
-    xcb_assert(c, pthread_equal(c->xlib.thread, pthread_self()));
-    c->xlib.lock = 0;
-    pthread_cond_broadcast(&c->xlib.cond);
+    if (c->xlib.lock) {
+      xcb_assert(c, c->xlib.lock);
+      xcb_assert(c, pthread_equal(c->xlib.thread, pthread_self()));
+      c->xlib.lock = 0;
+      pthread_cond_broadcast(&c->xlib.cond);
+    }
     _xcb_unlock_io(c);
 }