diff --git a/hw/xquartz/threadSafety.c b/hw/xquartz/threadSafety.c
index ff19863f0..c0ec1e4e6 100644
--- a/hw/xquartz/threadSafety.c
+++ b/hw/xquartz/threadSafety.c
@@ -36,7 +36,7 @@
 pthread_t SERVER_THREAD;
 pthread_t APPKIT_THREAD;
 
-static void spewCallStack(void) {
+static inline void spewCallStack(void) {
     void* callstack[128];
     int i, frames = backtrace(callstack, 128);
     char** strs = backtrace_symbols(callstack, frames);
@@ -48,12 +48,13 @@ static void spewCallStack(void) {
     free(strs);
 }
 
-void threadAssert(pthread_t tid) {
+void _threadAssert(pthread_t tid, const char *file, const char *fun, int line) {
     if(pthread_equal(pthread_self(), tid))
         return;
     
     /* NOOOO! */
-    ErrorF("Thread Assertion Failed: self=%s, expected=%s\n",
-            threadSafetyID(pthread_self()), threadSafetyID(tid));
+    ErrorF("Thread Assertion Failed: self=%s, expected=%s\n%s:%s:%d\n",
+           threadSafetyID(pthread_self()), threadSafetyID(tid),
+           file, fun, line);
     spewCallStack();
 }
diff --git a/hw/xquartz/threadSafety.h b/hw/xquartz/threadSafety.h
index 050469e4b..da3b5992e 100644
--- a/hw/xquartz/threadSafety.h
+++ b/hw/xquartz/threadSafety.h
@@ -27,6 +27,8 @@
 #ifndef _XQ_THREAD_SAFETY_H_
 #define _XQ_THREAD_SAFETY_H_
 
+#define DEBUG_THREADS 1
+
 #include <pthread.h>
 
 extern pthread_t SERVER_THREAD;
@@ -35,9 +37,16 @@ extern pthread_t APPKIT_THREAD;
 #define threadSafetyID(tid) (pthread_equal((tid), SERVER_THREAD) ? "X Server Thread" : "Appkit Thread")
 
 /* Print message to ErrorF if we're in the wrong thread */
-void threadAssert(pthread_t tid);
+void _threadAssert(pthread_t tid, const char *file, const char *fun, int line);
 
+#define threadAssert(tid) _threadAssert(tid, __FILE__, __FUNCTION__, __LINE__)
+
+#ifdef DEBUG_THREADS
 #define TA_SERVER() threadAssert(SERVER_THREAD)
 #define TA_APPKIT() threadAssert(APPKIT_THREAD)
+#else
+#define TA_SERVER() 
+#define TA_APPKIT() 
+#endif
 
 #endif _XQ_THREAD_SAFETY_H_