diff -Naur libdrm-2.4.26-orig/intel/intel_bufmgr_gem.c libdrm-2.4.26/intel/intel_bufmgr_gem.c
--- libdrm-2.4.26-orig/intel/intel_bufmgr_gem.c	2011-04-01 10:30:51.000000000 -0400
+++ libdrm-2.4.26/intel/intel_bufmgr_gem.c	2011-08-29 02:17:20.000000000 -0400
@@ -51,6 +51,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <stdbool.h>
+#include <sys/time.h>
 
 #include "errno.h"
 #include "libdrm_lists.h"
@@ -987,9 +988,9 @@
 	if (atomic_dec_and_test(&bo_gem->refcount)) {
 		drm_intel_bufmgr_gem *bufmgr_gem =
 		    (drm_intel_bufmgr_gem *) bo->bufmgr;
-		struct timespec time;
+		struct timeval time;
 
-		clock_gettime(CLOCK_MONOTONIC, &time);
+		gettimeofday(&time, NULL);
 
 		pthread_mutex_lock(&bufmgr_gem->lock);
 		drm_intel_gem_bo_unreference_final(bo, time.tv_sec);
diff -Naur libdrm-2.4.26-orig/xf86drm.c libdrm-2.4.26/xf86drm.c
--- libdrm-2.4.26-orig/xf86drm.c	2011-03-21 09:39:24.000000000 -0400
+++ libdrm-2.4.26/xf86drm.c	2011-08-29 02:17:49.000000000 -0400
@@ -51,6 +51,9 @@
 #include <sys/mman.h>
 #include <sys/time.h>
 #include <stdarg.h>
+#if defined(__APPLE__) && defined(__MACH__)
+#include <mach/mach_time.h>
+#endif
 
 /* Not all systems have MAP_FAILED defined */
 #ifndef MAP_FAILED
@@ -1941,20 +1944,43 @@
  */
 int drmWaitVBlank(int fd, drmVBlankPtr vbl)
 {
+#if defined(__APPLE__) && defined(__MACH__)
+    uint64_t start, end, elapsed, elapsedNano;
+    static const uint64_t maxElapsed = 2000000000;
+    static mach_timebase_info_data_t timebaseInfo;
+    if ( timebaseInfo.denom == 0 ) {
+	(void) mach_timebase_info(&timebaseInfo);
+    }
+#else
     struct timespec timeout, cur;
+#endif
     int ret;
 
+#if defined(__APPLE__) && defined(__MACH__)
+    start = mach_absolute_time();
+#else
     ret = clock_gettime(CLOCK_MONOTONIC, &timeout);
     if (ret < 0) {
 	fprintf(stderr, "clock_gettime failed: %s\n", strerror(ret));
 	goto out;
     }
     timeout.tv_sec++;
+#endif
 
     do {
        ret = ioctl(fd, DRM_IOCTL_WAIT_VBLANK, vbl);
        vbl->request.type &= ~DRM_VBLANK_RELATIVE;
        if (ret && errno == EINTR) {
+#if defined(__APPLE__) && defined(__MACH__)
+	       end = mach_absolute_time();
+	       elapsed = end - start;
+	       elapsedNano = elapsed * timebaseInfo.numer / timebaseInfo.denom;
+	       if (elapsedNano > maxElapsed) {
+		   errno = EBUSY;
+		   ret = -1;
+		   break;
+	       }
+#else
 	       clock_gettime(CLOCK_MONOTONIC, &cur);
 	       /* Timeout after 1s */
 	       if (cur.tv_sec > timeout.tv_sec + 1 ||
@@ -1964,6 +1990,7 @@
 		       ret = -1;
 		       break;
 	       }
+#endif
        }
     } while (ret && errno == EINTR);