diff -up Mesa-7.11/src/mesa/drivers/dri/sis/sis_context.h.jx Mesa-7.11/src/mesa/drivers/dri/sis/sis_context.h
--- Mesa-7.11/src/mesa/drivers/dri/sis/sis_context.h.jx 2010-12-14 16:43:15.000000000 -0500
+++ Mesa-7.11/src/mesa/drivers/dri/sis/sis_context.h 2011-09-09 11:47:56.454465358 -0400
@@ -405,7 +405,7 @@ struct sis_context
#elif defined(__ia64__)
#define MMIO_WMB() __asm __volatile("mf" : : : "memory")
#else
-#error platform needs WMB
+#define MMIO_WMB() __sync_synchronize()
#endif
#define mEndPrimitive() \