--- /dev/null
+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() \