$NetBSD: patch-af,v 1.12 2009/06/05 11:10:35 wiz Exp $

--- src/mesa/drivers/dri/sis/sis_context.h.orig	2009-05-19 11:47:27 +0300
+++ src/mesa/drivers/dri/sis/sis_context.h	2009-05-19 11:48:44 +0300
@@ -404,7 +404,14 @@ struct sis_context
 #define MMIO_WMB()	__asm __volatile("" : : : "memory")
 #elif defined(__ia64__)
 #define MMIO_WMB()	__asm __volatile("mf" : : : "memory")
+#elif defined(HAVE_NETBSD_ATOMIC_H)
+#include <sys/atomic.h>
+#define MMIO_WMB()     membar_sync()   /* XXX is this adequate? */
+#elif defined(__sync_synchronize)      /* gcc built-in */
+#define MMIO_WMB()     __sync_synchronize()
 #else
+#warning Please define MMIO_WMB for this platform
+#define MMIO_WMB()
 #error platform needs WMB
 #endif