diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index b4e504b914e4..f679a11a7e7f 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -17,7 +17,7 @@
 struct device_node;
 struct property;
 
-#define MIN_RMA			512		/* Minimum RMA (in MB) for CAS negotiation */
+#define MIN_RMA			768		/* Minimum RMA (in MB) for CAS negotiation */
 
 #define OF_DT_BEGIN_NODE	0x1		/* Start of node, full name */
 #define OF_DT_END_NODE		0x2		/* End node */