diff --git a/arch/mips/sgi-ip27/Kconfig b/arch/mips/sgi-ip27/Kconfig
index 4b7c3c6751744f210a48d44fa1dccd653e7baf3b..f14ef38646d02258cf7997844bb76c60f7c12414 100644
--- a/arch/mips/sgi-ip27/Kconfig
+++ b/arch/mips/sgi-ip27/Kconfig
@@ -4,14 +4,29 @@
 #	  This options adds support for userspace processes upto 16TB size.
 #	  Normally the limit is just .5TB.
 
+choice
+	prompt "Node addressing mode"
+	depends on SGI_IP27
+	default SGI_SN_M_MODE
+
+config SGI_SN_M_MODE
+	bool "IP27 M-Mode"
+	help
+	  The nodes of Origin, Onyx, Fuel and Tezro systems can be configured
+	  in either N-Modes which allows for more nodes or M-Mode which allows
+	  for more memory.  Your hardware is almost certainly running in
+	  M-Mode, so choose M-mode here.
+
 config SGI_SN_N_MODE
 	bool "IP27 N-Mode"
-	depends on SGI_IP27
+	depends on EXPERIMENTAL
 	help
-	  The nodes of Origin 200, Origin 2000 and Onyx 2 systems can be
-	  configured in either N-Modes which allows for more nodes or M-Mode
-	  which allows for more memory.  Your system is most probably
-	  running in M-Mode, so you should say N here.
+	  The nodes of Origin, Onyx, Fuel and Tezro systems can be configured
+	  in either N-Modes which allows for more nodes or M-Mode which allows
+	  for more memory.  Your hardware is almost certainly running in
+	  M-Mode, so choose M-mode here.
+
+endchoice
 
 config MAPPED_KERNEL
 	bool "Mapped kernel support"
diff --git a/include/asm-mips/sn/sn0/arch.h b/include/asm-mips/sn/sn0/arch.h
index 0ecbaa0d3837e88bc126a5ee7350a9532d06b4ee..f7c43fa24aa8374cf8ab2d8bd5b94c1540e4dea7 100644
--- a/include/asm-mips/sn/sn0/arch.h
+++ b/include/asm-mips/sn/sn0/arch.h
@@ -59,9 +59,9 @@
  */
 #ifdef CONFIG_SGI_SN_N_MODE
 #define MAX_MEM_SLOTS   16                      /* max slots per node */
-#else /* !CONFIG_SGI_SN_N_MODE, assume M_MODE */
+#else /* !CONFIG_SGI_SN_N_MODE, assume CONFIG_SGI_SN_M_MODE */
 #define MAX_MEM_SLOTS   32                      /* max slots per node */
-#endif /* defined(N_MODE) */
+#endif /* CONFIG_SGI_SN_M_MODE */
 
 #define SLOT_SHIFT      	(27)
 #define SLOT_MIN_MEM_SIZE	(32*1024*1024)