diff --git a/include/asm-ia64/acpi.h b/include/asm-ia64/acpi.h
index d734585a23cf..09a5dd0e44a8 100644
--- a/include/asm-ia64/acpi.h
+++ b/include/asm-ia64/acpi.h
@@ -110,9 +110,8 @@ extern void prefill_possible_map(void);
 extern int additional_cpus;
 
 #ifdef CONFIG_ACPI_NUMA
-/* Proximity bitmap length; _PXM is at most 255 (8 bit)*/
-#ifdef CONFIG_IA64_NR_NODES
-#define MAX_PXM_DOMAINS CONFIG_IA64_NR_NODES
+#if MAX_NUMNODES > 256
+#define MAX_PXM_DOMAINS MAX_NUMNODES
 #else
 #define MAX_PXM_DOMAINS (256)
 #endif