--- linux-2.5.64/arch/ia64/Kconfig~	Fri Mar 14 14:18:38 2003
+++ linux-2.5.64/arch/ia64/Kconfig	Fri Mar 14 14:55:58 2003
@@ -405,6 +405,15 @@
 
 endchoice
 
+config IA64_PAL_IDLE
+	bool "Use PAL_HALT_LIGHT in idle loop"
+	---help---
+	  Say Y here to enable use of PAL_HALT_LIGHT in the cpu_idle loop.
+	  This allows the CPU to enter a low power state when idle.  You
+	  can enable CONFIG_IA64_PALINFO and check /proc/pal/cpu0/power_info
+	  to see the power consumption and latency for this state.  If you're
+	  unsure your firmware supports it, answer N.
+
 config SMP
 	bool "SMP support"
 	---help---
--- linux-2.5.64/arch/ia64/kernel/process.c~	Fri Mar 14 14:25:24 2003
+++ linux-2.5.64/arch/ia64/kernel/process.c	Fri Mar 14 14:46:17 2003
@@ -169,7 +169,10 @@
 void
 default_idle (void)
 {
-	/* may want to do PAL_LIGHT_HALT here... */
+#ifdef CONFIG_IA64_PAL_IDLE
+	if (!need_resched())
+		safe_halt();
+#endif
 }
 
 void __attribute__((noreturn))
@@ -177,6 +180,10 @@
 {
 	/* endless idle loop with no priority at all */
 	while (1) {
+		void (*idle)(void) = pm_idle;
+		if (!idle)
+			idle = default_idle;
+
 #ifdef CONFIG_SMP
 		if (!need_resched())
 			min_xtp();
@@ -186,10 +193,7 @@
 #ifdef CONFIG_IA64_SGI_SN
 			snidle();
 #endif
-			if (pm_idle)
-				(*pm_idle)();
-			else
-				default_idle();
+			idle();
 		}
 
 #ifdef CONFIG_IA64_SGI_SN
--- linux-2.5.64/include/asm-ia64/system.h~	Fri Mar 14 10:55:23 2003
+++ linux-2.5.64/include/asm-ia64/system.h	Fri Mar 14 10:55:51 2003
@@ -108,7 +108,7 @@
 #define set_mb(var, value)	do { (var) = (value); mb(); } while (0)
 #define set_wmb(var, value)	do { (var) = (value); mb(); } while (0)
 
-#define safe_halt()         ia64_pal_halt(1)                /* PAL_HALT */
+#define safe_halt()         ia64_pal_halt_light()    /* PAL_HALT_LIGHT */
 
 /*
  * The group barrier in front of the rsm & ssm are necessary to ensure