--- linux-2.4.20/Documentation/Configure.help~	Fri Mar 14 09:52:58 2003
+++ linux-2.4.20/Documentation/Configure.help	Fri Mar 14 09:53:50 2003
@@ -25479,6 +25479,14 @@
   Say Y here to enable machine check support for IA-64.  If you're
   unsure, answer Y.
 
+Use PAL_HALT_LIGHT in idle loop
+CONFIG_IA64_PAL_IDLE
+  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.
+
 Disable IA-64 Virtual Hash Page Table
 CONFIG_DISABLE_VHPT
   The Virtual Hash Page Table (VHPT) enhances virtual address
--- linux-2.4.20/arch/ia64/config.in~	Fri Mar 14 09:53:08 2003
+++ linux-2.4.20/arch/ia64/config.in	Fri Mar 14 11:00:36 2003
@@ -86,6 +86,7 @@
 
 define_bool CONFIG_KCORE_ELF y	# On IA-64, we always want an ELF /proc/kcore.
 
+bool 'Use PAL_HALT_LIGHT in idle loop' CONFIG_IA64_PAL_IDLE
 bool 'SMP support' CONFIG_SMP
 tristate 'Support running of Linux/x86 binaries' CONFIG_IA32_SUPPORT
 bool 'Performance monitor support' CONFIG_PERFMON
--- linux-2.4.20/arch/ia64/kernel/process.c~	Fri Mar 14 09:53:16 2003
+++ linux-2.4.20/arch/ia64/kernel/process.c	Fri Mar 14 14:49:02 2003
@@ -122,6 +122,15 @@
 		show_stack(0);
 }
 
+static void
+default_idle(void)
+{
+#ifdef CONFIG_IA64_PAL_IDLE
+	if (!current->need_resched)
+		safe_halt();
+#endif
+}
+
 void __attribute__((noreturn))
 cpu_idle (void *unused)
 {
@@ -132,6 +141,10 @@
 
 
 	while (1) {
+		void (*idle)(void) = pm_idle;
+		if (!idle)
+			idle = default_idle;
+
 #ifdef CONFIG_SMP
 		if (!current->need_resched)
 			min_xtp();
@@ -141,7 +154,7 @@
 #ifdef CONFIG_IA64_SGI_SN
 			snidle();
 #endif
-			continue;
+			idle();
 		}
 
 #ifdef CONFIG_IA64_SGI_SN
@@ -153,8 +166,6 @@
 #endif
 		schedule();
 		check_pgt_cache();
-		if (pm_idle)
-			(*pm_idle)();
 	}
 }
 
--- linux-2.4.20/include/asm-ia64/system.h~	Fri Mar 14 09:55:42 2003
+++ linux-2.4.20/include/asm-ia64/system.h	Fri Mar 14 10:11:01 2003
@@ -104,7 +104,7 @@
 #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