[patch 20/60] cpuidle: fix AMD C1E suspend hang

From: Greg KH
Date: Tue Jun 09 2009 - 23:39:03 EST

-stable review patch. If anyone has any objections, please let us know.

From: Shaohua Li <shaohua.li@xxxxxxxxx>

commit 7d60e8ab0d5507229dfbdf456501cc378610fa01 upstream.

When AMD C1E is enabled, local APIC timer will stop even in C1. To avoid
suspend/resume hang, this patch removes C1 and replace it with a cpu_relax() in
suspend/resume path. This hasn't any impact in runtime path.


[ impact: avoid suspend/resume hang in AMD CPU with C1E enabled ]

Tested-by: Dmitry Lyzhyn <thisistempbox@xxxxxxxxx>
Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/acpi/processor_idle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1468,8 +1468,8 @@ static int acpi_idle_enter_c1(struct cpu

/* Do not access any ACPI IO ports in suspend path */
if (acpi_idle_suspend) {
- acpi_safe_halt();
+ cpu_relax();
return 0;

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