[Xen-devel] [PATCH] acpi: Fix an incorrect code path in acpi_processor_idle()

[Wei Wang <wei.wang2@xxxxxxx>]

Hi, There seems to be an incorrect code path in acpi_processor_idle(). 
ACPI_STATE_C3 code path might need to be avoided when cpu tries to enter 
c2 but lapic_timer_c2_ok is not set. This bug affects some amd systems 
which have c2 state available. The XenServer 6.0 performance issue[1] 
should also be fixed by this patch. If it looks fine, please apply it to 
unstable, 4.1 and 4.0
Thanks,
Wei

[1]
http://forums.citrix.com/thread.jspa?threadID=297461&tstart=0&start=0

# HG changeset patch
# User Wei Wang <wei.wang2@xxxxxxx>
# Date 1333626300 -7200
# Node ID bc0e1869ba5c77e85f3ed012a979ac8061094367
# Parent  d690c7e896a26c54a5ab85458824059de72d5cba
Fix an incorrect code path in acpi_processor_idle()

Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>

diff -r d690c7e896a2 -r bc0e1869ba5c xen/arch/x86/acpi/cpu_idle.c
--- a/xen/arch/x86/acpi/cpu_idle.c      Thu Apr 05 11:06:03 2012 +0100
+++ b/xen/arch/x86/acpi/cpu_idle.c      Thu Apr 05 13:45:00 2012 +0200
@@ -466,8 +466,8 @@ static void acpi_processor_idle(void)
             local_irq_enable();
             /* Compute time (ticks) that we were actually asleep */
             sleep_ticks = ticks_elapsed(t1, t2);
-            break;
         }
+        break;

     case ACPI_STATE_C3:
         /*


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