From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Wang <wei.wang2@amd.com>
Subject: [PATCH] acpi: Fix an incorrect code path in
	acpi_processor_idle()
Date: Thu, 5 Apr 2012 15:39:14 +0200
Message-ID: <4F7DA082.5030503@amd.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, Jan Beulich <JBeulich@suse.com>, Keir Fraser <keir@xen.org>
List-Id: xen-devel@lists.xenproject.org

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@amd.com>
# Date 1333626300 -7200
# Node ID bc0e1869ba5c77e85f3ed012a979ac8061094367
# Parent  d690c7e896a26c54a5ab85458824059de72d5cba
Fix an incorrect code path in acpi_processor_idle()

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

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:
          /*