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From: Wei Wang <wei.wang2@amd.com>
To: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
	Jan Beulich <JBeulich@suse.com>, Keir Fraser <keir@xen.org>
Subject: [PATCH] acpi: Fix an incorrect code path in acpi_processor_idle()
Date: Thu, 5 Apr 2012 15:39:14 +0200	[thread overview]
Message-ID: <4F7DA082.5030503@amd.com> (raw)

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:
          /*

             reply	other threads:[~2012-04-05 13:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-05 13:39 Wei Wang [this message]
2012-04-05 14:02 ` [PATCH] acpi: Fix an incorrect code path in acpi_processor_idle() Jan Beulich

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