From d1857056904d5f313f11184fcfa624652ff9620a Mon Sep 17 00:00:00 2001
From: Vegard Nossum <vegard.nossum@gmail.com>
Date: Fri, 20 Jun 2008 15:39:09 +0200
Subject: [PATCH] ACPI: don't walk tables if ACPI was disabled
Ingo Molnar wrote:
> -tip auto-testing started triggering this spinlock corruption message
> yesterday:
>
> [ 3.976213] calling acpi_rtc_init+0x0/0xd3
> [ 3.980213] ACPI Exception (utmutex-0263): AE_BAD_PARAMETER, Thread F7C50000 could not acquire Mutex [3] [20080321]
> [ 3.992213] BUG: spinlock bad magic on CPU#0, swapper/1
> [ 3.992213] lock: c2508dc4, .magic: 00000000, .owner: swapper/1, .owner_cpu: 0
This is apparently because some parts of ACPI, including mutexes, are not
initialized when acpi=off is passed to the kernel.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
drivers/acpi/glue.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 9b227d4dc9c9..6d18ca34b6aa 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -333,6 +333,9 @@ static int __init acpi_rtc_init(void)
{
struct device *dev = get_rtc_dev();
+ if (acpi_disabled)
+ return 0;
+
if (acpi_disabled)
return 0;
--
2.20.1