From: Vegard Nossum <vegard.nossum@gmail.com>
Date: Fri, 20 Jun 2008 13:39:09 +0000 (+0200)
Subject: ACPI: don't walk tables if ACPI was disabled
X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=d1857056904d5f313f11184fcfa624652ff9620a;p=linux-edison.git

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>
---

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 9b227d4dc9c..6d18ca34b6a 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -336,6 +336,9 @@ static int __init acpi_rtc_init(void)
 	if (acpi_disabled)
 		return 0;
 
+	if (acpi_disabled)
+		return 0;
+
 	if (dev) {
 		rtc_wake_setup();
 		rtc_info.wake_on = rtc_wake_on;