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authorAndi Kleen <ak@suse.de>2006-09-26 10:52:27 +0200
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 10:52:27 +0200
commit1de84979dfc527c422abf63f27beabe43892989b (patch)
tree4cf32ce7c374118c04edca7bfdff25e187da63d2
parent260d6790b6a2a0a048b7f96d154c2b49f1e6515a (diff)
[PATCH] i386: Enable NMI watchdog by default
I've had good experiences with having this on by default on x86-64. It turns nasty hangs into easier to debug oopses. Enable the local APIC wdog by default for systems newer than 2004. This comes from a strange compromise: according to arjan the reason it was off by default was some old IBM systems that corrupted registered when NMI happened in SMI. Can't remember more specific, but >= 2004 should avoid these. It's probably overly broad because most older systems should be ok (and the really old systems won't be supported by the local apic watchdog anyways) Signed-off-by: Andi Kleen <ak@suse.de>
-rw-r--r--arch/i386/kernel/nmi.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index 8e4ed930ce6..6e5085d5d2f 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -21,6 +21,7 @@
#include <linux/sysdev.h>
#include <linux/sysctl.h>
#include <linux/percpu.h>
+#include <linux/dmi.h>
#include <asm/smp.h>
#include <asm/nmi.h>
@@ -204,6 +205,14 @@ static int __init check_nmi_watchdog(void)
unsigned int *prev_nmi_count;
int cpu;
+ /* Enable NMI watchdog for newer systems.
+ Actually it should be safe for most systems before 2004 too except
+ for some IBM systems that corrupt registers when NMI happens
+ during SMM. Unfortunately we don't have more exact information
+ on these and use this coarse check. */
+ if (nmi_watchdog == NMI_DEFAULT && dmi_get_year(DMI_BIOS_DATE) >= 2004)
+ nmi_watchdog = NMI_LOCAL_APIC;
+
if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DEFAULT))
return 0;