Disable NMI watchdog by default properly

This reverts commit 6ebf622b2577c50b1f496bd6a5e8739e55ae7b1c and
replaces it with one that actually works.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 3 insertions, 14 deletions

diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index 821df34d2b3a..14702427b104 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -245,14 +245,6 @@ static int __init check_nmi_watchdog(void)
         unsigned int *prev_nmi_count;
         int cpu;
 
-        /* Enable NMI watchdog for newer systems.
-           Probably safe on most older systems too, but let's be careful.
-           IBM ThinkPads use INT10 inside SMM and that allows early NMI inside SMM
-           which hangs the system. Disable watchdog for all thinkpads */
-        if (nmi_watchdog == NMI_DEFAULT && dmi_get_year(DMI_BIOS_DATE) >= 2004 &&
-                !dmi_name_in_vendors("ThinkPad"))
-                nmi_watchdog = NMI_LOCAL_APIC;
-
         if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DEFAULT))
                 return 0;
 
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 486f4c61a948..82d9d85d5270 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -187,10 +187,7 @@ void nmi_watchdog_default(void)
 {
         if (nmi_watchdog != NMI_DEFAULT)
                 return;
-        if (nmi_known_cpu())
-                nmi_watchdog = NMI_LOCAL_APIC;
-        else
-                nmi_watchdog = NMI_IO_APIC;
+        nmi_watchdog = NMI_NONE;
 }
 
 static int endflag __initdata = 0;
diff --git a/include/asm-i386/nmi.h b/include/asm-i386/nmi.h
index 64544cb85d6a..b04333ea6f31 100644
--- a/include/asm-i386/nmi.h
+++ b/include/asm-i386/nmi.h
@@ -33,7 +33,7 @@ extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
 
 extern atomic_t nmi_active;
 extern unsigned int nmi_watchdog;
-#define NMI_DEFAULT     0
+#define NMI_DEFAULT     -1
 #define NMI_NONE        0
 #define NMI_IO_APIC     1
 #define NMI_LOCAL_APIC  2
diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
index ceb3d8dac33d..72375e7d32a8 100644
--- a/include/asm-x86_64/nmi.h
+++ b/include/asm-x86_64/nmi.h
@@ -64,7 +64,7 @@ extern int setup_nmi_watchdog(char *);
 
 extern atomic_t nmi_active;
 extern unsigned int nmi_watchdog;
-#define NMI_DEFAULT     0
+#define NMI_DEFAULT     -1
 #define NMI_NONE        0
 #define NMI_IO_APIC     1
 #define NMI_LOCAL_APIC  2