[ltp] Fwd: [PATCH] [14/19] i386: Disable nmi watchdog on all ThinkPads

[Shem Multinymous]

FYI:
---------- Forwarded message ----------
From: Andi Kleen <ak@suse.de>
Date: Oct 21, 2006 6:51 PM
Subject: [PATCH] [14/19] i386: Disable nmi watchdog on all ThinkPads
To: patches@x86-64.org, linux-kernel@vger.kernel.org



Even newer Thinkpads have bugs in SMM code that causes hangs with
NMI watchdog.

Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/i386/kernel/nmi.c      |   10 +++++-----
 drivers/firmware/dmi_scan.c |   20 ++++++++++++++++++++
 include/linux/dmi.h         |    2 ++
 3 files changed, 27 insertions(+), 5 deletions(-)

Index: linux/arch/i386/kernel/nmi.c
===================================================================
--- linux.orig/arch/i386/kernel/nmi.c
+++ linux/arch/i386/kernel/nmi.c
@@ -219,11 +219,11 @@ static int __init check_nmi_watchdog(voi
        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)
+          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))
Index: linux/drivers/firmware/dmi_scan.c
===================================================================
--- linux.orig/drivers/firmware/dmi_scan.c
+++ linux/drivers/firmware/dmi_scan.c
@@ -326,6 +326,26 @@ char *dmi_get_system_info(int field)
 }
 EXPORT_SYMBOL(dmi_get_system_info);

+
+/**
+ *     dmi_name_in_vendors - Check if string is anywhere in the DMI
vendor information.
+ *     @str:   Case sensitive Name
+ */
+int dmi_name_in_vendors(char *str)
+{
+       static int fields[] = { DMI_BIOS_VENDOR, DMI_BIOS_VERSION,
DMI_SYS_VENDOR,
+                               DMI_PRODUCT_NAME, DMI_PRODUCT_VERSION,
DMI_BOARD_VENDOR,
+                               DMI_BOARD_NAME, DMI_BOARD_VERSION, DMI_NONE };
+       int i;
+       for (i = 0; fields[i] != DMI_NONE; i++) {
+               int f = fields[i];
+               if (dmi_ident[f] && strstr(dmi_ident[f], str))
+                       return 1;
+       }
+       return 0;
+}
+EXPORT_SYMBOL(dmi_name_in_vendors);
+
 /**
  *     dmi_find_device - find onboard device by type/name
  *     @type: device type or %DMI_DEV_TYPE_ANY to match all device types
Index: linux/include/linux/dmi.h
===================================================================
--- linux.orig/include/linux/dmi.h
+++ linux/include/linux/dmi.h
@@ -69,6 +69,7 @@ extern struct dmi_device * dmi_find_devi
        struct dmi_device *from);
 extern void dmi_scan_machine(void);
 extern int dmi_get_year(int field);
+extern int dmi_name_in_vendors(char *str);

 #else

@@ -77,6 +78,7 @@ static inline char * dmi_get_system_info
 static inline struct dmi_device * dmi_find_device(int type, const char *name,
        struct dmi_device *from) { return NULL; }
 static inline int dmi_get_year(int year) { return 0; }
+static inline int dmi_name_in_vendors(char *s) { return 0; }

 #endif

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