[PATCH] i386: Disable nmi watchdog on all ThinkPads
Even newer Thinkpads have bugs in SMM code that causes hangs with
NMI watchdog.
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index 3e8e3ad..eaafe23 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -219,11 +219,11 @@
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))
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index b8b596d..37deee6 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -326,6 +326,26 @@
}
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
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index 38dc403..904bf3d 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -69,6 +69,7 @@
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 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