x86: fix cpu MHz reporting for AMD family 0x11

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / mfgpt_32.c

diff --git a/arch/x86/kernel/mfgpt_32.c b/arch/x86/kernel/mfgpt_32.c
index 3960ab7e149773aa1c3dd4b7f3160cf9b76d944b..219f86eb612301766771651eb56cb1e8f98189ac 100644 (file)
--- a/arch/x86/kernel/mfgpt_32.c
+++ b/arch/x86/kernel/mfgpt_32.c
@@ -63,6 +63,21 @@ static int __init mfgpt_disable(char *s)
 }
 __setup("nomfgpt", mfgpt_disable);
 
+/* Reset the MFGPT timers. This is required by some broken BIOSes which already
+ * do the same and leave the system in an unstable state. TinyBIOS 0.98 is
+ * affected at least (0.99 is OK with MFGPT workaround left to off).
+ */
+static int __init mfgpt_fix(char *s)
+{
+       u32 val, dummy;
+
+       /* The following udocumented bit resets the MFGPT timers */
+       val = 0xFF; dummy = 0;
+       wrmsr(0x5140002B, val, dummy);
+       return 1;
+}
+__setup("mfgptfix", mfgpt_fix);
+
 /*
  * Check whether any MFGPTs are available for the kernel to use.  In most
  * cases, firmware that uses AMD's VSA code will claim all timers during