[PATCH] x86: fix cpu_khz with clock=pit

Fix http://bugzilla.kernel.org/show_bug.cgi?id=5546

The cpu_khz global is not initialized and remains 0 if you boot with
clock=pit, even if the processor does have a TSC.  This may have bad
ramifications since the variable is used in various places scattered around
the kernel, though I didn't check them all to see if they can tolerate cpu_khz
= 0.  You can observe the problem by doing "cat /proc/cpuinfo"; the cpu MHz
line says 0.000.

The fix is trivial; call init_cpu_khz() from init_pit(), just as it's called
from the timers/timer_foo.c:init_foo() for other values of foo.

Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/timers/timer_pit.c b/arch/i386/kernel/timers/timer_pit.c
index e42e46d..b9b6bd5 100644 (file)
--- a/arch/i386/kernel/timers/timer_pit.c
+++ b/arch/i386/kernel/timers/timer_pit.c
@@ -25,8 +25,9 @@ static int __init init_pit(char* override)
 {
        /* check clock override */
        if (override[0] && strncmp(override,"pit",3))
-               printk(KERN_ERR "Warning: clock= override failed. Defaulting to PIT\n");
- 
+               printk(KERN_ERR "Warning: clock= override failed. Defaulting "
+                               "to PIT\n");
+       init_cpu_khz();
        count_p = LATCH;
        return 0;
 }