Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[uclinux-h8/linux.git] / arch / x86 / kernel / tsc.c

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 5054497..7437b41 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -598,10 +598,19 @@ static unsigned long quick_pit_calibrate(void)
                        if (!pit_expect_msb(0xff-i, &delta, &d2))
                                break;
 
+                       delta -= tsc;
+
+                       /*
+                        * Extrapolate the error and fail fast if the error will
+                        * never be below 500 ppm.
+                        */
+                       if (i == 1 &&
+                           d1 + d2 >= (delta * MAX_QUICK_PIT_ITERATIONS) >> 11)
+                               return 0;
+
                        /*
                         * Iterate until the error is less than 500 ppm
                         */
-                       delta -= tsc;
                        if (d1+d2 >= delta >> 11)
                                continue;