[79/80] clocksource: Fix bug with max_deferment margin calculation

Greg KH
2011-12-07T16:20:32Z

From: "Yang Honggang (Joseph)" <eagle.rtlinux@gmail.com>

commit b1f919664d04a8d0ba29cb76673c7ca3325a2006 upstream.

In order to leave a margin of 12.5% we should >> 3 not >> 5.

Signed-off-by: Yang Honggang (Joseph) <eagle.rtlinux@gmail.com>
[jstultz: Modified commit subject]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
kernel/time/clocksource.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -531,7 +531,7 @@ static u64 clocksource_max_deferment(str
* note a margin of 12.5% is used because this can be computed with
* a shift, versus say 10% which would require division.
*/
- return max_nsecs - (max_nsecs >> 5);
+ return max_nsecs - (max_nsecs >> 3);
}

#ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
@@ -653,7 +653,7 @@ void __clocksource_updatefreq_scale(stru
* ~ 0.06ppm granularity for NTP. We apply the same 12.5%
* margin as we do in clocksource_max_deferment()
*/
- sec = (cs->mask - (cs->mask >> 5));
+ sec = (cs->mask - (cs->mask >> 3));
do_div(sec, freq);
do_div(sec, scale);
if (!sec)