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authorYang Honggang (Joseph) <eagle.rtlinux@gmail.com>2011-12-01 22:22:41 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2011-12-09 08:52:52 -0800
commit4078977c46f627f553ed2d8ea047b9bf25dee48d (patch)
treefd257cf2fde90205159813141edc07102e387901 /kernel/time
parent0bbf5c70251286fbc3b7aac5e7961b4568115bfd (diff)
clocksource: Fix bug with max_deferment margin calculation
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>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/clocksource.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e0980f0d9a0a..8b270063b515 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -531,7 +531,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs)
* 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(struct clocksource *cs, u32 scale, u32 freq)
* ~ 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)