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Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  time: Fix stupid KERN_WARN compile issue
  rtc: Avoid accumulating time drift in suspend/resume
  time: Avoid accumulating time drift in suspend/resume
  time: Catch invalid timespec sleep values in __timekeeping_inject_sleeptime
This commit is contained in:
Linus Torvalds
2011-07-22 16:52:18 -07:00
parent a99a7d1436 cbaa51524b
commit 112ec46966
2 changed files with 76 additions and 17 deletions
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28
kernel/time/timekeeping.c
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@@ -604,6 +604,12 @@ static struct timespec timekeeping_suspend_time;
*/
static void __timekeeping_inject_sleeptime(struct timespec *delta)
{
if (!timespec_valid(delta)) {
printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "
"sleep delta value!\n");
return;
}
xtime = timespec_add(xtime, *delta);
wall_to_monotonic = timespec_sub(wall_to_monotonic, *delta);
total_sleep_time = timespec_add(total_sleep_time, *delta);
@@ -686,12 +692,34 @@ static void timekeeping_resume(void)
static int timekeeping_suspend(void)
{
unsigned long flags;
struct timespec delta, delta_delta;
static struct timespec old_delta;
read_persistent_clock(&timekeeping_suspend_time);
write_seqlock_irqsave(&xtime_lock, flags);
timekeeping_forward_now();
timekeeping_suspended = 1;
/*
* To avoid drift caused by repeated suspend/resumes,
* which each can add ~1 second drift error,
* try to compensate so the difference in system time
* and persistent_clock time stays close to constant.
*/
delta = timespec_sub(xtime, timekeeping_suspend_time);
delta_delta = timespec_sub(delta, old_delta);
if (abs(delta_delta.tv_sec) >= 2) {
/*
* if delta_delta is too large, assume time correction
* has occured and set old_delta to the current delta.
*/
old_delta = delta;
} else {
/* Otherwise try to adjust old_system to compensate */
timekeeping_suspend_time =
timespec_add(timekeeping_suspend_time, delta_delta);
}
write_sequnlock_irqrestore(&xtime_lock, flags);
clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);