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| author | john stultz <johnstul@us.ibm.com> | 2006-07-14 00:24:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-14 21:53:54 -0700 |
| commit | 3e143475c22036847f898d7e76ba337c1d7dbf6f (patch) | |
| tree | 4bbd8f322f6a1cd43be409393742967234d23151 /kernel/timer.c | |
| parent | 635adb6cd25c8f816c9017a0a0349cd389eafcd3 (diff) | |
| download | lwn-3e143475c22036847f898d7e76ba337c1d7dbf6f.tar.gz lwn-3e143475c22036847f898d7e76ba337c1d7dbf6f.zip | |
[PATCH] improve timekeeping resume robustness
Resolve problems seen w/ APM suspend.
Due to resume initialization ordering, its possible we could get a timer
interrupt before the timekeeping resume() function is called. This patch
ensures we don't do any timekeeping accounting before we're fully resumed.
(akpm: fixes the machine-freezes-on-APM-resume bug)
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/timer.c')
| -rw-r--r-- | kernel/timer.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/kernel/timer.c b/kernel/timer.c index acfa557e685b..05809c2e2fd6 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -969,6 +969,7 @@ void __init timekeeping_init(void) } +static int timekeeping_suspended; /* * timekeeping_resume - Resumes the generic timekeeping subsystem. * @dev: unused @@ -984,6 +985,18 @@ static int timekeeping_resume(struct sys_device *dev) write_seqlock_irqsave(&xtime_lock, flags); /* restart the last cycle value */ clock->cycle_last = clocksource_read(clock); + clock->error = 0; + timekeeping_suspended = 0; + write_sequnlock_irqrestore(&xtime_lock, flags); + return 0; +} + +static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) +{ + unsigned long flags; + + write_seqlock_irqsave(&xtime_lock, flags); + timekeeping_suspended = 1; write_sequnlock_irqrestore(&xtime_lock, flags); return 0; } @@ -991,6 +1004,7 @@ static int timekeeping_resume(struct sys_device *dev) /* sysfs resume/suspend bits for timekeeping */ static struct sysdev_class timekeeping_sysclass = { .resume = timekeeping_resume, + .suspend = timekeeping_suspend, set_kset_name("timekeeping"), }; @@ -1101,13 +1115,16 @@ static void update_wall_time(void) { cycle_t offset; - clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift; + /* Make sure we're fully resumed: */ + if (unlikely(timekeeping_suspended)) + return; #ifdef CONFIG_GENERIC_TIME offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask; #else offset = clock->cycle_interval; #endif + clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift; /* normally this loop will run just once, however in the * case of lost or late ticks, it will accumulate correctly. |