diff options
| author | Rafael J. Wysocki <rjw@sisk.pl> | 2006-09-25 23:32:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-26 08:49:04 -0700 |
| commit | 7d145aa3abf4d96c91f37c012facd5cfbb9010d1 (patch) | |
| tree | 2ce0d857a23844b8501111f8e43c8ae91289e682 | |
| parent | e1da95ae38afdcda83328300c4aed755d9fc01a6 (diff) | |
| download | linux-7d145aa3abf4d96c91f37c012facd5cfbb9010d1.tar.gz | |
[PATCH] i386: Detect clock skew during suspend
Detect the situations in which the time after a resume from disk would be
earlier than the time before the suspend and prevent them from happening on
i386.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: John Stultz <johnstul@us.ibm.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | arch/i386/kernel/time.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c index 6f333e7fb23cca..1302e4ab3c4f67 100644 --- a/arch/i386/kernel/time.c +++ b/arch/i386/kernel/time.c @@ -270,16 +270,19 @@ void notify_arch_cmos_timer(void) mod_timer(&sync_cmos_timer, jiffies + 1); } -static long clock_cmos_diff, sleep_start; +static long clock_cmos_diff; +static unsigned long sleep_start; static int timer_suspend(struct sys_device *dev, pm_message_t state) { /* * Estimate time zone so that set_time can update the clock */ - clock_cmos_diff = -get_cmos_time(); + unsigned long ctime = get_cmos_time(); + + clock_cmos_diff = -ctime; clock_cmos_diff += get_seconds(); - sleep_start = get_cmos_time(); + sleep_start = ctime; return 0; } @@ -287,16 +290,25 @@ static int timer_resume(struct sys_device *dev) { unsigned long flags; unsigned long sec; - unsigned long sleep_length; + unsigned long ctime = get_cmos_time(); + long sleep_length = (ctime - sleep_start) * HZ; struct timespec ts; + + if (sleep_length < 0) { + printk(KERN_WARNING "CMOS clock skew detected in timer resume!\n"); + /* The time after the resume must not be earlier than the time + * before the suspend or some nasty things will happen + */ + sleep_length = 0; + ctime = sleep_start; + } #ifdef CONFIG_HPET_TIMER if (is_hpet_enabled()) hpet_reenable(); #endif setup_pit_timer(); - sec = get_cmos_time() + clock_cmos_diff; - sleep_length = (get_cmos_time() - sleep_start) * HZ; + sec = ctime + clock_cmos_diff; ts.tv_sec = sec; ts.tv_nsec = 0; do_settimeofday(&ts); |