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[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>
wifi-calibration
Rafael J. Wysocki 2006-09-25 23:32:57 -07:00 committed by Linus Torvalds
parent e1da95ae38
commit 7d145aa3ab
1 changed files with 18 additions and 6 deletions
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24
arch/i386/kernel/time.c
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@ -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);