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Commit 7d145aa3 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
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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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarJohn Stultz <johnstul@us.ibm.com>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e1da95ae

arch/i386/kernel/time.c

+18 −6
Original line number Original line Diff line number Diff line
@@ -270,16 +270,19 @@ void notify_arch_cmos_timer(void) 
	mod_timer(&sync_cmos_timer, jiffies + 1);

	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)

static int timer_suspend(struct sys_device *dev, pm_message_t state)

{

{

	/*

	/*

	 * Estimate time zone so that set_time can update the clock

	 * 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();

	clock_cmos_diff += get_seconds();

	sleep_start = get_cmos_time();

	sleep_start = ctime;

	return 0;

	return 0;

}

}
@@ -287,16 +290,25 @@ static int timer_resume(struct sys_device *dev) 
{

{

	unsigned long flags;

	unsigned long flags;

	unsigned long sec;

	unsigned long sec;

	unsigned long sleep_length;

	unsigned long ctime = get_cmos_time();

	long sleep_length = (ctime - sleep_start) * HZ;

	struct timespec ts;

	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

#ifdef CONFIG_HPET_TIMER

	if (is_hpet_enabled())

	if (is_hpet_enabled())

		hpet_reenable();

		hpet_reenable();

#endif

#endif

	setup_pit_timer();

	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_sec = sec;

	ts.tv_nsec = 0;

	ts.tv_nsec = 0;

	do_settimeofday(&ts);

	do_settimeofday(&ts);