Commit 7d145aa3 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds

[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
...@@ -270,16 +270,19 @@ void notify_arch_cmos_timer(void) ...@@ -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) ...@@ -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);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment