On Monday 14 August 2006 21:58, john stultz wrote:
> On Sun, 2006-08-13 at 23:06 +0200, Rafael J. Wysocki wrote:
> > 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 <[email protected]>
>
> One minor comment, but otherwise looks good.
>
> > @@ -302,16 +305,25 @@ static int timer_resume(struct sys_devic
> > {
> > 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 "Time skew detected in timer resume!\n");
>
> Please make sure the warning describes the CMOS clock going backwards,
> rather then just the vague "time skew detected" comment.
>
> > + /* The time after the resume must not be earlier than the time
>
> s/time/CMOS clock/
>
>
>
> Acked-by: John Stultz <[email protected]>
Thanks for the comment and ACK. :-)
Second revision of the patch follows.
Greetings,
Rafael
---
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 <[email protected]>
Acked-by: John Stultz <[email protected]>
Acked-by: Pavel Machek <[email protected]>
---
arch/i386/kernel/time.c | 24 ++++++++++++++++++------
1 files changed, 18 insertions(+), 6 deletions(-)
Index: linux-2.6.18-rc4-mm1/arch/i386/kernel/time.c
===================================================================
--- linux-2.6.18-rc4-mm1.orig/arch/i386/kernel/time.c
+++ linux-2.6.18-rc4-mm1/arch/i386/kernel/time.c
@@ -285,16 +285,19 @@ 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;
}
@@ -302,16 +305,25 @@ static int timer_resume(struct sys_devic
{
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);
-
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