On Wed, 30 Jun 2010, Rafael J. Wysocki wrote:
> > Since there's no longer any way to cancel a call to pm_wakeup_event()
> > or close the "no suspend" period early, there is no need to use
> > dynamically-allocated delayed_work structures. You can make do with a
> > single static timer; always keep it set to expire at the latest time
> > passed to pm_wakeup_event().
>
> The decremenations of events_in_progress wouldn't be balanced with
> incrementations this way. Or do you have any clever way of dealing with
> that in mind?
Keep track of the current expiration time in a static variable called
wakeup_timeout, and use 0 to indicate there is no timeout.
In pm_wakeup_event() (everything protected by the spinlock):
unsigned long new_timeout = jiffies + msecs_to_jiffies(msecs);
if (new_timeout == 0)
new_timeout = 1;
++event_count;
if (!wakeup_timeout || time_after(new_timeout, wakeup_timeout)) {
if (!wakeup_timeout)
++events_in_progress;
wakeup_timeout = new_timeout;
mod_timer(&wakeup_timer, wakeup_timeout);
}
In the timer routine:
if (wakeup_timeout && time_before_eq(wakeup_timeout, jiffies)) {
--events_in_progres;
wakeup_timeout = 0;
}
Alan Stern
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