Messages in this thread | | | Date | Wed, 30 Jun 2010 15:58:36 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [update] Re: [PATCH] PM: Make it possible to avoid wakeup events from being lost |
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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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