Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH 3/3] PM / Sleep: Make __pm_stay_awake() delete wakeup source timers | Date | Thu, 16 Feb 2012 23:20:44 +0100 |
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On Thursday, February 16, 2012, Arve Hjønnevåg wrote: > 2012/2/15 Rafael J. Wysocki <rjw@sisk.pl>: > ... > > --- linux.orig/drivers/base/power/wakeup.c > > +++ linux/drivers/base/power/wakeup.c > > @@ -365,9 +365,15 @@ void __pm_stay_awake(struct wakeup_sourc > > return; > > > > spin_lock_irqsave(&ws->lock, flags); > > + > > + del_timer(&ws->timer); > > + ws->timer_expires = 0; > > timer_expires gets overwritten in wakeup_source_activate,
I actually don't remember why it does that and with the $subject changes it's just pointless.
> so __pm_relax followed by __pm_stay_awake is still not safe.
Yes, I overlooked that timer_expires modification. Updated patch follows.
> ... > > @@ -529,8 +535,12 @@ void __pm_wakeup_event(struct wakeup_sou > > spin_lock_irqsave(&ws->lock, flags); > > > > ws->event_count++; > > - if (!ws->active) > > + if (ws->active) { > > + if (!ws->timer_expires) > > + goto unlock; > > + } else { > > wakeup_source_activate(ws); > > + } > > > > if (!msec) { > > wakeup_source_deactivate(ws); > > > > I suggest dropping this and adding:
Well, what exactly would you like to drop? The above proposed changes I guess?
> - if (time_after(expires, ws->timer_expires)) { > + if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
I've tried to follow your suggestion, so that __pm_wakeup_event() always sets the timer, if msec is positive, or deactivates the wakeup source, if msec is 0. Please let me know if that's what you wanted. :-)
Thanks, Rafael
--- From: Rafael J. Wysocki <rjw@sisk.pl> Subject: PM / Sleep: Make __pm_stay_awake() delete wakeup source timers
If __pm_stay_awake() is called after __pm_wakeup_event() for the same wakep source object before its timer expires, it won't cancel the timer, so the wakeup source will be deactivated from the timer function as scheduled by __pm_wakeup_event(). In that case __pm_stay_awake() doesn't have any effect beyond incrementing the wakeup source's event_count field, although it should cancel the timer and make the wakeup source stay active until __pm_relax() is called for it.
To fix this problem make __pm_stay_awake() delete the wakeup source's timer and ensure that it won't be deactivated from the timer funtion afterwards by clearing its timer_expires field.
Reported-by: Arve Hjønnevåg <arve@android.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> --- drivers/base/power/wakeup.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
Index: linux/drivers/base/power/wakeup.c =================================================================== --- linux.orig/drivers/base/power/wakeup.c +++ linux/drivers/base/power/wakeup.c @@ -344,7 +344,6 @@ static void wakeup_source_activate(struc { ws->active = true; ws->active_count++; - ws->timer_expires = jiffies; ws->last_time = ktime_get(); /* Increment the counter of events in progress. */ @@ -365,9 +364,14 @@ void __pm_stay_awake(struct wakeup_sourc return; spin_lock_irqsave(&ws->lock, flags); + ws->event_count++; if (!ws->active) wakeup_source_activate(ws); + + del_timer(&ws->timer); + ws->timer_expires = 0; + spin_unlock_irqrestore(&ws->lock, flags); } EXPORT_SYMBOL_GPL(__pm_stay_awake); @@ -541,7 +545,7 @@ void __pm_wakeup_event(struct wakeup_sou if (!expires) expires = 1; - if (time_after(expires, ws->timer_expires)) { + if (!ws->timer_expires || time_after(expires, ws->timer_expires)) { mod_timer(&ws->timer, expires); ws->timer_expires = expires; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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