Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] PM: Make it possible to avoid wakeup events from being lost | Date | Thu, 1 Jul 2010 21:02:27 +0200 |
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On Thursday, July 01, 2010, Pavel Machek wrote: > Hi! > > > @@ -114,3 +114,17 @@ Description: > > if this file contains "1", which is the default. It may be > > disabled by writing "0" to this file, in which case all devices > > will be suspended and resumed synchronously. > > + > > +What: /sys/power/wakeup_count > > +Date: July 2010 > > +Contact: Rafael J. Wysocki <rjw@sisk.pl> > > +Description: > > + The /sys/power/wakeup_count file allows user space to avoid > > + losing wakeup events when transitioning the system into a sleep > > + state. Reading from it returns the current number of registered > > + wakeup events and it blocks if some wakeup events are being > > + processed at the time the file is read from. Writing to it > > + will only succeed if the current number of wakeup events is > > + equal to the written value and, if successful, will make the > > + kernel abort a subsequent transition to a sleep state if any > > + wakeup events are reported after the write has returned. > > I assume that second suspend always succeeds?
The mechanism is one-shot if that's what you're asking for.
> I can't say I quite like the way two sysfs files interact with each > other, but it is certainly better then wakelocks... > > Maybe we should create sys_suspend()?
Well, one can modify pm-utils to use the new sysfs file quite easily, but it wouldn't be that easy with sys_suspend() IMO.
Rafael
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