On Thu 2010-07-01 21:02:27, Rafael J. Wysocki wrote: > 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@xxxxxxx> > > > +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. Yep, it would be nice to document it. Plus maybe... should there be way to clear the wakeup_count? For example when userspace decides that battery is low and that it wants to go to sleep now? > > 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. Well... small C helper should be easy... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
