On Wednesday 19 May 2010, Arve Hjønnevåg wrote: > 2010/5/18 Rafael J. Wysocki <rjw@xxxxxxx>: > > On Tuesday 18 May 2010, Arve Hjønnevåg wrote: > >> 2010/5/18 Rafael J. Wysocki <rjw@xxxxxxx>: > >> > On Tuesday 18 May 2010, Arve Hjønnevåg wrote: > >> >> On Mon, May 17, 2010 at 2:44 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > >> >> > On Monday 17 May 2010, Brian Swetland wrote: > >> >> >> On Mon, May 17, 2010 at 1:40 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > >> >> >> > On Monday 17 May 2010, Arve Hjønnevåg wrote: > >> >> >> >> > > ... > >> > >> > Now, to make it more "user-friendly", we can simply use > >> > queue_delayed_work() with a reasonable delay instead of queue_work() to queue > >> > the suspend work (the delay may be configurable via sysfs). > >> > > >> > >> I can add a delay (and the timeout support code does add a delay as an > >> optimization) to the unknown wakeup case, but this does not fix the > >> problem of a user turning on opportunistic suspend with a user space > >> framework that does not use suspend blockers. If the kernel uses > >> suspend blockers to make sure the wakeup event makes it to user space, > >> but user space does not block suspend, then the system will suspend > >> before the event is processed. > > > > But the user can still manually write to /sys/power/state. :-) > > > > Does adding or removing a delay change this? It seems in only changes > how quickly the user can finish that write. Yes, but that should allow the user to avoid rebooting the system if he does the "wrong thing". > I'm not convinced adding a configurable delay here is necessary. No, it's not, but it would be useful in some cases IMO. Pretty much the same way your debug features are useful. > Once the driver that enabled the wakeup event has been updated to block > suspend until this event gets to user space, then this delay will > never be triggered. The kernel cannot tell the difference between a > user enabling opportunistic suspend but not wanting it and > opportunistic suspend aware user space code deciding that this wakeup > event should be ignored. The point is, if there's a delay, it may be too aggressive for some users and too conservative for some other users, so it makes sense to provide a means to adjust it to the user's needs. Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
