2010/5/18 Rafael J. Wysocki <rjw@xxxxxxx>: > 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. > My point is that the delay will not be used at all if the driver uses a suspend blocker (like it should). Why add a configuration option for opportunistic suspend that only works when the driver does not support opportunistic suspend. -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
