On Wed, May 26, 2010 at 2:33 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Wed, 2010-05-26 at 11:23 +0200, Florian Mickler wrote: > >> There is polling, because the suspend manager in userspace doesn't have >> the whole picture. i.e. it doesn't know if a suspend will be >> successfull. >> So for aggressive suspending as a powersave-feature you need to poll >> (i.e. retry upon failure). because you don't want to stay unsuspended. > > Clearly if it fails, there something to be done, right? So whoever does > the thing will communicate with the suspend manager that it's going to > do and has finished doing its thing, at which point it will try again. > If you are talking about user-space code here, then that does not work. Not all kernel events that need to block suspend make it to user-space. > That's event driven, not polled. > > Also, if you want you can keep the kernel-side auto-suspend side, and > have the suspend manager clear on !0 and re-establish the auto-suspend > state on 0. > > But you really don't need this device thingy. > I'm not sure what you are proposing that we use instead. Both user-space and kernel code needs to block suspend. If we don't have suspend blockers in the kernel then user-space needs to poll when a driver blocks suspend by returning an error from its suspend hook. -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
