Messages in this thread | | | Date | Fri, 11 Nov 2016 14:32:35 -0800 | From | Tony Lindgren <> | Subject | Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs |
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* Tony Lindgren <tony@atomide.com> [161111 14:29]: > * Rafael J. Wysocki <rafael@kernel.org> [161111 13:33]: > > On Fri, Nov 11, 2016 at 5:31 PM, Tony Lindgren <tony@atomide.com> wrote: > > > * Rafael J. Wysocki <rafael@kernel.org> [161110 16:06]: > > >> On Thu, Nov 10, 2016 at 7:49 PM, Brian Norris <briannorris@chromium.org> wrote: > > >> > On Thu, Nov 10, 2016 at 10:13:55AM -0800, Dmitry Torokhov wrote: > > >> >> On Thu, Nov 10, 2016 at 10:07 AM, Brian Norris <briannorris@chromium.org> wrote: > > >> >> > It's important that user space can figure out what device woke the > > >> >> > system from suspend -- e.g., for debugging, or for implementing > > >> >> > conditional wake behavior. Dedicated wakeup IRQs don't currently do > > >> >> > that. > > >> >> > > > >> >> > Let's report the event (pm_wakeup_event()) and also allow drivers to > > >> >> > synchronize with these events in their resume path (hence, disable_irq() > > >> >> > instead of disable_irq_nosync()). > > >> >> > > >> >> Hmm, dev_pm_disable_wake_irq() is called from > > >> >> rpm_suspend()/rpm_resume() that take dev->power.lock spinlock and > > >> >> disable interrupts. Dropping _nosync() feels dangerous. > > >> > > > >> > Indeed. So how do you suggest we get sane wakeup reports? Every device > > >> > or bus that's going to use the dedicated wake APIs has to > > >> > synchronize_irq() [1] in their resume() routine? Seems like an odd > > >> > implementation detail to have to remember (and therefore most drivers > > >> > will get it wrong). > > >> > > > >> > Brian > > >> > > > >> > [1] Or maybe at least create a helper API that will extract the > > >> > dedicated wake IRQ number and do the synchronize_irq() for us, so > > >> > drivers don't have to stash this separately (or poke at > > >> > dev->power.wakeirq->irq) for no good reason. > > >> > > >> Well, in the first place, can anyone please refresh my memory on why > > >> it is necessary to call dev_pm_disable_wake_irq() under power.lock? > > > > > > I guess no other reason except we need to manage the wakeirq > > > for rpm_callback(). So we dev_pm_enable_wake_irq() before > > > rpm_callback() in rpm_suspend(), then disable on resume. > > > > But we drop the lock in rpm_callback(), so can't it be moved to where > > the callback is invoked? > > Then we're back to patching all the drivers again, no?
Sorry I misunderstood, yeah that should work if rpm_callback() drops the lock.
Somehow I remembered we're calling the consumer callback function directly :)
Regards,
Tony
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