Messages in this thread | | | Date | Fri, 11 Nov 2016 08:31:48 -0800 | From | Tony Lindgren <> | Subject | Re: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs |
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* 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.
Regards,
Tony
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