* Rafael J. Wysocki <raf...@kernel.org> [161111 15:35]: > On Fri, Nov 11, 2016 at 11:32 PM, Tony Lindgren <t...@atomide.com> wrote: > > * Tony Lindgren <t...@atomide.com> [161111 14:29]: > >> * Rafael J. Wysocki <raf...@kernel.org> [161111 13:33]: > >> > On Fri, Nov 11, 2016 at 5:31 PM, Tony Lindgren <t...@atomide.com> wrote: > >> > > * Rafael J. Wysocki <raf...@kernel.org> [161110 16:06]: > >> > >> On Thu, Nov 10, 2016 at 7:49 PM, Brian Norris > >> > >> <briannor...@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 > >> > >> >> <briannor...@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. > > It still will not re-enable interrupts if the irq_safe flag is set. I > wonder if we really care about this case, though.
We have at least 8250-omap and serial-omap using wakeirqs with irq_safe flag set. Regards, Tony
