[lkml]   [2016]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] PM / wakeirq: report wakeup events in dedicated wake-IRQs
On Thu, Nov 10, 2016 at 10:13:55AM -0800, Dmitry Torokhov wrote:
> On Thu, Nov 10, 2016 at 10:07 AM, Brian Norris <> 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).


[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.

 \ /
  Last update: 2016-11-10 19:50    [W:0.094 / U:5.556 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site