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SubjectRe: [PATCH] genirq: do not disable IRQ_WAKEUP marked irqs on suspend
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On Monday 22 June 2009, Andrew Morton wrote:
> On Fri, 12 Jun 2009 21:52:46 +0200 (CEST)
> Thomas Gleixner <tglx@linutronix.de> wrote:
>
> > On Fri, 12 Jun 2009, Kevin Hilman wrote:
> > > http://lkml.org/lkml/2009/5/4/448
> > >
> > > Only difference is I did the checking outside of the lock, which is
> > > probably wrong. In any case, you'll be interested in the thread that
> > > follows.
> >
> > Hmm, darn. That means that on hardware which has trouble with the
> > delayed disable and therefor uses it's own chip->disable_irq() method
> > the suspend logic is wreckaged.
>
> Does this maen that your original patch is no longer applicable to
> mainline/-stable?

I'd say so. There are good arguments for not doing this.

> > But there is always a way to get broken hardware tamed. :)
> >
> > suspend does:
> > __disable_irq();
> > status |= IRQ_SUSPENDED;
> > chip->disable_irq();
> >
> > resume does:
> > __enable_irq();
> > status &= ~IRQ_SUSPENDED;
> > chip->enable_irq();
> >
> > So
> >
> > - set_irq_handler(handle_level_irq);
> > + set_irq_handler(my_own_handler);
> >
> > +my_own_handler()
> > +{
> > + if (!(status & IRQ_SUSPENDED)) {
> > + handle_level_irq();
> > + } else {
> > + mask_at_hardware_level();
> > + status |= IRQ_PENDING;
> > + save_important_information();
> > + }
> > +}
> >
> > my_disable_irq()
> > {
> > + if (!(status & IRQ_SUSPENDED))
> > mask_at_hardware_level();
> > }
> >
> > my_enable_irq()
> > {
> > + if (important_information_has_been_saved)
> > + replay_what_happened();
> > +
> > unmask_at_hardware_level();
> > }
> >
> > Ugly, but that might work somehow. Not sure about the replay part, but
> > that can be deferred via some more hackery as well :)
> >
> > Raphael, these delayed disable and the chip->irq_disable() override
> > implications vs. suspend really need to be documented. The current
> > comment of suspend_device_irqs() is bogus:
> >
> > * During system-wide suspend or hibernation device interrupts need to be
> > * disabled at the chip level and this function is provided for this purpose.
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^


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