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SubjectRe: [PATCH] genirq: do not disable IRQ_WAKEUP marked irqs on suspend
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Does this maen that your original patch is no longer applicable to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?


> 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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