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SubjectRe: [PATCH 2/3] IRQ: allow check_wakeup_irqs to notice level-triggered interrupts.
On Wed, 25 Apr 2012, NeilBrown wrote:

> Level triggered interrupts do not cause IRQS_PENDING to be set, so
> check_wakeup_irqs ignores them.
> They don't need to set IRQS_PENDING as the level stays high which
> shows that they must be pending. However if such an interrupt fired
> during late suspend, it will have been masked so the fact that it
> is still asserted will not cause the suspend to abort.
>
> So if any wakeup interrupt is masked, unmask it when checking wakeup
> irqs. If the interrupt is asserted, suspend will abort.
>
> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
>
> kernel/irq/pm.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
> index 15e53b1..0d26206 100644
> --- a/kernel/irq/pm.c
> +++ b/kernel/irq/pm.c
> @@ -106,6 +106,12 @@ int check_wakeup_irqs(void)
> if (irqd_is_wakeup_set(&desc->irq_data)) {
> if (desc->istate & IRQS_PENDING)
> return -EBUSY;
> + if (irqd_irq_masked(&desc->irq_data))
> + /* Probably a level interrupt
> + * which fired recently and was
> + * masked
> + */
> + unmask_irq(desc);

Oh no. We don't unmask unconditionally. What about an interrupt which
is disabled, has no handler ..... ? That needs more thought.

Thanks,

tglx


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