Messages in this thread | | | Date | Fri, 25 Jul 2014 14:40:37 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH] irq: Rework IRQF_NO_SUSPENDED |
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On Fri, Jul 25, 2014 at 11:40:48AM +0200, Thomas Gleixner wrote: > On Thu, 24 Jul 2014, Peter Zijlstra wrote: > > @@ -29,14 +29,20 @@ void suspend_device_irqs(void) > > for_each_irq_desc(irq, desc) { > > unsigned long flags; > > > > + /* > > + * Ideally this would be a global state, but we cannot > > + * for the trainwreck that is IRQD_WAKEUP_STATE. > > + */ > > raw_spin_lock_irqsave(&desc->lock, flags); > > - __disable_irq(desc, irq, true); > > + if (!irqd_has_set(&desc->irq_data, IRQD_WAKEUP_STATE)) > > + desc->istate |= IRQS_SUSPENDED; > > raw_spin_unlock_irqrestore(&desc->lock, flags); > > } > > > > - for_each_irq_desc(irq, desc) > > + for_each_irq_desc(irq, desc) { > > if (desc->istate & IRQS_SUSPENDED) > > synchronize_irq(irq); > > + } > > } > > So, instead of disabling the interrupt you just mark it > suspended. Good luck with level triggered interrupt lines then. > > Assume the interrupt fires after you marked it suspended. Then the > flow handler will call handle_irq_event() which will do nothing and > return handled. So the flow handler will reenable the interrupt line, > which will cause the interrupt to fire immediately again after the > RETI. Guess how much progress the system is going to make when that > happens.
Urgh, right. I knew it was too easy. Can we have do_irqhandler() ACK the interrupt and not call the handler?
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