Re: [RFC][PATCH] irq: Rework IRQF_NO_SUSPENDED

Thomas Gleixner
2014-07-25T21:00:17Z

On Fri, 25 Jul 2014, Rafael J. Wysocki wrote:
> On Friday, July 25, 2014 03:25:41 PM Peter Zijlstra wrote:
> > OK, so Rafael said there's devices that keep on raising their interrupt
> > until they get attention. Ideally this won't happen because the device
> > is suspended etc.. But I'm sure there's some broken piece of hardware
> > out there that'll make it go boom.
>
> So here's an idea.
>
> What about returning IRQ_NONE rather than IRQ_HANDLED for "suspended"
> interrupts (after all, that's what a sane driver would do for a
> suspended device I suppose)?
>
> If the line is really shared and the interrupt is taken care of by
> the other guy sharing the line, we'll be all fine.
>
> If that is not the case, on the other hand, and something's really
> broken, we'll end up disabling the interrupt and marking it as
> IRQS_SPURIOUS_DISABLED (if I understand things correctly).

We should not wait 100k unhandled interrupts in that case. We know
already at the first unhandled interrupt that the shit hit the fan.

I'll have a deeper look how we can sanitize the whole wake/no_suspend
logic vs. shared interrupts. Need to look at the usage sites first.

Thanks,

tglx