Re: irq 16: nobody cared

From: Paul E. McKenney
Date: Mon Apr 22 2013 - 10:44:49 EST


On Mon, Apr 22, 2013 at 04:23:56PM +0200, Borislav Petkov wrote:
> On Mon, Apr 22, 2013 at 02:56:08PM +0200, Thomas Gleixner wrote:
> > Boris, can you please provide the irq16 line of /proc/interrupts
> > before you invoke suspend?
> >
> > If it's shared we know which driver is shutdown before hda_intel and
> > perhaps leaves its device in a weird state.
> >
> > If it's not shared, it still might be shared behind the scene. The
> > other device uses MSI(X) and when shutdown MSI is disabled so the
> > default IRQ route which points to IRQ16 would be active again.
> >
> > I assume, that the RCU stuff just causes enough timing difference to
> > uncover the underlying issue.
>
> Hmm, as Takashi reminded me, this box has two audio controllers. So
> could it be that when we shutdown and disable MSI, the interrupts get
> routed to to IRQ16 and they overflow there? Just a wild guess, I guess.

Would it make sense to try shutting off the hardware, waiting (say)
100 milliseconds, then diabling the irq? (Hey, had to ask!)

Thanx, Paul

> I very well can imagine that those two audio controllers to be one where
> some f*cked up BIOS shim switches between the two but can't keep them
> apart properly.
>
> Something like the HPET fiascos...
>
> * This is irq counts with my patch to expedite RCU grace periods:
>
> - before suspend:
> # grep snd /proc/interrupts
> 16: 1304 1340 1335 1329 1293 1348 1357 1363 IO-APIC-fasteoi snd_hda_intel
> 90: 3 3 4 4 4 4 3 3 PCI-MSI-edge snd_hda_intel
>
> - after resume:
> # grep snd /proc/interrupts
> 16: 1354 1389 1386 1380 1344 1400 1409 1495 IO-APIC-fasteoi snd_hda_intel
> 90: 0 0 0 0 0 0 0 5 PCI-MSI-edge snd_hda_intel
>
>
> * "normal" RCU grace periods:
>
> - before suspend:
> # grep snd /proc/interrupts
> 16: 109 108 107 108 108 108 109 111 IO-APIC-fasteoi snd_hda_intel
> 90: 3 3 4 4 4 4 3 3 PCI-MSI-edge snd_hda_intel
>
> - after resume:
> # grep snd /proc/interrupts
> 16: 154 154 153 155 157 157 235 164 IO-APIC-fasteoi snd_hda_intel
> 90: 0 0 0 0 0 0 5 0 PCI-MSI-edge snd_hda_intel
>
> More "hmm.."
>
> --
> Regards/Gruss,
> Boris.
>
> Sent from a fat crate under my desk. Formatting is fine.
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