Re: [ 57/72] genirq: Unmask oneshot irqs when thread was not woken

From: Stefan Lippers-Hollmann
Date: Tue Mar 06 2012 - 16:09:20 EST


Hi

On Tuesday 06 March 2012, Thomas Gleixner wrote:
> On Tue, 6 Mar 2012, Sven Joachim wrote:
> > Am 06.03.2012 um 20:31 schrieb Thomas Gleixner:
> >
> > > Stephan, Sven: Can you please provide the output of /proc/interrupts ?
> >
> > Here is mine, from a freshly booted 3.3-rc6 kernel.
> >
> > Cheers,
> > Sven
> >
> > CPU0
> > 0: 25050 XT-PIC-XT-PIC timer
[â]
> > 10: 341 XT-PIC-XT-PIC uhci_hcd:usb4, snd_hda_intel, b43
>
> Ah, XT-PIC uses handle_level_irq(). /me bangs head against desk.
>
> Does the patch below fix the problem for you ?
>
> Thanks,
>
> tglx
>
> ----------------->
> Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set
>
> commit ac5637611(genirq: Unmask oneshot irqs when thread was not
> woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled
> by handle_level_irq. This happens because thread_mask is or'ed
> unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts
> never cleared. So the check for !desc->thread_active fails and keeps
> the interrupt disabled.
>
> Keep the thread_mask zero for !IRQ_ONESHOT interrupts.
[â]

I can confirm that this patch, applied to 2.6.9, including "genirq:
Unmask oneshot irqs when thread was not woken", and + the current
stable queue-3.2 fixes b43 wlan operations. Feel free to add
Tested-by: Stefan Lippers-Hollmann <s.l-h@xxxxxx>
if you like.

Thanks a lot
Stefan Lippers-Hollmann

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