linux-kernel - Re: Threaded interrupt handlers broken?

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Date:	Sun, 16 Aug 2009 22:05:59 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Michael Buesch <mb@...sch.de>
cc:	linux-kernel@...r.kernel.org
Subject: Re: Threaded interrupt handlers broken?

On Sun, 16 Aug 2009, Michael Buesch wrote:
> On Sunday 16 August 2009 16:25:13 Thomas Gleixner wrote:
> > On Sun, 16 Aug 2009, Michael Buesch wrote:
> > > On Sunday 16 August 2009 15:22:29 Thomas Gleixner wrote:
> > >
> > > > > +		if (0&&unlikely(desc->status & IRQ_DISABLED)) {
> > > > 
> > > > So the interrupt is marked disabled. How do you setup the handler
> > > > ?  And what does the primary handler do ? Can you post your driver
> > > > code please?
> > > 
> > > This patch converts the b43 driver to threaded interrupts:
> > > http://bu3sch.de/patches/wireless-testing/20090816-1535/patches/002-b43-threaded-irq-handler.patch
> > 
> > On the first glance this looks not too bad. the unlocked access to the
> > irq status registers looks a bit scary, but that is not relevant for
> > the problem at hand.
> 
> Yeah it does ;)
> 
> > > It kind of works with this hack applied to kernel/irq/manage.c
> > 
> > Hmm. Is the interrupt of the device shared ?
> 
> It's registered as shared, but on my machine it is not shared with anything else.
> 
> > If yes, what's the other 
> > device on that interrupt line ? what puzzles me is the fact that the
> > IRQ_DISABLED flag is set. Is there anything unusual in dmesg ?
> 
> Here's my current kernel log with the two patches applied:
> http://bu3sch.de/misc/dmesg

Hmm. Nothing interesting AFAICT, but it would be really interesting to
find out why the IRQ_DISABLED flag is set.

Can you add some debug into disable_irq() e.g. WARN_ON(irq ==
BC43_IRQ_NR); so we can see what disables that interrupt.

Thanks,

	tglx


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