Date: Sun, 21 Apr 2013 11:47:49 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Borislav Petkov <bp@alien8.de>
Cc: x86-ml <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>,
        tiwai@suse.de
Subject: Re: irq 16: nobody cared
Message-ID: <20130421184749.GC3509@linux.vnet.ibm.com>
Reply-To: paulmck@linux.vnet.ibm.com
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 <20130421103403.GA4594@pd.tnic>
 <20130421163002.GB3509@linux.vnet.ibm.com>
 <20130421165653.GA4623@pd.tnic>
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On Sun, Apr 21, 2013 at 06:56:54PM +0200, Borislav Petkov wrote:
> On Sun, Apr 21, 2013 at 09:30:02AM -0700, Paul E. McKenney wrote:
> > Thank you for the info!  Now to figure out what the heck is causing this.
> > 
> > I am also guessing that your system does have hardware that could do an
> > irq 16.  Of course, if removing or disabing this hardware is an option,
> > it would be interesting to see what happens.
> 
> Onboard sound chip so only BIOS disable should help, if present. Let me
> check. Oh, I can take out the laser and cut it out of the silicon. :-)
> 
> What about not enabling any sound support and thus not using this IRQ
> handler? Would that tell us something?

Using a laser to cut out the silicon would be more entertaining, but
either BIOS disable or compiling out sound support should work.  ;-)

> > Especially given that at the very bottom of the .jpg, there is a
> > chopped-off line that appears to read "Disabling IRQ #16". Which of
> > course leads me to wonder whether we hit a race between the last
> > interrupt arriving and the device being disabled.
> 
> Well, the "Disabling IRQ..." line comes from note_interrupt() down the
> do_IRQ() path. It looks like
> 
> 	if (unlikely(desc->irqs_unhandled > 99900)) {
> 
> we hit some high number of unhandled interrupts, issue the message about
> the bad IRQ and then disable it by dumping the handlers beforehand.

It would also be interesting to print out desc->irqs_unhandled at some
point during suspend to get a feel for the magnitude of the difference.
After all, 99900 is an interesting choice of number!

> > Hmmm...  Do you have either CONFIG_PM_SLEEP, SUPPORT_VGA_SWITCHEROO,
> > or CONFIG_PM_RUNTIME set for these runs?
> 
> CONFIG_PM_SLEEP=y
> # CONFIG_VGA_SWITCHEROO is not set
> # CONFIG_PM_RUNTIME is not set
> 
> You meant CONFIG_VGA_SWITCHEROO and not SUPPORT_VGA_SWITCHEROO, right?

You are quite correct.

							Thanx, Paul

> Ok, let me try to disable the soundcard in the BIOS.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Sent from a fat crate under my desk. Formatting is fine.
> --
> 

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