Re: irq 16: nobody cared

[Takashi Iwai <tiwai@suse.de>]

At Sun, 21 Apr 2013 09:30:02 -0700,
Paul E. McKenney wrote:
> 
> On Sun, Apr 21, 2013 at 12:34:03PM +0200, Borislav Petkov wrote:
> > On Sat, Apr 20, 2013 at 04:52:07PM -0700, Paul E. McKenney wrote:
> > > Hmmm... Does this problem occur only with CONFIG_RCU_FAST_NO_HZ=y, or
> > > does it occur unconditionally? (My guess is the former, but figured I
> > > should check.)
> > 
> > Your guess is correct, sir.
> > 
> > >From quickly grepping in /boot/, I have CONFIG_RCU_FAST_NO_HZ=y in all
> > my 3.9 configs. So I went and turned it off and the issue doesn't appear
> > anymore.
> 
> 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.  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.
> 
> Hmmm...  Do you have either CONFIG_PM_SLEEP, SUPPORT_VGA_SWITCHEROO,
> or CONFIG_PM_RUNTIME set for these runs?
> 
> Adding Takashi Iwai on CC in case he has any insight.

Hm, if it's really due to a stray irq, just adding the missing
synchronize_irq() like below would help?


Takashi

---
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 7b213d5..262dbf1 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -2682,6 +2682,8 @@ static void azx_stop_chip(struct azx *chip)
 	/* disable interrupts */
 	azx_int_disable(chip);
 	azx_int_clear(chip);
+	if (chip->irq >= 0)
+		synchronize_irq(chip->irq);
 
 	/* disable CORB/RIRB */
 	azx_free_cmd_io(chip);