Re: radeon in dom0/ivtv in domU: irq 16 nobody cared

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, Apr 09, 2010 at 01:47:35AM +0200, Mark Hurenkamp wrote:
> Hi,
> 
> > > With a fairly recent (~march 29th) xen/next kernel and a recent
> > > xen-4.0.rc9-pre build, i still get occasional 'nobody cared' messages on a
> > > IRQ which is shared between dom0 radeon driver, and domU ivtv driver. 
> Meanwhile i moved to an even more recent xen/stable-2.6.32 (.11) kernel,
> and a xen-4.0.0 release, the problem still shows.
> 
> > > Is there something i can do about this?
> > 
> > Yes,

I've been working on this problem and came up with some code that
follows Jeremy suggestion. But my test rig shows some weird behavior
(with and without the patch) and starts having an IRQ storm which
I think are unrelated.

Anyhow, what I would like you test is to provide 'noirqdebug' flag on
your Linux kernel command line. That should take care of the 'nobody
cared IRQ'. Please test and see if you your machine is more or less
sluggish.


Also, please do run this:
while (true)
do
 sleep 10
 cat /proc/interrupts | grep 16
done

during the lifecycle of the whole machine. I am curious to see whether
you also get an IRQ storm (or if it is just a trickle - which is OK)
after launching the DomU guest.