Re: Strange EHCI/OHCI IRQ and other PCI errors on boot with 2.6.32(which 2.6.26 did not see) on Geode LX/CS5536.

From: Alan Stern
Date: Wed Jan 20 2010 - 20:52:34 EST

On Wed, 20 Jan 2010, Lennart Sorensen wrote:

> > > If I boot with 'irqpoll' then everything seems fine.
> > >
> > > Any idea how I can figure out why irqpoll makes it happy? Does it give
> > > any reports anywhere about misrouted irqs?
> >
> > Not that I know of.
> That's unfortunate. After all it would be nice if irqpoll found an
> unhandled irq and called all the other handlers and the irq went away,
> then a report of which handler cleared it would be very helpful.

You could try changing the set of drivers loaded in memory. For
example, after booting with irqpoll you can unload ehci-hcd plus some
other driver, and then load ehci-hcd again. If the IRQ storm occurs
then you'll know where to look.

> > Does 2.6.26 fail on the new machine?
> Yes.
> As far as I can tell some machines don't see the problem. I am still
> investigating that.

Same kernel, initramfs, and everything else?

> > Are you using a .config different from the one that used to work with
> > 2.6.26?
> Well of course, but not for the USB settings. It is supposed to be the
> same as far as possible. I will go compare them in more detail.

What I meant was: Is your current 2.6.26 still built using the same
.config as the old 2.6.26 which used to work okay?

Alan Stern

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