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 - 15:13:34 EST

On Wed, 20 Jan 2010, Lennart Sorensen wrote:

> On Wed, Jan 20, 2010 at 11:37:07AM -0500, Alan Stern wrote:
> > It's true that the USB controllers appear to be the only devices using
> > IRQ 5. But your startup log shows that only two of the three
> > controllers have an associated driver. Maybe the third controller is
> > generating the unwanted interrupts?
> Could be. But I never saw the problem with 2.6.26. That's puzzling me.
> Now I think the 3rd controller may be a client mode interface on the
> Geode LX, which I certainly don't use if it has such a thing.
> I know what EHCI and OHCI mean. I don't know what UDC is. I see mention
> of UDC under USB gadget support. I will try enabling that driver and
> see what it does.

"UDC" stands for "USB Device Controller". It is for use in device
mode, as opposed to host mode (i.e., you could plug that controller
into a regular PC and then use the Geode as a USB peripheral).

It's possible that some change in the PCI setup is allowing that
controller to generate interrupts whereas before it didn't. Or this
could be a total red herring.

Alan Stern

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