Re: How to go about debuging a system lockup?

From: Lennart Sorensen
Date: Mon Nov 20 2006 - 10:21:59 EST


On Sat, Nov 18, 2006 at 12:09:54AM +0100, Stefan Richter wrote:
> Lennart Sorensen wrote:
> > OK, I have now tried connecting with firescope to just follow the dmesg
> > buffer across firewire. Works great, until the system hangs, then
> > firescope reports that it couldn't perform the read. I wonder what part
> > of the system has to lock up for the firewire card to no longer be able
> > to read memory on the system.
>
> I suppose the PCI bus is no longer accessible to the chip.

Sure seems that way. Makes me wonder if somehow a PCI transfer fails,
and the PCI controller isn't aborting the transfer after a timeout
(quite likely given the timeout timer is never enabled, and whenever I
try to do so, it seems to hang the system). Time to start scoping the
lines.

--
Len Sorensen
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