Re: hdc: lost interrupt

[Mike Kershaw <urmk@reason.marist.edu>]

On Fri, Jan 21, 2005 at 04:08:07PM -0600, David F Barrera wrote:
> I am seeing a kernel message, "hdc: lost interrupt", when running LTP on 
> the xen0 domain.  The first time I saw the 'kernel: hdc: lost interrupt' 
> in /var/log/messages, I was running LTP on both xen0 and xenU domains.  
> The xenU domain was totally hung at this point. Suspecting a setup 
> error, I re-checked the installation and reran LTP on xen0 alone, 
> without having anything running on xenU. Again, I saw the error. To rule 
> out a hardware problem, I decided to run the same tests on a regular 
> kernel from kernel.org (2.6.10) and on the RHEL 4 kernel from Red Hat, 
> both of which ran without showing the error.  I don't know what to make 
> of it.  I am not suspecting a hardware error since the message does not 
> show up when running on non-xen kernels.

This may be a false lead, but I saw this (and other significant IO-related 
weirdness) when I moved hardware around and forgot to enable kernel DMA support
for the IDE chipset.  Overall system performance tanked (obviously), I got
a large number of hdX: Lost interrupt warnings, and even some outright panics.

Turning on DMA in dom0's kernel config cleared it all up.

Might be worth investigating anyhow,

-m



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