From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martin Shepherd <mcs@astro.caltech.edu>
Subject: Re: Debugging a hard lockup with no symptoms
Date: Thu, 15 Apr 2010 15:47:07 -0700 (PDT)
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To: Thomas Gleixner <tglx@linutronix.de>
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It is now looking as though the lockups may be caused by a problem in
the commercial analog I/O card that I am using, rather than in either
my code or the kernel. The dramatic increase in the frequency of the
lockups today, allowed me to associate the lockups with a couple of
outw() instructions that pass values to two digital to analog
converters on the card. When I comment out those instructions, or put
a few microseconds of delay between them, then the lockups stop. I
have talked to the manufacturer's tech support, and they have a
suspicion of the cause, and are working on trying to reproduce the
problem.

Martin