Re: [2.6.13] pktcdvd: IO-errors

From: Peter Osterlund
Date: Sat Oct 15 2005 - 10:40:23 EST

Peter Osterlund <petero2@xxxxxxxxx> writes:

> Guennadi Liakhovetski <g.liakhovetski@xxxxxx> writes:
> > Well, I've had this patch (to 2.6.13) failing once, whereas I still
> > haven't been able to reproduce the error with your previous patch. What
> > now? A bit worrying is that test results are not 100% deterministic now...
> > Which means, until recently my standard test (copy about 150M co the
> > CD-RW && sync) produced always consistent results, now I've seen a couple
> > of times the same driver version either failing or succeeding...
> My current theory is that there is something wrong with the firmware
> or hardware in your drive, and different I/O patterns have different
> probabilities of triggering this problem.
> Maybe you could use Jens' IO tracing patch to identify the sequence of
> commands that make the drive fail. See subject "[PATCH] Block device
> io tracing" posted by Jens earlier today.
> If the problem is always caused by some well defined sequence of
> commands, it might be possible to implement a workaround in the
> pktcdvd driver.

I have found a problem on one of my drives. On my FC4 system, hald and
kded are constantly doing something with the drive, and this makes it
fail when I try to do packet writing. Killing those processes make
that drive work correctly. Maybe this helps in your case too. Try
packet writing from single user mode to see if it helps.

I don't know yet how to make hald and kded stay away from the drive
while packet writing is in progress.

Peter Osterlund - petero2@xxxxxxxxx
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