[mythtv-users] Problems with multiple pvr cards

[Karl E. Jorgensen]

On Tue, May 08, 2007 at 08:31:28PM -0400, Brian L. Walter wrote:
> Greetings,
> 
> I've got 1 pvr-500 and one pvr-150, running ivtv 0.10.1 with myth 
> 0.20-fixes as of 5/6.
> 
> I have run a couple 30 minute cat /dev/videoN against all 3 devices 
> simultaneously, with no problem.

Was this a simple "cat /dev/videoN > /dev/null" or did the output go to
disk?

> However, when Myth goes to record on all 3, I start getting ENC DMA 
> Errors, anywhere from  immediately to 20-30 minutes.

Obviously, myth writes to disk :-)

> I've read that there is an interrupt issue with the 0.10.1, and was
> wondering if this is a result of that issue.

Could be. But you need to take the total load of the box into account -
so myth's disk activity may become significant.

> This problem does not occur when only 2 of the three inputs are in
> use, only with all three.  The only way to clear it up is to reboot,
> because this situation will eventually lead to dma timeouts, and
> driver not responding....then...system crash.

Yuck.

If your tests before did not write to disk, try some that do. If the
to-disk tests produce DMA errors whereas the not-to-disk ones do not,
then the disk activity is significant (but not necessarily the cause).
Then it would be time to try things bonnie++ (without touching the PVRs)
to elimiate disk DMA problems...

Hope this helps

-- 
Karl E. Jorgensen
karl at jorgensen.org.uk  http://www.jorgensen.org.uk/
karl at jorgensen.com     http://karl.jorgensen.com
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