[mythtv-users] System constantly locks up

[chris at cpr.homelinux.net]

On Tue, Aug 22, 2006 at 09:15:21PM -0700, Tim Berger wrote:
> Sometimes the linux kernel may crash but not be able to write to your local
> messages  file.
> 
> If you have another linux box on your network, configure it to accept syslog
> messages from your myth box.

Alternatively, compile a kernel that has support for "serial console"
and use a null-modem cable to connect your computer's serial port to
some other device (serial printer, serial TTY, other computer).

My backend was locking up constantly and it turned out to be an IRQ
problem.  I could see what was happening because I have a split
front/back system and the back-end has only an 80x24 console display.
The symptoms were that the box would freeze during heavy I/O and then
I'd get a DMA error message from ivtv, a timeout message from the LAN
card and then a "drive not ready" error from /dev/hde.  The solution in
my case was to shuffle the cards around (so that no card occupied the
PCI slot that was sharing interrupts with the on-board LAN or USB
devices) and using the BIOS to manually assign IRQs to each card.

I still get DMA errors from the ivtv card (a known problem with no known
solution) but at least the ivtv code doesn't block the IDE/ETH0
interrupts from getting through.