On Thursday 19 July 2007 17:42:26 Mark Bryars wrote:
> I'm trying to figure out if I can reset a card without rebooting the
> machine to get the card going again.
>
> I had four cards lock up in the one machine, rmmoded ivtv and
> reloaded it, one of the four resumed operation, so clearly sometimes
> the card will get out of this locked up state, the driver should
> probably try and reset the card after a timeout.
I've never been able to get it working again without a full reboot. This
might indicate that something else is wrong. Did you check the kernel
log to verify that that card did have a DMA TIMEOUT?
> Whilst looking for a way to reset a PCI slot, I found the kernel
> documentation on PCI error handling, so I added a stubbed error
> handler with a printk to the driver to see if it would get called to
> be able to return with a slot reset request from that... It didn't
> get called during the dma errors or timeouts.
You don't get a PCI error, instead the DMA engine on the MPEG card just
freezes and the DMA never finishes (it probably even never starts). The
timeout message is from a timer in the driver that is started whenever
a DMA command is given, and ends if no DMA completes after some time.
> Is there a simple way to request a PCI card/bus gets reset? Would
> this bump the card back into an operational state? Is there a better
> way?
Not to my knowledge. But I'm no expert in this field.
However, I do recommend that you upgrade to ivtv-0.10.5 (just released).
See the comments with the 0.10.5 announcement why that is a good idea.
What chipset/CPU are you using BTW? Are you certain you do not have a
CPU frequency changer daemon or whatever running? This tends to be one
of the biggest culprits: changing the CPU frequency on the fly seems to
wreak havoc on quite a few systems. My new Asus P5K-E motherboard is
the first one that remains stable when I do that, on all other
nVidia/ATI motherboards that I have the DMA engine just dies within a
few minutes of continuous frequency changing.
Regards,
Hans
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