Re: Greetings. Having a FIFO overrun when my amplc_pci230 card is set on the other side of a PCI bridge

On Wed, 2006-01-04 at 16:59 +0000, steve.sharples_at_nottingham.ac.uk
wrote:
> Hi there,

> So the short answer is I don't really know. My guesses (more like
> wild shots in the dark) are...
> 
> - certain voltages on your extra PCI bus are not being supplied (5V or
>   3.3V) or are set to the wrong voltage, this may be causing the PCI230
>   card to go a bit mad (PCI230_INT_ADC held up high by something).
> 
> - propagation delays along the path of the interrupts is causing several
>   versions of the code to be run at the same time. I gather there are ways
>   of fixing this, I have no experience of it.

This is my guess. I have another (externally housed) bridged bus that is
attached via a PCI card and I get the same result when the card is on
any of the busses (there are 4) attached to that bridge. I suspect that
since I get the same result on both bridges, they are both acting
"properly".


> Practical solutions if we can't find the cause of this and can't fix it:
> plug your PCI230 card into your main bus; buy an "industrial PC" with lots
> of PCI slots.

I believe what I have is such a beast. The extra PCI (total of 12) slots
are provided by the bridge. I don't have the option to use the main bus.
In fact, the card must actually be housed on the external bus.

> Sorry there's not much more I can suggest. Anybody else out there had any
> similar problems/got any sensible solutions?

Thanks for the help. I'm also poking the kernel mailing list about PCI
bridges in general...

> 
> Cheers,
> 
>    Steve.
> 
> On Wed, 4 Jan 2006, Michael R. Head wrote:
> 
> > Hello, I'm having some issues with my amplc_pci230 card. I have a 4U box
> > here that has a PCI bus (#2) with a Pericom Semiconductor PCI to PCI
> > bridge to another PCI bus (#3). When my PCI230 card is on bus #2, it
> > functions just fine with comedi (comedi_test runs and appears to
> > complete successfully). When I shut down and plug the card into a slot
> > on bus #3, I get nonstop messages in /var/log/messages (this is a RHEL 3
> > box)  once the driver is loaded.
> >
> > kernel: comedi0: amplc_pci230: FIFO overrun
> > ...
> >
> > Any hints or clues? Right now, it's the only thing plugged into any of
> > the PCI slots on the motherboard.
> >
> > mike
> >
> > --
> > Michael R. Head <burner_at_suppressingfire.org>
> > GPG: http://www.suppressingfire.org/~burner/gpg.key.txt [0x4C9DA1D0]
> >
> 
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-- 
Michael R. Head <burner_at_suppressingfire.org>
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