[nzlug] Linux + Audigy2: weird PCI effect

[Simon Bridge]

On Mon, 2007-11-19 at 12:27 +1300, Raimund Eimann wrote:
> Hi,
> 
> I'm not quite sure whether I'm sending this to the right place, but if not, 
> maybe someone can redirect me to a more appropriate mailing list.
> 
> I've got a SoundBlaster Audigy 2 card. This card provides three PCI devices:
> 
> 1) x:yz.0 Audio device
> 2) x:yz.1 Gameport
> 3) x:yz.2 Firewire port
> 
> I've got three PCI Slots (mainboard: ASUS P4R800-VM). When I plug the card 
> into the PCI slot furthest from the AGP, the card is not recognized at all 
> (lspci lists no devices). When I plug the card into the middle PCI slot, 
> three devices are recognized, but the uame port is listed as an unknown 
> Creative Labs device. When I put the card into the PCI next to AGP port, all 
> devices are recognized correctly, and the gameport is no longer unknown.
> 
> I've got an nVidia TI4200 graphics card that gets quite warm. There's only 
> about 1mm space between the back of the Audigy card and the fan of the 
> graphics card, so the audio card blocks the airflow and the both, audio and 
> video card get quite hot as a result.
> 
Which is why you don't want to use this slot.

This is curious - I'd suspect something to do with the war the card
itself is constructed. PCI devices are accessed serially, one after the
other. The PCI slots are also accessed one after the other. So your
different performance seems to depend on the order the slots get
accessed. May be an IRQ conflict of course.

But, if your keen, another thing to check is the effect of the nvidia
card. It shouldn't, but then it shouldn't matter which PCI slot you use
either. Use the onboard graphics and see if the card mysteriously fixes
itself.

Note: swapping mobos won't tell you anything unless the serial bus is
built differently on each one.

Now... somebody is going to tell me exactly why I'm wrong - count on
it :)

> My question is: Why does the card not work properly in arbitrary PCI slots? I 
> don't think it's a mainboard problem, because the machine otherwise works 
> fine and I had the same effect with other mainboards (due to this issue I 
> swapped the mainboard a couple of times...)
> 
> If this is not a good place to ask this question, does anyone have a 
> suggestion where else I could try to resolve this issue?
> 
I'd complain to Audigy.

> Cheers,
> Raimund
> 
> Today's wisdom:
> A radioactive cat has eighteen half-lives.
That means it can expect 12.24 whole lives... on average.

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