PCIe card not appearing when in slot #2 on a certain brand of Dell machines

[Yaacov Weiss]

2012/1/24 Shachar Shemesh <shachar at shemesh.biz>:
> I know, the subject is strange, but the truth is that the actual problem is
> also strange.
>
> At work, we have a batch of Dell machines. We also, regularly, use a certain
> type of PCI-express x1 card for video capture and playback. Strangely, on
> those machines, if we insert the card into slot 2 of the machine, the card
> is not visible to the kernel. It does not appear on lspci, and obviously,
> the driver is not loaded and does not work. Moving the card to a different
> slot resolves all of the above problems. The machine's BIOS has an option to
> enumerate all cards, and does see the card without a problem.
>
> The problem happens with Fedora Core 15, and happened on at least three
> different machines, so we can rule out a machine failure.
>
> I am at a loss as to how to even begin to debug this problem.

I would probably begin by checking if some other type of card works
in slot 2, and if these cards work in slot 2 using different distributions
and/or kernel versions.

--yaacov