Re: e100 PCI bridge problem

[Krzysztof Halasa <khc@pm.waw.pl>]

William Montgomery <william@opinicus.com> writes:

> In an earlier post to the list I described a hard lockup condition
> that occurs on linux kernels 2.4.22, 2.6.13, and 2.6.17 when using
> a 4 port 10/100 fast ethernet card.  The lockup is easily repeatable
> and occurs on 2 out of 3 computers.
>
> Further testing has revealed that the lockup can be prevented on all
> computers by making sure the card is installed on the primary PCI bus.
> If the card is installed in a slot on the secondary PCI bus (behind a
> PCI to PCI bridge) the lockup occurs.

Does the machine #3 have a PCI slot connected to a "secondary" bus?
Have you tried with any other machine with a secondary bus?

> Are there any PCI tuning registers that I can tweak to get around
> this problem?  Any changes I could make to the e100 driver to fix this?

Could be a hardware/BIOS problem on machines #1 and #2. Could be
a Linux bug as well, though similar configurations are known to work
fine. I don't think it has anything to do with IRQs.

Perhaps it doesn't like a bridge (on the card) behind a bridge
(on the motherboard). I would test with another multiport card
such as old DLink DFE-570TX (using a DEC 21150 bridge and four
21143 Ethernet chips).

I'd probably use some PCI analyzer or, at least, I'd check
the bus state with a multimeter.
-- 
Krzysztof Halasa
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