Re: e100 PCI bridge problem

William Montgomery
2007-07-14T00:55:25Z

Kok, Auke wrote:

> William Montgomery wrote:
>
>> Thanks for responding. I am very interested to find the source of
>> this problem.
>>
>> Kok, Auke wrote:
>>
>>> William Montgomery wrote:
>>>
>>>> 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.
>>>
>>>
>>> sounds like int-A/B/C/D routing issues
>>
>>
>> The strange thing is that all the ports on the card work fine for a
>> few minutes, then when some condition (as yet unknown) occurs the
>> system locks up hard. I am currently using a PCI bus analyzer to
>> capture bus activity just prior to the lockup to try and find out
>> what leads up to this condition.
>
>
> are you running any form of irqbalance, either in-kernel (bad) or the
> userspace (better) one?

No. This is a Pentium 4 - single core, 2.8GHz.

>
>>>> 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?
>>>
>>>
>>> this issue might be resolvable by quirking the bridgee chips and
>>> adjusting any APIC where needed. Unfortunately I don't know much
>>> about this but it's physically not possible from the e100 driver.
>>> The special (non-intel) card that has these 4 ports onboard contains
>>> a bridge chip itself which explains the issues. Even a BIOS issue
>>> could be the cause here.
>>
>>
>> I am aware of the bridge chip on the card but not sure what you mean
>> when you say this explains the issues? I sure would like to figure
>> out a way around this.
>
>
> irq routing in linux may not be the same as in windows. I have no idea
> how to compare them either (dmesg will show the linux setup, but I
> don't know how to retreive this info under linux).

Not sure how windows applies here; I only use Linux. The main data
point so far is that the card works fine when on the primary PCI bus but
locks up hard after a few minutes when installed in a slot behind a PCI
to PCI bridge. I can provide the dmesg info on Monday.