Re: e100 PCI bridge problem

Kok, Auke
2007-07-13T20:36:38Z

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

> 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.

Perhaps the linuxfirmwarekit will reveal more information. In any case, fixing
this in software would be a gigantic effort.

Auke