No ethernet works for me since upgrade! (suggestions?)

[Andrew Reilly]

Very strange problem:

I have an AMD64-X2 in a Gigabyte K8NF-9 (nForce4) system that I
have been running in 64-bit mode relatively happily since I set
it up, earlier this year.  I've been tracking 6-STABLE.  The on
board MCP9 gigabit ethernet was recognised by nve0 but didn't
work reliably, so I put an Intel 21143 PCI card in, and that was
fine.  The last working kernel was vintage april sometime (one
of the 6.1-RC series).  I got back from holidays recently and
yesterday I got around to upgrading to the latest CVSupped
6-STABLE, and now I can't get *any* network cards to work.

I tried re-booting the SMP kernel with kern.smp.disabled="1" in
loader.conf: no difference.  I've tried options DEVICE_POLLING.
I'm currently running a stock GENERIC kernel.

I now have three network interfaces in the box: the nve0 on the
motherboard, the dc0 that was working nicely before, and a new
RealTek 8139[d].  None work.

I've verified that the ethernet cable and switch port work, by
swapping it to the working box sitting next to it.

When plugged into the dc0, the carrier light doesn't even come
on.  When plugged into the nve0 the carrier light comes on but
so does the error light.  In the rl0 I get carrier and no error
light, but can't ping the local net and have no arp responses.

Hmm.  That's odd.  In the time it's taken me to type this, the
rl0 seems to have come good.  /var/log/messages tails with a
bunch of "rl0: link state changed to {UP,DOWN}" and "rlo:
watchdog timeout" messages, so I doubt that it's completely
happy...

Any thoughts?

Any other experiments or changes I could usefully make?

[Sounds like the motherboard chipset is just totally failing to
deliver PCI interrupts reliably, to me.  Might that be something
that could be improved by upgrading the BIOS?  Changing a BIOS
configuration setting?  I've never upgraded a BIOS that before;
is it hard?  Can it be done from FreeBSD?]

Cheers,

-- 
Andrew