[vortex] 3c905 Problem - Please Help

[Donald Becker]

On Wed, 21 Nov 2001, Timo Boettcher wrote:

>  I'm having some trouble with 3Com 3c905-Cards (namely a 3c905B-TX and
>  a 3c905c-TX-M) in one of my Systems.
> 
>  During times of high load on the netword-card, I get errors like:
>  
> ======================begin paste======================
> eth0: Transmit error, Tx status register 82.
> Probably a duplex mismatch.  See Documentation/networking/vortex.txt

Andrew (I think) added this message.  It's a very good thing.

>  Depending on network-load, I get this up to two times per second,
>  on the active console, even if I am not logged in.
...
>  vortex.txt says:
> "This is a common error which is almost always caused by another host on
> the same network being in full-duplex mode, while this host is in
> half-duplex mode..."
> 
>  Since the System in question is running Half-duplex (see below),
>  and it is connected to a Hub (Netgear DS108) which is afaik only able
>  to do HalfDuplex anyway, this should not be the problem.

Yes, it is.  Read the description.  Some other host on the network is
incorrectly set to forced full duplex mode.  That other host is
corrupting packets by causing out-of-window collisions.  This is a very
bad situation that greatly increases the chance of undetected data
corruption.

> [root@server /root]# mii-tool -v
> eth0: negotiated 100baseTx-HD, link ok
...
>   link partner: 100baseTx-HD 10baseT-HD

You have a bridged repeater.  The errant host is running at 100baseTx,
since OOW collisions do not cross a bridge.

> The network card *seems* to be working correctly in another machine
> with Win2k.

The network card is working correctly.  Win2k is just not reporting the
error.

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993