[vortex] correct setting for 100Mbps full-duplex on 3Com 905C

[Jürgen Sandner]

We use 3COM 905B and 905C Network Adaptors at work, connected to CISCO 
Catalyst 3500 Switches.

Autosensing doesn't work (data loss, errors), but not only under Linux, but 
also under Windows NT.
We have to configure the Cards to 100 Mbps full-duplex or 10 Mbps full-duplex, 
and the switch port of course the same.
We can do it with a DOS-Tool, that stops the Card from autosensing, and gives 
it fixed values. But I'd prefer to let the operating-system do it.

My question:
What is the correct way to this under Linux?
I checked http://www.scyld.com/network/vortex.html, but the setting of the 
option-field for 100 Mbps is not really clear to me.

I use this entry in /etc/modules.conf, and it seams to work:
----------------------------------------------------------------------
options 3c59x          options=4 debug=1 full_duplex=1
----------------------------------------------------------------------
or
------------------------------------------------
options 3c59x          options=0x204
------------------------------------------------
But the description of the options-field tells me "4 is 100baseTx valid for 
3c959"

Thank you
Juergen Sandner