On Tue, 16 Oct 2001, Hadmut Danisch wrote:
> I just have some trouble with a 3c905
> (Dell Optiplex PC with 3c905 in motherboard)
> and a CenterCom hub (Linux 2.4.12).
> The hub doesn't stand full duplex, but the
> 3c905 always goes into full duplex when
> using 100 MBit.
How do you know this? The output of 'vortex-diag'?
Note that the card's EEPROM may be configured to forced full duplex
mode. This would have been programmed explicitly, the EEPROM doesn't
get reprogrammed by accident.
> The module parameters allow forcing into
> full duplex, but is there a way to force
> into half duplex?
The Ethernet default is half duplex.
The only standard-conforming method of doing full duplex over twisted
pair is if the duplex is autonegotiated.
The option to force full duplex is to handle the obscure/bogus cases,
such where you your Cisco administrator set the equipment to forced
full duplex because Cisco shipped broken autonegotiation and doesn't
want to replace the hardware.
Donald Becker becker@xxxxxxxxx
Scyld Computing Corporation http://www.scyld.com
410 Severn Ave. Suite 210 Second Generation Beowulf Clusters
Annapolis MD 21403 410-990-9993