[tulip] 21140 full duplex?

[Donald Becker]

On Tue, 17 Oct 2000, Dan Hollis wrote:

> I have been trying to get a quadport 21140 (Osicom 2340-TX) to do FDX to a
> SMC EZ-NET 24SW. The Osicom does not have MII.
> 
> No matter what options I give tulip module, it always comes up on the
> switch as 100bt half duplex, and file transfers max out around
> 54mbps. With a pair of Linksys LNE100TX's it comes up as 100bt full duplex
> and I can easily get 90mbps out of the link.
> 
> I assume this is because the 21140 does not do NWay? Is there any
> workaround?

Correct.  The 21140 does not have NWay support.  Usually the 21140 is
connected to a MII transceiver, and the MII transceiver does the NWay
autonegotiation.  If the 21140 is connected to a SYM transceiver the
combination cannot do NWay and might not even be able to detect link beat.

> Is it possible to do NWay in software or does this require hardware
> support at the chipset level?

The major feature of the initial 21142/21143 chip was the addition of NWay
with certain SYM transceivers.


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