force half duplex with 3com 905b

Donald Becker
Mon Aug 24 21:23:11 1998

On Mon, 24 Aug 1998, Oscar Stiffelman wrote:

> Does anyone know how to force half duplex mode with the 3com905b?  Is
> there an options value I can set in the 3c59x.c file?

Note: I'm still working on the 10mbps-only problem.

Anyway, use 'mii-diag -A 0x00A0' to advertise only half-duplex types:
   0x0080 100baseTx-HD
   0x0020  10baseT-HD

> If I boot with the card connected to my switch, it autonegotiates and runs
> at full duplex, but the performance is terrible.  If I unplug the card
> from the switch and then reconnect it after booting, it runs at half
> duplex with excellent performance.  Rather than unplug the card every time
> I boot, I would prefer to force the card into half duplex.

Errrk?  Are you error counts in /proc/net/dev

> I am running a PC164LX alpha machine with Alpha Bios and ARC Console (not
> SRM).

I'll have to take the 3c905B card home someday and try it my 164LX.

Donald Becker
USRA-CESDIS, Center of Excellence in Space Data and Information Sciences.
Code 930.5, Goddard Space Flight Center,  Greenbelt, MD.  20771