Re: 8139 full duplex?

From: Rogier Wolff (
Date: Fri Feb 16 2001 - 04:40:53 EST

James Sutherland wrote:
> > That would explain me seeing way too many collisions on that old hub
> > (which obviously doesn't support full-duplex).
> No, it would just prevent your card working. Large numbers of collisions
> are normal during fast transfers across a hub.

Why would it completely "not work"?

As long as the host doesn't have something to send while a recieve is
in progress, everything should work. A friend reports that he spent
lots of time trying to debug a network where "too many" collisions
were happening. Turns out one card was in full-duplex, while the other
side wasn't.

I benchmarked my old network at 10-12 seconds for a 100Mb
transfer. That sounds indeed as if there isn't a whole lot of
collisions happening. And I can immagine that the acks run into the
next data-packet all the time, so that performance would indeed be
very bad if the card was misconfigured. On the other hand I had one
machine that was taking 180 seconds for the 100Mb transfer.

Anyway, I remember fiddling with the eexpress 100 driver, and there
the driver was involved in switching the speeds, and doing some
management of the switchover of full-duplex/half-duplex. I'd expect
some message from the driver if it saw such a change.

But you're saying that the 8139 chip does it internally, and fully
automatically? Ok. Good.


** ** ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
* There are old pilots, and there are bold pilots. 
* There are also old, bald pilots. 
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:12 EST