Re: 3c905 errors on RX with kernel 2.2.3

Donald Becker (
Fri, 12 Mar 1999 19:20:46 -0500 (EST)

On Fri, 12 Mar 1999, Tuan Hoang wrote:

> Subject: 3c905 errors on RX with kernel 2.2.3
> I just switched my machine from a Dell Penium 200 to a custom
> Tyan Trinity 100AT (S1590S). I am running kernel 2.2.3 with all
> the rpm updates for it. I have the same exact ethernet card in my
> machine: 3com 3c905 TX PCI.

The 3c905, or one of the several 3c905B "Cyclone" types?

> I set the media type to 10BaseT which
> disabled full duplex (correct I believe). What I'm seeing is

Don't do this!
The correct media type for the Cyclone is a new type, "NWay-autosense".
That's the type used by default, and is almost always correct.

You should never need to disable full duplex -- Ethernet driver always use
half duplex, unless they NWay-autonegotiate full duplex. You can also
explicitly specify full-duplex to the driver, but that should only be done
in the very rare case that you have an older Ethernet *switch*.

(I've often gotten email from people that think FDX is a secret
performance-enhancing flag that can be used with repeaters. It's not.)

> a lot of errors and collisions on my ethernet card. In about 10 min
> I total of over 1500 errors when transferring a 13MB file to a
> Linux 2.0.35 machine.

Receive errors or transmit errors?

> RX packets:18837 errors:1515 dropped:0 overruns:0 frame:2640
> TX packets:10644 errors:0 dropped:0 overruns:0 carrier:4293
> collisions:1170 txqueuelen:100

Ahhh, both. Tx carrier errors often indicates a duplex mismatch, with the
local end using half duplex while the remote end is using full duplex. Try
using the default setting on both cards, rather than trying to explicitly
set the interface type or duplex.

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

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