Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 6 Feb 2015 11:01:02 +0000 (GMT) | From | "Maciej W. Rozycki" <> | Subject | Re: Ethernet: how to disable gigabit support |
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On Thu, 5 Feb 2015, Pavel Machek wrote:
> This happened on more than one project: there's gigabit-capable chip, > but the connector is not designed for gigabit speed. > > I'd like to have speed autonegotiation, but not offer gigabit (as it > will not work). > > Is there way to do that without hacking the kernel? Should mii-tool do > that?
It used to work for me with a 3Com 3c905C adapter when I needed to force full duplex for an old non-negotiating 100baseTx-FD network switch.
> root@ib8315:~# mii-tool.net-tools -A 100baseTx,10baseT eth1 > restarting autonegotiation... > root@ib8315:~# [32432.443883] libphy: mdio@e0024520:01 - Link is Down > > root@ib8315:~# [32435.447863] libphy: mdio@e0024520:01 - Link is Up - 1000/Full > > root@ib8315:~# mii-tool.net-tools -v eth1 > eth1: negotiated 1000baseT-FD flow-control, link ok > product info: vendor 00:01:c1, model 3 rev 1 > basic mode: autonegotiation enabled > basic status: autonegotiation complete, link ok > capabilities: 1000baseT-FD 100baseTx-FD 100baseTx-HD > 10baseT-FD 10baseT-HD > advertising: 1000baseT-FD 100baseTx-FD 100baseTx-HD > 10baseT-FD 10baseT-HD > link partner: 1000baseT-FD 100baseTx-FD 100baseTx-HD > 10baseT-FD 10baseT-HD flow-control > root@ib8315:~# mii-tool.net-tools -V > $Id: mii-tool.c,v 1.9 2006/09/27 20:59:18 ecki Exp $ > (Author: David Hinds based on Donald Becker's mii-diag) > net-tools 1.60 > root@ib8315:~#
You may have to spell out media names in full, e.g.:
# mii-tool -A 100baseTx-FD,100baseTx-HD,10baseT-FD,10baseT-HD eth1
Also the driver may have a way to override the capabilities advertised via a module parameter. This is what I eventually ended up with with the 3c905C adapter.
Maciej
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