I want to force 1/2 duplex from my network card. How?

[Andre Costa]

On Tue, 30 Mar 2004 10:51:03 -0600 (CST)
Gilbert Sebenste <sebenste at weather3.admin.niu.edu> wrote:

> Sorry, my bad. It is a Syskonnect SK-98xx (subvariant) Gigabit
> ethernet card. It is currently running 100 MB full duplex.
> 
> > anyway, what you probably need is some module parameters (assuming
> > NIC support is configured as a module on your system).
> >
> > eg. here with my nForce2 chipset, nvnet allows the following
> > parameters:
[...]
> > You could then provide the above params (speed, duplex,
> > optimization) on the /etc/modules.conf file. Maybe something similar
> > can be done for your network card module.
> 
> Hmmm. I'm scared to try this out since I frankly admit I have no idea
> what I am doing. 

Ok, no rush: linux kernel can have some of its components compiled as
modules, which means they're loaded on demand. If you type

lsmod

you will see which modules are currently loaded for your kernel. Modules
configuration stays on /etc/modules.conf (man is your friend). Modules
usually can tell how to configure them with the 'modinfo' command I
showed above. This means that if you run

modinfo [module-name]

you will be presented some basic description and the allowed parameters.
Combining all the above info, you can infer what this entry on my
/etc/modules.conf does:

options nvnet duplex=2 

(answer: it is saying that nvnet modules should be loaded with
param 'duplex' set to 2, which means full-duplex on my case).

TIP: do a 'man modprobe'.
             
> >To you problem: use either ethtool or mii-tool to force half duplex
> >mode.
> >
> >Alexander
> 
> %ethtool -s eth1 duplex half
> Cannot get current device settings: Operation not supported not
> setting duplex
> 
> Hmmm. OK, what am I doing wrong here?

Maybe it's not your fault. eththool doesn't work with my NIC either.

HTH,

Andre

-- 
Andre Oliveira da Costa