Disabling ethernet link on an Intel nic?

Marius Strobl marius at alchemy.franken.de
Thu Aug 16 09:13:44 UTC 2012


On Mon, Aug 13, 2012 at 01:47:01PM -0700, Adrian Chadd wrote:
> Hi,
> 
> On 11 August 2012 06:35, David Duchscher <daved at tamu.edu> wrote:
> > Greetings,
> >
> > I have a need to turn off the link of an ethernet port on a Intel nic.  The issue is not a big deal but one we would like to solve.  we have no way of signaling an upstream router that a path is down but via turning off the link of the ethernet port.  This would only be used when something goes wrong. The hope is that we could automate some problems and handle other situations remotely avoiding having to visit the system in person.
> >
> > Any thoughts?  We can modify the system so if it means modifying the driver or some other code, I am willing to try.  Just need a little direction.
> 
> Marius talked about doing this. Maybe it's time we added it as a
> device option, so people can have the PHY disabled when the NIC is
> brought down?
> 

I'm working on adding support to mii(4) for powering down PHYs when
the network interface is down, but as you have noticed this non-
trivial to get right, i.e. so they actually come out of power down
mode again when bringing up the interface regardless of the media
options used. We also clearly need a way to disable this behavior
for the known-broken PHYs.
This is orthogonal to the 1 and 10 Gigabit Intel Ethernet drivers
so as these don't take advantage of mii(4). Some time ago someone
posted patches to net@ implementing/activating powering down the
PHYs when these interfaces are down though.

Marius



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