Subject: Re: PATCH: Network Device Naming mechanism and policy

From: Greg KH <[email-masked]>
Date: Fri, 9 Oct 2009 22:23:08 -0700

On Fri, Oct 09, 2009 at 11:40:57PM -0500, Matt Domsch wrote:
> The fundamental roadblock to this is that enumeration != naming,
> except that it is for network devices, and we keep changing the
> enumeration order.

No, the hardware changes the enumeration order, it places _no_
guarantees on what order stuff will be found in.  So this is not the
kernel changing, just to be clear.

Again, I have a machine here that likes to reorder PCI devices every 4th
or so boot times, and that's fine according to the PCI spec.  Yeah, it's
a crappy BIOS, but the manufacturer rightly pointed out that it is not
in violation of anything.

> Today, port naming is completely nondeterministic.  If you have but
> one NIC, there are few chances to get the name wrong (it'll be eth0).
> If you have >1 NIC, chances increase to get it wrong.

That is why all distros name network devices based on the only
deterministic thing they have today, the MAC address.  I still fail to
see why you do not like this solution, it is honestly the only way to
properly name network devices in a sane manner.

All distros also provide a way to easily rename the network devices, to
place a specific name on a specific MAC address, so again, this should
all be solved already.

No matter how badly your BIOS teams mess up the PCI enumeration order :)

thanks,

greg k-h