From: "Michael Chan" <mchan@broadcom.com>
Date: Wed, 24 Jun 2009 09:59:20 -0700

On Wed, 2009-06-24 at 09:43 -0700, Rick Jones wrote:

quoted

Why?  Sure, there is no IP on the link, but does that mean the link is 
otherwise unusable?  Is ethtool only about IP status?

Once the device is closed, we no longer keep track of the link state and
no longer have register access to determine the link state.  So we
assume it is down.  In reality, it may still be up if WoL is enabled or
management firmware is running, but the driver can no longer keep track
of it.  If we have to assume one or the other, I think it is more
correct to assume it is down.

This is a big problem.  I misread this situation when I decided to
apply the patch yesterday, sorry.  We're going to have to revert it.

Applications like NetworkManager decide which devices to bring up and
attempt DHCP etc. on based upon the link status.

So if we report link down, the interface won't even be tried even if a
cable is plugged in.

Actually I wonder, does NM bring the interface "up" before checking
link state?  Does anyone know?