Re: [PATCH net-next v19 00/13] ax88179_178a: Add support for AX88179A-based chips

[Andrew Lunn]

> > - After a WoL wake the link goes down and up twice within about 2.5 s,
> >    where a normal resume shows a single link up. It comes back fine
> >    either way.
> I see this, too. It is not triggered in any way by the host or the link
> partner, I checked. It appears that this is due to the firmware on the
> device trying to optimize the link settings further, the out-of tree ASIX
> driver displays the same behaviour, although it works very differently.

phylink/phylib might be playing a role in this.

It takes about 1 Watt more energy to have a 1G link vs a 10Mbps link,
even when there is no traffic. So during suspend with WoL enabled,
phylib tries to reduce the link speed to the lowest common speed,
hopefully 10Mbps, by only advertising that one link speed. On resume
it goes back to advertising the full link capabilities.

So one of the down/up you are seeing might be this.

   Andrew