Re: [net PATCH 1/2] net: phy: Cleanup handling of recent changes to phy_lookup_setting

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Fri, Apr 04, 2025 at 03:46:38PM -0700, Alexander Duyck wrote:
> On Fri, Apr 4, 2025 at 9:33 AM Andrew Lunn <andrew@lunn.ch> wrote:
> > So for us, we have:
> >
> > MAC - PHY
> > MAC - PCS - PHY
> > MAC - PCS - SFP cage
> > MAC - PCS - PHY - SFP cage
> 
> Is this last one correct? I would have thought it would be MAC - PCS -
> SFP cage - PHY. At least that is how I remember it being with some of
> the igb setups I worked on back in the day.

Yes.

Macchiatobin:

-Part of SoC -|                         /----- RJ45
MAC - PCS --------- 88X3310 Ethernet PHY
--------------|                         \----- SFP cage

Things get more interesting when one plugs in a SFP which itself
contains a PHY, where we effectively end up with:

MAC - PCS - PHY - PHY on SFP module - media

which we don't support very well, partly because it doesn't fit into
the higher levels of the networking model (that's being worked on), and
the 88X3310 doesn't support SGMII on its "fibre" port.

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