Which reminds me -- I was suggesting that we add an order / id to the
stages, not just name. Because AFAIU being able to request the loopback
"very last loopback point of MAC" or "first loopback point of PHY"

How do you define where the MAC ends?

I suspect some vendors will include the PCS and the PMA, because the
MAC ends at the MII pins on their SoC. Other vendors are going to say
the MAC ends at the interface to the PCS, especially those who have
licensed the PCS, and are using the shared Linux driver for the
PCS. And the PMA might again be a shared implementation, since it is
also used for USB, PCIe and SATA.

If Linux is driving the hardware, using phylink, phylib, PCS drivers
and generic PHY, we are very likely to have a uniform definition of
all these parts. Are we happy firmware devices will have a much
fuzzier, different interpretation, conglomerating it all together?

	Andrew