[Linux-stm32] [PATCH net-next 1/2] dt-bindings: net: Add Siflower SF19A2890 GMAC

[Joseph Telaak]

> Do you have access to another board which has a PHY connected, not a
> switch?

No. The GL-SFT1200 is the only SF19A2890 board I have, and the only
other one I know of, the vendor's evaluation board in OpenWrt, also has
a fixed-link on this port.

> There are unexplained delays here. Is it the switch, this MAC, or the
> PCB?
>
> We need to understand if tx-internal-delay 0 really means 0, or it
> actually means 1065ps.

I can't tell that from this board. The sweeps measure the sum of the
MAC's delay line, the switch and the PCB, and I have no documentation
of the line's own delay at step 0.

What they do show, in the MAC's steps: the windows repeat every 8 ns,
which puts the start of both eyes about 4 steps (0.2 ns) below 0. TX
ends at step 51 and RX at step 28. So with every delay at 0 the link
works, but right at the early edge of both eyes.

Until that is known, how would you like v2 to describe this board?