> I'll make the water muddier (hopefully clearer?). I have access to the > board schematic (not SIP/SOM stuff though), but that should help here. > > MAC0 owns its own MDIO bus (we'll call it MDIO0). It is pinmuxed to > gpio8/gpio9 for mdc/mdio. MAC1 owns its own bus (MDIO1) which is > pinmuxed to gpio21/22. > > On MDIO0 there are two SGMII ethernet phys. One is connected to MAC0, > one is connected to MAC1. > > MDIO1 is not connected to anything on the board. So there is only one > MDIO master, MAC0 on MDIO0, and it manages the ethernet phy for both > MAC0/MAC1. > > Does that make sense? I don't think from a hardware design standpoint > this is violating anything, it isn't a multimaster setup on MDIO. Thanks for taking a detailed look at the schematics. This is how i would expect it to be. > > > > Good point, but it's worse than that: when MAC0 is unbound, it will > > > > unregister the MDIO bus and destroy all PHY devices. These are not > > > > refcounted so they will literally go from under MAC1. Not sure how > > > > this can be dealt with? > > > > > > unbinding is not a normal operation. So i would just live with it, and > > > if root decides to shoot herself in the foot, that is her choice. > > > > > > > I disagree. Unbinding is very much a normal operation. What do you use it for? I don't think i've ever manually done it. Maybe as part of a script to unbind the FTDI driver from an FTDI device in order to use user space tools to program the EEPROM? But that is about it. I actually expect many unbind operations are broken because it is very rarely used. Andrew