On Thu, May 24, 2018 at 04:54:41PM +0200, Andrew Lunn wrote:

If you cannot get an IP address, it is plain broken. The whole idea is
that switch port interfaces are just linux interfaces. A linux
interface which cannot get an IP address is broken.

The switch interfaces can get ip addresses just like every linux interface. The
cpu port can't (sw0p0)

quoted

Similar cases exist for customers on adding MDBs as far as i know. So they want
the "customer facing ports" to have the MDBs present but not the cpu port.

That i can understand. And it should actually work now with
switchdev. It performs IGMP snooping, and if there is nothing joining
the group on the CPU, it won't add an MDB entry to forward traffic to
the CPU.

Yes, but this should be configurable (i.e the customer can deny adding the MDB
on the cpu port)

quoted

Adding a cpu port that cannot transmit or receive traffic is a bit "weird"

And how is it supposed to send BPDUs? STP is going to be broken....

Not sure about this, i'll have to check

Regards
Ilias