Re: [PATCH net-next 16/17] Documentation: networking: dsa: Add details about NXP SJA1105 driver

From: Andrew Lunn
Date: Tue Apr 02 2019 - 17:24:29 EST


> +The switches do not support switch tagging in hardware. But they do support
> +customizing the TPID by which VLAN traffic is identified as such. The switch
> +driver is leveraging CONFIG_NET_DSA_TAG_8021Q by requesting that special VLANs
> +(with a custom TPID of ETH_P_EDSA instead of ETH_P_8021Q)

Hi Vladimir

Reusing ETH_P_EDSA is possibility going to case problems in tcpdump.
It has code which looks for this Ethertype and uses it to call the
Marvell EDSA header decoder code. This is not going to work for your
switch, where you have a normal VLAN header.

I wounder if we should allocate a new EtherType for this application
of VLANs?

Andrew