Re: [PATCH net-next v2 07/10] net: dsa: lan9303: Added basic offloading of unicast traffic

[Andrew Lunn]

> >I think you are over-simplifying here. Say i have a layer 2 VPN and i
> >bridge port 1 and the VPN? The software bridge still wants to do STP
> >on port 1, in order to solve loops.
> >
> 
> Problem is that the mainline lan9303_separate_ports() does its
> work by setting port 1 & 2 in STP BLOCKING state (and port 0 in
> FORWARDING state). So my understanding is that it would break port
> separation if LAN9303_SWE_PORT_STATE is written while the driver
> is in the non-bridged state.

If the hardware cannot do it, that is a different matter. But if the
hardware can do STP states per port, you should try to make use of it
here.

> I thought the SW bridge would carry doing its STP work even if
> there is a port_stp_state_set method on a DSA port?

It will, but it means you are dropping frames in software, adding
extra load to the CPU, reducing the available bandwidth for the other
port, etc.

       Andrew