On Sun, Mar 28, 2021 at 05:52:43PM +0200, Andrew Lunn wrote: > > +static int dsa_switch_setup_tag_protocol(struct dsa_switch *ds) > > +{ > > + const struct dsa_device_ops *tag_ops = ds->dst->tag_ops; > > + struct dsa_switch_tree *dst = ds->dst; > > + int port, err; > > + > > + if (tag_ops->proto == dst->default_proto) > > + return 0; > > + > > + if (!ds->ops->change_tag_protocol) { > > + dev_err(ds->dev, "Tag protocol cannot be modified\n"); > > + return -EINVAL; > > + } > > + > > + for (port = 0; port < ds->num_ports; port++) { > > + if (!(dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))) > > + continue; > > dsa_is_dsa_port() is interesting. Do we care about the tagging > protocol on DSA ports? We never see that traffic? I believe this comes from me (see dsa_switch_tag_proto_match). I did not take into consideration at that time the fact that Marvell switches can translate between DSA and EDSA. So I assumed that every switch in the tree needs a notification about the tagging protocol, not just the top-most one.