Re: [PATCH RFC net-next v3 2/4] net: dsa: add tag formats for MxL862xx switches

[Vladimir Oltean]

On Tue, Jan 06, 2026 at 02:57:56AM +0000, Daniel Golle wrote:
> On Tue, Dec 16, 2025 at 10:39:35PM +0200, Vladimir Oltean wrote:
> > On Mon, Dec 15, 2025 at 12:11:43AM +0000, Daniel Golle wrote:
> > > the actual tag format differs significantly, hence we need a dedicated
> > > tag driver for that.
> > 
> > Reusing the same EtherType for two different DSA tagging protocols is
> > very bad news, possibly with implications also for libpcap. Is the
> > EtherType configurable in the MXL862xx family?
> 
> Only the egress EtherType can be configured, there is currently no way
> to configure the ingress EtherType the switch expects to receive on
> special-tag packets on the CPU port. MaxLinear, however, said they could
> in theory release a new firmware changing the EtherType to any suggested
> value, but it would be incompatible with existing downstream drivers in
> the field, obviously.

Sorry for the late response.

I don't think it is a deal breaker. For all I know so far, we can
probably live with the same EtherType being used for multiple protocols,
and the distinction is made by the /sys/class/net/eth0/dsa/tagging string.