On Fri, 22 Jul 2022 14:23:18 +0100 "Russell King (Oracle)" <linux@xxxxxxxxxxxxxxx> wrote: > On Fri, Jul 22, 2022 at 02:59:36PM +0200, Marek Behún wrote: > > The 2.5GBASE-X PCS does not support Clause 37 Auto-Negotiation. > > Hence, the 1000BASE-X PCS is expected to have its Clause 37 > > Auto-Negotiation functionality disabled so that the /C/ ordered set > > will not be transmitted. If a 2.5GBASE-X PCS receives /C/ ordered > > set, then undefined behavior may occur. > > ... > > The reason that's probably stated is because there hasn't been any > standardisation of it, different implementations behave differently, > so they can't define a standard behaviour without breaking what's > already out there. I think they are also considering clause 73 AN, which is supported with 1000base-KX (if I am not mistaken). Maybe the intention was to use clause 73 with >1G speeds, and so they've forbid clause 37 on 2500base-x.
