On Fri, Aug 20, 2021 at 06:30:02PM +0000, Machnikowski, Maciej wrote: > Since the 40.5.2 is not applicable to higher-speed ethernet which > don't use auto-negotiation, but rather the link training sequence > where the RX side always syncs its clock to the TX side. By "the RX side always syncs its clock to the TX side" do you mean the RX channel synchronizes to the link partner's TX channel? Wow, that brings back the 100 megabit scheme I guess. That's cool, because the same basic idea applies to the PHYTER then. Still we are doing to need a way for user space to query the HW topology to discover whether a given ports may be syntonized from a second port. I don't think your pin selection thing works unless user space can tell what the pins are connected to. Thanks, Richard