RE: [RFC net-next 1/7] ptp: Add interface for acquiring DPLL state

From: Machnikowski, Maciej
Date: Mon Aug 23 2021 - 04:29:27 EST




> -----Original Message-----
> From: Richard Cochran <richardcochran@xxxxxxxxx>
> Sent: Sunday, August 22, 2021 4:31 AM
> Subject: Re: [RFC net-next 1/7] ptp: Add interface for acquiring DPLL state
>
> 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.
>

Yes! Sounds very similar! :)

> 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

And a good catch! I'll update the RFC to add the query functionality and move the SyncE logic/pins to the netdev subsystem.

Thanks