netdev - Re: [PTP][KSZ9477][p2p1step] Questions for PTP support on KSZ9477 device

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Message-ID: <aFJcP74s0xprhWLz@pengutronix.de>
Date: Wed, 18 Jun 2025 08:27:11 +0200
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Richard Cochran <richardcochran@...il.com>
Cc: Vadim Fedorenko <vadim.fedorenko@...ux.dev>,
	Lukasz Majewski <lukma@...x.de>, netdev@...r.kernel.org,
	Arun Ramadoss <arun.ramadoss@...rochip.com>,
	Vladimir Oltean <olteanv@...il.com>, Tristram.Ha@...rochip.com,
	Christian Eggers <ceggers@...i.de>
Subject: Re: [PTP][KSZ9477][p2p1step] Questions for PTP support on KSZ9477
 device

On Tue, Jun 17, 2025 at 10:07:32PM -0700, Richard Cochran wrote:
> On Tue, Jun 17, 2025 at 05:10:11PM +0100, Vadim Fedorenko wrote:
> > On 17/06/2025 06:25, Oleksij Rempel wrote:
> > > No, this will not work correctly. Both sides must use the same timestamping
> > > mode: either both "one step" or both "two step".
> > 
> > I'm not quite sure this statement is fully correct. I don't have a
> > hardware on hands to make this setup, but reading through the code in
> > linuxptp - the two-step fsm kicks off based on the message type bit. In case
> > when linuxptp receives 1-step sync, it does all the calculations.
> 
> Correct.
> 
> > For delay response packets on GM side it doesn't matter as GM doesn't do
> > any calculations. I don't see any requirements here from the perspective
> > of protocol itself.
> 
> Running on a PTP client, ptp4l will happily use either one or two step
> Sync messages from the server.

Thank you for clarification! In this case, something else was wrong, and
I made a wrong assumption. I had a non-working configuration, so I made
the assumption without verifying the code.

Best Regards,
Oleksij
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