Subject: Re: [PATCH net-next 0/5] PTP support for the SJA1105 DSA driver

From: Richard Cochran <[email-masked]>
Date: Thu, 30 May 2019 08:05:57 -0700

On Thu, May 30, 2019 at 05:57:30PM +0300, Vladimir Oltean wrote:
> On Thu, 30 May 2019 at 17:30, Richard Cochran <[email-masked]> wrote:
> >
> > Not necessarily.  If two frames that arrive at nearly the same time
> > get their timestamps mixed up, that would be enough to break the time
> > values but without breaking your state machine.
> >
> 
> This doesn't exactly sound like the type of thing I can check for.

And that is why it cannot work.

> The RX and TX timestamps *are* monotonically increasing with time for
> all frames when I'm printing them in the {rx,tx}tstamp callbacks.

But are the frames received in the same order?  What happens your MAC
drops a frame?
 
> The driver returns free-running timestamps altered with a timecounter
> frequency set by adjfine and offset set by adjtime.

That should be correct.

Thanks,
Richard