So it's also the cable that needs to be compensated? Didn't think of that tought it would get that somehow throught the timestamp Thanks anyways now we need to find the correct offset off the FEC to get it to sub 100ns delay.
Will be a lot of tweaking does somebody know how intel got those offsets? And howlong one needs to measure to get a more or less good value? Von: Miroslav Lichvar <mlich...@redhat.com> An: Armin HAMAR <armin.ha...@sprecher-automation.com> Kopie: Linuxptp-users@lists.sourceforge.net Datum: 02.07.2019 13:18 Betreff: Re: Antwort: Re: Antwort: Re: Re: [Linuxptp-users] PPS to Linux PTP offset/delay? On Tue, Jul 02, 2019 at 01:14:44PM +0200, Armin HAMAR wrote: > Ah found out that: > > ingressLatency 769 > egressLatency 169 > > Makes the offset about 17ns from the Master. > Where did you get the values from? Somewhere in a data sheet or just > guessing? >From the values you have provided, as I have explained in a previous post. 769 + 169 = 938 (769 - 169) / 2 = 300 This assumes the timestamping on the I210 is perfectly compensated, which it is not. And that the cable has zero length. You can tweak it as necessary. -- Miroslav Lichvar
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