Re: [Linuxptp-users] Finding the Fixed offset between two Ports of the same NIC.

[Deshpande, Y. <yas...@tu...>]

> PPS signal is the best way.  I think it is also "easy" because it removes the guesswork.


Thanks a lot.

Is there any source on how to enable the PPS output on the SDP pins and loop it back into the same NICs SDP inputs?


My plan is this: 1) enable PPS output from port1 to SDP0 2) Then loopback a single wire from SDP0 of port1 to SDP0 of port2. 3) Run ts2phc for port2 in free-running mode. This should give me the fixed offset I mentioned in the first message of the thread.


Also my two options are:

./ts2phc --free_running=1 -c enp2s0f0 -s enp2s0f1

./ts2phc --free_running=1 -c enp2s0f0 -s generic

but I am not sure which one is the correct one.


Do I need to change my igb driver from the default one being able to enable pps input/output?


Can step 1 be done by ts2phc or should I do it before running ts2phc?

I tried a dry run of ts2phc and it failed with the following error:

ts2phc[100692.637]: PTP_EXTTS_REQUEST2 failed: Invalid argument
ts2phc[100692.637]: PTP_EXTTS_REQUEST2 failed: Invalid argument
failed to arm PPS sinks
ts2phc[100692.637]: PTP_EXTTS_REQUEST2 failed: Invalid argument

is it because of the wrong igb driver or not having done step 1 or is it another problem altogether?




Best Regards,

Yash

________________________________
From: Richard Cochran <ric...@gm...>
Sent: Tuesday, June 28, 2022 4:09:04 PM
To: Deshpande, Yash
Cc: Miroslav Lichvar; lin...@li...
Subject: Re: [Linuxptp-users] Finding the Fixed offset between two Ports of the same NIC.

On Tue, Jun 28, 2022 at 01:30:32PM +0000, Deshpande, Yash wrote:

> I would like to ask the second part of the question once again. I
> dont wish to synchronize the two ports. I know that their relative
> offset is constant as they are running on the same oscillator. This
> is also reported by the ptp4l. I would just like to know this offset
> without running ptp4l.Is there an easier way than PPS loopback?

PPS signal is the best way.  I think it is also "easy" because it
removes the guess work.

Thanks,
Richard