Re: [chrony-users] gpsd, pps and chrony

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On 15 March 2011 11:06, Ed W <lists@xxxxxxxxxxxxxx> wrote:
On 15/03/2011 09:07, Damien R wrote:
> Hi,
> I want to use chrony to synchronize the system clock between two
> computers (with no connection between them), each equipped with a gps
> (gps emmit a pps).

I guess it's just a mis-phrasing, but if there is no connection between
the two machines, how are you hoping that they will communicate between
each other to be synchronised?

No it's not a mis-phrasing, I hope both computer are synchronized with the gps clock, and so both computer should be synchronize.
Is it not possible to add some connection between the two machines?

No, it is impossible.

However, yes I believe that as long as you configure gpsd also then SHM
should work.  I have something like this in my chrony.conf:

refclock SHM 1 poll 4 offset 0.0 refid GPS1
Note I'm not currently using a gps, but your question was asked in
January on this list by Michael Ashley. Perhaps have a look through that?

I have already looked at this post but, although PPS is mentioned, this post does not say if chrony is able to retrieve the PPS with shm reflclock.
But if it worked for you with
refclock SHM 1 poll 4 offset 0.0 refid GPS1
it looks like that chrony supports pps with gpsd.

Also, it's in the back of my mind, but some older versions of gpsd
benefited from a patch by Miroslav to smooth PPS? If you are on some
distribution which only has antique gpsd versions then try getting up to
date?  Half remembered advice though...

I did not use a recent version but I will try with a new one.

Best regards,
Damien R.

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