Re: [chrony-users] PPS time

[Miroslav Lichvar <mlichvar@xxxxxxxxxx>]

On Wed, Jul 03, 2019 at 02:17:03PM -0400, Steve Summit wrote:
> Miroslav Lichvar wrote:
> > The SHM refclock provided by gpsd is not a PPS refclock from the
> > chronyd's point of view. The timestamps already have seconds.
> > chronyd supports PPS refclocks using a /dev/pps* device directly.
> 
> If I'm understanding you correctly, then: If I want to use
> "raw" PPS, I need to (a) configure chronyd with something like
> "refclock PPS /dev/pps0" and (b) configure the Linux kernel so
> that /dev/pps0 reflects my actual PPS input.

You can use also the SOCK refclock to feed chronyd with PPS samples,
if you don't have a PPS device (although I'm now wondering how you got
it working with gpsd, which AFAIK requires a PPS device).

There is a "pulse" field in the sock_sample struct. If non-zero, the
offset is assumed to contain only sub-second data.

-- 
Miroslav Lichvar

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