[ntp:questions] ntpd connect gpsd shared memory driver

Richard Cagley rcagley at gmail.com
Tue Jun 18 19:28:14 UTC 2013

On Tue, Jun 18, 2013 at 11:56 AM, David Taylor <
david-taylor at blueyonder.co.uk.invalid> wrote:

> If you have PPS support in the kernel you need a type 22 driver as well as
> the type 28.0 driver.  Type 28.1 assumes you have some software poking
> timestamps into the second shared memory segment provided by gpsd, as my
> user-mode Raspberry Pi system has.
> Something like:
> # Kernel-mode PPS ref-clock for the precise seconds
> server minpoll 4 maxpoll 4
> fudge  flag3 1  refid PPS

I'm having a hard time understanding this. Let's consider two cases:

1.) I have pps support built into my kernel:
In addition to the to grab nmea time data You suggest using
the pps line driver instead of You're saying that gpsd will
not do this for me? I'm not sure what "some software" refers to. Should I
be using ever?

2.) I don't have pps support:
Well, I'm not sure what to do in this case but others have indicated that
gpsd can grab both nmea and pps. Hence, I would think I'd use

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