[gpsd-users] PPS from kernel into gpsd

[Tomalak Geret'kal]

Hi

I've run out of reading material, or I have failed to find 
any that's directly pertinent.

We have an ARM platform running a busybox distribution of 
Linux with an attached GPS receiver; the receiver is 
proprietary and provides PPS via a PIO. A kernel mod maps 
this PPS through LinuxPPS and makes it available on 
/dev/pps0. The receiver does not make PPS available over the 
GPS device's serial connection.

Now I want to use this PPS to steer ntpd in SHM(1), along 
with the NMEA-derived time that's already serving me well in 
SHM(0).

According to http://catb.org/gpsd/gpsd.html [1], gpsd can 
use the RFC 2783 kernel PPS API "for extra accuracy". Can I 
use it as the sole source of PPS? How? Do I add /dev/pps0 to 
gpsd's device list? Because gpsd 3.2 didn't like that:

gpsd: control socket connect on fd 5
gpsd: <= control(5): adding /dev/pps0
gpsd: opening read-only GPS data source type 0 and at 
'/dev/pps0'
gpsd: gpsd_activate(): opened GPS (fd 6)
gpsd: packet sniffer failed sync with /dev/pps0
gpsd: closing GPS=/dev/pps0 (6)

Then some other technique, perhaps?

Any tips appreciated.

Tom


[1] - This is still nigh-on impossible to find on Google, 
which insists on referring to the old site, which presumably 
may disappear at any time...