[ntp:questions] ntpd connect gpsd shared memory driver

A C agcarver+ntp at acarver.net
Tue Jun 18 16:08:06 UTC 2013


On 6/18/2013 08:50, Richard Cagley wrote:

>
> Hmmm, i had tried the -n before. It doesn't seem to help. After several
> minutes there is no change to  ntpq -p. Any other ideas for something
> stupid I'm doing? Do you think it's a ntpd or gpsd issue...or something
> else?
>
> After several minutes, no change to ntqp -p
> ---
> / # ntpq -p
>       remote           refid      st t when poll reach   delay   offset
>   jitter
> ==============================================================================
>   SHM(0)          .SHM.            0 l    -   16    0    0.000    0.000
> 0.000
> ---
> but gpsd seems to be active...
>
> / # gpsd -bn -N -D5 /dev/ttyO0
> gpsd:INFO: launching (Version 3.9)
> gpsd:IO: opening IPv4 socket
> gpsd:INFO: listening on port 2947
> gpsd:PROG: NTPDnew PPS source OMAP-SERIAL0 at ID 0
>   shmat(0,0,0) suPPS source #0 "/dev/ttyO0" added
> cceeded, segment 0
> gpsd:PROG: NTPD shmat(32769,0,0) succeeded, segment 1
> gpsd:PROG: NTPD shmat(65538,0,0) succeeded, segment 2
> gpsd:PROG: NTPD shmat(98307,0,0) succeeded, segment 3
> gpsd:PROG: PPS thread launched
> gpsd:INFO: NTPD ntpd_link_activate: 1
> gpsd:INFO: stashing device /dev/ttyO0 at slot 0
> gpsd:PROG: no /etc/gpsd/device-hook present, skipped running ACTIVATE hook
> gpsd:INFO: opening read-only GPS data source type 2 and at '/dev/ttyO0'
> gpsd:PROG: PPS Create Thread gpsd_ppsmonitor
> gpsd:PROG: PPS chrony socket /var/run/chrony.ttyO0.sock doesn't exist
> gpsd:INFO: KPPS checking /sys/devices/virtual/pps/pps0/path, /dev/ttyO0
> gpsd:INFO: KPPS caps 1133
> gpsd:WARN: KPPS kernel PPS will be used
> gpsd:PROG: KPPS assert 0.000000000, sequence: 0 - clear
>   946685867.302809818, s1
> gpsd:PROG: KPPS data: using clear
> gpsd:INFO: KPPS cycle: 2060820377, duration:       0 @ 946685867.302809818
> gpsd:INFO: PPS cycle: 2060820434, duration: 2060820434 @ 946685867.302866
> gpsd:PROG: KPPS assert 946685867.402807225, sequence: 1 - clear
>   946685867.30281
> gpsd:PROG: KPPS data: using assert
> gpsd:INFO: KPPS cycle: 2060920375, duration:   99997 @ 946685867.402807225
> gpsd:INFO: speed 4800, 8N1
> gpsd:PROG: no probe matched...

Right here is your answer.  "no probe matched" means it couldn't figure 
out the data stream from your GPS and gave up.  That's why you see no 
data in SHM(0) because there is no valid data to put there.  So the 
first thing to do is figure out what protocol your GPS receiver is 
speaking, then determine if gpsd was compiled for that protocol.


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