I configured ntpd on my system like so:
~$ cat /etc/ntp.conf
# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help
driftfile /var/lib/ntp/ntp.drift
logfile /var/log/ntp.log
statsdir /var/log/ntpstats/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
server 0.de.pool.ntp.org
server 1.de.pool.ntp.org
server 2.de.pool.ntp.org
server 3.de.pool.ntp.org
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 127.0.0.1
restrict ::1
server 127.127.8.0 mode 2 # standard time string with 9600, 7E2
# gpsd
server 127.127.28.0
fudge 127.127.28.0 refid GPSa
server 127.127.28.1
fudge 127.127.28.1 refid GPSp
ntpq tells me that ntpd gets the time from gps as desired:
~$ ntpq -c peers
remote refid st t when poll reach delay offset jitter
==============================================================================
-ns2.bvc-cloud.d 192.53.103.104 2 u 64 64 177 14.959 155.440 113.066
+mail.danzuck.eu 192.53.103.104 2 u - 64 377 10.176 -54.295 129.782
-ntp01.cc-netzwe 240.67.35.84 3 u 65 64 177 13.674 63.774 64.264
-server2.as2.ch 131.188.3.223 2 u 59 64 177 14.758 87.117 67.824
*GENERIC(0) .DCFa. 0 l 2 64 3 0.000 -65.610 0.733
+SHM(0) .GPSa. 0 l 323 64 140 0.000 -18.353 12.003
SHM(1) .GPSp. 0 l - 64 0 0.000 0.000 0.000
So obivously gpsd must be running. However ntpd does not get the pps signal. Is this to be expected for an USB GPS? That is: should I remove the configuration for GPSp? If not so: how can I find out why it fails?