You can slightly improve NTPS's performance by suppressing all the NMEA messages except the one NTPD needs for the time, such as RMC. That way the program does not have to sort through the receive buffer looking for the particular message type it needs, and there is much less traffic on the RS-232 line. Many GPS device manufacturers have manuals that tell how to change the NMEA message output rate. If you have a SiRF or SURE chip, I can help with such a manual.
Charles Elliott > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On > Behalf Of Richard Cagley > Sent: Tuesday, June 18, 2013 2:16 PM > To: A C > Cc: [email protected] > Subject: Re: [ntp:questions] ntpd connect gpsd shared memory driver > > On Tue, Jun 18, 2013 at 11:06 AM, A C <[email protected]> wrote: > > > I suspect you may have a conflict between the kernel attempting to > control > > PPS and gpsd attempting to use it. Try adding "disable kernel" to > the > > ntp.conf to shut off the kernel's use of PPS and see if that wakes up > gpsd. > > If so, your serial driver doesn't want to play nice and share the > DCD line > > between two processes. > > > Yeah, I agree. This definitely seems like the problem. I have pps > support > built into the kernel. Should I remove that support? It's slightly > confusing to me who "controls" the pps line as there are several actors > in > play here...gpsd, ntpd, the kernel. > > With the new entry "disable kernel" in ntpd.conf... > --- > server 127.127.28.0 minpoll 4 maxpoll 4 > fudge 127.127.28.0 time1 0.420 refid GPS > server 127.127.28.1 minpoll 4 maxpoll 4 prefer > fudge 127.127.28.1 refid GPS1 > server clock.redhat.com > server 0.us.pool.ntp.org > server 1.us.pool.ntp.org > server 2.us.pool.ntp.org > server 3.us.pool.ntp.org > disable kernel > --- > I get this after about 5 min... > --- > / # ntpq -p > remote refid st t when poll reach delay offset > jitter > ======================================================================= > ======= > *SHM(0) .GPS. 0 l 14 16 177 0.000 20.062 > 12.250 > SHM(1) .GPS1. 0 l - 16 0 0.000 0.000 > 0.000 > clock1.redhat.c .CDMA. 1 u 56 64 3 81.138 -165.16 > 14.327 > vimo.dorui.net 198.82.1.203 3 u 56 64 3 81.730 -166.40 > 14.743 > soft-sjc-01.ser 64.250.229.100 2 u 56 64 3 12.289 -165.71 > 10.420 > 199.4.29.166 64.113.32.5 2 u 56 64 3 74.375 -162.43 > 11.199 > 66-162-15-65.li 64.236.96.53 2 u 59 64 3 64.446 -159.15 > 10.202 > --- > _______________________________________________ > questions mailing list > [email protected] > http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
