HOWTO: scons gpsd build incorrect and ntpshmmon gives no data

Gary E. Miller gem at
Wed Aug 8 04:01:15 UTC 2018


On Wed, 8 Aug 2018 03:15:54 +0000 (UTC)
MIKE MAJOR via devel <devel at> wrote:

> In the HOWTO section "Live-test the GPS", the reader is instructed to
> build gpsd using: $scons timeservice=yes magic_hat=yes nmea0183=yes
> fixed_port_speed=9600 fixed_stop_bits=1

Not really.  That is just an eplanation for what clockmaker --build

> When running gpsmon /dev/gpsd0, it is expected that there are
> scrolling lines at the bottom showing raw data. I didn't get that.

Not good.  Is your GPS really on /dev/gpsd0?  Is your GPS running

> Cross checking with the clockmaker script showed that 2 options are
> missing from the HOWTO text: ublox=yes mtk3301=yes

Not really.  The script is for NMEA mode.  To keep things simple.

> I did a scons --clean and rebuilt adding the 2 options and voila,
> scrolling raw data at the bottom. 

Fair enough, but not the intent of the script.

> Paul, can you submit a fix for that too?

No fix here.  Just something different.  Something not intended
by the clockmaker script.

> Here is where I hit the hard stop. Upon running ntpshmmon, there is
> no data available.

That is usually because gpsd not started as root.

Debug it this way:

# killall gpsd
{ wait 2 seconds ]
# gpsd -nND 4 /dev/gpsd0 |& fgrep PPS

> I am performing all steps by hand and checking against the clockmaker
> script. The script installs some s/w packages that the reader has not
> been instructed to do at this point in the HOWTO text.

The point is that the reader NOT install them, but have clockmaker
install them.

> Oh yeah, one question: debian stretch offers the gspd package. We
> could just perform apt install gpsd. Why do we build from source? 

Because the options in Debian are different than the clockmaer options.
The script is for RaspBian, not for Debian.  The secret agenda of
the clockmaker script is to introduce the reader to git, building from
source, etc.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin
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