Re: [gpsd-dev] Possible error report

[Eric S. Raymond]

Sanjeev Gupta <address@hidden>:
> This is based on a git snapshot as of 1400 UTC Thursday.  Build and run is
> on an up-to-date Ubuntu Precise.  GPS device is a new GR601-W (thanks,
> Gary).
> 
> (First tested with gpsd 3.4, which is the latest version on Precise.  All
> works well, device reported as Generic NMEA.  I then purged the gpsd and
> associated packages).
> 
> The scons build and install into /usr/local seems to have gone well.
> 
> When I run gpsd, all seems well.  See attached output at
> https://www.dropbox.com/s/bv4jlxfszu0ibh0/gpsd.txt .  gpsd was run as:
>    gpsd -N /dev/ttyUSB0 -D 4
> 
> 
> The gpsmon output, however, is strange.  I have a (approx 3MB) video
> capture of the screen output, at
> https://www.dropbox.com/s/5freiybtywawsch/out-2.ogv .  Note how information
> appears and disappears.  gpsmon status at the top does say "uBlox".  BTW,
> the values it reports on the left are also wrong.
> 
> What have I done wrong?

Nothing.  You've tripped over a misfeature of the GR601-W; I have a bit set
to poke Navisys to fix it in future production.

The GR-601-W has a half-assed reaction to an attempt to switch it to
binary-only mode, which gpsd does as soon as it recognizes the chip as
a u-blox. On the GR-601-W you can turn on binary but you can't turn off
ASCII.

This used to cause gpsd to flap back and forth between u-blox and NMEA
modes as packets of different types came in.  I fixed that recently,
but for reasons I don't completely understand gpsmon sometimes still
flaps.  I'll look into it, but the problem is no longer serious enough
to be a pre-3.10 issue.

This is a purely cosmetic glitch, limited to gpsmon - as you note,
conventional clients don't see it.  If you unplug the GR601-W it will
reset to its default NMEA-only mode; running gpsmon on that is
well-behaved until gpsd tries to mode-switch it to binary again.

My EVK 6H eval box, using the same LEA 6H module, doesn't exhibit this
problem, because the ability to switch off NMEA has not been disabled.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>