[maemo-users] what exactly is the GPS management framework for N810?

From: Joshua Layne joshua at willowisp.net
Date: Mon Dec 10 20:40:24 EET 2007
I am continuing to have problems with the gps functionality on my N810. 
Please note the use of "functionality" here - from everything I can tell,
the gps hardware works fine - this looks to be a firmware/driver bug or a
problem somewhere else in the management stack of the gps 'subsystem'

The problem is this:
When newly booted, the GPS works basically fine - seems to take a little
long to get a fix, but workable.  If I then shut the GPS off (using the
panel applet, or by closing the map application.  When I try to start the
GPS back up, I get nothing.  A `cat /dev/pgps` gives absolutely nothing, so
there is a problem somewhere in the stack, not with getting a fix - when
the gps is activated and gpsd is running, /dev/pgps should ALWAYS be
emitting some form of data.  Correct me if I'm wrong.

`killall -HUP gpsdriver`
`killall -HUP gpsd`

do not solve the problem.  A reboot does (although sometimes the reboot
doesn't seem to entirely 'take' and has to be repeated)

My understanding of the gps stack (from forums and `ps -aef|grep gps` is:
SirfIII gps hardware

gpsd 1.0-23 (osso branded) (/usr/sbin/gpsd -n -N -F /tmp/.gpsd_ctrl_sock
/dev/pgp) -- I believe it is really "/dev/pgps" and is being truncated for
some reason in ps

gpsdriver (?proprietary? - no help available for runtime parametes) --

[gpsd] -- ?what is this?  I have never seen anything like this with gpsd on
other systems

/usr/libexec/navicore-gpsd-helper (bundled 3rd party binary app that kick
starts the gps unit) OR the control panel applet.

How can I trace what is going when the gps subsystem fails?  Do I actually
have a bad unit?  I'm past the return from where I bought it so this would
be a warranty issue, but I really think it is a bug somewhere in the
software stack, not a problem in the hardware.

I would appreciate any pointers on troubleshooting this - when the GPS
works, it is great, but it is _extremely_ frustrating to have these kind of
issues on a $450 device.

Also, if there is (or can be made) any documentation available for how to
programmatically interface to the gps, that would be very helpful.  I did
not buy this unit for the built in mapping program and have no intention of
using it - I want to be able to control the gps (including power on and
power off) from the OS (and not using GUI applets or binary-only 3rd party

Thanks in advance,

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