Re: MM Location API and MBM GPS

[Sjoerd Simons <sjoerd simons collabora co uk>]

On Tue, 2010-09-07 at 17:38 +0100, Bastien Nocera wrote:
> On Sun, 2010-09-05 at 15:15 +0100, Sjoerd Simons wrote:
> > Comments, suggestions, flames ? :)
> 
> Dan, rightly so, didn't like the idea of just handing out a socket to
> Gypsy. There are multiple reasons for that:
> - you want MM to still have complete control over the ports offered

reasonable point, in this case the port isn't used by MM for any of its
functionality so handing it out to an accomplish isn't so bad.

> - it would make it hard to push vendor specific hacks to Gypsy

I don't understand what you mean here.

> - a lot of modems don't actually give you NMEA data at all, so it
> wouldn't make sense to parse the proprietary format, put it into NMEA,
> just to have it parsed again

Well sure, this wouldn't be something that suitable for all modems (i
never said it would be a general mechanism). But the specific modem i'm
looking at (which is quite common) does actually have a real actual full
GPS hidden in its guts, you just have to poke it a bit so it comes out
of hiding.

It seems pointless to re-implement the functionality to read an NMEA
stream out of a serial port when we already have Gypsy that does this
nicely for us (and parses it and exposes it over dbus etc). 

One could go for a middle ground where MM reads from the serial device
and passed the nmea stream over a unix socket or whatever to Gypsy.
(This means MM is in full control, we don't cause loads of dbus traffic
and we can let Gypsy do what it's good at).

> The right way to implement this would be through a Geoclue provider,
> which you could hit directly from your application if you're so
> enclined, or just let it be one more provider amongst others.

A Geoclue provider is great and all (oh look there is already one for
gypsy :p), but it doesn't expose all the information you get from a GPS.
And neither should it, things like satelite position and signal quality
will only ever be useful in the context of GPS. So abstracting that in
geoclue doesn't make much sense to me, Gypsy already has those
abstractions for us so we should just use them.

-- 
Sjoerd Simons <sjoerd simons collabora co uk>
Collabora Ltd.