[Thumbgps-devel] USB handshake signals and Linux

[Eric S. Raymond]

tz <tz2026 at gmail.com>:
> The problem is that if I hook up an Arduino (on most Distros including
> gpsd or even gpsd installed new), gpsd fires up and tries probing.

Yes, I know.  There's no help for this short of disabling GPSD autostart
by udev.  That would hurt a lot more people (as in, everybody who wants
to just plug in a USB GPS and go) than it would help. 
 
> My argument is not with the others with unique ids (vendor/product)
> but the one with the plain, default vendor/product ID that is on by
> default in udev (instead of commented out with a note).

You apparently don't quite get it yet (no blame, this stuff is ugly
and obscure). There are *no* "unique" VID/PID pairs for GPSes. All the
VID/PID pairs in gpsd.rules do is recognize USB-to-serial adapters,
because that's all that can be done.  GPSD has no way to know what the
device on the other side of the adapter is - it starts on the premise
that the thing might be a GPS, then releases the device if it fails to
recognize GPS packets over the wire.

> It would also be nice if it would autoconfigure which pin/pins were
> used.  You could enable it and then use something to figure out which
> pin (or enable change on any of them?).

Hm, that's an interesting idea.  Enabling change on any of them would
fit our design philosophy.  ckuethe, are you listening?  Can you think
of any reason this might break something?
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>