Re: GSM modem via Bluetooth?

[Dan Williams <dcbw redhat com>]

On Tue, 2011-01-11 at 17:49 +0000, Bastien Nocera wrote:
> On Thu, 2011-01-06 at 13:16 -0600, Dan Williams wrote:
> <snip>
> > I spend some time on this over the holidays to figure out what it would
> > take for manually started rfcomm ports to show up as Bluetooth modems
> > and be configurable without the BT wizard.
> 
> You'll still need to pair the device at some point anyway.
> 
> >   The short answer is that
> > yes, this is possible, though it's somewhat icky.  But even if NM
> > exported the device as a Bluetooth modem, you'll still need connection
> > details (APN, username, password) before you can ask NM to connect the
> > device.
> 
> Exactly.
> 
> > I'll look into further cleaning up the proof-of-concept patches I did
> > and see if they can be merged in some form in the near future.
> 
> I think that this is probably best left alone until someone implements
> Bluetooth line discipline in pppd and the Linux kernel directly, so that
> reliance on rfcomm, or creation of "serial ports" through bluetoothd is
> unneeded.
> 
> If you want to be able to use the /dev/rfcomm devices directly, I'd
> recommend making this "hard" to setup, so that people don't try and use
> it as the main way to create a connection to their device, rather as a
> debugging method (wrong Bluetooth port used for example).
> 
> Creating an rfcomm device, making sure it stays across reboots, and
> making sure it points to the right port (which has absolutely no
> guarantees of staying the same across enabling/disabling the feature on
> the device), is a sure way to break things, and requires root access.

It's more for KDE, which doesn't have a bluetooth wizard that does the
same thing as the Gnome applet.  Ideally, KDE should get that
functionality, but making already-paired-but-unconfigured devices show
up as NM bluetooth devices would let the kde bits at least configure the
device.

I don't think it's very useful to have a raw rfcomm port show up as
non-bluetooth device though (ie, a USB 3G stick) because then you have
to start up the rfcomm port every single time manually.  That sucks, and
the real fix there is to either (1) get a bluetooth wizard if you don't
have one, or (2) modify the applet you're using to be able to create new
BT DUN configs if NM presents the device.  The patches I did would do
#2, which could also be useful in Gnome if you didn't check the boxes at
the end of pairing for some reason.

Dan