Comment 8 for bug 583728

Yes, in fact it is a kernel bug.

Working with 3.15.6 from the ppa mainline, modemmanager can see the modem and you can connect.

So, if you really need bluetooth DUN, just move to a recent kernel.

Unfortunately it is not really enough, because after you have fixed the kernel bug, you can start having fun with the modemmanager/networkmanager bugs, and after the first connection you cannot reconnect anymore.

This is because after you ask network manager to drop the connection, for some funny reason the modemmanager/networkmanager/bluetooth stack does not drop the rfcomm connection. Conversely, it re-asks the phone for coupling permission and when this is granted it happily keeps the connection open, pinging the phone all the time to try to inquire about the signal quality level. Pure evil, since it certainly helps your phone battery to drain faster.

But do not fear, because with a couple of user friendly moves you can fix this too.

Get a console, become root, switch off the modemmanager

service modemmanager stop

then on again

service modemmanager start

and you are ready for another (just one!) bluetooth dun connection. Then, do not forget to get the console to reboot the modemmanager and be ready to start one more time.

Now, really... all this stuff is far too buggy for the average user. Please, hide it.