In 11.04 and before, I could do all operations to my Sony-ericsson phone including using it as a 3G Internet interface. This can still be demonstrated by using a live CD.
The first problem with 11.10 was that once the 3G Internet interface was used, the computer would no longer suspend or hibernate because "bluetoothd" would not "freeze" after 20 seconds of trying.
However, since around the end of December, the only bluetooth function that works is "send file to device". Any attempt to connect the network from the network manager icon or to connect or browse from the bluetooth icon silently fails. Dmesg reveals nothing in these cases; I don't know what other logs I should look at.
I tried rebooting with the previous kernel (3.0.0-13) but it behaved the same as the new one (3.0.0-14).