0a5c:2100 Broadcom Corp. Bluetooth 2.0+eDR dongle not working
Open up a terminal from Applications -> Accessories. Type:
sudo gedit /etc/modules
At the bottom of the file, make two new lines, like this:
usbserial
option
Then close the editor program and save it. Reboot the computer and hopefully you’ll be right from now on!
This worked for me
sudo hciconfig hci0 reset
Source : https://askubuntu.com/a/204427/69743
Running Gnome-Ubuntu 13.10