Comment 18 for bug 1072118

After some more investigations I can come up with this consistent behaviour:

If I reboot the laptop of with bluetooth enabled, it will come up the next time working. Working means the status is correctly recognized by the Kubuntu applet and bluetooth is working.

If I disable Bluetooth, the hardware display on the laptop remains lit. In Kubuntu 12.04, the display went off. However, the device is properly unpowered, as it saves 4 Watts (checked with meter). After reboot, the state is correctly remembered, that means the device is unpowered (the hardware indication is still lit btw.) However, the bluetooth icon in panel will recognize the adapter as powered. Unpowering has no effect and doesn't work: If I choose unpower in the applet, simply nothing happens, it remains thinking it is still powered, while it is unpowered. In other words, there is not way to power bluetooth with the applet.

service bluetooth stop
service bluetooth start

will not bring bluetooth back ... it will remain unpowered and the applet thinking it is powered.

However, issuing

sudo hciconfig hci0 reset

WILL power bluetooth AND the applet back working, so that it can be powered / unpowered.

So I think the bluetoothd stack doesn't recognize the unpowered adapter, yet correctly remains it unpowered (state keeps preserved).