I am experiencing an issue where my phone ( an actually physical device) has become a ghost device in adb. even when not connect I receive:
adb devices
List of devices attached
xxxxxxxxxxxxxxxx no permissions
I have run kill-server as well as rebooted several times (for other reasons). The real problem with this is that I can no longer connect my device to adb ( except by wireless-adb which is a pain.
I found this post Ghost devices in adb devices in which a terrible workaround in accepted, and its for windows plus my problem is that my physical device is the ghost id not an emulator.
Update just tried adb disconnect xxxxxxxxxxxxxxxx
and got no such device error
Found this http://www.janosgyerik.com/adding-udev-rules-for-usb-debugging-android-devices/
somehow my udev rules had changed