I am using Debian 8.1, Android Studio 1.2.2 and a rooted Android TV Box with Android 4.2.2
Now I am trying to connect the TV Box to Android Studio via LAN, to directly test the app that I am developing.
My PC and the Android Box are in the same network. Also I can connect to the box in the Linux-console via:
adb connect 192.168.50.104
connected to 192.168.50.104:5555
I finally found the solution to the problem.
On the linux system I renamed the adb that came with the package-manager
cd /usr/bin/ sudo mv adb backup_adb
Then I created a symlink to the adb, that is provided with the Android Studio SDK:
sudo ln -s ~/Android/Sdk/platform-tools/adb /usr/bin/adb
Restart adb and reconnect to the device and it finally shows up in Android Studio.
Instead of renaming the adb-file you could probably just remove it, with your package manager.