I have a Nexus 6 device with Android 6.0, stock version without root. To avoid to permanently connect device with usb cable i used this procedure:
- I connected the device by USB cable to PC
 - type on terminal 
adb tcpip 5555. - type 
adb connect <device-ip>:5555to connect in wifi mode. 
When i try to deploy an app from Android Studio, the connection is lost.
I used this procedure many times and with other devices (without Android 6) and i have no problem.
Any idea?