Solutions for Ubuntu and Windows adb device no permissions

I have been under windows and Ubuntu have encountered the Android device is not recognized, when the run as Android application, target display "??????", using ADB devices to view the status of the device, display

List of devices attached
???????????? No permissions

There are a lot of solutions on the internet for Ubuntu, some people say because of the USB permissions, the problem

Enter sudo lsusb to find your USB device, locate your device file in the/etc/udev/rules.d/directory, and add a piece of code.

I have tried many times to find that this is not the case, the actual reason, should be the same as Windows, port is occupied.

Workaround.

Input sudo adb kill-server

Then sudo adb start-server

The following paragraph appears

* Daemon not running. Starting it now on Port 5037 *
* Daemon started successfully *

Then enter ADB devices

Discover device online Problem solving!

Solutions for Ubuntu and Windows adb device no permissions