如果显示如下：
List of devices attached
???????????? no permissions
就要设置usb
$ lsusb
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 003: ID 413c:2106 Dell Computer Corp.
Bus 002 Device 002: ID 0461:4d81 Primax Electronics, Ltd
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 010: ID 0bb4:0c87 High Tech Computer Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
找到你设备到到usb ID
$sudo vim /etc/udev/rules.d/70-android.rules
SUBSYSTEM=="usb", ATTRS{idVendor}=="0bb4", ATTRS{idProduct}=="0c87",MODE="0666"
ID 0bb4 就是idVendor ，0c87就是 idProduct
$sudo chmod a+rx /etc/udev/rules.d/70-android.rules
$sudo service udev restart
拔掉usb重新连上再执行：
sudo ./adb kill-server
./adb devices
./adb root
List of devices attached ???????????? no permissions
原文：http://www.cnblogs.com/ts-develpoer/p/4390342.html