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