Windows7在安全移除USB设备后自动切断其电源

1. 定位到如下注册表位置

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\usbhub

2. 在usbhub里面新建一个键值项hubg
3. Now within hubg make a new DWORD (32-bit) called DisableOnSoftRemove. To do this right click the empty right pane and select New >> DWORD (32-bit) Value.
4. Now open up the new DWORD and change the value data to 1 – Hexadecimal. You can do this by double-clicking the DWORD or right-click it and selecting Modify. Click OK to save and exit.

参考：
https://www.groovypost.com/howto/windows-safely-remove-usb-devices-power-off/
https://support.microsoft.com/zh-cn/help/2401954/usb-port-remains-active-for-disabled-or-safely-removed-usb-device