Similar discussion here http://superuser.com/a/528492
I have usb modem (under linux) that needs to be plug/unplugged every time it lost connection, I think this is common problem.
I have done simple research, and I think power-off a usb device is not supported by the kernel, it could ask, but if the device refused to shutdown or the operation is not supported there’s nothing the kernel could do.
My current solution is using homemade python monitoring script, arduino and MOSFET to forcefully power-off the usb modem.
My current problem is since I am using cheap usb hub, the usb hub itself need to be plug/unplugged sometimes
Does pluggable usb hub supports hub-ctrl.c mentioned in the superuser.com link? If it does I could drop my arduino setup.
PS: sorry for my bad english