Stuck glass, lifter cables come off or some other fault with them, door control module or motor itself faulty. All possible. Take the panel off the door if not already, try unplugging and replugging each electrical plug to wipe the contacts.Take off the motor and controller then the inner aluminium door trim and look at the cables that run round the lower frame to operate the window with a good torch. May even help to look at the passenger side to help spot anything wrong. Try swapping the motor door control units to see if that cures it. Could just be a faulty switch but doen't look like it. You never said if the window rises and falls or if it is stuck somewhere in between.