ref: 7d88d76bc42e2b3f3cabde82673af4107e951797
dir: /sys/src/cmd/nusb/usbd/fns.h/
int attachdev(Port*); void detachdev(Port*); void work(void); Hub* newhub(char *, Dev*); int hname(char *); void assignhname(Dev *dev); void checkidle(void); int portfeature(Hub*, int, int, int);