ref: a8361bc1b4b71a2ee495b23cfca1f03b5a844f28
dir: /sys/src/cmd/nusb/usbd/fns.h/
void attachdev(Dev*); void detachdev(Dev*); void work(void); Hub* newhub(char *, Dev*); int hname(char *); void assignhname(Dev *dev); void checkidle(void); int portfeature(Hub*, int, int, int);