ref: 3a47c8bfbe9298fed2b6dcc5ac19a7af4c96c52f 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 checkidle(void);