struct tty_struct *tty, int irq);
extern int parse_chan_pair(char *str, struct line *line, int device,
const struct chan_opts *opts, char **error_out);
-extern int open_chan(struct list_head *chans);
extern int write_chan(struct list_head *chans, const char *buf, int len,
int write_irq);
extern int console_write_chan(struct list_head *chans, const char *buf,