diff options
Diffstat (limited to 'include/linux/tty_ldisc.h')
| -rw-r--r-- | include/linux/tty_ldisc.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h index e85002b56752..ede6f2157f32 100644 --- a/include/linux/tty_ldisc.h +++ b/include/linux/tty_ldisc.h @@ -186,6 +186,18 @@ int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass, * indicate all data received is %TTY_NORMAL. If assigned, prefer this * function for automatic flow control. * + * @lookahead_buf: [DRV] ``void ()(struct tty_struct *tty, + * const unsigned char *cp, const char *fp, int count)`` + * + * This function is called by the low-level tty driver for characters + * not eaten by ->receive_buf() or ->receive_buf2(). It is useful for + * processing high-priority characters such as software flow-control + * characters that could otherwise get stuck into the intermediate + * buffer until tty has room to receive them. Ldisc must be able to + * handle later a ->receive_buf() or ->receive_buf2() call for the + * same characters (e.g. by skipping the actions for high-priority + * characters already handled by ->lookahead_buf()). + * * @owner: module containting this ldisc (for reference counting) * * This structure defines the interface between the tty line discipline @@ -229,6 +241,8 @@ struct tty_ldisc_ops { void (*dcd_change)(struct tty_struct *tty, unsigned int status); int (*receive_buf2)(struct tty_struct *tty, const unsigned char *cp, const char *fp, int count); + void (*lookahead_buf)(struct tty_struct *tty, const unsigned char *cp, + const unsigned char *fp, unsigned int count); struct module *owner; }; |