From 35b46c174ca0b97bf69ecb57511641641ba86247 Mon Sep 17 00:00:00 2001
From: Bruce Evans <bde@FreeBSD.org>
Date: Mon, 31 Jul 1995 22:48:46 +0000
Subject: [PATCH] Obtained from:	partly from ancient patches of mine via 1.1.5

Handle MDMBUF a little better.  Prepare to handle 4 different kinds of
output flow control.
---
 sys/kern/tty.c | 8 ++++++--
 sys/sys/tty.h  | 9 ++++++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index f271101f47db..7db76e15747a 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tty.c	8.8 (Berkeley) 1/21/94
- * $Id: tty.c,v 1.63 1995/07/31 21:01:23 bde Exp $
+ * $Id: tty.c,v 1.64 1995/07/31 21:43:37 bde Exp $
  */
 
 /*-
@@ -1297,11 +1297,15 @@ ttymodem(tp, flag)
 	if (ISSET(tp->t_state, TS_CARR_ON) && ISSET(tp->t_cflag, MDMBUF)) {
 		/*
 		 * MDMBUF: do flow control according to carrier flag
+		 * XXX TS_CAR_OFLOW doesn't do anything yet.  TS_TTSTOP
+		 * works if IXON and IXANY are clear.
 		 */
 		if (flag) {
+			CLR(tp->t_state, TS_CAR_OFLOW);
 			CLR(tp->t_state, TS_TTSTOP);
 			ttstart(tp);
-		} else if (!ISSET(tp->t_state, TS_TTSTOP)) {
+		} else if (!ISSET(tp->t_state, TS_CAR_OFLOW)) {
+			SET(tp->t_state, TS_CAR_OFLOW);
 			SET(tp->t_state, TS_TTSTOP);
 #ifdef sun4c						/* XXX */
 			(*tp->t_stop)(tp, 0);
diff --git a/sys/sys/tty.h b/sys/sys/tty.h
index e3206ff5b5c8..99568d4979c0 100644
--- a/sys/sys/tty.h
+++ b/sys/sys/tty.h
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tty.h	8.6 (Berkeley) 1/21/94
- * $Id: tty.h,v 1.28 1995/07/31 19:17:19 bde Exp $
+ * $Id: tty.h,v 1.29 1995/07/31 21:02:00 bde Exp $
  */
 
 #ifndef _SYS_TTY_H_
@@ -159,6 +159,13 @@ struct tty {
 #define	TS_SO_OCOMPLETE	0x080000	/* Wake up when output completes. */
 #define	TS_ZOMBIE	0x100000	/* Connection lost. */
 
+/* Hardware flow-control-invoked bits. */
+#define	TS_CAR_OFLOW	0x200000	/* For MDMBUF (XXX handle in driver). */
+#ifdef notyet
+#define	TS_CTS_OFLOW	0x400000	/* For CCTS_OFLOW. */
+#define	TS_DSR_OFLOW	0x800000	/* For CDSR_OFLOW. */
+#endif
+
 /* Character type information. */
 #define	ORDINARY	0
 #define	CONTROL		1