From 4470f3d596cc20c7dc9a20846eecabe7d58f4a0b Mon Sep 17 00:00:00 2001
From: dg <dg@FreeBSD.org>
Date: Mon, 1 Aug 1994 10:42:26 +0000
Subject: [PATCH] Allow for output processing routine to handle entire
 character buffer and thus not require a sleep/wakeup. Reviewed by: Submitted
 by:

---
 sys/kern/tty.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index ed5724d77e00..fd3c051a50c1 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1531,8 +1531,10 @@ ovhiwat:
 		uio->uio_resid += cc;
 		return (uio->uio_resid == cnt ? EWOULDBLOCK : 0);
 	}
-	SET(tp->t_state, TS_ASLEEP);
-	error = ttysleep(tp, &tp->t_outq, TTOPRI | PCATCH, ttyout, 0);
+	if (tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) {
+		SET(tp->t_state, TS_ASLEEP);
+		error = ttysleep(tp, &tp->t_outq, TTOPRI | PCATCH, ttyout, 0);
+	}
 	splx(s);
 	if (error)
 		goto out;