From 4e55f7230a93fa32a4c4918dff3ac5a3138bfe43 Mon Sep 17 00:00:00 2001
From: Marcel Moolenaar <marcel@FreeBSD.org>
Date: Fri, 2 Apr 2004 07:37:28 +0000
Subject: [PATCH] In ns8250_putc() insert a barrier between writing the
 character and checking for transmitter empty.

---
 sys/dev/uart/uart_dev_ns8250.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sys/dev/uart/uart_dev_ns8250.c b/sys/dev/uart/uart_dev_ns8250.c
index 44d1304fc149..ae4a3f80a038 100644
--- a/sys/dev/uart/uart_dev_ns8250.c
+++ b/sys/dev/uart/uart_dev_ns8250.c
@@ -304,6 +304,7 @@ ns8250_putc(struct uart_bas *bas, int c)
 	while ((uart_getreg(bas, REG_LSR) & LSR_THRE) == 0 && --limit)
 		DELAY(delay);
 	uart_setreg(bas, REG_DATA, c);
+	uart_barrier(bas);
 	limit = 40;
 	while ((uart_getreg(bas, REG_LSR) & LSR_TEMT) == 0 && --limit)
 		DELAY(delay);