From 16ae2a877bf4179737921235e85ceffd7b79354f Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 4 Jan 2010 16:26:21 +0000
Subject: [PATCH] serial: Fix crash if the minimum rate of the device is > 9600
 baud

In that situation if the old rate is invalid and the new rate is invalid
and the chip cannot do 9600 baud we report zero, which makes all the
drivers explode.

Instead force the rate based on min/max

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/serial/serial_core.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index fa4f170f2e86..7f2830709512 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -385,13 +385,20 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 		}
 
 		/*
-		 * As a last resort, if the quotient is zero,
-		 * default to 9600 bps
+		 * As a last resort, if the range cannot be met then clip to
+		 * the nearest chip supported rate.
 		 */
-		if (!hung_up)
-			tty_termios_encode_baud_rate(termios, 9600, 9600);
+		if (!hung_up) {
+			if (baud <= min)
+				tty_termios_encode_baud_rate(termios,
+							min + 1, min + 1);
+			else
+				tty_termios_encode_baud_rate(termios,
+							max - 1, max - 1);
+		}
 	}
-
+	/* Should never happen */
+	WARN_ON(1);
 	return 0;
 }
 
-- 
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