From b83cea4f99b4fdba28cf7a57114d86955c19c39d Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Fri, 13 Mar 2015 10:40:09 -0600
Subject: [PATCH] Back out 70cb75adaf3243478276cebf367c5f47c4725715

---
 drivers/serial/serial.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index d9f161b18a..b2719e62a2 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -877,7 +877,7 @@ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
                 }
               else
                 {
-                  count = dev->xmit.size - (dev->xmit.head - dev->xmit.tail);
+                  count = dev->xmit.size - (dev->xmit.head - dev->xmit.tail) - 1;
                 }
 
               irqrestore(state);