From 9d46ae69a724aeccf841a403e5bdee263728c482 Mon Sep 17 00:00:00 2001
From: Bernard Xiong <bernard.xiong@gmail.com>
Date: Tue, 10 Nov 2015 10:24:35 +0800
Subject: [PATCH] [DeviceDrivers] fix the poll_rx issue in serial when there is
 no data.

---
 components/drivers/serial/serial.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index 3bae89c740..2cb298d7ff 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -29,6 +29,7 @@
  * 2014-12-31     bernard      use open_flag for poll_tx stream mode.
  * 2015-05-19     Quintin      fix DMA tx mod tx_dma->activated flag !=RT_FALSE BUG 
  *                             in open function.
+ * 2015-11-10     bernard      fix the poll rx issue when there is no data.
  */
 
 #include <rthw.h>
@@ -49,6 +50,8 @@ rt_inline int _serial_poll_rx(struct rt_serial_device *serial, rt_uint8_t *data,
     while (length)
     {
         ch = serial->ops->getc(serial);
+        if (ch == -1) break;
+
         *data = ch; 
         data ++; length --;