serial.c: Fix an error in FIONWRITE calculation

2016-07-26 06:47:53 -06:00 · 2016-07-26 06:47:53 -06:00 · eaaa69da0a
parent 312e30026b
commit eaaa69da0a
1 changed files with 1 additions and 1 deletions
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@ -946,7 +946,7 @@ static int uart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)

              /* Determine the number of bytes waiting in the TX buffer */

-              if (dev->xmit.head < dev->xmit.tail)
+              if (dev->xmit.tail <= dev->xmit.head)
                {
                  count = dev->xmit.head - dev->xmit.tail;
                }