diff --git a/drivers/serial/serial_dma.c b/drivers/serial/serial_dma.c
index a638ac4c292..7e831c97e32 100644
--- a/drivers/serial/serial_dma.c
+++ b/drivers/serial/serial_dma.c
@@ -206,10 +206,13 @@ void uart_xmitchars_done(FAR uart_dev_t *dev)
       /* Move tail for nbytes. */
 
       txbuf->tail  = (txbuf->tail + nbytes) % txbuf->size;
-      xfer->nbytes = 0;
-      xfer->length = xfer->nlength = 0;
     }
 
+  /* Reset xmit buffer. */
+
+  xfer->nbytes = 0;
+  xfer->length = xfer->nlength = 0;
+
   /* If any bytes were removed from the buffer, inform any waiters there
    * there is space available.
    */