serial: imx: always wake up the processes in the TX callback

The current code only wakes up the processes when the circle
buffer has less data then the WAKEUP_CHARS.

But sometimes, the circle buffer may has data more then the WAKEUP_CHARS,
in such case, the processes will hang.

This patch makes it always wakes up the processes in the TX callback.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index d799140..dff0f0a 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -496,8 +496,7 @@ static void dma_tx_callback(void *data)
 
        dev_dbg(sport->port.dev, "we finish the TX DMA.\n");
 
-       if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
-               uart_write_wakeup(&sport->port);
+       uart_write_wakeup(&sport->port);
 
        if (waitqueue_active(&sport->dma_wait)) {
                wake_up(&sport->dma_wait);