serial_core might call the .start_tx callback without any data being
available to send. In this case return early instead of going through
all the setup needed for sending which might include disabling RX in
RS485 half-duplex mode.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/tty/serial/imx.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 28eccc0ba344..849c28efbe64 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -652,6 +652,9 @@ static void imx_start_tx(struct uart_port *port)
struct imx_port *sport = (struct imx_port *)port;
unsigned long temp;
+ if (!sport->port.x_char && uart_circ_empty(&port->state->xmit))
+ return;
+
if (port->rs485.flags & SER_RS485_ENABLED) {
temp = imx_uart_readl(sport, UCR2);
if (port->rs485.flags & SER_RS485_RTS_ON_SEND)
--
2.16.1
--
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