Commit 932d596378b0 ("serial: 8250: Return early in .start_tx() if there
are no chars to send") caused a regression where the drivers implementing
runtime PM stopped idling.
We need to call serial8250_rpm_put_tx() on early exit, it normally gets
called later on at __stop_tx().
Fixes: 932d596378b0 ("serial: 8250: Return early in .start_tx() if there are no chars to send")
Cc: Steffen Trumtrar <s.trumtrar@xxxxxxxxxxxxxx>
Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_port.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1677,8 +1677,10 @@ static void serial8250_start_tx(struct uart_port *port)
serial8250_rpm_get_tx(up);
- if (!port->x_char && uart_circ_empty(&port->state->xmit))
+ if (!port->x_char && uart_circ_empty(&port->state->xmit)) {
+ serial8250_rpm_put_tx(up);
return;
+ }
if (em485 &&
em485->active_timer == &em485->start_tx_timer) {
--
2.35.1
