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authorTony Lindgren <[email protected]>2022-04-11 14:16:57 +0300
committerGreg Kroah-Hartman <[email protected]>2022-04-15 11:42:09 +0200
commitcc994bb97587787b8f0c094a9bc6945d82075b1d (patch)
tree09fabfc205a9364d793f7dd8bab29cf815e19379
parent3ee82c6e41f3d2212647ce0bc5a05a0f69097824 (diff)
serial: 8250: Fix runtime PM for start_tx() for empty buffer
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. This is because serial8250_rpm_put_tx() is now unbalanced on early return, it normally gets called at __stop_tx(). Fixes: 932d596378b0 ("serial: 8250: Return early in .start_tx() if there are no chars to send") Cc: Steffen Trumtrar <[email protected]> Cc: Uwe Kleine-König <[email protected]> Reviewed-by: Johan Hovold <[email protected]> Reviewed-by: Uwe Kleine-König <[email protected]> Signed-off-by: Tony Lindgren <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
-rw-r--r--drivers/tty/serial/8250/8250_port.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 318af6f13605..26f9330094bc 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1675,11 +1675,11 @@ static void serial8250_start_tx(struct uart_port *port)
struct uart_8250_port *up = up_to_u8250p(port);
struct uart_8250_em485 *em485 = up->em485;
- serial8250_rpm_get_tx(up);
-
if (!port->x_char && uart_circ_empty(&port->state->xmit))
return;
+ serial8250_rpm_get_tx(up);
+
if (em485 &&
em485->active_timer == &em485->start_tx_timer)
return;