[PATCH V1] serial: qcom_geni: Disable closing_wait for console to prevent shutdown timeout

[Aniket Randive]

During system power-off, systemd closes the console UART and blocks in
tty_wait_until_sent() waiting for pending TX completion before
uart_shutdown() can cancel pending TX operations. With the default
closing_wait of 30s, this causes a watchdog reset when systemd is
responsible for watchdog feeding.

Set closing_wait to ASYNC_CLOSING_WAIT_NONE in startup() for console
ports to bypass tty_wait_until_sent() on close, allowing uart_shutdown()
to cancel TX commands cleanly. This change doesn't impact regular ports
functionality.

Signed-off-by: Aniket Randive <aniket.randive@xxxxxxxxxxxxxxxx>
---
 drivers/tty/serial/qcom_geni_serial.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 7ead87b4eb65..3d3bed0923eb 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -1245,6 +1245,7 @@ static int qcom_geni_serial_startup(struct uart_port *uport)
 {
 	int ret;
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	struct tty_port *tport = &uport->state->port;
 
 	if (!port->setup) {
 		ret = qcom_geni_serial_port_setup(uport);
@@ -1252,6 +1253,13 @@ static int qcom_geni_serial_startup(struct uart_port *uport)
 			return ret;
 	}
 
+	/*
+	 * Skip the close-time transmit drain for console ports so that
+	 * shutdown can proceed without waiting for pending TX completion.
+	 */
+	if (uart_console(uport))
+		tport->closing_wait = ASYNC_CLOSING_WAIT_NONE;
+
 	uart_port_lock_irq(uport);
 	qcom_geni_serial_start_rx(uport);
 	uart_port_unlock_irq(uport);
-- 
2.34.1