Commit 7f9803072ff6 ("serial: 8250: Support console on software emulated
rs485 ports") amended serial8250_console_write() with rs485 support, but
positioned the invocation of ->rs485_stop_tx() after re-enablement of
interrupts. The irq handler and ->console_write() are serialized with
the port spinlock, so no problem there, but due to the rs485 delay, the
irq handler may unnecessarily spin for a while. Avoid that by moving
->rs485_stop_tx() before re-enablement of interrupts, which also mirrors
the order at the beginning of serial8250_console_write().
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
v2:
fix hash of referenced commit
drivers/tty/serial/8250/8250_port.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index a1d3aef3c406..f77bf820b7a3 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3268,7 +3268,6 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
* and restore the IER
*/
wait_for_xmitr(up, BOTH_EMPTY);
- serial_port_out(port, UART_IER, ier);
if (em485) {
mdelay(port->rs485.delay_rts_after_send);
@@ -3276,6 +3275,8 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
up->rs485_stop_tx(up);
}
+ serial_port_out(port, UART_IER, ier);
+
/*
* The receive handling will happen properly because the
* receive ready bit will still be set; it is not cleared
--
2.25.0
