From: Rasmus Villemoes linux@rasmusvillemoes.dk
When 7c7f9bc986e6 ("serial: Deassert Transmit Enable on probe in driver-specific way") got backported to 5.10.y, there known as 26a2b9c468de, some hunks were accidentally left out.
In serial_core.c, it is possible that the omission in uart_suspend_port() is harmless, but the backport did have the corresponding hunk in uart_resume_port(), it runs counter to the original commit's intention of
Skip any invocation of ->set_mctrl() if RS485 is enabled.
and it's certainly better to be aligned with upstream.
Link: https://lkml.kernel.org/r/20221222114414.1886632-1-linux@rasmusvillemoes.dk Fixes: 26a2b9c468de ("serial: Deassert Transmit Enable on probe in driver-specific way") Signed-off-by: Rasmus Villemoes linux@rasmusvillemoes.dk [the fsl_lpuart part of the 5.15 patch is not required on 5.10, because the code before 26a2b9c468de was incorrectly not calling uart_remove_one_port on failed_get_rs485] Signed-off-by: Dominique Martinet dominique.martinet@atmark-techno.com ---
The part in v2 of the patch still makes sense, so here's just that for 5.10. (I've kept Rasmus as author for the 5.10 version as well, thanks again!)
drivers/tty/serial/serial_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 605f928f0636..40fff38588d4 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2254,7 +2254,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
spin_lock_irq(&uport->lock); ops->stop_tx(uport); - ops->set_mctrl(uport, 0); + if (!(uport->rs485.flags & SER_RS485_ENABLED)) + ops->set_mctrl(uport, 0); ops->stop_rx(uport); spin_unlock_irq(&uport->lock);