This is a note to let you know that I've just added the patch titled

serial: 8250_fintek: Fix rs485 disablement on invalid ioctl()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: serial-8250_fintek-fix-rs485-disablement-on-invalid-ioctl.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Dec 6 16:43:17 CET 2017

From: Lukas Wunner lukas@wunner.de Date: Sat, 28 Oct 2017 11:35:49 +0200 Subject: serial: 8250_fintek: Fix rs485 disablement on invalid ioctl()

From: Lukas Wunner lukas@wunner.de

[ Upstream commit 3236a965486ba0c6043cf2c7b51943d8b382ae29 ]

This driver's ->rs485_config callback checks if SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND have the same value. If they do, it means the user has passed in invalid data with the TIOCSRS485 ioctl() since RTS must have a different polarity when sending and when not sending. In this case, rs485 mode is not enabled (the RS485_URA bit is not set in the RS485 Enable Register) and this is supposed to be signaled back to the user by clearing the SER_RS485_ENABLED bit in struct serial_rs485 ... except a missing tilde character is preventing that from happening.

Fixes: 28e3fb6c4dce ("serial: Add support for Fintek F81216A LPC to 4 UART") Cc: Ricardo Ribalda Delgado ricardo.ribalda@gmail.com Cc: "Ji-Ze Hong (Peter Hong)" hpeter@gmail.com Signed-off-by: Lukas Wunner lukas@wunner.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_fintek.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/tty/serial/8250/8250_fintek.c +++ b/drivers/tty/serial/8250/8250_fintek.c @@ -117,7 +117,7 @@ static int fintek_8250_rs485_config(stru

if ((!!(rs485->flags & SER_RS485_RTS_ON_SEND)) == (!!(rs485->flags & SER_RS485_RTS_AFTER_SEND))) - rs485->flags &= SER_RS485_ENABLED; + rs485->flags &= ~SER_RS485_ENABLED; else config |= RS485_URA;

Patches currently in stable-queue which might be from lukas@wunner.de are

queue-4.4/serial-8250_fintek-fix-rs485-disablement-on-invalid-ioctl.patch