From: Lukas Wunner Date: Sat, 28 Oct 2017 09:35:49 +0000 (+0200) Subject: serial: 8250_fintek: Fix rs485 disablement on invalid ioctl() X-Git-Tag: v3.18.87~22 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=826b2a0b10bf91e84fdc220e26e9c7daeda60161;p=thirdparty%2Fkernel%2Fstable.git serial: 8250_fintek: Fix rs485 disablement on invalid ioctl() [ 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 Cc: "Ji-Ze Hong (Peter Hong)" Signed-off-by: Lukas Wunner Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c index 1bb28cb69493a..c72283f2be6d0 100644 --- a/drivers/tty/serial/8250/8250_fintek.c +++ b/drivers/tty/serial/8250/8250_fintek.c @@ -118,7 +118,7 @@ static int fintek_8250_rs4850_config(struct uart_8250_port *uart, 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;