Patch "serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X" has been added to the 4.14-stable tree

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

    serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     serial-8250-preserve-dld-for-port_xr17v35x.patch

and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Aaron Sierra <[email protected]>
Date: Wed, 4 Oct 2017 10:01:28 -0500
Subject: serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X

From: Aaron Sierra <[email protected]>

[ Upstream commit 0ab84da2e076948c49d36197ee7d254125c53eab ]

The upper four bits of the XR17V35x fractional divisor register (DLD) control general chip function (RS-485 direction pin polarity, multidrop mode, XON/XOFF parity check, and fast IR mode). Don't allow these bits to be clobbered when setting the baudrate.

---
 drivers/tty/serial/8250/8250_port.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

@@ -2586,8 +2586,11 @@ static void serial8250_set_divisor(struc
 	serial_dl_write(up, quot);
 
 	/* XR17V35x UARTs have an extra fractional divisor register (DLD) */
-	if (up->port.type == PORT_XR17V35X)
+	if (up->port.type == PORT_XR17V35X) {
+		/* Preserve bits not related to baudrate; DLD[7:4]. */
+		quot_frac |= serial_port_in(port, 0x2) & 0xf0;
 		serial_port_out(port, 0x2, quot_frac);
+	}
 }
 
 static unsigned int serial8250_get_baud_rate(struct uart_port *port,

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/serial-8250-preserve-dld-for-port_xr17v35x.patch