From: <gregkh@linuxfoundation.org>
To: asierra@xes-inc.com, alexander.levin@verizon.com,
gregkh@linuxfoundation.org
Cc: <stable@vger.kernel.org>, <stable-commits@vger.kernel.org>
Subject: Patch "serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X" has been added to the 4.9-stable tree
Date: Wed, 06 Dec 2017 18:00:29 +0100 [thread overview]
Message-ID: <151257962953169@kroah.com> (raw)
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 4.9-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-4.9 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 17:39:55 CET 2017
From: Aaron Sierra <asierra@xes-inc.com>
Date: Wed, 4 Oct 2017 10:01:28 -0500
Subject: serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X
From: Aaron Sierra <asierra@xes-inc.com>
[ 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.
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
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_port.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2526,8 +2526,11 @@ 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 asierra@xes-inc.com are
queue-4.9/serial-8250-preserve-dld-for-port_xr17v35x.patch
reply other threads:[~2017-12-06 17:01 UTC|newest]
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