This is a note to let you know that I've just added the patch titled
USB: ftdi_sio: fixed handling of unsupported CSIZE setting
to the 3.4-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:
usb-ftdi_sio-fixed-handling-of-unsupported-csize-setting.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 75a4cfafc7379ed99dbb85f4b92de7e86a534876 Mon Sep 17 00:00:00 2001
From: Colin Leitner <colin.leitner@xxxxxxxxxxxxxx>
Date: Tue, 5 Nov 2013 18:02:34 +0100
Subject: USB: ftdi_sio: fixed handling of unsupported CSIZE setting
From: Colin Leitner <colin.leitner@xxxxxxxxxxxxxx>
commit 8704211f65a2106ba01b6ac9727cdaf9ca11594c upstream.
FTDI UARTs support only 7 or 8 data bits. Until now the ftdi_sio driver would
only report this limitation for CS6 to dmesg and fail to reflect this fact to
tcgetattr.
This patch reverts the unsupported CSIZE setting and reports the fact with less
severance to dmesg for both CS5 and CS6.
To test the patch it's sufficient to call
stty -F /dev/ttyUSB0 cs5
which will succeed without the patch and report an error with the patch
applied.
As an additional fix this patch ensures that the control request will always
include a data bit size.
Signed-off-by: Colin Leitner <colin.leitner@xxxxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
[bwh: Backported to 3.2:
- Old code is cosmetically different
- s/ddev/\&port->dev/]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/ftdi_sio.c | 31 ++++++++++++++++++++++++-------
1 file changed, 24 insertions(+), 7 deletions(-)
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -2201,6 +2201,20 @@ static void ftdi_set_termios(struct tty_
termios->c_cflag |= CRTSCTS;
}
+ /*
+ * All FTDI UART chips are limited to CS7/8. We won't pretend to
+ * support CS5/6 and revert the CSIZE setting instead.
+ */
+ if ((C_CSIZE(tty) != CS8) && (C_CSIZE(tty) != CS7)) {
+ dev_warn(&port->dev, "requested CSIZE setting not supported\n");
+
+ termios->c_cflag &= ~CSIZE;
+ if (old_termios)
+ termios->c_cflag |= old_termios->c_cflag & CSIZE;
+ else
+ termios->c_cflag |= CS8;
+ }
+
cflag = termios->c_cflag;
if (!old_termios)
@@ -2237,13 +2251,16 @@ no_skip:
} else {
urb_value |= FTDI_SIO_SET_DATA_PARITY_NONE;
}
- if (cflag & CSIZE) {
- switch (cflag & CSIZE) {
- case CS7: urb_value |= 7; dbg("Setting CS7"); break;
- case CS8: urb_value |= 8; dbg("Setting CS8"); break;
- default:
- dev_err(&port->dev, "CSIZE was set but not CS7-CS8\n");
- }
+ switch (cflag & CSIZE) {
+ case CS7:
+ urb_value |= 7;
+ dev_dbg(&port->dev, "Setting CS7\n");
+ break;
+ default:
+ case CS8:
+ urb_value |= 8;
+ dev_dbg(&port->dev, "Setting CS8\n");
+ break;
}
/* This is needed by the break command since it uses the same command
Patches currently in stable-queue which might be from colin.leitner@xxxxxxxxxxxxxx are
queue-3.4/usb-ftdi_sio-fixed-handling-of-unsupported-csize-setting.patch
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