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authorColin Leitner <colin.leitner@googlemail.com>2013-11-05 18:02:34 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-11 22:36:28 -0800
commit536169b1c9a29a1931e07ec1115781be733e1a4c (patch)
treee8872f915b7c1a39ceb305e9fbf989cb09cd8090
parent98e0cc7766b1f11856e3975f82184f513051c4f5 (diff)
USB: ftdi_sio: fixed handling of unsupported CSIZE setting
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@gmail.com> Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/serial/ftdi_sio.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index aa3aed5458a6..92549cc4665f 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -2131,6 +2131,20 @@ static void ftdi_set_termios(struct tty_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(ddev, "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)
@@ -2167,19 +2181,16 @@ no_skip:
} else {
urb_value |= FTDI_SIO_SET_DATA_PARITY_NONE;
}
- if (cflag & CSIZE) {
- switch (cflag & CSIZE) {
- case CS7:
- urb_value |= 7;
- dev_dbg(ddev, "Setting CS7\n");
- break;
- case CS8:
- urb_value |= 8;
- dev_dbg(ddev, "Setting CS8\n");
- break;
- default:
- dev_err(ddev, "CSIZE was set but not CS7-CS8\n");
- }
+ switch (cflag & CSIZE) {
+ case CS7:
+ urb_value |= 7;
+ dev_dbg(ddev, "Setting CS7\n");
+ break;
+ default:
+ case CS8:
+ urb_value |= 8;
+ dev_dbg(ddev, "Setting CS8\n");
+ break;
}
/* This is needed by the break command since it uses the same command