From 8704211f65a2106ba01b6ac9727cdaf9ca11594c Mon Sep 17 00:00:00 2001 From: Colin Leitner Date: Tue, 5 Nov 2013 18:02:34 +0100 Subject: [PATCH] USB: ftdi_sio: fixed handling of unsupported CSIZE setting 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 Signed-off-by: Johan Hovold Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 37 +++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 13 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 9ced8937a8f3..fb0d537435eb 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2123,6 +2123,20 @@ 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) @@ -2159,19 +2173,16 @@ 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 -- 2.20.1