USB: ftdi_sio: fixed handling of unsupported CSIZE setting (8704211f) · Commits · 戴 / test

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> Cc: stable <stable@vger.kernel.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/ftdi_sio.c

+24 −13

Original line number	Diff line number	Diff line
		@@ -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;
		default:
		case CS8:
		urb_value \|= 8;
		dev_dbg(ddev, "Setting CS8\n");
		break;
		default:
		dev_err(ddev, "CSIZE was set but not CS7-CS8\n");
		}
		}

		/* This is needed by the break command since it uses the same command

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