@@ -2162,10 +2162,20 @@ static void ftdi_set_termios(struct tty_struct *tty,
}
/*
- * All FTDI UART chips are limited to CS7/8. We won't pretend to
+ * All FTDI UART chips are limited to CS7/8. We shouldn't pretend to
* support CS5/6 and revert the CSIZE setting instead.
+ *
+ * CS5 however is used to control some smartcard readers which abuse
+ * this limitation to switch modes. Original FTDI chips fall back to
+ * eight data bits.
+ *
+ * TODO: Implement a quirk to only allow this with mentioned
+ * readers. One I know of (Argolis Smartreader V1)
+ * returns "USB smartcard server" as iInterface string.
+ * The vendor didn't bother with a custom VID/PID of
+ * course.
*/
- if ((C_CSIZE(tty) != CS8) && (C_CSIZE(tty) != CS7)) {
+ if (C_CSIZE(tty) == CS6) {
dev_warn(&port->dev, "requested CSIZE setting not supported\n");
termios->c_cflag &= ~CSIZE;
@@ -2212,6 +2222,9 @@ no_skip:
urb_value |= FTDI_SIO_SET_DATA_PARITY_NONE;
}
switch (cflag & CSIZE) {
+ case CS5:
+ dbg("Setting CS5 quirk\n");
+ break;
case CS7:
urb_value |= 7;
dbg("Setting CS7\n");
This is a note to let you know that I have just added a patch titled USB: ftdi_sio: added CS5 quirk for broken smartcard readers to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From d4cbf7f47e4977e494ff6ac7d2f2c979bee3a827 Mon Sep 17 00:00:00 2001 From: Colin Leitner <colin.leitner@googlemail.com> Date: Mon, 6 Jan 2014 21:33:54 +0100 Subject: USB: ftdi_sio: added CS5 quirk for broken smartcard readers commit c1f15196ac3b541d084dc80a8fbd8a74c6a0bd44 upstream. Genuine FTDI chips support only CS7/8. A previous fix in commit 8704211f65a2 ("USB: ftdi_sio: fixed handling of unsupported CSIZE setting") enforced this limitation and reported it back to userspace. However, certain types of smartcard readers depend on specific driver behaviour that requests 0 data bits (not 5) to change into a different operating mode if CS5 has been set. This patch reenables this behaviour for all FTDI devices. Tagged to be added to stable, because it affects a lot of users of embedded systems which rely on these readers to work properly. Reported-by: Heinrich Siebmanns <H.Siebmanns@t-online.de> Tested-by: Heinrich Siebmanns <H.Siebmanns@t-online.de> 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> [ luis: backported to 3.5: - adjusted context - replace dev_dbg() by dbg() ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/usb/serial/ftdi_sio.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) -- 1.8.3.2