Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935848AbaBDWYR (ORCPT ); Tue, 4 Feb 2014 17:24:17 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56611 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933809AbaBDVIW (ORCPT ); Tue, 4 Feb 2014 16:08:22 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heinrich Siebmanns , Colin Leitner , Johan Hovold Subject: [PATCH 3.12 022/133] USB: ftdi_sio: added CS5 quirk for broken smartcard readers Date: Tue, 4 Feb 2014 13:07:03 -0800 Message-Id: <20140204210737.653796786@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <20140204210737.008598235@linuxfoundation.org> References: <20140204210737.008598235@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Colin Leitner 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 Tested-by: Heinrich Siebmanns Signed-off-by: Colin Leitner Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2116,10 +2116,20 @@ static void ftdi_set_termios(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(ddev, "requested CSIZE setting not supported\n"); termios->c_cflag &= ~CSIZE; @@ -2166,6 +2176,9 @@ no_skip: urb_value |= FTDI_SIO_SET_DATA_PARITY_NONE; } switch (cflag & CSIZE) { + case CS5: + dev_dbg(ddev, "Setting CS5 quirk\n"); + break; case CS7: urb_value |= 7; dev_dbg(ddev, "Setting CS7\n"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/