Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752007Ab0FCL5e (ORCPT ); Thu, 3 Jun 2010 07:57:34 -0400 Received: from buzzloop.caiaq.de ([212.112.241.133]:47151 "EHLO buzzloop.caiaq.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322Ab0FCL5d (ORCPT ); Thu, 3 Jun 2010 07:57:33 -0400 Date: Thu, 3 Jun 2010 13:57:27 +0200 From: Daniel Mack To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , Johan Hovold , Alan Cox , linux-usb@vger.kernel.org Subject: Re: [PATCH] usb-serial/ftdi_sio: fix DTR/RTS line modes Message-ID: <20100603115727.GY2695@buzzloop.caiaq.de> References: <1275566102-5613-1-git-send-email-daniel@caiaq.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1275566102-5613-1-git-send-email-daniel@caiaq.de> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1930 Lines: 58 On Thu, Jun 03, 2010 at 01:55:02PM +0200, Daniel Mack wrote: > Call set_mctrl() and clear_mctrl() according to the flow control mode > selected. This makes serial communication for FT232 connected devices > work when CRTSCTS is not set. > > This fixes a regression introduced by 4175f3e31 ("tty_port: If we are > opened non blocking we still need to raise the carrier"). This patch > calls the low-level driver's dtr_rts() function which consequently sets > TIOCM_DTR | TIOCM_RTS. A later call to set_termios() without CRTSCTS in > cflags, however, does not reset these bits, and so data is not actually > sent out on the serial wire. > > Signed-off-by: Daniel Mack > Cc: Greg Kroah-Hartman > Cc: Johan Hovold > Cc: Alan Cox > Cc: linux-usb@vger.kernel.org Oops. I forgot to Cc: stable@kernel.org. This is in fact broken since 2.6.31-something. > --- > drivers/usb/serial/ftdi_sio.c | 4 ++++ > 1 files changed, 4 insertions(+), 0 deletions(-) > > diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c > index 050211a..79dd1ae 100644 > --- a/drivers/usb/serial/ftdi_sio.c > +++ b/drivers/usb/serial/ftdi_sio.c > @@ -2005,6 +2005,8 @@ static void ftdi_set_termios(struct tty_struct *tty, > "urb failed to set to rts/cts flow control\n"); > } > > + /* raise DTR/RTS */ > + set_mctrl(port, TIOCM_DTR | TIOCM_RTS); > } else { > /* > * Xon/Xoff code > @@ -2052,6 +2054,8 @@ static void ftdi_set_termios(struct tty_struct *tty, > } > } > > + /* lower DTR/RTS */ > + clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); > } > return; > } > -- > 1.7.1 > -- 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/