linux-kernel - [PATCH] usb-serial/ftdi_sio: fix DTR/RTS line modes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1275566102-5613-1-git-send-email-daniel@caiaq.de>
Date:	Thu,  3 Jun 2010 13:55:02 +0200
From:	Daniel Mack <daniel@...aq.de>
To:	linux-kernel@...r.kernel.org
Cc:	Daniel Mack <daniel@...aq.de>, Greg Kroah-Hartman <gregkh@...e.de>,
	Johan Hovold <jhovold@...il.com>,
	Alan Cox <alan@...ux.intel.com>, linux-usb@...r.kernel.org
Subject: [PATCH] usb-serial/ftdi_sio: fix DTR/RTS line modes

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 <daniel@...aq.de>
Cc: Greg Kroah-Hartman <gregkh@...e.de>
Cc: Johan Hovold <jhovold@...il.com>
Cc: Alan Cox <alan@...ux.intel.com>
Cc: linux-usb@...r.kernel.org
---
 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@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/