[PATCH] USB: ftdi_sio doesn't re-assert DTR modem control line

I've dredged up another old ftdi_sio patch that I never Cc'd to you
the first time.  Please see Nathan's description below.

It applies okay against your usb-2.6 tree, with or without the patch
I posted yesterday to support the FT2232C chip and neither patch
invalidates the other in any way.


On 25/06/2004 21:56, Croy, Nathan wrote:
> SUMMARY
> =======
> ftdi_sio never reasserts modem control lines once the baud has been set to
> B0.
>
> DESCRIPTION
> ===========
> Setting the baud to B0 (hangup) drops DTR.  When the baud is raised again,
> DTR is not raised.  This can cause a modem to ignore any commands sent to it
> until the device is closed and reopened.  This renders minicom (and other
> software) useless, unless you instruct the modem to ignore DTR.
>
> The following patch is intended to make ftdi_sio act like other serial
> devices I have used (i.e. the standard serial ports (/dev/ttyS*) and
> stallion ports (/dev/ttyE*)).  Upon setting the baud to something other than
> B0, it ensures the modem control lines are set back to the way they were
> when the port was opened.
>
> Thanks to Ian Abbott for confirming my suspicions:
> http://sourceforge.net/mailarchive/forum.php?thread_id=4984710&forum_id=12120

Nathan's email suffered from a line-folding bug (blame M$,
probably!), so his patch came out corrupted. I'm reposting an
uncorrupted version.


Signed off by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/serial/ftdi_sio.c

@@ -1903,6 +1903,13 @@ static void ftdi_set_termios (struct usb_serial_port *port, struct termios *old_
 		if (change_speed(port)) {
 			err("%s urb failed to set baurdrate", __FUNCTION__);
 		}
+		/* Ensure  RTS and DTR are raised */
+		else if (set_dtr(port, HIGH) < 0){
+			err("%s Error from DTR HIGH urb", __FUNCTION__);
+		}
+		else if (set_rts(port, HIGH) < 0){
+			err("%s Error from RTS HIGH urb", __FUNCTION__);
+		}	
 	}
 
 	/* Set flow control */