Messages in this thread Patch in this message | | | Date | Thu, 22 Sep 2005 00:48:49 -0700 | From | Greg KH <> | Subject | [patch 11/18] USB: ftdi_sio: allow baud rate to be changed without raising RTS and DTR |
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From: Peter Favrholdt <pfavr@how.dk>
I'm using a 2 port USB RS232 dongle to connect to a serial-IR cradle for a bar code reader). Detecting the baudrate of the serial-IR involves keeping DTR low while changing baudrate.
This works using normal 16550A serial ports as well as the FTDI driver version 1.4.0 (Linux 2.6.8) but stopped working with the change to "ensure RTS and DTR are raised when changing baudrate" introduced in version 1.4.1 (Linux 2.6.9).
The attached patch fixes this, so RTS and DTR is only raised when changing baudrate iff the previous baudrate was B0.
Signed-off-by: Peter Favrholdt <pfavr@how.dk> Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/usb/serial/ftdi_sio.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- scsi-2.6.orig/drivers/usb/serial/ftdi_sio.c 2005-09-20 06:00:04.000000000 -0700 +++ scsi-2.6/drivers/usb/serial/ftdi_sio.c 2005-09-21 17:29:41.000000000 -0700 @@ -1846,10 +1846,12 @@ } else { /* set the baudrate determined before */ if (change_speed(port)) { - err("%s urb failed to set baurdrate", __FUNCTION__); + err("%s urb failed to set baudrate", __FUNCTION__); + } + /* Ensure RTS and DTR are raised when baudrate changed from 0 */ + if ((old_termios->c_cflag & CBAUD) == B0) { + set_mctrl(port, TIOCM_DTR | TIOCM_RTS); } - /* Ensure RTS and DTR are raised */ - set_mctrl(port, TIOCM_DTR | TIOCM_RTS); } /* Set flow control */ -- - 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/
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