Commit:     79492689e40d4f4d3d8a7262781d56fb295b4b86
Parent:     23936cc0b5d89619c34c2dab11d8cf3d6f7ca028
Author:     Yinghai Lu <[EMAIL PROTECTED]>
AuthorDate: Sun Jul 15 23:37:25 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Jul 16 09:05:34 2007 -0700

    serial: assert DTR for serial console devices
    Some RS-232 devices require DTR to be asserted before they can be used.  DTR
    is normally asserted in uart_startup() when the port is opened.  But we 
    actually open serial console ports, so assert DTR when the port is added.
    earlyprintk and early_uart are hard coded to set DTR/RTS.
    rmk says
      The only issue I can think of is the possibility for an attached modem to
      auto-answer or maybe even auto-dial before the system is ready for it to 
      so.  Might have an undesirable cost implication for some running with 
such a
      Apart from that, I can't think of any other side effect of this specific
    Signed-off-by: Yinghai Lu <[EMAIL PROTECTED]>
    Acked-by: Russell King <[EMAIL PROTECTED]>
    Cc: Andi Kleen <[EMAIL PROTECTED]>
    Cc: Bjorn Helgaas <[EMAIL PROTECTED]>
    Cc: Gerd Hoffmann <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 drivers/serial/serial_core.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 326020f..9c57486 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1910,6 +1910,12 @@ uart_set_options(struct uart_port *port, struct console 
        if (flow == 'r')
                termios.c_cflag |= CRTSCTS;
+       /*
+        * some uarts on other side don't support no flow control.
+        * So we set * DTR in host uart to make them happy
+        */
+       port->mctrl |= TIOCM_DTR;
        port->ops->set_termios(port, &termios, NULL);
        co->cflag = termios.c_cflag;
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