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    SubjectRe: [PATCH] serial: set RTS and DTR if flow is 'r'
    On Mon, 14 May 2007 10:26:26 -0700 Yinghai Lu wrote:

    > [PATCH] serial: set RTS and DTR if flow is 'r'
    >
    > if the serial console flow is set to 'r', We need to set RTS and DTR.
    > Some UARTs on other side need these bit set, otherwise will send char to or
    > receive char from the host that kernel is runing esp for kernel boot stage.
    >
    > BTW:
    > earlyprintk and early_uart are hard coded to set DTR/RTS.
    >
    > Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
    > Cc: Russell King <rmk@arm.linux.org.uk>
    > Cc: Andi Kleen <ak@suse.de>
    > Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
    >
    > diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
    > index 48e259a..439a00a 100644
    > --- a/drivers/serial/8250.c
    > +++ b/drivers/serial/8250.c
    > @@ -2154,6 +2154,16 @@ serial8250_set_termios(struct uart_port *port,
    > struct ktermios *termios,
    > }
    > serial_outp(up, UART_FCR, fcr); /* set fcr */

    Something is eating tabs above and presumably in the new patch lines...

    > }
    > +
    > + /* if serial console flow is 'r', we need to set RTS and DTR to MCR.
    > + * some uarts on other side don't support no flow control. So we state
    > + * console=ttyS0,9600n8r in kernel command line to make those uart can
    > + * work.
    > + */

    /*
    * Linux long comment style is
    * like this.
    */

    > + if (termios->c_cflag & CRTSCTS) {
    > + up->port.mctrl |= TIOCM_RTS | TIOCM_DTR;
    > + }

    Don't use braces on one-statement blocks.

    > +
    > serial8250_set_mctrl(&up->port, up->port.mctrl);
    > spin_unlock_irqrestore(&up->port.lock, flags);
    > }



    ---
    ~Randy
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