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    Subject[PATCH] serial: set DTR in uart for kernel serial console
    Hope format is OK. Sending with KMail Message/Insert File

    YH

    [PATCH] serial: set DTR in uart for kernel serial console

    Some UARTs on other side need host uart DTR is set, otherwise will not
    receive char from the host that kernel is runing during 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..a925547 100644
    --- a/drivers/serial/8250.c
    +++ b/drivers/serial/8250.c
    @@ -2397,6 +2397,11 @@ static void __init serial8250_isa_init_ports(void)
    up->mcr_force = ALPHA_KLUDGE_MCR;

    up->port.ops = &serial8250_pops;
    +
    + /* some uarts on other side don't support no flow control. So we set
    + * DTR in host uart to make them happy --- YHLU
    + */
    + up->port.mctrl |= TIOCM_DTR;
    }

    for (i = 0, up = serial8250_ports;
    -
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