On Mon, May 14, 2007 at 12:04:44PM -0700, Yinghai Lu wrote:
> Russell King wrote:
> >There may be some sense, however, in allowing DTR to be permanently
> >raised for serial consoles. However, I would err on caution since
> >DTR is used to reliably instruct modems to drop the line, so making
> >such a change would be undesirable for those folk.
> >
> please check following is OK.
Still wrong, and unfortunately you haven't understood what I was saying
at all because this is worse. ;(
Do not put the code in serial8250_set_termios. It is the wrong place.
>
> 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 <[email protected]>
> Cc: Russell King <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Cc: Bjorn Helgaas <[email protected]>
>
> *diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c*
> index 48e259a..29c051c 100644
> *--- a/drivers/serial/8250.c*
> *+++ b/drivers/serial/8250.c*
> @@ -2154,6 +2154,12 @@ serial8250_set_termios(struct uart_port *port,
> struct ktermios *termios,
> }
> serial_outp(up, UART_FCR, fcr); /* set fcr */
> }
> +
> + /* some uarts on other side don't support no flow control. So we set
> + * DTR in host uart to make them happy
> + */
> + up->port.mctrl |= TIOCM_DTR;
> +
> serial8250_set_mctrl(&up->port, up->port.mctrl);
> spin_unlock_irqrestore(&up->port.lock, flags);
> }
>
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
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