Re: [PATCH] tty: serial: 8250: add CON_CONSDEV to flags

[Jiri Slaby <jslaby@suse.cz>]

On 06/21/2016, 05:19 PM, Matthew Leach wrote:
> When using the 8250 as a boot console and the main console results in
> messages being printed twice.  The console framework will only
> unregister boot consoles if a new console is registered with the
> CON_CONSDEV flag set.
> 
> Set this flag for the univ8250 console to prevent double-registration.
> 
> Signed-off-by: Matthew Leach <matthew.leach@codethink.co.uk>
> ---
>  drivers/tty/serial/8250/8250_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 2f4f5ee..7a7453d 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -675,7 +675,7 @@ static struct console univ8250_console = {
>  	.device		= uart_console_device,
>  	.setup		= univ8250_console_setup,
>  	.match		= univ8250_console_match,
> -	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
> +	.flags		= CON_PRINTBUFFER | CON_ANYTIME | CON_CONSDEV,

This patch breaks console= parameter handling. Passing:
  console=ttyS0 console=tty0
no longer means /dev/console is tty0 and it should be as is documented.

I have not investigated further yet.

thanks,
-- 
js
suse labs