Re: [PATCH v8 1/4] ttynull: Always initialize console index to -1

[Petr Mladek]

On Mon 2025-03-10 23:31:30, adamsimonelli@xxxxxxxxx wrote:
> From: Adam Simonelli <adamsimonelli@xxxxxxxxx>
> 
> This allows ttynull to be considered in console selection.

This is not true. It should be possible to register ttynull even
when .index == 0.

The .index is important only for drivers which support more devices,
e.g. the serial port or virtual terminal.

> 
> Suggested-by: Petr Mladek <pmladek@xxxxxxxx>
> Signed-off-by: Adam Simonelli <adamsimonelli@xxxxxxxxx>
> ---
>  drivers/tty/ttynull.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/tty/ttynull.c b/drivers/tty/ttynull.c
> index 6b2f7208b564..d8b51edde628 100644
> --- a/drivers/tty/ttynull.c
> +++ b/drivers/tty/ttynull.c
> @@ -57,6 +57,7 @@ static struct tty_driver *ttynull_device(struct console *c, int *index)
>  static struct console ttynull_console = {
>  	.name = "ttynull",
>  	.device = ttynull_device,
> +	.index = -1,

There is only one "/dev/ttynull". And its index is initialized to "0".
At least it seems to be the last parameter in:

static int __init ttynull_init(void)
{
[...]
	tty_port_link_device(&ttynull_port, driver, 0);
[...]
}

So, I believe this it should be perfectly fine to keep the default "0"
here. Note that it is special for ttynull because it is only one...

IMHO, this patch adds more harm than good :-)

Best Regards,
Petr