Re: [PATCH tty v11 1/2] serial: 8250: Switch to nbcon console, take 2

[Jon Hunter]

Hi John,

On 27/08/2026 13:59, John Ogness wrote:
> Hi Jon,
>
> On 2026-08-26, Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
> > If that irq_work is the problem that making nbcon_irq_work LAZY should
> > delay it, masking the problem.
>
> Making nbcon_irq_work LAZY should work around this problem. And,
> actually, it should be fine to make nbcon_irq_work LAZY in general since
> it is only related to non-emergency messages, which are delayed anyway.
>
> Jon, could you run your tests with only the following patch applied? If
> this works for you, I will submit an official version of the patch.
>
> diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
> index a5921a84a80ed..ad79e30afd647 100644
> --- a/kernel/printk/nbcon.c
> +++ b/kernel/printk/nbcon.c
> @@ -1782,7 +1782,7 @@ bool nbcon_alloc(struct console *con)
>   	}
>   
>   	rcuwait_init(&con->rcuwait);
> -	init_irq_work(&con->irq_work, nbcon_irq_work);
> +	con->irq_work = IRQ_WORK_INIT_LAZY(nbcon_irq_work);
>   	atomic_long_set(&ACCESS_PRIVATE(con, nbcon_prev_seq), -1UL);
>   	nbcon_state_set(con, &state);
>   

I gave this a quick try on Tegra20 and Tegra30 and I can confirm that
this does work.

Thanks!
Jon

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