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

[John Ogness <john.ogness@linutronix.de>]

On 2026-08-18, Petr Mladek <pmladek@suse.com> wrote:
>> [0] https://pastebin.com/FhQVSqfy

...

> Almost everything works as expected except for:
>
>   1. I am not sure why "printk: console [ttyS0] disabled" is printed.
>      It does not make any sense to me.

I have seen this in the past. It can happens unregister_console_locked()
has always printed the disabled message before actually checking if the
console is registered.

IIRC it has something to do with serial8250_register_8250_port() calling
uart_remove_one_port(). I remember starting to look into how to fix it
but then was going down a rabbit hole that exceeded my scope at the
time.

>   2. The WARNING would be handled with NBCON_PRIO_EMERGENCY.
>      I wonder if this warning happened also with "v5" of this
>      patchset.

The tegra issue we had with v5 was related to irqwork being scheduled
when suspending. When keep_bootcon is specified, there will be no
irqwork scheduled during boot because legacy_direct=true.

From the backtrace in the posted boot log we see that the warning is
within tegra_pmc_enter_suspend_mode(). I am wondering if this is the
same issue we saw with v5... an irqwork getting scheduled when the tegra
is entering some suspend state.

Back then I was able to reproduce the suspend issue on a Phytec-WEGA
board. I will see if I can reproduce this report on it as well.

John