Re: [PATCH 0/8] printk: Clean up preferred console handling

[John Ogness]

Hi Petr,

On 2026-02-06, Petr Mladek <pmladek@xxxxxxxx> wrote:
> this patches does some clean up of the code for handling preferred consoles
> in the console registration code.
>
>   + 1st and 2nd patch try to improve a naming.
>
>     The meaning of struct console_cmdline has changed over time.
>     The meaning of "preferred_console" variable has always been a bit
>     confusing and it has got even worse after adding the support for
>     Braille consoles.
>
>
>   + 3rd patch remove some code duplication. It better defines and describes
>     the rules for adding and updating preferred consoles. It uses a more
>     defensive coding style.
>
>
>   + 4th, 5th, and 6th patch improve handling of Braille consoles.
>     They are preferred via the command line but they do not get
>     printk() messages and are not associated with /dev/console.
>
>     The new code makes this more obvious. Also it explicitly
>     defines the relation against default consoles and other
>     non-Braille preferred consoles.
>
>
>   + 7th patch removes a hidden side effect of
>     try_enable_preferred_console()
>
>
>   + 8th patch removes the last hidden side effect of
>     try_enable_preferred_console() and allows to call it
>     only when there are any non-Braille preferred consoles.
>
>
> I tested many scenarios of fixed several bugs. I did my best to
> prevent regressions.
>
> This patchset is a prerequisite for Marcos' clean up of CON_ENABLE
> flag handling. It should prevent regressions caused by the
> hidden effects of try_enable_preferred_console(), for example,
> see https://lore.kernel.org/r/89409a0f48e6998ff6dd2245691b9954f0e1e435.camel@xxxxxxxx
>
> Also I am working on a feature which would allow to explicitly
> enable/prefer consoles proposed by SPCR, device tree, or
> platform-specific code using a generic "console=platform".
> This clean up is a prerequisite, see
> https://github.com/pmladek/linux/tree/console-platform-poc1-iter9
>
> The patchset has been re-based on top of v6.19-rc8.

I have finished my review. I just had feedback relating to
update_preferred_console() and also adding some function description
comments to __add_preferred_console().

John