Re: [PATCH v4 0/2] Optionally allow ttynull to be selected as a default console

[Andy Shevchenko]

Sun, Feb 23, 2025 at 03:44:54PM -0500, adamsimonelli@xxxxxxxxx kirjoitti:
> From: Adam Simonelli <adamsimonelli@xxxxxxxxx>
> 
> When switching to a CONFIG_VT=n world, at least on x86 systems,
> /dev/console becomes /dev/ttyS0. This can cause some undesired effects.
> /dev/console's behavior is now tied to the physical /dev/ttyS0, which when
> disconnected can cause isatty() to fail when /dev/ttyS0 is disconnected,
> and users who upgrade to a theoretical vt-less kernel from their
> distribution who have a device such as a science instrument connected to
> their /dev/ttyS0 port will suddenly see it receive kernel log messages.
> 
> When the new CONFIG_NULL_TTY_CONSOLE option is turned on, this will allow
> the ttynull device to be leveraged as the default console. Distributions
> that had CONFIG_VT turned on before will be able to leverage this option
> to where /dev/console is still backed by a psuedo device, avoiding these
> issues, without needing to enable the entire VT subsystem.

This rings a bell of the following

https://lore.kernel.org/all/20201111135450.11214-1-pmladek@xxxxxxxx/
https://lore.kernel.org/all/20210107164400.17904-1-pmladek@xxxxxxxx/
https://lore.kernel.org/all/20210108114847.23469-1-pmladek@xxxxxxxx/

I don't see any mention in the commit message about these, have you studied the
cases? Will your change anyhow affect the described there?

-- 
With Best Regards,
Andy Shevchenko