Re: [PATCH] printk: remove BOOT_PRINTK_DELAY config

[Petr Mladek <pmladek@suse.com>]

On Sun 2026-05-03 14:42:14, Randy Dunlap wrote:
> This boot option is ancient and probably not being used.
> Dave Jones used it successfully maybe 15 years ago...
> AFAIK it doesn't work reliably, especially on SMP.

I agree that it most likely does not have many users and is not
reliable.

In addition, it was kind of obsoleted by printk_delay() which
does very similar thing except that it can only be set
at runtime via sysctl.

Which brings an idea. What about doing the obsoleting properly?
I mean to:

  1. Add "printk_delay" early_param() which would allow
     to set "printk_delay_msec" via command line.

  2. Modify boot_delay_setup() to set "printk_delay_msec" as well.
     In addition, it might print a message that it has been
     obsoleted by "printk_delay" and will be removed.

Would you mind to do it this way, please?

Regarding the reliability, it might get improved by moving the delay
to console handling code. It would even allow to use sleeping wait
when the consoles are handled in kthreads. But the wait might
get multiplied when more consoles are registered and proceed
on the same CPU. Anyway, this is out of scope for this patch.

Best Regards,
Petr