Re: [PATCH v2] printk: Document that CONFIG_BOOT_PRINTK_DELAY required for boot_delay=

From: Randy Dunlap
Date: Thu Jan 26 2023 - 20:12:23 EST




On 1/26/23 14:54, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> Document the fact that CONFIG_BOOT_PRINTK_DELAY must be enabled for the
> "boot_delay" kernel parameter to work. Also mention that "lpj=" may be
> necessary.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

Thanks.

> ---
> Changes from v1 (https://lore.kernel.org/all/20230123180440.901793-1-helgaas@xxxxxxxxxx/):
> - Clarify use of "lpj=". Reword consequences of delay larger than 10000.
>
> Documentation/admin-guide/kernel-parameters.txt | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6cfa6e3996cf..814e58487239 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -480,8 +480,10 @@
> See Documentation/block/cmdline-partition.rst
>
> boot_delay= Milliseconds to delay each printk during boot.
> - Values larger than 10 seconds (10000) are changed to
> - no delay (0).
> + Only works if CONFIG_BOOT_PRINTK_DELAY is enabled,
> + and you may also have to specify "lpj=". Boot_delay
> + values larger than 10 seconds (10000) are assumed
> + erroneous and ignored.
> Format: integer
>
> bootconfig [KNL]

--
~Randy