Re: [PATCH] clk: Warn (and therefore taint the kernel) on clk_ignore_unused

[Stephen Boyd]

Quoting Konrad Dybcio (2025-02-01 08:52:30)
> From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
> 
> If any sort of ignore_unused is in place, it means one of:
> 
> * power is going to waste
> * the platform description is incomplete (missing consumer-provider
>   relationships)
> * the platform description is just broken
> 
> Many people will happily declare their job done when a platform
> magically happens to work as they make use of bootloader-enabled
> resources, which then leads to double or triple the amount of work
> of another person, as they attempt to reduce the unnecessary power
> drainage and/or ensure stabiility throughout a suspend-resume cycle.
> 
> Issue a good ol' warning (and taint the kernel) to make such cases
> obvious and hopefully draw more attention to it. This way, it'll be
> easier to avoid effectively untested code or DT description getting
> merged into the kernel, or worse, going into production.
> 
> The clock subsystem plays a crucial part in this quest, as even if
> the clock controllers themselves don't draw a lot of power when on
> (comparatively), improper description of clock requirements has been
> the #1 cause of incomplete/incorrect devicetree bindings in my
> experience.

What is a user supposed to do about this warning stack? We already print
a warning. I don't see us dumping the stack when a driver is unfinished
and doesn't implement runtime PM to save power.