Re: Kernel is using a lot of CPU

> 12.4 autoloaded acpi_wmi with dubious results:
>
> Autoloading module: acpi_wmi
> acpi_wmi0: <ACPI-WMI mapping> on acpi0
> acpi_wmi0: cannot find EC device
> device_attach: acpi_wmi0 attach returned 6
> acpi_wmi0: <ACPI-WMI mapping> on acpi0
> acpi_wmi0: cannot find EC device
> device_attach: acpi_wmi0 attach returned 6
>
> 12.2 did not autoload it.

Ah, the EC.
If it "cannot find" the EC, then that might account for unexpected
strangeness.

The EC is an "embedded controller" that is controlled by the ACPI and
does certain kinds of strange things, for instance managing the
battery. Some background information is here:
https://queue.acm.org/blogposting.cfm?id=18995

If this is a usual elderly desktop connected to mains power, then you
may not have it and/or not need it. On my desktop (ivybridge) I can
safely do
> devmatch_blacklist="acpi_wmi"

On my rather modern Lifebook (tigerlake I think) I also get errors
from it, but there I need it because otherwise some battery stuff
is not done.
In my case the error is "no response" and I did not experience unduly
CPU load.