> This is almost certainly an issue with the ACPI system-controller
> interrupt, which is misconfigured at boot time by many systems.
What exactly do you mean by ``at boot time''? Do you mean it's
misconfigured by the BIOS (or, the ACPI information given by the BIOS
is wrong or is it misconfigured by NetBSD?

> A workaround may be to turn off ACPI if you have it turned on, or
> on if you have it turned off.
Thanks for that hint. GENERIC.NOACPI doesn't exhibit the problem.

> There have been several efforts to add code to NetBSD to fix this
> but I don't believe any have been committed as each turned out to
> be not quite right in some way.
Any way I can help to improve that? Anything I can test?