ACPI enable on Thinkpad X60 hangs when temperatures are high

From: Pavel Machek
Date: Mon May 27 2019 - 06:35:35 EST


Hi!

> > So if you compile a kernel, then reboot, boot will hang after "Freeing SMP
> > alternatives memory" (and then wastes power, making thermal situation even worse).
>
> Normally, next message is "smpboot: CPU0: Genuine Intel...".
>
> I added some printks, and check_bugs() returns. Then it goes to ACPI and never
> comes back...
>
> kernel-parameters.txt points to Documentation/acpi/debug.txt, but that one does not exist.
>
> Any ideas what debugging parameters to use for ACPI? I either get nothing or
> so much that machine does not boot...

I ended up adding printks...

It hangs in acpi_hw_set_mode().

ACPI enable: set mode: acpi
ACPI: hw_set_mode
ACPI: hw_set_mode mode switch
ACPI: write_port?
ACPI: os write port

we write to the port but that never returns.

I assume SMM is doing its magic at that point. Any ideas how to debug it further?

Is it possible that it is some kind of screaming interrupt?

Pavel


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