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Patch acpi_thermal to work on CPUs with independent frequency control.
Needs ReviewPublic

Authored by crahman_gmail.com on Jul 3 2022, 9:02 PM.

Details

Reviewers
cem
Summary

The current acpi_thermal scheme only changes the frequency of CPU0. With
independent processor frequencies, such as with the Cerleron N4120 Quad, this
no longer has an adequate affect upon power consumption.

This patch sets all the processors to the same frequency, following the example of
kern/kern_cpu.c.

Test Plan

Performing a 'make -j 5 buildkernel' with the cooling fan on and off on a GPD MicroPC.

With the fan on and hw.acpi.thermal.tz0._PSV=90C, a build takes 18:16. With
the fan off, passive cooling works well, the target temperature is not
exceeded, and the CPU frequencies are seen to drop as needed. However, the
build takes 25:51.

Diff Detail

Repository
rS FreeBSD src repository - subversion
Lint
Lint OK
Unit
No Unit Test Coverage
Build Status
Buildable 46241
Build 43130: arc lint + arc unit