Linux 5.12 Should See ACPI Platform Profile Support To Alter System Thermal/Power Levels
Written by Michael Larabel in Hardware on 31 December 2020 at 04:57 PM EST. 13 Comments
HARDWARE --
Thanks to the ongoing upstream improvements being pursued by Lenovo as part of their effort to enhance their product support, the Linux power management tree has picked up the initial ACPI Platform Profile implementation for benefiting newer devices like Lenovo laptops.

The ACPI Platform Profile support is around modifying the system's operating profile to control characteristics around power/performance levels, thermal, and fan speed behavior. The Linux kernel ACPI Platform Profile support allows for the operating profile to be modified via sysfs.

The overall concept is similar to that of what's found in Linux 5.11 with Intel's INT340X "workload hints" support but rather than just being around Intel SoCs, this is at the platform level for the entire device on supported (newer) hardware.

Via /sys/firmware/acpi/platform_profile the desired platform profile can be written whether the system should be gearing up for the best performance or rather optimized for thermal / power efficiency. The /sys/firmware/acpi/platform_profile_choices interface will report available platform profile options for a given system. The basic modes are low-power, cool, quiet, balanced, and performance.

Building off this common Power Platform infrastructure, patches are pending for the ThinkPad ACPI driver to make use of it. Lenovo devices with DYTC Version 5 or newer support the Platform Profile capability. With time other hardware vendors will likely make use of the Platform Profile functionality as well and there has seemingly been some interest by Dell while it has been Lenovo driving these patches forward in cooperation with Red Hat.

Over in user-space, there are patches pending for the Power Profiles Daemon for making use of the new interface. There is also talk of potentially tieing this platform profile functionality into the likes of other ongoing features like lap proximity to avoid running in the performance (hot) mode if the laptop is running on your lap.


The Platform Profile support was queued into linux-pm's bleeding-edge Git branch and in turn should make its way into "-next" after testing. Thus for the Linux 5.12 release next spring should be this infrastructure plus at least the ThinkPad ACPI driver support.
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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter or contacted via MichaelLarabel.com.

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