Lenovo's Platform Profile Support For AMD Systems On Linux Has Been Busted

Written by Michael Larabel in AMD on 2 February 2022 at 05:29 AM EST. 17 Comments
ACPI Platform Profile support on Linux has been useful for catering to balancing your power or performance preferences with modern laptops on Linux. It has worked well in general across various devices tested but it turns out to be a dud currently when it comes to AMD Ryzen powered Lenovo systems.

ACPI Platform Profile support allows setting the power/balance/power-savings preference (among other possible profiles) on Linux with recent kernel activity that so far has seen major support available for major laptop brands like Lenovo, Dell, and ASUS. The user's profile preference can be set via a sysfs interface or desktops like KDE Plasma and GNOME have already added convenient user interfaces for setting it nicely from the system settings area.

On supported systems, GNOME offers the ACPI Platform Profile to be set via the "Power Mode" area of the system settings.

While Lenovo ThinkPad laptops with AMD Ryzen processors may be advertising ACPI Platform Profile support on Linux, it's not actually behaving correctly. I had stumbled upon this myself in December with the ThinkPad T14s Gen2 / AMD Ryzen 7 PRO 5850U. Back then I ran some power profile benchmarks on it and was surprised to see no change between the different profiles, unlike Intel-powered Lenovo systems and other laptop brands I have tested over the past year with this ACPI Platform Profile support being available in the kernel.
Lenovo ThinkPad T14s Gen2 Power Mode

Lenovo ThinkPad T14s Gen2 Power Mode

I hadn't the time yet to do any further testing or dig into it any deeper with my ever-long TODO list, while this week an explanation arose... While the code has been in the kernel, Lenovo's support is actually busted for AMD laptops.

This patch working its way to the mainline kernel at least for Linux 5.17 ends up disabling the support for its non-working state. The Lenovo contributed patch explains, "Lenovo AMD based platforms have been offering platform_profiles but they are not working correctly. This is because the mode we are using on the Intel platforms (MMC) is not available on the AMD platforms. This commit adds checking of the functional capabilities returned by the BIOS to confirm if MMC is supported or not. Profiles will not be available if the platform is not MMC capable."

In other words, the Platform Profile support will just be disabled for now on Lenovo systems with AMD processors given this pending patch. Lenovo is looking at other means of properly supporting it for AMD hardware but no solution yet.
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Michael Larabel

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, LinkedIn, or contacted via MichaelLarabel.com.

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