AMD-Powered Lenovo ThinkPads To Soon Have Working Platform Profile Support On Linux

[phoronix]

Phoronix: AMD-Powered Lenovo ThinkPads To Soon Have Working Platform Profile Support On Linux

Last month I covered the issue of Lenovo's ACPI Platform Profile support for AMD-powered laptops was busted on Linux. The platform profile controls were exposed but in reality did not work. Fortunately, fixed up support for this feature is now on the way to the Linux kernel for letting users choose between better performance or extended battery life and cooler operating device...

https://www.phoronix.com/scan.php?page=news_item&px=AMD-Lenovo-Platform-Profile

[timrichardson]

I have Fedora on my X1 intel-based thinkpad, and when using gnome power profiles, the Thinkpads Fn shortcuts for changing power profiles seem to work (Fn-H,M,L as documented). So that's a convenient way to change. But AMD owners: I'm not really convinced they do much: the battery saving profile severely throttles the CPU. I'm sure this caps the maximum rate of energy it consumes , but it makes the laptop perform like it's ten years old ... if it runs more slowly, things take longer. Considering this could mean you have the screen on longer, and that's a fixed cost independent of CPU frequency, I am not sure this actually saves battery. In idle mode, power consumption is the same regardless of the profile (under F35, stock kernel, or tlp, or power saving profile deliver the same idle which is < 2W with wifi, and they all work with modern standby). Because there is no advantage in idle , I don't think the low power profile is doing anything clever that the kernel (or tlp) does not already do.

PS tlp can also be configured to invoke a certain power profile on battery and another on AC.

[brucethemoose]

I have Fedora on my X1 intel-based thinkpad, and when using gnome power profiles, the Thinkpads Fn shortcuts for changing power profiles seem to work (Fn-H,M,L as documented). So that's a convenient way to change. But AMD owners: I'm not really convinced they do much: the battery saving profile severely throttles the CPU. I'm sure this caps the maximum rate of energy it consumes , but it makes the laptop perform like it's ten years old ... if it runs more slowly, things take longer. Considering this could mean you have the screen on longer, and that's a fixed cost independent of CPU frequency, I am not sure this actually saves battery. In idle mode, power consumption is the same regardless of the profile (under F35, stock kernel, or tlp, or power saving profile deliver the same idle which is < 2W with wifi, and they all work with modern standby). Because there is no advantage in idle , I don't think the low power profile is doing anything clever that the kernel (or tlp) does not already do.

PS tlp can also be configured to invoke a certain power profile on battery and another on AC.

Its definitely different on my (35W) renoir laptop. Idle usage is indeed a little lower in the power saving profile, and even limiting it to 15W with turbo disabled feels just fine. In fact, the only time I really need to take it out of power saving on linux is for threaded, batched workloads, which really pushes Zen out of its sub-3Ghz comfort zone.



IIRC Intel laptops will turbo with the powersave scheduler, and perhaps that part is getting disabled by the GNOME toggle, locking you at base clocks?

[direc85]

I don't really get how this is still so broken, but I'm glad it's getting fixed!

[-MacNuke-]

I guess other non-ThinkPad AMD notebooks from Lenovo are not supported?

[direc85]

Not sure... How could we test this?