nfr/linux-configs
nfr/linux-configs
1
1
Fork 0
Code Issues Activity

amd_pstate: Enable if UEFI fw does support it #1

New issue
Closed
opened 2023-08-06 08:52:31 +02:00 by nfr · 1 comment
nfr commented 2023-08-06 08:52:31 +02:00
Owner
Copy link

It would be nice to test and probably use amd_pstate, but it seems as the EFI/fw currently does not support a necessary ACPI feature:

amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

https://forums.lenovo.com/t5/Other-Linux-Discussions/amd-pstate-driver-support-for-AMD-laptops/m-p/5135917

It would be nice to test and probably use amd_pstate, but it seems as the EFI/fw currently does not support a necessary ACPI feature: `amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled` https://forums.lenovo.com/t5/Other-Linux-Discussions/amd-pstate-driver-support-for-AMD-laptops/m-p/5135917
nfr commented 2025-07-26 10:37:46 +02:00
Author
Owner
Copy link

Obsolete, probably not supported by hardware:

https://forums.lenovo.com/t5/Other-Linux-Discussions/amd-pstate-driver-support-for-AMD-laptops/m-p/5135917?page=12#6602223

After digging into the topic, here's what I've found:

Zen 2 processors do not expose the necessary MSR (Model-Specific Register) entries required for CPPC (Collaborative Processor Performance Control) support, as defined in processor programming reference documentation. For Lenovo systems using Zen 2, this means CPPC cannot be enabled without significant backporting of firmware and ACPI support—which Lenovo has chosen not to pursue. While CPPC typically relies on MSRs and CPC (Collaborative Performance Control) interfaces, some other manufacturers have implemented partial CPPC support on Zen 2 platforms by utilizing PCCT (Platform Communications Channel Table) as a workaround instead of MSRs.
It's important to note that any attempts to force CPPC on Zen 2 through Linux kernel patches, boot flags, or other software-based hacks are ineffective due to the fundamental lack of hardware and firmware support. So save yourself the time and effort.
In contrast, later generations (e.g., Zen 3 and beyond) fully support CPPC with MSR, making them far more compatible with modern CPU frequency scaling and power management features in both Windows and Linux environments.

-- user "mooboo"

Obsolete, probably not supported by hardware: https://forums.lenovo.com/t5/Other-Linux-Discussions/amd-pstate-driver-support-for-AMD-laptops/m-p/5135917?page=12#6602223 > After digging into the topic, here's what I've found: > > Zen 2 processors do not expose the necessary MSR (Model-Specific Register) entries required for CPPC (Collaborative Processor Performance Control) support, as defined in processor programming reference documentation. For Lenovo systems using Zen 2, this means CPPC cannot be enabled without significant backporting of firmware and ACPI support—which Lenovo has chosen not to pursue. While CPPC typically relies on MSRs and CPC (Collaborative Performance Control) interfaces, some other manufacturers have implemented partial CPPC support on Zen 2 platforms by utilizing PCCT (Platform Communications Channel Table) as a workaround instead of MSRs. > It's important to note that any attempts to force CPPC on Zen 2 through Linux kernel patches, boot flags, or other software-based hacks are ineffective due to the fundamental lack of hardware and firmware support. So save yourself the time and effort. > In contrast, later generations (e.g., Zen 3 and beyond) fully support CPPC with MSR, making them far more compatible with modern CPU frequency scaling and power management features in both Windows and Linux environments. -- user "mooboo"
nfr closed this issue 2025-07-26 10:37:46 +02:00
Sign in to join this conversation.
No Branch/Tag specified
Branches Tags
master
updates
No results found.
Labels
Clear labels
No items
No labels
Milestone
Clear milestone
No items
No milestone
Projects
Clear projects
No items
No project
Assignees
Clear assignees
No assignees
1 participant
Notifications
Due date
The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference: nfr/linux-configs#1
No description provided.
Delete branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?