Kernel 6.11 ignores fixed CPU frequency

CPU: AḾD Ryzen 9 7940 HS
Amd_pstate set to passive mode
Kernel: cachyos-znver4 6.11.0-5

Though min/max Cpu Frequency is set to 2500 Mhz some cores run about 400 Mhz higher.
Frequency is set correctly when using Kernel 6.10 or when using Kernel 6.11 on my Manjaro System.
So this seems to be an CachyOS Kernel issue.

Can you share sudo cachyos-bugreport.sh?

Edit: Why are you using the passive driver instead of the active driver? I’m just curious.

CachyOS does only carry the upcoming 6.12 amd-pstate patches, so maybe check if this is present in the linux-mainline kernel.

Even tough, why not just disabling boost instead of limiting manually via tdp? Doesnt look very useful to me.

Not a great issue to fill an extra bug report.
Was just wondering why its working with Kernel 6.11 in Manjaro and with 6.10 in Cachy.
Meanwhile I set amd_pstate to active. Thought I could only set a fixed Cpu freq when I set amd_pstate to passive.

Waiting for linux-zen 6.11 to be available. Will check if it’s working there.

The command doesn’t “fill” anything. It just grabs logs from your system via journalctl, dmesg, etc to see whats wrong.

Why you dont use the disable boost function, e.g via power-profiles-daemon put to powersave and then it will disable the boost. That will help you more then using the passive driver and switching their manually things around.

We had a lot of discussion, testing together with AMD.

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What software is this?

tlp-gui is it

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Question is not about boost. It’s why Cachy Kernel 6.11 does not keep a fixed set CPU Freq, while Cachy Kernel 6.10 does, and while Manjaro Kernel 6.11 does.
At least on my system.
The issue is the same with boost disabled, and with amd_pstate set to active.

Actually, you can try to bisect through this, even tough I have tried to set a fixed freq on my 9950X and have zero problems.

We are carrying the 6.12 amd-pstate patches, as you can see here: kernel-patches/6.11/0001-amd-pstate.patch at master · CachyOS/kernel-patches · GitHub

You can try to build the kernel without these patches, and if it works you can do a report to AMD.

This is my Manjaro System. Kernel 6.11.0-3. None of the cores goes beyond 2500 Mhz.

So it is very likely, that the 6.12 patches are the culprit.
Hopefully it gets fixed until 6.12 release.
Thanks so far!

Can you run the command with passive driver and you setting the min-max freqs? From this log, it’s using the active driver and there are no apparent log messages that help figure out what the issue is.

Also, please test it with the official arch linux kernel Arch Linux - linux 6.11.arch1-1 (x86_64)

so that we can report this issue to AMD.

Tested with linux 6.11.arch1-1.
Working, no such issue.
On my Manjaro System I tested with Kernel 6.12. rc0.
The issue is the same.
So it’s definetly the amd_pstate patch from 6.12 causing this issue on my CPU.

Also tested with Linux 6.11.0 zen 1-1.
Working, no such issue.

I don’t know if I’ve asked before but can you please share log sudo cachyos-bugreport.sh after you tried to reproduce the bug. We can forward to our contact at AMD after.

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Do you know how to bisect?
We have sent to AMD the report, but they dont see what the issue would be. So, we need to go through every commit and compile a kernel.

You would need to revert every commit per build. If you need help, let us know.

Oh, sorry, that’s too complicated and too much action for the issue for me.
I guess maybe other users will come up with the issue and it gets fixed until final 6.12 release.
For now I use the 6.11 zen-kernel.