Linux 6.9 To Allow AMD P-State With ACPI CPPC V2 For Threadripper 3000 Series CPUs

[phoronix]

Phoronix: Linux 6.9 To Allow AMD P-State With ACPI CPPC V2 For Threadripper 3000 Series CPUs

The AMD P-State CPU frequency scaling driver works with Zen 2 and newer processors supporting ACPI Collaborative Processor Performance Controls (CPPC) but to date this hasn't worked for Threadripper 3000 series processors with the TRX40 chipset. That though is finally being fixed up with Linux 6.9 thanks to a one-line code change...

https://www.phoronix.com/news/AMD-P-State-TRX40-Linux-6.9

[JEBjames]

Michael

typo

"it was noted in a bug report> last year that" (extra greater than ">" symbol in link)

[indepe]

With the help of a few users relentlessly trying to figure it out and posting the info in a bug report....

[ptr1337]

With the help of a few users relentlessly trying to figure it out and posting the info in a bug report....

It felt more like, that this issue was addressed after torvalds faced it and posted it public. I think it was in the schedutil rework changes lkml.
It should also work for him, if he did updated his motherboard. But good to see it working

[indepe]

It felt more like, that this issue was addressed after torvalds faced it and posted it public. I think it was in the schedutil rework changes lkml.
It should also work for him, if he did updated his motherboard. But good to see it working

As far as I understand it doesn't require a motherboard (BIOS) update. And actually the fix was posted 3 days after a user posted info indicating that this is not a motherboard BIOS issue as was previously assumed. Maybe not the same thing?

[mozin]

AMD P-state was experimental before, so most of the TRX40 users thought it would be enabled eventually, but then we realized it wasn't the case. AMD P-state is now the default and gets more attention from AMD than cpufreq. We have seen it in the case of Linus Torvalds having performance degradation. Honestly, I believe Linus doesn't even care whether it is cpufreq or amd p-state as long as performance doesn't change.

Like Michael said, better late than never, TRX40 platform received the TLC and it works now. We will never know whether it was Linus or us TRX40 users who pointed out where the problem is.

Gnome power-profiles-daemon has better integration with AMD P-state, so more users will benefit from this new driver.

[varikonniemi]

embarrassing for amd...

[luno]

embarrassing for amd...

embarrassing would be understatement

[Keith Myers]

I still can't use anything but passive mode on my Zen 2 7H12 Epyc cpu. If I try to use active mode, it just slows down to a crawl defaulting back to acpi_cpufreq driver.

And X86_FEATURE_CPPC is exposed in the BIOS and is exposed in the _SBIOS_CPC output.

I don't have a clue through all my research why I am unable to use anything but amd_pstate=passive mode.

I am on kernel 6.9.1-generic and I thought the patch for missing Zen 2 model families for Threadripper 3000 cpus would have covered my 0x17 family 0x31 model also based on the patch notes.