[Bug 219348] New: [6.12] amd cpb boost disabling does not lock frequency

[Bug 219348] New: [6.12] amd cpb boost disabling does not lock frequency

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=219348

            Bug ID: 219348
           Summary: [6.12] amd cpb boost disabling does not lock frequency
           Product: Power Management
           Version: 2.5
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: high
          Priority: P3
         Component: cpufreq
          Assignee: linux-pm@vger.kernel.org
          Reporter: ptr1337@cachyos.org
        Regression: No

Created attachment 306956
  --> https://bugzilla.kernel.org/attachment.cgi?id=306956&action=edit
Visulizing the problem

Hi together,

The 6.12 Kernel introduces an amd-pstate regression, which makes disabling
boost not possible. 

The max frequency reported by cpupower is correct (4.3 GHz), when  boost is
disabled but it reaches the max frequency and this is not limited.

I have bisected it down to following commit
https://lore.kernel.org/lkml/20240905163007.1350840-9-superm1@kernel.org/ :

```
cpufreq: amd-pstate: Merge amd_pstate_highest_perf_set() into
amd_get_boost_ratio_numerator()

The special case in amd_pstate_highest_perf_set() is the value used
for calculating the boost numerator.  Merge this into
amd_get_boost_ratio_numerator() and then use that to calculate boost
ratio.

This allows dropping more special casing of the highest perf value.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.sheoy@amd.com>
```

Reverting this commit does fix the **used** frequency limits.
In the attachments is a picture, which visualize this issue.

Info:
```
Operating System: CachyOS Linux 
KDE Plasma Version: 6.1.90
KDE Frameworks Version: 6.6.0
Qt Version: 6.8.0
Kernel Version: 6.12.0-rc1 (64-bit)
Graphics Platform: Wayland
Processors: 32 × AMD Ryzen 9 9950X 16-Core Processor
Memory: 62,4 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 4070 SUPER/PCIe/SSE2
Manufacturer: ASRock
Product Name: X670E Pro RS
```

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[Bug 219348] [6.12] amd cpb boost disabling does not lock frequency

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=219348

Mario Limonciello (AMD) (mario.limonciello@amd.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|linux-pm@vger.kernel.org    |mario.limonciello@amd.com

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