Re: linux-6.6.y: Regression in amd-pstate cpufreq driver since 6.6.34

[Mario Limonciello <mario.limonciello@amd.com>]

On 7/2/2024 4:23, Greg Kroah-Hartman wrote:
> On Tue, Jul 02, 2024 at 11:15:14AM +0200, Greg Kroah-Hartman wrote:
>> On Mon, Jul 01, 2024 at 04:53:20PM -0500, Mario Limonciello wrote:
>>> On 7/1/2024 11:13, Lars Wendler wrote:
>>>> Hello Mario,
>>>>
>>>> Am Mon, 1 Jul 2024 10:58:17 -0500
>>>> schrieb Mario Limonciello <mario.limonciello@amd.com>:
>>>>
>>>>>> I've tested both, 6.9.7 and 6.10-rc6 and they both don't have that
>>>>>> issue. I can disable CPU boost with both kernel versions.
>>>>>
>>>>> Thanks for checking those.  That's good to hear it's only an issue in
>>>>> the LTS series.
>>>>>
>>>>> It means we have the option to either drop that patch from LTS kernel
>>>>> series or identify the other commit(s) that helped it.
>>>>>
>>>>> Can you see if adding this commit to 6.6.y helps you?
>>>>>
>>>>> https://git.kernel.org/superm1/c/8164f743326404fbe00a721a12efd86b2a8d74d2
>>>>
>>>> that commit does not fix the regression.
>>>>
>>>
>>> I think I might have found the issue.
>>>
>>> With that commit backported on 6.6.y in amd_pstate_set_boost() the policy
>>> max frequency is nominal  *1000 [1].
>>>
>>> However amd_get_nominal_freq() already returns nominal *1000 [2].
>>>
>>> If you compare on 6.9 get_nominal_freq() doesn't return * 1000 [3].
>>>
>>> So the patch only makes sense on 6.9 and later.
>>>
>>> We should revert it in 6.6.y.
>>>
>>>
>>>
>>> Greg,
>>>
>>>
>>> Can you please revert 8f893e52b9e0 ("cpufreq: amd-pstate: Fix the
>>> inconsistency in max frequency units") in 6.6.y?
>>
>> Sure, but why only 6.6.y?  What about 6.1.y, should it be reverted from
>> there as well?
> 
> And have now done so.

Thanks; totally agree with you.
I just didn't realize it was backported to 6.1 also.