RE: [REGRESSION] amd-pstate doesn't work since v5.18.11

["Yuan, Perry" <Perry.Yuan@amd.com>]

[AMD Official Use Only - General]

Hi Oleksandr:

> -----Original Message-----
> From: Oleksandr Natalenko <oleksandr@natalenko.name>
> Sent: Wednesday, July 13, 2022 1:40 AM
> To: Limonciello, Mario <Mario.Limonciello@amd.com>; linux-
> kernel@vger.kernel.org
> Cc: Yuan, Perry <Perry.Yuan@amd.com>; Rafael J. Wysocki
> <rafael.j.wysocki@intel.com>; Sasha Levin <sashal@kernel.org>;
> x86@kernel.org; H. Peter Anvin <hpa@zytor.com>; Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>
> Subject: [REGRESSION] amd-pstate doesn't work since v5.18.11
> 
> [CAUTION: External Email]
> 
> Hello Mario.
> 
> The following commits were pulled into v5.18.11:
> 
> ```
> $ git log --oneline --no-merges v5.18.10..v5.18.11 | grep ACPI
> 2783414e6ef7 ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is
> supported
> 3068cfeca3b5 ACPI: CPPC: Only probe for _CPC if CPPC v2 is acked
> 8beb71759cc8 ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is
> supported
> 13bb696dd2f3 ACPI: CPPC: Check _OSC for flexible address space ```
> 
> and now this happens:
> 
> ```
> $ sudo modprobe amd-pstate shared_mem=1
> modprobe: ERROR: could not insert 'amd_pstate': No such device ```
> 
> With v5.18.10 this worked just fine.
> 
> In your upstream commit 8b356e536e69f3a4d6778ae9f0858a1beadabb1f
> you write:
> 
> ```
> If there is additional breakage on the shared memory designs also missing
> this _OSC, additional follow up changes may be needed.
> ```
> 
> So the question is what else should be pulled into the stable tree to
> unbreak amd-pstate?
> 
> Thanks.
> 
> --
> Oleksandr Natalenko (post-factum)
> 

Could you share the lscpu output ?

Perry.