linux-kernel - Re: [PATCH v3 0/5] AMD Pstate driver Urgent Change

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Message-ID: <CAJZ5v0gZxQOmHsx6=rwuKQbhi-tUTW1nvHk2wY3xpSEJgh+AVg@mail.gmail.com>
Date:   Mon, 21 Nov 2022 20:23:54 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Perry Yuan <Perry.Yuan@....com>
Cc:     rafael.j.wysocki@...el.com, ray.huang@....com,
        viresh.kumar@...aro.org, Mario.Limonciello@....com,
        Nathan.Fontenot@....com, Alexander.Deucher@....com,
        Deepak.Sharma@....com, Shimmer.Huang@....com, Li.Meng@....com,
        Xiaojian.Du@....com, wyes.karny@....com, gautham.shenoy@....com,
        ananth.narayan@....com, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/5] AMD Pstate driver Urgent Change

On Thu, Nov 17, 2022 at 8:36 AM Perry Yuan <Perry.Yuan@....com> wrote:
>
> The patchset changed amd-pstate driver as built-in type to resolve the
> driver loading sequence problem, otherwise the acpi-cpufreq driver will
> be loaded as the default cpufreq scaling driver instead of amd-pstate.
>
> Some new kernel parameters are added to allow user to disable pstate driver
> and load driver with passive mode which use governors to do the
> frequency scaling control.
>
> * `amd_pstate=disabled` or no parameters will not load pstate driver.
> * `amd_pstate=passive` will load pstate driver with passive mode.
>
> Set the `amd_pstate` driver disabled by default because of performance
> degradation on a number of AMD ASICs in the passive mode driver,
> especially the shared memory support processors.
>
> EPP support for the amd_pstate driver is under review. With EPP support,
> the said performance issue is resolved. Once that gets upstream,
> the `active` mode amd_pstate_epp driver may be enabled by default.
>
> Changes from v2:
>  * pick up Acked-by flag of Huang Rui
>  * fix typo in the cover letter
>
> Changes from v1:
>  * fix commit info in v1 patch PATCH 4/5
>  * pick up Reviewed-by flag of Gautham R. Shenoy
>  * pick up Tested-by flag of  Wyes Karny
>
> v2: https://lore.kernel.org/lkml/20221117071910.3347052-1-Perry.Yuan@amd.com/
> v1: https://lore.kernel.org/lkml/20221117024955.3319484-1-Perry.Yuan@amd.com/
>
> Perry Yuan (4):
>   cpufreq: amd-pstate: change amd-pstate driver to be built-in type
>   cpufreq: amd-pstate: add amd-pstate driver parameter for mode
>     selection
>   Documentation: amd-pstate: add driver working mode introduction
>   Documentation: add amd-pstate kernel command line options
>
> Wyes Karny (1):
>   cpufreq: amd-pstate: cpufreq: amd-pstate: reset MSR_AMD_PERF_CTL
>     register at init
>
>  .../admin-guide/kernel-parameters.txt         | 11 +++++
>  Documentation/admin-guide/pm/amd-pstate.rst   | 30 +++++-------
>  drivers/cpufreq/Kconfig.x86                   |  2 +-
>  drivers/cpufreq/amd-pstate.c                  | 49 +++++++++++++------
>  4 files changed, 59 insertions(+), 33 deletions(-)
>
> --

I have applied this series as 6.1-rc7 material.

Please let me know if you'd rather want to defer it till 6.2-rc1.

Thanks!