linux-kernel - Re: [PATCH 2/2] cpufreq/amd-pstate: Adding Zen4 support in introduction

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Date: Wed, 10 Jan 2024 15:21:20 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Erwan Velu <erwanaliasr1@...il.com>
Cc: Erwan Velu <e.velu@...teo.com>, Huang Rui <ray.huang@....com>, 
	"Rafael J. Wysocki" <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] cpufreq/amd-pstate: Adding Zen4 support in introduction

On Tue, Jan 9, 2024 at 6:58 PM Erwan Velu <erwanaliasr1@...il.com> wrote:
>
> amd-pstate is implemented on Zen4, adding this architecture in the
> introduction.
>
> Signed-off-by: Erwan Velu <e.velu@...teo.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 1f6186475715..9a8d083f6ba5 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -14,7 +14,7 @@
>   * communicate the performance hints to hardware.
>   *
>   * AMD P-State is supported on recent AMD Zen base CPU series include some of
> - * Zen2 and Zen3 processors. _CPC needs to be present in the ACPI tables of AMD
> + * Zen2, Zen3 and Zen4 processors. _CPC needs to be present in the ACPI tables of AMD

IMO, it would be really nice to avoid extending this line so much, but
this is up to the AMD people.

Also, while you are at it, "include" in the first sentence should be
"including" and a new paragraph after "processors." would make this
comment easier to follow from the logical standpoint, because the
first sentence is about the supported platforms and the second one is
about additional requirements (ie. something else).

>   * P-State supported system. And there are two types of hardware implementations
>   * for AMD P-State: 1) Full MSR Solution and 2) Shared Memory Solution.
>   * X86_FEATURE_CPPC CPU feature flag is used to distinguish the different types.
> --