linux-kernel - Re: [PATCH 2/2] cpufreq: amd-pstate: Use amd_get_highest

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Date: Wed, 26 Jun 2024 19:18:09 +0200
From: Borislav Petkov <bp@...en8.de>
To: Mario Limonciello <mario.limonciello@....com>
Cc: "Gautham R . Shenoy" <gautham.shenoy@....com>,
	Perry Yuan <perry.yuan@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
	"H . Peter Anvin" <hpa@...or.com>, Huang Rui <ray.huang@....com>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Nikolay Borisov <nik.borisov@...e.com>,
	Peter Zijlstra <peterz@...radead.org>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <linux-kernel@...r.kernel.org>,
	"open list:AMD PSTATE DRIVER" <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 2/2] cpufreq: amd-pstate: Use amd_get_highest_perf() to
 lookup perf values

On Tue, Jun 25, 2024 at 11:20:43PM -0500, Mario Limonciello wrote:
> +	/*
> +	 * For AMD CPUs with Family ID 19H and Model ID range 0x70 to 0x7f,
> +	 * the highest performance level is set to 196.
> +	 * https://bugzilla.kernel.org/show_bug.cgi?id=218759
> +	 */
> +	if (cpu_feature_enabled(X86_FEATURE_ZEN4)) {
> +		switch (c->x86_model) {
> +		case 0x70 ... 0x7f:

Aha, so here it is non-inclusive - "<" and not "<=".

So you need to check the model ranges first.

> +			return CPPC_HIGHEST_PERF_PERFORMANCE;
> +		default:
> +			return CPPC_HIGHEST_PERF_DEFAULT;

As for patch 1.

> +		}
> +	}
> +
> +	return CPPC_HIGHEST_PERF_DEFAULT;
>  }
>  EXPORT_SYMBOL_GPL(amd_get_highest_perf);
>  
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 80eaa58f1405..f468d8562e17 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -52,8 +52,6 @@
>  #define AMD_PSTATE_TRANSITION_LATENCY	20000
>  #define AMD_PSTATE_TRANSITION_DELAY	1000
>  #define AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY 600
> -#define CPPC_HIGHEST_PERF_PERFORMANCE	196
> -#define CPPC_HIGHEST_PERF_DEFAULT	166
>  
>  #define AMD_CPPC_EPP_PERFORMANCE		0x00
>  #define AMD_CPPC_EPP_BALANCE_PERFORMANCE	0x80

This already doesn't apply:

checking file arch/x86/kernel/cpu/amd.c
checking file drivers/cpufreq/amd-pstate.c
Hunk #1 FAILED at 52.

-- 
Regards/Gruss,
    Boris.

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