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Message-ID: <638e0a6e-10d2-8552-a61f-c4c001a2cbe9@arm.com>
Date:   Mon, 22 Aug 2022 13:08:51 +0100
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Subject: Re: [PATCH v4 2/2] cpufreq: CPPC: Change FIE default
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To:     Jeremy Linton <jeremy.linton@arm.com>
Cc:     rafael@kernel.org, lenb@kernel.org, viresh.kumar@linaro.org,
        robert.moore@intel.com, punit.agrawal@bytedance.com,
        ionela.voinescu@arm.com, pierre.gondois@arm.com,
        linux-kernel@vger.kernel.org, devel@acpica.org,
        linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org
References: <20220819162547.141333-1-jeremy.linton@arm.com>
 <20220819162547.141333-3-jeremy.linton@arm.com>
From:   Lukasz Luba <lukasz.luba@arm.com>
In-Reply-To: <20220819162547.141333-3-jeremy.linton@arm.com>
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On 8/19/22 17:25, Jeremy Linton wrote:
> FIE is mostly implemented as PCC mailboxes on arm machines.  This was
> enabled by default without any data suggesting that it does anything
> but hurt system performance. Lets change the default to 'n' until
> hardware appears which clearly benefits.
> 
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
>   drivers/cpufreq/Kconfig.arm | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 954749afb5fe..ad66d8f15db0 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -22,7 +22,7 @@ config ACPI_CPPC_CPUFREQ
>   config ACPI_CPPC_CPUFREQ_FIE
>   	bool "Frequency Invariance support for CPPC cpufreq driver"
>   	depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY
> -	default y
> +	default n
>   	help
>   	  This extends frequency invariance support in the CPPC cpufreq driver,
>   	  by using CPPC delivered and reference performance counters.

LGTM

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>