linux-kernel - Re: [PATCH v1 4/5] cpufreq: CPPC: Enable fast

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Message-ID: <20220511144116.ir2wyfqwdpnhkldx@bogus>
Date:   Wed, 11 May 2022 15:41:16 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Pierre Gondois <pierre.gondois@....com>
Cc:     linux-kernel@...r.kernel.org, Ionela.Voinescu@....com,
        Sudeep Holla <sudeep.holla@....com>, Dietmar.Eggemann@....com,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Robert Moore <robert.moore@...el.com>,
        linux-acpi@...r.kernel.org, linux-pm@...r.kernel.org,
        devel@...ica.org
Subject: Re: [PATCH v1 4/5] cpufreq: CPPC: Enable fast_switch

On Wed, May 11, 2022 at 03:45:58PM +0200, Pierre Gondois wrote:
> From: Pierre Gondois <Pierre.Gondois@....com>
> 
> The communication mean of the _CPC desired performance can be
> PCC, System Memory, System IO, or Functional Fixed Hardware.
> 
> commit b7898fda5bc7 ("cpufreq: Support for fast frequency switching")
> fast_switching is 'for switching CPU frequencies from interrupt
> context'.
> Writes to SystemMemory and SystemIo are fast and suitable this.
> This is not the case for PCC and might not be the case for FFH.
> 
> Enable fast_switching for the cppc_cpufreq driver in above cases.
> 
> Add cppc_allow_fast_switch() to check the desired performance
> register address space and set fast_switching accordingly.
>

Reviewed-by: Sudeep Holla <sudeep.holla@....com>

-- 
Regards,
Sudeep