linux-kernel - Re: [PATCH v2 1/2] cpufreq: Allow drivers to advertise boost enabled

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Date: Thu, 27 Jun 2024 11:59:14 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <mario.limonciello@....com>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sibi Sankar <quic_sibis@...cinc.com>, Dhruva Gole <d-gole@...com>, 
	Viresh Kumar <viresh.kumar@...aro.org>, "Gautham R . Shenoy" <gautham.shenoy@....com>, 
	Dietmar Eggemann <dietmar.eggemann@....com>, Yipeng Zou <zouyipeng@...wei.com>, 
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH v2 1/2] cpufreq: Allow drivers to advertise boost enabled

On Wed, Jun 26, 2024 at 10:47 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> The behavior introduced in commit f37a4d6b4a2c ("cpufreq: Fix per-policy
> boost behavior on SoCs using cpufreq_boost_set_sw()") sets up the boost
> policy incorrectly when boost has been enabled by the platform firmware
> initially even if a driver sets the policy up.
>
> This is because policy_has_boost_freq() assumes that there is a frequency
> table set up by the driver and that the boost frequencies are advertised
> in that table. This assumption doesn't work for acpi-cpufreq or
> amd-pstate. Only use this check to enable boost if it's not already
> enabled instead of also disabling it if alreayd enabled.
>
> Reviewed-by: Sibi Sankar <quic_sibis@...cinc.com>
> Reviewed-by: Dhruva Gole <d-gole@...com>
> Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>
> Fixes: f37a4d6b4a2c ("cpufreq: Fix per-policy boost behavior on SoCs using cpufreq_boost_set_sw()")

CC: stable I suppose?

> Suggested-by: Viresh Kumar <viresh.kumar@...aro.org>
> Suggested-by: Gautham R. Shenoy <gautham.shenoy@....com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> Cc: Sibi Sankar <quic_sibis@...cinc.com>
> Cc: Dietmar Eggemann <dietmar.eggemann@....com>
> Cc: Viresh Kumar <viresh.kumar@...aro.org>
> Cc: Dhruva Gole <d-gole@...com>
> Cc: Yipeng Zou <zouyipeng@...wei.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> v1->v2
>  * Pick up tags
> ---
>  drivers/cpufreq/cpufreq.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 1fdabb660231..270ea04fb616 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1430,7 +1430,8 @@ static int cpufreq_online(unsigned int cpu)
>                 }
>
>                 /* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
> -               policy->boost_enabled = cpufreq_boost_enabled() && policy_has_boost_freq(policy);
> +               if (cpufreq_boost_enabled() && policy_has_boost_freq(policy))
> +                       policy->boost_enabled = true;
>
>                 /*
>                  * The initialization has succeeded and the policy is online.
> --