linux-kernel - Re: [PATCH 05/15] cpufreq: amd: Set policy->boost

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Message-ID: <ebd0ad3c-7f91-4a59-b32a-1de98341ad13@amd.com>
Date: Thu, 30 Jan 2025 14:45:59 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: Viresh Kumar <viresh.kumar@...aro.org>,
 "Rafael J. Wysocki" <rafael@...nel.org>, Huang Rui <ray.huang@....com>,
 "Gautham R. Shenoy" <gautham.shenoy@....com>,
 Mario Limonciello <mario.limonciello@....com>,
 Perry Yuan <perry.yuan@....com>
Cc: linux-pm@...r.kernel.org, Vincent Guittot <vincent.guittot@...aro.org>,
 Lifeng Zheng <zhenglifeng1@...wei.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 05/15] cpufreq: amd: Set policy->boost_supported

Hello Viresh,

On 1/24/2025 2:28 PM, Viresh Kumar wrote:
> With a later commit, the cpufreq core will call the ->set_boost()
> callback only if the policy supports boost frequency. The
> boost_supported flag is set by the cpufreq core if policy->freq_table is
> set and one or more boost frequencies are present.
> 
> For other drivers, the flag must be set explicitly.
> 
> The policy->boost_enabled flag is set by the cpufreq core once the
> policy is initialized, don't set it anymore.

This patch uncovers a bug in the amd_pstate mode switch path (e.g when 
we do "echo passive > /sys/devices/system/cpu/amd_pstate/status"). 
I have posted a fix for it at 
https://lore.kernel.org/all/20250130085251.155146-1-dhananjay.ugwekar@amd.com/T/#u

Can we try to merge this fix before your patch?, so we fix the bug 
before it is uncovered. Currently, the fix is based on top of superm1/bleeding-edge 
(amd-pstate maintainer's dev tree). It wont apply cleanly on your tree i.e. 
vireshk/pm/cpufreq/boost. I can rebase it on your tree and repost, if needed.

Thanks,
Dhananjay

> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/cpufreq/amd-pstate.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index d7630bab2516..8d3cc494c92c 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -995,7 +995,7 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	policy->cpuinfo.min_freq = min_freq;
>  	policy->cpuinfo.max_freq = max_freq;
>  
> -	policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
> +	policy->boost_supported = READ_ONCE(cpudata->boost_supported);
>  
>  	/* It will be updated by governor */
>  	policy->cur = policy->cpuinfo.min_freq;
> @@ -1480,7 +1480,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	policy->min = policy->cpuinfo.min_freq;
>  	policy->max = policy->cpuinfo.max_freq;
>  
> -	policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
> +	policy->boost_supported = READ_ONCE(cpudata->boost_supported);
>  
>  	/*
>  	 * Set the policy to provide a valid fallback value in case