linux-kernel - Re: [PATCH] cpufreq/amd-pstate: Fix setting scaling max/min freq values

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Date: Mon, 22 Jan 2024 20:27:07 +0530
From: Wyes Karny <wkarny@...il.com>
To: Mario Limonciello <mario.limonciello@....com>
Cc: ray.huang@....com, rafael@...nel.org, viresh.kumar@...aro.org, 
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	stable@...r.kernel.org
Subject: Re: [PATCH] cpufreq/amd-pstate: Fix setting scaling max/min freq values

On Sat, Jan 20, 2024 at 5:49 AM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> Scaling min/max freq values were being cached and lagging a setting
> each time.  Fix the ordering of the clamp call to ensure they work.
>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> Cc: stable@...r.kernel.org
> Cc: wkarny@...il.com
> Fixes: febab20caeba ("cpufreq/amd-pstate: Fix scaling_min_freq and scaling_max_freq update")
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>

Reviewed-by: Wyes Karny <wkarny@...il.com>

> ---
>  drivers/cpufreq/amd-pstate.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 1f6186475715..1791d37fbc53 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1232,14 +1232,13 @@ static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
>         max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
>         min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
>
> +       WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
> +       WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
> +
>         max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
>                         cpudata->max_limit_perf);
>         min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
>                         cpudata->max_limit_perf);
> -
> -       WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
> -       WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
> -
>         value = READ_ONCE(cpudata->cppc_req_cached);
>
>         if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> --
> 2.34.1
>


-- 
Thanks & Regards
Wyes