linux-kernel - Re: [PATCH] acpi-cpufreq: Fix nominal_freq units to KHz in get_max_boost

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Message-ID: <CAJZ5v0h27Re4UwoyCrauNfQupojpfwKSOzSppC9mwR-ATWD3Vg@mail.gmail.com>
Date: Thu, 29 May 2025 15:23:42 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: "Gautham R. Shenoy" <gautham.shenoy@....com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>, 
	Mario Limonciello <mario.limonciello@....com>, Manu Bretelle <chantr4@...il.com>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] acpi-cpufreq: Fix nominal_freq units to KHz in get_max_boost_ratio()

On Thu, May 29, 2025 at 10:52 AM Gautham R. Shenoy
<gautham.shenoy@....com> wrote:
>
> commit 083466754596 ("cpufreq: ACPI: Fix max-frequency computation")
> modified get_max_boost_ratio() to return the nominal_freq advertised
> in the _CPC object. This was for the purposes of computing the maximum
> frequency. The frequencies advertised in _CPC objects are in
> MHz. However, cpufreq expects the frequency to be in KHz. Since the
> nominal_freq returned by get_max_boost_ratio() was not in KHz but
> instead in MHz,the cpuinfo_max_frequency that was computed using this
> nominal_freq was incorrect and an invalid value which resulted in
> cpufreq reporting the P0 frequency as the cpuinfo_max_freq.
>
> Fix this by converting the nominal_freq to KHz before returning the
> same from get_max_boost_ratio().
>
> Reported-by: Manu Bretelle <chantr4@...il.com>
> Closes: https://lore.kernel.org/lkml/aDaB63tDvbdcV0cg@HQ-GR2X1W2P57/
> Fixes: 083466754596 ("cpufreq: ACPI: Fix max-frequency computation")
> Signed-off-by: Gautham R. Shenoy <gautham.shenoy@....com>
> ---
>  drivers/cpufreq/acpi-cpufreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index d26b610e4f24..76768fe213a9 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -660,7 +660,7 @@ static u64 get_max_boost_ratio(unsigned int cpu, u64 *nominal_freq)
>         nominal_perf = perf_caps.nominal_perf;
>
>         if (nominal_freq)
> -               *nominal_freq = perf_caps.nominal_freq;
> +               *nominal_freq = perf_caps.nominal_freq * 1000;
>
>         if (!highest_perf || !nominal_perf) {
>                 pr_debug("CPU%d: highest or nominal performance missing\n", cpu);
> --

Applied, thanks!