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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 18 Apr 2023 14:57:05 +0200
Message-ID: <CAJZ5v0iMcVZMd3YpEC++BZzCwOM2ocYQuK98tm9gQq0fjO41gg@mail.gmail.com>
Subject: Re: [Patch 1/6] cpufreq: use correct unit when verify cur freq
To:     Sumit Gupta <sumitg@nvidia.com>
Cc:     viresh.kumar@linaro.org, rafael@kernel.org,
        ionela.voinescu@arm.com, mark.rutland@arm.com,
        sudeep.holla@arm.com, lpieralisi@kernel.org,
        catalin.marinas@arm.com, will@kernel.org, linux-pm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-tegra@vger.kernel.org, treding@nvidia.com,
        jonathanh@nvidia.com, vsethi@nvidia.com, sdonthineni@nvidia.com,
        sanjayc@nvidia.com, ksitaraman@nvidia.com, bbasu@nvidia.com
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On Tue, Apr 18, 2023 at 1:35 PM Sumit Gupta <sumitg@nvidia.com> wrote:
>
> From: Sanjay Chandrashekara <sanjayc@nvidia.com>
>
> cpufreq_verify_current_freq checks if the frequency returned by
> the hardware has a slight delta with the valid frequency value
> last set and returns "policy->cur" if the delta is within "1 MHz".
> In the comparison, "policy->cur" is in "kHz" but it's compared
> against HZ_PER_MHZ. So, the comparison range becomes "1 GHz".
> Fix this by comparing against KHZ_PER_MHZ instead of HZ_PER_MHZ.
>
> Fixes: f55ae08c8987 ("cpufreq: Avoid unnecessary frequency updates due to mismatch")
> Signed-off-by: Sanjay Chandrashekara <sanjayc@nvidia.com>
> [ sumit gupta: Commit message update ]
> Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
> ---
>  drivers/cpufreq/cpufreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 8b0509f89f1b..6b52ebe5a890 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1732,7 +1732,7 @@ static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, b
>                  * MHz. In such cases it is better to avoid getting into
>                  * unnecessary frequency updates.
>                  */
> -               if (abs(policy->cur - new_freq) < HZ_PER_MHZ)
> +               if (abs(policy->cur - new_freq) < KHZ_PER_MHZ)
>                         return policy->cur;
>
>                 cpufreq_out_of_sync(policy, new_freq);
> --

So this is a fix that can be applied separately from the rest of the
series, isn't it?