linux-kernel - Re: [RFC PATCH 1/4] cpufreq: acpi-cpufreq: Re-factor overriding ACPI PSD

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Message-ID: <52d9b72c-5935-c28c-21cf-b24c6928de81@amd.com>
Date:   Mon, 7 Dec 2020 13:29:03 -0600
From:   Wei Huang <whuang2@....com>
To:     Punit Agrawal <punitagrawal@...il.com>, rjw@...ysocki.net
Cc:     wei.huang2@....com, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, bp@...en8.de, x86@...nel.org
Subject: Re: [RFC PATCH 1/4] cpufreq: acpi-cpufreq: Re-factor overriding ACPI
 PSD



On 11/25/20 8:48 AM, Punit Agrawal wrote:
> Re-factor the code to override the firmware provided frequency domain
> information (via PSD) to localise the checks in one function.
> 
> No functional change intended.
> 
> Signed-off-by: Punit Agrawal <punitagrawal@...il.com>
> Cc: Wei Huang <wei.huang2@....com>
> ---
>  drivers/cpufreq/acpi-cpufreq.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 1e4fbb002a31..b1e7df96d428 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -191,6 +191,20 @@ static int check_amd_hwpstate_cpu(unsigned int cpuid)
>  	return cpu_has(cpu, X86_FEATURE_HW_PSTATE);
>  }
>  
> +static int override_acpi_psd(unsigned int cpu_id)
         ^^^^^
int is fine, but it might be better to use bool. Otherwise I don't see
any issues with this patch.

> +{
> +	struct cpuinfo_x86 *c = &boot_cpu_data;
> +
> +	if (c->x86_vendor == X86_VENDOR_AMD) {
> +		if (!check_amd_hwpstate_cpu(cpu_id))
> +			return false;
> +
> +		return c->x86 < 0x19;
> +	}
> +
> +	return false;
> +}
> +
>  static unsigned extract_io(struct cpufreq_policy *policy, u32 value)
>  {
>  	struct acpi_cpufreq_data *data = policy->driver_data;
> @@ -691,8 +705,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
>  		cpumask_copy(policy->cpus, topology_core_cpumask(cpu));
>  	}
>  
> -	if (check_amd_hwpstate_cpu(cpu) && boot_cpu_data.x86 < 0x19 &&
> -	    !acpi_pstate_strict) {
> +	if (override_acpi_psd(cpu) && !acpi_pstate_strict) {
>  		cpumask_clear(policy->cpus);
>  		cpumask_set_cpu(cpu, policy->cpus);
>  		cpumask_copy(data->freqdomain_cpus,
>