On Wed, Dec 21, 2022 at 4:52 PM Pratyush Yadav <ptyadav@xxxxxxxxx> wrote:
>
> In some cases the ACPI table can have an incorrect frequency populated
> for a performance state. For example, in Intel platforms, the Turbo
> frequency is just listed as +1 MHz above the max non-turbo frequency.
Which is a known convention based on compatibility with some older OSes.
> The frequency can actually go much higher based on various factors like
> temperature, voltage, etc.
It can.
> Allow drivers like intel_pstate to fix up performance state frequencies
> with the actual maximum value.
Why do you want to do that?
> While at it, also update the QoS
> constraints if needed to match the new frequency values.
>
> Signed-off-by: Pratyush Yadav <ptyadav@xxxxxxxxx>
> ---
> drivers/acpi/processor_perflib.c | 40 ++++++++++++++++++++++++++++++++
> include/acpi/processor.h | 2 ++
> 2 files changed, 42 insertions(+)
>
> diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
> index 970f04a958cd..4958aee4c024 100644
> --- a/drivers/acpi/processor_perflib.c
> +++ b/drivers/acpi/processor_perflib.c
> @@ -766,3 +766,43 @@ void acpi_processor_unregister_performance(unsigned int cpu)
> mutex_unlock(&performance_mutex);
> }
> EXPORT_SYMBOL(acpi_processor_unregister_performance);
> +
> +int acpi_processor_fixup_perf_state(unsigned int cpu, unsigned int state,
> + unsigned int frequency)
> +{
> + struct acpi_processor *pr;
> + int ret;
> +
> + mutex_lock(&performance_mutex);
> +
> + pr = per_cpu(processors, cpu);
> + if (!pr) {
> + mutex_unlock(&performance_mutex);
> + return -ENODEV;
> + }
> +
> + if (!pr->performance) {
> + mutex_unlock(&performance_mutex);
> + return -EINVAL;
> + }
> +
> + if (state >= pr->performance->state_count) {
> + mutex_unlock(&performance_mutex);
> + return -EINVAL;
> + }
> +
> + pr->performance->states[state].core_frequency = frequency;
> +
> + if (ignore_ppc != 1 && state == pr->performance_platform_limit &&
> + freq_qos_request_active(&pr->perflib_req)) {
> + ret = freq_qos_update_request(&pr->perflib_req,
> + frequency * 1000);
> + if (ret < 0)
> + pr_warn("Failed to update perflib freq constraint: CPU%d (%d)\n",
> + pr->id, ret);
> + }
> +
> + mutex_unlock(&performance_mutex);
> + return 0;
> +}
> +EXPORT_SYMBOL(acpi_processor_fixup_perf_state);
> diff --git a/include/acpi/processor.h b/include/acpi/processor.h
> index 94181fe9780a..daff978cfa7d 100644
> --- a/include/acpi/processor.h
> +++ b/include/acpi/processor.h
> @@ -258,6 +258,8 @@ extern int acpi_processor_preregister_performance(struct
> extern int acpi_processor_register_performance(struct acpi_processor_performance
> *performance, unsigned int cpu);
> extern void acpi_processor_unregister_performance(unsigned int cpu);
> +extern int acpi_processor_fixup_perf_state(unsigned int cpu, unsigned int state,
> + unsigned int frequency);
>
> int acpi_processor_pstate_control(void);
> /* note: this locks both the calling module and the processor module
> --
> 2.38.1
>
