Re: [PATCH v3 1/2] ACPI: CPPC: Disable FIE if registers in PCC regions

[Jeremy Linton <jeremy.linton@xxxxxxx>]

Hi,

On 8/24/22 01:13, Viresh Kumar wrote:
> On 18-08-22, 16:16, Jeremy Linton wrote:
> > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> > +bool cppc_perf_ctrs_in_pcc(void)
> > +{
> > +	int cpu;
> > +
> > +	for_each_present_cpu(cpu) {
> > +		struct cpc_register_resource *ref_perf_reg;
> > +		struct cpc_desc *cpc_desc;
> > +
> > +		cpc_desc = per_cpu(cpc_desc_ptr, cpu);
> > +
> > +		if (CPC_IN_PCC(&cpc_desc->cpc_regs[DELIVERED_CTR]) ||
> > +		    CPC_IN_PCC(&cpc_desc->cpc_regs[REFERENCE_CTR]) ||
> > +		    CPC_IN_PCC(&cpc_desc->cpc_regs[CTR_WRAP_TIME]))
> > +			return true;
> > +
> > +
> > +		ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
> > +
> > +		/*
> > +		 * If reference perf register is not supported then we should
> > +		 * use the nominal perf value
> > +		 */
> > +		if (!CPC_SUPPORTED(ref_perf_reg))
> > +			ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
> > +
> > +		if (CPC_IN_PCC(ref_perf_reg))
> > +			return true;
> > +	}
>
> Add a blank line here please.

Sure,

> > +	return false;
> > +}
> > +EXPORT_SYMBOL_GPL(cppc_perf_ctrs_in_pcc);
> > +
> >   /**
> >    * cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
> >    * @cpunum: CPU from which to read counters.
> > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> > index 24eaf0ec344d..32fcb0bf74a4 100644
> > --- a/drivers/cpufreq/cppc_cpufreq.c
> > +++ b/drivers/cpufreq/cppc_cpufreq.c
> > @@ -63,7 +63,15 @@ static struct cppc_workaround_oem_info wa_info[] = {
> >   
> >   static struct cpufreq_driver cppc_cpufreq_driver;
> >   
> > +static enum {
> > +	FIE_UNSET = -1,
> > +	FIE_ENABLED,
> > +	FIE_DISABLED
> > +} fie_disabled = FIE_UNSET;
> > +
> >   #ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE
> > +module_param(fie_disabled, int, 0444);
> > +MODULE_PARM_DESC(fie_disabled, "Disable Frequency Invariance Engine (FIE)");
> >   
> >   /* Frequency invariance support */
> >   struct cppc_freq_invariance {
> > @@ -158,7 +166,7 @@ static void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy)
> >   	struct cppc_freq_invariance *cppc_fi;
> >   	int cpu, ret;
> >   
> > -	if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
> > +	if (fie_disabled)
> >   		return;
> >   
> >   	for_each_cpu(cpu, policy->cpus) {
> > @@ -199,7 +207,7 @@ static void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy)
> >   	struct cppc_freq_invariance *cppc_fi;
> >   	int cpu;
> >   
> > -	if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
> > +	if (fie_disabled)
> >   		return;
> >   
> >   	/* policy->cpus will be empty here, use related_cpus instead */
> > @@ -229,7 +237,21 @@ static void __init cppc_freq_invariance_init(void)
> >   	};
> >   	int ret;
> >   
> > -	if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
> > +	switch (fie_disabled) {
> > +	/* honor user request */
> > +	case FIE_DISABLED:
> > +	case FIE_ENABLED:
> > +		break;
> > +	case FIE_UNSET:
> > +	default:
> > +		fie_disabled = FIE_ENABLED;
> > +		if (cppc_perf_ctrs_in_pcc()) {
> > +			pr_info("FIE not enabled on systems with registers in PCC\n");
> > +			fie_disabled = FIE_DISABLED;
> > +		}
> > +		break;
> > +	}
>
> here too.

Sure,

> > +	if (fie_disabled)
> >   		return;
> >   
> >   	kworker_fie = kthread_create_worker(0, "cppc_fie");
> > @@ -247,7 +269,7 @@ static void __init cppc_freq_invariance_init(void)
> >   
> >   static void cppc_freq_invariance_exit(void)
> >   {
> > -	if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
> > +	if (fie_disabled)
> >   		return;
> >   
> >   	kthread_destroy_worker(kworker_fie);
> > @@ -936,6 +958,7 @@ static void cppc_check_hisi_workaround(void)
> >   		    wa_info[i].oem_revision == tbl->oem_revision) {
> >   			/* Overwrite the get() callback */
> >   			cppc_cpufreq_driver.get = hisi_cppc_cpufreq_get_rate;
> > +			fie_disabled = FIE_DISABLED;
> >   			break;
> >   		}
> >   	}
> > diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> > index f73d357ecdf5..c5614444031f 100644
> > --- a/include/acpi/cppc_acpi.h
> > +++ b/include/acpi/cppc_acpi.h
> > @@ -140,6 +140,7 @@ extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
> >   extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
> >   extern int cppc_set_enable(int cpu, bool enable);
> >   extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
> > +extern bool cppc_perf_ctrs_in_pcc(void);
> >   extern bool acpi_cpc_valid(void);
> >   extern bool cppc_allow_fast_switch(void);
> >   extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data);
> > @@ -173,6 +174,10 @@ static inline int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps)
> >   {
> >   	return -ENOTSUPP;
> >   }
> > +static inline bool cppc_perf_ctrs_in_pcc(void)
> > +{
> > +	return false;
> > +}
> >   static inline bool acpi_cpc_valid(void)
> >   {
> >   	return false;
>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>


Thanks for looking at this.