Re: [PATCH 1/3] intel_pstate: skip the driver if Sun server has ACPI _PPC method

[Dirk Brandewie]

On 11/19/2014 12:22 PM, Linda Knippers wrote:
> On 11/18/2014 3:37 AM, Ethan Zhao wrote:
> > Oracle Sun X86 servers have dynamic power capping capability that works via
> > ACPI _PPC method etc, so skip loading this driver if Sun server has ACPI _PPC
> > enabled.
> >
> > Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
> > ---
> >   drivers/cpufreq/intel_pstate.c | 20 ++++++++++++++++++++
> >   1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> > index 27bb6d3..5498eb0 100644
> > --- a/drivers/cpufreq/intel_pstate.c
> > +++ b/drivers/cpufreq/intel_pstate.c
> > @@ -943,6 +943,21 @@ static bool intel_pstate_no_acpi_pss(void)
> >   	return true;
> >   }
> >
> > +static bool intel_pstate_has_acpi_ppc(void)
> > +{
> > +	int i;
> > +
> > +	for_each_possible_cpu(i) {
> > +		struct acpi_processor *pr = per_cpu(processors, i);
> > +
> > +		if (!pr)
> > +			continue;
> > +		if (acpi_has_method(pr->handle, "_PPC"))
> > +			return true;
> > +	}
> > +	return false;
> > +}
> > +
> >   struct hw_vendor_info {
> >   	u16  valid;
> >   	char oem_id[ACPI_OEM_ID_SIZE];
> > @@ -952,6 +967,7 @@ struct hw_vendor_info {
> >   /* Hardware vendor-specific info that has its own power management modes */
> >   static struct hw_vendor_info vendor_info[] = {
> >   	{1, "HP    ", "ProLiant"},
> > +	{1, "ORACLE", ""},
> >   	{0, "", ""},
> >   };
> >
> > @@ -969,12 +985,16 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
> >   		    !strncmp(hdr.oem_table_id, v_info->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
> >   		    intel_pstate_no_acpi_pss())
> >   			return true;
> > +		if (!strncmp(hdr.oem_id, v_info->oem_id, ACPI_OEM_ID_SIZE) &&
> > +			intel_pstate_has_acpi_ppc())
>
> We need try this on a few platforms to make sure this patch doesn't break the
> HP platforms that may or may not need this driver, depending on the BIOS settings.

It looks like HP systems would get swept up in this check too if they have _PPC

What about extending the hw_vendor_info struct to include whether _PSS or
_PPC should be done for the platform since it appears that oracle and HP
have implemented similar functionality using two different methods.


> I don't suppose you tested on a ProLiant too?
>
> -- ljk
>
> > +			return true;
> >   	}
> >
> >   	return false;
> >   }
> >   #else /* CONFIG_ACPI not enabled */
> >   static inline bool intel_pstate_platform_pwr_mgmt_exists(void) { return false; }
> > +static inline bool intel_pstate_has_acpi_ppc(void) { return false; }
> >   #endif /* CONFIG_ACPI */
> >
> >   static int __init intel_pstate_init(void)

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