Re: [PATCH RFC 2/5] ACPI / processor: always compile perflib if CONFIG_ACPI_PROCESSOR

[Hanjun Guo]

On 2015å05æ07æ 02:36, Ashwin Chaugule wrote:
> Hello,
>
> On 6 May 2015 at 10:31, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
> > Similar to the  idle, thermal and throttling libraries, always compile
> > the perflib if CONFIG_ACPI_PROCESSOR is enabled. This not only makes
> > perflib alligned with other libraries but also helps in some sanity
> > testing of these ACPI methods even when a particular feature is not
> > enabled in the kernel configuration.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > ---
> >   drivers/acpi/Makefile    |  2 +-
> >   include/acpi/processor.h | 29 -----------------------------
> >   include/linux/cpufreq.h  |  4 ++++
> >   3 files changed, 5 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> > index 8a063e276530..33aef9d8b260 100644
> > --- a/drivers/acpi/Makefile
> > +++ b/drivers/acpi/Makefile
> > @@ -84,7 +84,7 @@ obj-$(CONFIG_ACPI_BGRT)               += bgrt.o
> >   # processor has its own "processor." module_param namespace
> >   processor-y                    := processor_driver.o processor_throttling.o
> >   processor-y                    += processor_idle.o processor_thermal.o
> > -processor-$(CONFIG_CPU_FREQ)   += processor_perflib.o
> > +processor-y                    += processor_perflib.o
>
> I'd prefer that we create a separate kconfig option for this. (perhaps
> even default it to 'y'). This library is quite specific to a certain
> type of CPU performance management methods (includes _PSS and friends)
> which are superseded by CPPC. The OS is not expected to support both
> at runtime, so by keeping this a config option, we can then disable it
> at compile time when CPPC is enabled. We could couple

I agree. CPPC and _PSS are different way of controlling CPU freq,
and I think _PSS may not be used on ARM.

Thanks
Hanjun
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