Re: [PATCH] powercap / RAPL : remove dependency on iosf_mbi

[Pengyu Ma]

On 09/22/2015 05:36 AM, Jacob Pan wrote:
> On Mon, 21 Sep 2015 11:48:14 +0800
> Pengyu Ma <pengyu.ma@xxxxxxxxxxxxx> wrote:
>
> > On 09/18/2015 11:43 PM, Jacob Pan wrote:
> > > On Fri, 18 Sep 2015 02:09:55 +0200
> > > "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> wrote:
> > >
> > > > On Thursday, September 17, 2015 03:31:41 PM Pengyu Ma wrote:
> > > > > iosf_mbi is supported on Quark, Braswell, Baytrail and some Atom
> > > > > SoC, but RAPL is not limited to these SoC, it supports almost
> > > > > Intel CPUs. Remove this dependece to make RAPL support more Intel
> > > > > CPUs.
> > > > >
> > > > > Please select IOSF_MBI on Atom SoCs.
> > > Unlike Quark, I don't think we want to or do differentiate Atom from
> > > other x86 at compile time. IOSF driver can be compiled as a module
> > > also, therefore RAPL driver needs this explicit dependency at
> > > compile time.
> > As commit had exported iosf_mbi to let user use it.
> >
> > commit aa8e4f22ab7773352ba3895597189b8097f2c307
> > Author: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> > Date:   Wed Aug 27 14:40:39 2014 -0700
> >
> >       x86/iosf: Add Kconfig prompt for IOSF_MBI selection
> >
> >
> > While selecting IOSF_MBI is preferred, it does mean carrying extra
> > code on non-SoC architectures.
> >
> > We can NOT force user to build in iosf_mbi if they want use RAPL on
> > haswell/broadwell/skylake.
> > And RAPL can be compiled and worked well on haswell/broadwell/skylake
> > without IOSF_MBI.
> > RAPL is really NOT depended on IOSF_MBI.
> True for haswell/broadwell/skylake platforms. But if we want binary
> compatibility for Atom and Core, I can' see how simply removing the
> dependency would work, unless we have runtime detection of IOSF.
If you want use iosf_mbi on atom, please select it on generic x86 config.
But not force it depend on another feature that not related on it with 
other boards.
I don't care how iosf_mbi is added to kernel config, but why should I be 
forced to add it if I want use RAPL?
It doesn't make any sense.

Pengyu

> > Pengyu
> > > > > Signed-off-by: Pengyu Ma <pengyu.ma@xxxxxxxxxxxxx>
> > > > Jacob?
> > > >
> > > > > ---
> > > > >    drivers/powercap/Kconfig | 2 +-
> > > > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/powercap/Kconfig b/drivers/powercap/Kconfig
> > > > > index 85727ef..a7c81b5 100644
> > > > > --- a/drivers/powercap/Kconfig
> > > > > +++ b/drivers/powercap/Kconfig
> > > > > @@ -17,7 +17,7 @@ if POWERCAP
> > > > >    # Client driver configurations go here.
> > > > >    config INTEL_RAPL
> > > > >    	tristate "Intel RAPL Support"
> > > > > -	depends on X86 && IOSF_MBI
> > > > > +	depends on X86
> > > > >    	default n
> > > > >    	---help---
> > > > >    	  This enables support for the Intel Running Average
> > > > > Power Limit (RAPL)
> > > [Jacob Pan]
> [Jacob Pan]

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