linux-kernel - RE: [PATCH 3/3] platform/x86: Add Audio domain PG status events

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Date:   Thu, 20 Jul 2017 04:06:14 +0000
From:   "Chakravarty, Souvik K" <souvik.k.chakravarty@...el.com>
To:     "Bhardwaj, Rajneesh" <rajneesh.bhardwaj@...el.com>
CC:     "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "dvhart@...radead.org" <dvhart@...radead.org>,
        "andy@...radead.org" <andy@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Murthy, Shanth" <shanth.murthy@...el.com>
Subject: RE: [PATCH 3/3] platform/x86: Add Audio domain PG status events



> -----Original Message-----
> From: Bhardwaj, Rajneesh
> Sent: Wednesday, July 19, 2017 7:08 PM
> To: Chakravarty, Souvik K <souvik.k.chakravarty@...el.com>
> Cc: platform-driver-x86@...r.kernel.org; dvhart@...radead.org;
> andy@...radead.org; linux-kernel@...r.kernel.org; Murthy, Shanth
> <shanth.murthy@...el.com>
> Subject: Re: [PATCH 3/3] platform/x86: Add Audio domain PG status events
> 
> On Mon, Jul 17, 2017 at 10:48:30AM +0530, Chakravarty, Souvik K wrote:
> >
> >
> > > -----Original Message-----
> > > From: Bhardwaj, Rajneesh
> > > Sent: Friday, July 14, 2017 5:24 PM
> > > To: platform-driver-x86@...r.kernel.org
> > > Cc: dvhart@...radead.org; andy@...radead.org; linux-
> > > kernel@...r.kernel.org; Murthy, Shanth <shanth.murthy@...el.com>;
> > > Chakravarty, Souvik K <souvik.k.chakravarty@...el.com>; Bhardwaj,
> > > Rajneesh <rajneesh.bhardwaj@...el.com>
> > > Subject: [PATCH 3/3] platform/x86: Add Audio domain PG status events
> > >
> > > From: "Murthy, Shanth" <shanth.murthy@...el.com>
> > >
> > > This patch adds events to ioss telemetry to read the power gating
> > > status for the audio domain.
> > >
> > > Signed-off-by: Shanth Murthy <shanth.murthy@...el.com>
> > > Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@...el.com>
> > > ---
> > >  arch/x86/include/asm/intel_telemetry.h        | 2 +-
> > >  drivers/platform/x86/intel_telemetry_pltdrv.c | 6 ++++++
> > >  2 files changed, 7 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/x86/include/asm/intel_telemetry.h
> > > b/arch/x86/include/asm/intel_telemetry.h
> > > index 85029b58d0cd..4eeae0a4f9a2 100644
> > > --- a/arch/x86/include/asm/intel_telemetry.h
> > > +++ b/arch/x86/include/asm/intel_telemetry.h
> > > @@ -17,7 +17,7 @@
> > >  #define INTEL_TELEMETRY_H
> > >
> > >  #define TELEM_MAX_EVENTS_SRAM		28
> > > -#define TELEM_MAX_OS_ALLOCATED_EVENTS	20
> > > +#define TELEM_MAX_OS_ALLOCATED_EVENTS	25
> >
> > This is something that should not be done without testing. There was an
> understanding to not use more than 20 counters in OS, so that tools like
> SoCWatch could use the rest 8 without total reconfiguration of the events.
> With this change we are not leaving much for tools and it may break
> SoCwatch/IMON or other tools dependent on using just 8.
> > The better way for this would be for the userspace tool to configure the
> extra 5 events via add_config() call and not increase the OS usage ceiling.
> >
> > Or you could add some more sysfs apis for get/set events and do it via a
> daemon/script.
> >
> > <snip>....
> 
> Thanks for the review and the feedback Souvik. Ideally user space tools
> should not put a restriction such as this one. It would be good to document
> such details.
Theoretically yes. But many of the tools have no maintaince budget/owner. 

> 
> Is there a plan to support more than 20 events in telemetry driver? If not
> then we can probably think of removing few events and add audio related
> events maintaining total count of 20?

Sure...why not.

> 
> For now i will respin the patches and drop this one.

Thanks. 
I will also add support for an 'add' sysfs entry so that you can configure it easily and not have to fiddle with the default set.

> 
> --
> Best Regards,
> Rajneesh