linux-kernel - Re: [PATCH] x86/ACPI/cstate: Output AMD on APCI C1 FFH MWAIT AMD systems

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Date:   Wed, 8 Aug 2018 23:06:36 +0200
From:   Pavel Machek <pavel@....cz>
To:     Len Brown <lenb@...nel.org>
Cc:     Prarit Bhargava <prarit@...hat.com>, linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, X86 ML <x86@...nel.org>,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH] x86/ACPI/cstate: Output AMD on APCI C1 FFH MWAIT AMD
 systems

On Wed 2018-08-08 16:01:41, Len Brown wrote:
> I think it is sufficient to simply delete the "INTEL" in that string.
> 
> In the unlikely event that this "change to a kernel API" breaks
> something, we can add it back.

I'd just leave it alone. But yes, just deleting INTEL is better than
patch below.
								Pavel

> > On Wed 2018-08-08 13:47:35, Prarit Bhargava wrote:
> > > commit 5209654a46ee ("x86/ACPI/cstate: Allow ACPI C1 FFH MWAIT use on AMD
> > > systems") allows use of FFH for ACPI C1 but tools like cpupower and turbostat
> > > display INTEL for the cstate description.
> > >
> > > Output "AMD" for AMD systems with FFH for ACPI C1.
> >
> > Um, is it good idea?
> >
> > First, you are changing kernel API.
> >
> > > @@ -107,9 +108,14 @@ static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
> > >                       "Monitor-Mwait will be used to enter C-%d state\n",
> > >                       cx->type);
> > >       }
> > > -     snprintf(cx->desc,
> > > -                     ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
> > > -                     cx->address);
> > > +     if (c->x86_vendor == X86_VENDOR_INTEL)
> > > +             snprintf(cx->desc,
> > > +                      ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
> > > +                      cx->address);
> > > +     else
> > > +             snprintf(cx->desc,
> > > +                      ACPI_CX_DESC_LEN, "ACPI FFH AMD MWAIT 0x%x",
> > > +                      cx->address);
> >
> > Second, I read it as "Intel MWAIT" instruction is used. Yes, AMD cpu can
> > use Intel MWAIT, too...
> >
> > Third, there are more CPU vendors out there.
> >
> >                                                                         Pavel
> > --
> > (english) http://www.livejournal.com/~pavelmachek
> > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> 
> 
> 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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