linux-kernel - Re: [RFC PATCH v4 03/21] x86/hpet: Calculate ticks-per-second in a separate function

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Date:   Wed, 19 Jun 2019 01:13:45 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
cc:     Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...e.de>,
        Ashok Raj <ashok.raj@...el.com>,
        Joerg Roedel <joro@...tes.org>,
        Andi Kleen <andi.kleen@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
        Stephane Eranian <eranian@...gle.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Randy Dunlap <rdunlap@...radead.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
        Ricardo Neri <ricardo.neri@...el.com>,
        "H. Peter Anvin" <hpa@...or.com>, Tony Luck <tony.luck@...el.com>,
        Clemens Ladisch <clemens@...isch.de>,
        Arnd Bergmann <arnd@...db.de>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [RFC PATCH v4 03/21] x86/hpet: Calculate ticks-per-second in a
 separate function

On Tue, 18 Jun 2019, Ricardo Neri wrote:
> On Fri, Jun 14, 2019 at 05:54:05PM +0200, Thomas Gleixner wrote:
> > 
> > So we already have ticks per second, aka frequency, right? So why do we
> > need yet another function instead of using the value which is computed
> > once? The frequency of the HPET channels has to be identical no matter
> > what. If it's not HPET is broken beyond repair.
> 
> I don't think it needs to be recomputed again. I missed the fact that
> the frequency was already computed here.
> 
> Also, the hpet char driver has its own frequency computation. Perhaps it
> could also obtain it from here, right?

No. It's separate on purpose. Hint: IA64, aka Itanic

Thanks,

	tglx