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    SubjectRe: device driver for the SGI system clock, mmtimer
    On Thu, Sep 16, 2004 at 10:54:51AM -0600, Bjorn Helgaas wrote:
    > On Thursday 16 September 2004 10:32 am, Christoph Lameter wrote:
    > > On Thu, 16 Sep 2004, Bjorn Helgaas wrote:
    > > > Christoph Lameter wrote:
    > > > > The timer hardware was designed around the multimedia timer specification by Intel
    > > > > but to my knowledge only SGI has implemented that standard. The driver was written
    > > > > by Jesse Barnes.
    > > >
    > > > As far as I can see, drivers/char/hpet.c talks to the same hardware.
    > > > HP sx1000 machines (and probably others) also implement the HPET.
    > >
    > > The Intel Multimedia Standard is a earlier and different timer spec.
    >
    > I have a spec that's labelled "IA-PC Multimedia Timers", preliminary
    > draft of June 2000, revision 0.97, which looks like the one mentioned
    > in your patch.
    >
    > I also have something labelled "IA-PC HPET (High Precision Event
    > Timers) Specification", draft of February 2002, revision 0.98,
    > which is what drivers/char/hpet.c supports.
    >
    > I admit I haven't compared them in great detail, but they certainly
    > *look* like they're close enough that the same driver could support
    > both, and the 0.98 revision history only mentions fairly cosmetic
    > changes (like the name :)).

    Indeed, I coded the x86-64 HPET support using the 0.97 spec, and then
    only did a few minor fixups when I got the 0.98 spec.

    > Is there something specific that drivers/char/hpet.c expects that
    > your hardware doesn't implement?

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    Vojtech Pavlik
    SuSE Labs, SuSE CR
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