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SubjectRE: HPET drift question
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Yes. Looks like "ti->drift = HPET_DRIFT;" is right here. However, I
would
like to double check this with Bob.

Thanks,
Venki

>-----Original Message-----
>From: Alex Williamson [mailto:alex.williamson@hp.com]
>Sent: Thursday, August 25, 2005 8:17 AM
>To: Pallipadi, Venkatesh
>Cc: robert.picco@hp.com; linux-kernel@vger.kernel.org
>Subject: HPET drift question
>
>Hi Venki,
>
> I'm confused by the calculation of the drift value in the hpet
>driver. The specs defines the recommended minimum hardware
>implementation is a frequency drift of 0.05% or 500ppm. However, the
>drift passed in when registering with the time interpolator is:
>
>ti->drift = ti->frequency * HPET_DRIFT / 1000000;
>
>Isn't that absolute number of ticks per second drift? The time
>interpolator defines the drift in parts per million. Shouldn't this
>simply be:
>
>ti->drift = HPET_DRIFT;
>
>The current code seems to greatly penalize any hpet timer with greater
>than a 1MHz frequency. Thanks,
>
> Alex
>
>--
>Alex Williamson HP Linux & Open Source Lab
>
>
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