Messages in this thread | | | From | Dag-Erling Smørgrav <> | Subject | Re: [RFC+PATCH] RTC calibration | Date | Tue, 11 Sep 2007 18:28:06 +0200 |
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Mark Gross <mgross@linux.intel.com> writes: > Is it necessary to change the rtc interface? Can't you detect within > your m48t59 driver that you are getting consistent time adjustments up > or down from whats in the rtc and infer it needs speeding up or slowing > down?
[I didn't notice this when I first replied]
Because of the RTC's low resolution and of how the calibration is implemented in the chip, you need to sample the clock at intervals of several hours in order to determine the direction of the required adjustment. Repeatedly setting the RTC to the correct time will actually prevent correct calibration.
DES -- Dag-Erling Smørgrav Senior Software Developer Linpro AS - www.linpro.no - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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