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* RTC drift in PPC
@ 2007-05-10 11:16 pjmaiya
  2007-05-10 14:45 ` John Reiser
  0 siblings, 1 reply; 3+ messages in thread
From: pjmaiya @ 2007-05-10 11:16 UTC (permalink / raw)
  To: linuxppc-embedded

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hi,
  We are running RTC on mpc860 board with external crystal. During boot we get date and time from h/w RTC chip and then it runs pn software tick, which is handled by kernel. We are getting 4 minutes drift for 21 hours. Can any one suggest, how to reduce the drift.

thnax in advance,
pjmaiya

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: RTC drift in PPC
  2007-05-10 11:16 RTC drift in PPC pjmaiya
@ 2007-05-10 14:45 ` John Reiser
  2007-06-05  7:26   ` Theo Gjaltema
  0 siblings, 1 reply; 3+ messages in thread
From: John Reiser @ 2007-05-10 14:45 UTC (permalink / raw)
  To: pjmaiya; +Cc: linuxppc-embedded

> We are running RTC on mpc860 board with external crystal...
> We are getting 4 minutes drift for 21 hours.

A slowdown in the approx. range 1:300 to 1:350 is endemic to linux ppc:
http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=157581

-- 

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: RTC drift in PPC
  2007-05-10 14:45 ` John Reiser
@ 2007-06-05  7:26   ` Theo Gjaltema
  0 siblings, 0 replies; 3+ messages in thread
From: Theo Gjaltema @ 2007-06-05  7:26 UTC (permalink / raw)
  To: linuxppc-embedded

I 'v measured the clock on a mpc8280 board running the 2.4.25 kernel 
obtained from ELDK3.1.1, no problem with the clock during a test period 
of a few days.

Theo.
>> We are running RTC on mpc860 board with external crystal...
>> We are getting 4 minutes drift for 21 hours.
>>     
>
> A slowdown in the approx. range 1:300 to 1:350 is endemic to linux ppc:
> http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=157581
>
>   

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2007-05-10 11:16 RTC drift in PPC pjmaiya
2007-05-10 14:45 ` John Reiser
2007-06-05  7:26   ` Theo Gjaltema

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