Re: RTC drift on Walnut?

tn Mon, Jul 09 2001, akuster@mvista.com wrote:

Torben Mathiasen wrote:

quoted

Hi,

I'm seeing a rather large drift of the RTC on a Walnut system. I haven't
got the exact numbers, but its something like 20mins in 24 hours.
This is with the montavista 2.4.2 kernel.

Has anyone seen this before?

Thanks in advance,

Torben

Torben;

I am not sure.  I will have to check, I will let you know tomorrow.

Thanks. I'm pretty sure its kernel related, I bet something's wrong in
arch/ppc/kernel/time.c. The kernel just reads the RTC at startup, and maintains
the system clok via the timer-interrupts. Coming to think of it, I'm not sure
if the hardware RTC drifts, or if its just the kernel 'software' clock. Will
check on that.

Maybe we're turning ints off for too long somewhere...

Thanks,
Torben

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Torben Mathiasen wrote:

Thanks. I'm pretty sure its kernel related, I bet something's wrong in
arch/ppc/kernel/time.c. The kernel just reads the RTC at startup, and maintains
the system clok via the timer-interrupts. Coming to think of it, I'm not sure
if the hardware RTC drifts, or if its just the kernel 'software' clock. Will
check on that.

Maybe we're turning ints off for too long somewhere...

Thanks,
Torben

Torben;

I am running on what will be the next version of 405 kernel from
MontaVista.  It is using the new todc_time routines.  I saw about a 30
second drift.

-- armin

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