RTC drift on Walnut?

RTC drift on Walnut?

[Torben Mathiasen]

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

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Re: RTC drift on Walnut?

[akuster]

Torben Mathiasen wrote:
>
> 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.

-- armin

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Re: RTC drift on Walnut?

[Torben Mathiasen]

tn Mon, Jul 09 2001, akuster@mvista.com wrote:
> Torben Mathiasen wrote:
> >
> > 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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Re: RTC drift on Walnut?

[Armin Kuster]

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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Re: RTC drift on Walnut?

[Torben Mathiasen]

On Tue, Jul 10 2001, Armin Kuster wrote:
> 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.
>

Thanks for the update. I assume you guys are continously merging your code with
the official PPC tree, so this bug must also be present there.

I think its weird this issue haven't come up on the list before. There seem to
be a lot of people running on the walnut system. It would be interesting to
hear from people _not_ having this drift.

Regards,
Torben Mathiasen

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RE: RTC drift on Walnut?

[Wright, David]

OK -- I'm running the 010303 version of Linux 2.4.2 from MontaVista
and I am *not* seeing significant clock drift on a Walnut.

  -- David Wright


> -----Original Message-----
> From: Torben Mathiasen [mailto:torben@kernel.dk]
> Sent: Tuesday, July 10, 2001 1:26 PM
> To: Armin Kuster
> Cc: Torben Mathiasen; linuxppc-embedded@lists.linuxppc.org
> Subject: Re: RTC drift on Walnut?
>
>
>
> On Tue, Jul 10 2001, Armin Kuster wrote:
> > 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.
> >
>
> Thanks for the update. I assume you guys are continously
> merging your code with
> the official PPC tree, so this bug must also be present there.
>
> I think its weird this issue haven't come up on the list
> before. There seem to
> be a lot of people running on the walnut system. It would be
> interesting to
> hear from people _not_ having this drift.
>
> Regards,
> Torben Mathiasen
>
>
>

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Re: RTC drift on Walnut?

[Torben Mathiasen]

On Tue, Jul 10 2001, Wright, David wrote:
> OK -- I'm running the 010303 version of Linux 2.4.2 from MontaVista
> and I am *not* seeing significant clock drift on a Walnut.
>

Thanks for letting us know.

I'm using the 01-04-12 mvista kernel, so I'll give 01-03-03 a try.

Torben

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Re: RTC drift on Walnut?

[Mark A. Greer]

Torben Mathiasen wrote:

> On Tue, Jul 10 2001, Wright, David wrote:
> > OK -- I'm running the 010303 version of Linux 2.4.2 from MontaVista
> > and I am *not* seeing significant clock drift on a Walnut.
> >
>
> Thanks for letting us know.
>
> I'm using the 01-04-12 mvista kernel, so I'll give 01-03-03 a try.

Did this work?

I made a few changes a couple weeks ago, maybe I messed something up.
I'll look again.

Mark


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Re: RTC drift on Walnut?

[Mark A. Greer]

Torben Mathiasen wrote:

> On Tue, Jul 10 2001, Wright, David wrote:
> > OK -- I'm running the 010303 version of Linux 2.4.2 from MontaVista
> > and I am *not* seeing significant clock drift on a Walnut.
> >
>
> Thanks for letting us know.
>
> I'm using the 01-04-12 mvista kernel, so I'll give 01-03-03 a try.

Duhhh, forget my last msg, I'm still trying to wake up from vacation.

Did the older version work?


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