"Page Fault" message on XO-1 and another Fix Clock question

James Cameron quozl at laptop.org
Sun Feb 3 22:32:32 EST 2013

On Mon, Feb 04, 2013 at 12:58:47AM +0200, Christoph Derndorfer wrote:
> (1) on Friday while looking at one of the XO-1s which didn't show
> anything on the display (even with a display which was known to
> work) with the serial adapter I saw the attached output.

Reviewed, thanks.

> Looking at the wiki now and given the number of "invalid system
> date" issues we saw on other machines I assume this is a case of the
> "page fault" message situation described on
> http://wiki.laptop.org/go/Fix_Clock# If_the_screen_does_not_turn_on.

Yes, this is likely.

> Or are there any other issues which could produce such an output?

There might be, but if you have a version before Q2D05 which was
released in 2007, there's almost no chance of anybody remembering
anything useful.  It has been more than five years!

To verify that the Page Fault is happening because of the known
problem (ticket #5391, svn 752), please use the Open Firmware ok
prompt to display the values in the real-time clock, using the .clock

	ok .clock

If the month is invalid, then the Page Fault is most likely to be the
one expected.

Another method would be to take an XO-1 with Q2D06 or earlier, remove
the clock battery, force the problem again, and see if the serial log
looks the same.  I expect it will.

There are other methods to diagnose, but these require immediate
collaboration with a firmware engineer, and I don't think it is worth
doing that yet.

> (2) Mike sent me a bunch of ML 1220 batteries as replacements for
> the XO-1 units which showed the "invalid system date"
> messages. However even with the new batteries in-place, after
> verifying that the (old) battery holders looked okay and having set
> the current time on the command-line the system date reverted back
> to 2000-01-01 00:00:00 after every reboot (and hence the "invalid
> system date" message kept coming up again). Any suggestions on what
> to do in such a situation?

Charge the battery before the power cycle test.  On the XO-1, "it will
recharge from the main power source while the laptop is powered on and
fully awake (not suspended)."

"When recharging an empty battery, it is expected that the battery
will reach normal voltage levels after around 30 minutes of charging,
but will require potentially 24 hours for a complete recharge."

http://wiki.laptop.org/go/Fix_Clock#RTC_power_dynamic has the above

Check that the battery voltage is reasonable.

Check that the connector is passing the voltage properly to the
circuit board.

Also, please make sure you upgrade the firmware as soon as you can, so
that you aren't impacted by this problem any further.

James Cameron

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