[Sugar-devel] Clocks on XOs

[Sascha Silbe]

Excerpts from Hal Murray's message of Sat Jul 03 18:42:48 +0000 2010:

> >>  On top of that, ntpd doesn't get along with power saving mode.
> > I haven't noticed anything odd. Either it's been fixed in the meantime or it
> > was only subtle misbehaviour. Do you have a ticket number or link to a
> > description of the problem that has been experienced before? 
> 
> Are you running XO-1s with power saving enabled?  Last I knew that didn't 
> work and recent OSes ship with it pre-configured to off.
I'm running Debian squeeze with powerd on both XO-1 and XO-1.5

> "doesn't get along" may be too strong.  The symptoms were that the clock 
> drifted wildly.
Then it seems fixed. I would have noticed a wildly drifting system clock.

> I'll dig out some data if it matters, but that was with the 
> old kernel from Fedora 9, when power saving worked.
This is with the latest OLPC kernel (2.6.31).

> Linux seems to break things when somebody cleans up something in this area.  
> I think there has been more work in this area recently, but it may not be 
> that recent.  I'm procrastinating until power saving works again.
Ah, so you're talking about power saving, not clocks (re. cleaning up). 
Yes, suspend still contains too many race conditions to enable auto-suspend
by default unfortunately. But as this is where the embedded world seems to
be going as well, there's a good chance this will improve near to medium
term.

> Clocks are hard.  Clocks on XOs are doubly hard because you don't have 
> anyplace to stand when the CPU and its clocks are powered down.
Unless you happen to hit the bad RTC battery holder problem or don't use
your XO for several months, the RTC will always be powered on the XO-1,
even if you took the battery out.

PS: Follow-Up set to devel at l.l.o as this is about XOs, not Sugar.

Sascha
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