Re: 2.6.27.7 built for Geode: Clock drift

From: Jordan Crouse
Date: Tue Dec 09 2008 - 10:09:59 EST


john stultz wrote:
On Sat, 2008-12-06 at 07:09 +0100, Harald Dunkel wrote:
john stultz wrote:
For both configs, can you run:
cat /sys/devices/system/clocksource/clocksource0/available_clocksource
and:
cat /sys/devices/system/clocksource/clocksource0/current_clocksource

Then send back the output?

Sure. For 486:

% cat /sys/devices/system/clocksource/clocksource0/available_clocksource
pit jiffies
% cat /sys/devices/system/clocksource/clocksource0/current_clocksource
pit


For Geode (clock is running too fast):
% cat /sys/devices/system/clocksource/clocksource0/available_clocksource
jiffies
% cat /sys/devices/system/clocksource/clocksource0/current_clocksource
jiffies


dmesg says for Geode:

:
TSC: Unable to calibrate against PIT
TSC: No reference (HPET/PMTIMER) available
Marking TSC unstable due to could not calculate TSC khz

Could you send your .config?

It seems the PIT (which is used in 486 build) is being disabled in the
Geode config. However, I thought the Geode's had their own clocksources,
either the SCx200 or the GEODE_MFGPT_TIMER. Maybe one of those needs to
be enabled?

He sent his original config in his first email - GEODE_MFGPT_TIMER was enabled. Its not always certain that there are MFGPT timers available (prior to about the middle of this year, most Geode BIOSes took all the timers for themselves). But in any case the system should fall back to PIT automatically, so regardless of more advanced timers. the absence of a PIT is troubling.

Jordan



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/