Comment 63 for bug 190414

I also get this message during boot - but from what I read it's not a problem:

"As far as i know Pentium M processors have dynamically changed clock
speed (ofc to save power). That's why kernel notice that TSC is
unstable (it is indeed). [...] I don't think that there is an easy way to fix it (it is not even a
bug), time-stamp counter is not perfect..." [Pawel Dziepak]
http://lkml.indiana.edu/hypermail/linux/kernel/0707.1/0621.html

Most laptops mentioned here do use a Pentium M (<- Centrino).

The tsc message still shows with 2.6.28-11-generic/Jaunty Alpha
[ 0.000000] Fast TSC calibration using PIT
[ 2.877852] Marking TSC unstable due to TSC halts in idle
[ 3.348014] Clocksource tsc unstable (delta = -412296801 ns)

Boot time tests (Acer 8106wlmi Pentium M 1.87Ghz):

Standard boot options: ~1:08
clocksource=tsc ~6:51 (I wouldn't want to use that)
clocksource=hpet ~1:08
clocksource=notsc ~1:08
acpi_pm ~1:08