Re: System clock speed too high - 2.6.3 kernel

From: Bill Davidsen
Date: Thu May 27 2004 - 08:35:22 EST


Joris van Rantwijk wrote:
On Tue, 25 May 2004, john stultz wrote:

On Tue, 2004-05-25 at 02:22, Joris van Rantwijk wrote:

If there are many systems with this problem, then calibrating the PM timer
against the PIT timer at boot time (possibly rejecting invalid rates)
might be an option.


I'll put it on my todo list, but if you'd like to take a swing at ti and
beat me to the implementation, I wouldn't complain.


Sounds fair. I tried something and it even seems to work here.
My dmesg now says:
PM-Timer running at invalid rate: 199% of normal - aborting.
Detected 400.816 MHz processor.
Using tsc for high-res timesource

Hmm, I think I'm enjoying this :-)
My patch is included below and also submitted at the Kernel Bugzilla
thing. I would appreciate it if someone else could also test it a bit.

Yesterday, I ran into a (hopefully) completely seperate issue with the
timer. This happened before I even started messing with the kernel and
while running with "clock=tsc". The kernel suddenly logged:
Losing too many ticks!
TSC cannot be used as a timesource
...
Falling back to a sane timesource now.


Have to say that since adding clock=tsc my test systems are all keeping perfect time (ntpd running) which has not been the case since I started using test kernels about 2.5.38.

You do seem to have an issue with the pit.

--
-bill davidsen (davidsen@xxxxxxx)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me
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