dmesg showing wrong frequency (IBM T30)

Kevin Oberman oberman at es.net
Fri Jul 18 08:08:00 PDT 2003


> Date: Fri, 18 Jul 2003 16:12:39 +0200
> From: Tobias Roth <roth at iam.unibe.ch>
> Sender: owner-freebsd-mobile at freebsd.org
> 
> Hi
> 
> On my IBM T30 1.8GHz, dmesg (with both 4.8 and 5.1) shows me this line:
> 
> CPU: Intel(R) Pentium(R) 4 Mobile CPU 1.8GHz (1196.13-MHz 686-class CPU)
> 
> Various windows utilities also claim that the cpu identification string
> marks my cpu as 1.8 GHz unit, while the maximum frequency always gets
> detected as something just below 1.2GHz.
> 
> What is wrong here? To other IBM T30 users: Is your CPU identification
> correct?

Were you on AC or battery when you booted? 

It seems that the T30 (and many other laptops from multiple vendors)
does not change the CPU speed when APM/ACPI from FreeBSD tells it
to. If I boot on battery, my system stays at 1.2 GHz and if I boot on
AC power, the system runs 1.8 GHz. Changes to the power source made
after it is up seem to have no effect.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634


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