dmesg showing wrong frequency (IBM T30)

Bruce Cran bruce at cran.org.uk
Fri Jul 18 13:49:02 PDT 2003


On Fri, Jul 18, 2003 at 07:24:20PM +0200, Tobias Roth wrote:
> On Fri, Jul 18, 2003 at 06:22:27PM +0200, Poul-Henning Kamp wrote:
> > What's "wrong" here is that the BIOS/ACPI firmware in your laptop
> > runs your CPU at a reduced rate in order to make the battery last
> > longer.
> 
> it should NOT do this. I set the bios to disable speedstep and to
> 'max performance' while on AC. also, i run apm and not acpi.
> 

That's probably the problem.   For some reason, certainly on my Dell, disabling
SpeedStep throttles the CPU down to 1.2GHz on bootup, from its full 2.0GHz.
Nothing the OS can do will change it.  Enabling SpeedStep means that FreeBSD
sees the full 2.0GHz.   I've also heard about someone whose Dell had a broken
BIOS, which meant that the CPU could never run at full speed, but was always
running at 60%.   Upgrading the BIOS was the solution in that case.

--

Bruce Cran




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