cpufreq & enhanced speedstep

Rui Paulo rpaulo at fnop.net
Tue May 15 12:15:13 UTC 2007

At Tue, 15 May 2007 13:51:52 +0200,
Harald Schmalzbauer wrote:
> I did (I had to copy src/backlight and src/msrtemp to src/sys/dev/ and 
> src/sys/modules/).

The patch should be applied with CWD == src/sys.

> Here is what I get when I load the module:
> msrtemp0: <CPU On-Die Thermal Sensors> on cpu0
> est1: <Enhanced SpeedStep Frequency Control> on cpu1
> est: CPU supports Enhanced Speedstep, but is not recognized.
> est: cpu_vendor GenuineIntel, msr 928092806000928
> device_attach: est1 attach returned 6
> msrtemp1: <CPU On-Die Thermal Sensors> on cpu1
> But these values are too high, my BIOS tells me ~50°C:
> dev.cpu.0.temperature: 68
> dev.cpu.1.temperature: 69

Well, the digital readout is relative to maximum Thermal Junction
So, the calculation is: Tj(max) - digital readout.
On some systems Tj(max) is 100, on others is 85, but there's no know
way to detect this realiably. Linux does a trick and I'm still
investigating whether or not to apply it.

It seems that your CPU's Tj(max) is 85 and not 100.
100-32 = 68
85-32  = 53

> Is there anything I can do to correct the ACPI table for the right power 
> values of my CPU?

Not likely.
As Colin said, it would probably require an NDA to give you all the

Rui Paulo

More information about the freebsd-current mailing list