From owner-freebsd-current@FreeBSD.ORG  Sat May 18 14:09:39 2013
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From: Michio Honda <micchie@sfc.wide.ad.jp>
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Subject: Changing CPU frequency for Xeon processors
Date: Sat, 18 May 2013 16:09:31 +0200
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Hi,

I'm trying to experiment with downclocking CPU.
My environment is 10.0-CURRENT amd64.

However, my CPU (Xeon E31220) seems not to be supported by the cpufreq =
module, thus dmesg shows:
est0: <Enhanced SpeedStep Frequency Control> on cpu0
est: CPU supports Enhanced Speedstep, but is not recognized.

As a result, although sysctl -a shows the list of available frequency =
values (dev.cpu.0.freq_levels: 3093/-1 2706/-1 2319/-1 1933/-1 1546/-1 =
1159/-1 773/-1 386/-1
dev.), I cannot set the value (the error message is "sysctl: =
dev.cpu.0.freq=3D773: Device not configured").

Do you have any idea to change CPU frequency for this CPU?

Cheers,
- Michio