CPU_ENABLE_TCC enables Thermal Control Circuitry (TCC) found in some
Pentium(tm) 4 and (possibly) later CPUs. When enabled and detected,
TCC allows to restrict power consumption by using machdep.cpuperf*
sysctls. This operates independently of SpeedStep and is useful on
systems where other mechanisms such as apm(4) or acpi(4) don't work.
Given the fact that many, even modern, notebooks don't work properly
with Intel ACPI, this is indeed very useful option for notebook owners.
Obtained from: OpenBSD
MFC after: 2 weeks
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