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32 .Nd Intel Speed Shift Technology driver
34 To compile this driver into your kernel
35 place the following line in your kernel
37 .Bd -ragged -offset indent
43 driver provides support for hardware-controlled performance states on Intel
44 platforms, also known as Intel Speed Shift Technology.
46 .Bl -tag -width indent
47 .It Va hint.hwpstate_intel.0.disabled
48 Can be used to disable
50 allowing other compatible drivers to manage performance states, like
55 .It Va machdep.hwpstate_pkg_ctrl
56 Selects between package-level control (the default) and per-core control.
58 selects package-level control and
60 selects core-level control.
66 .Bl -tag -width indent
67 .It Va dev.hwpstate_intel.%d.%desc
68 Describes the attached driver
69 .It dev.hwpstate_intel.0.%desc: Intel Speed Shift
70 .It Va dev.hwpstate_intel.%d.%driver
71 Driver in use, always hwpstate_intel.
72 .It dev.hwpstate_intel.0.%driver: hwpstate_intel
73 .It Va dev.hwpstate_intel.%d.%parent
74 The CPU that is exposing these frequencies.
77 .It dev.hwpstate_intel.0.%parent: cpu0
78 .It Va dev.hwpstate_intel.%d.epp
79 Energy/Performance Preference.
80 Valid values range from 0 to 100.
81 Setting this field conveys a hint to the hardware regarding a preference towards
82 performance (at value 0), energy efficiency (at value 100), or somewhere in
84 .It dev.hwpstate_intel.0.epp: 0
88 is only found on supported Intel CPUs.
92 .%T "Intel 64 and IA-32 Architectures Software Developer Manuals"
93 .%U "http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html"
96 This manual page was written by
97 .An D Scott Phillips Aq Mt scottph@FreeBSD.org .