1*8c3133f8Sguenther.\" $OpenBSD: acpicpu.4,v 1.10 2022/10/21 04:02:16 guenther Exp $ 283788af9Smk.\" 383788af9Smk.\" Copyright (c) 2006 Michael Knudsen <mk@openbsd.org> 483788af9Smk.\" 583788af9Smk.\" Permission to use, copy, modify, and distribute this software for any 683788af9Smk.\" purpose with or without fee is hereby granted, provided that the above 783788af9Smk.\" copyright notice and this permission notice appear in all copies. 883788af9Smk.\" 983788af9Smk.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 1083788af9Smk.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 1183788af9Smk.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 1283788af9Smk.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 1383788af9Smk.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 1483788af9Smk.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 1583788af9Smk.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 1683788af9Smk.\" 17*8c3133f8Sguenther.Dd $Mdocdate: October 21 2022 $ 1883788af9Smk.Dt ACPICPU 4 1983788af9Smk.Os 2083788af9Smk.Sh NAME 2183788af9Smk.Nm acpicpu 221bc926f7Sjmc.Nd ACPI processor power and performance state 2383788af9Smk.Sh SYNOPSIS 2483788af9Smk.Cd "acpicpu* at acpi?" 2583788af9Smk.Sh DESCRIPTION 2683788af9SmkThe 2783788af9Smk.Nm 2883788af9Smkdriver provides support for extracting processor power and performance 2983788af9Smklevels from ACPI tables. 300e2bb9c5SguentherThis information is used to enter deeper CPU power states when idle, 310193abd1Sguentherand can be used to throttle processor speed to reduce 3280bb9bceSjmcpower usage and extend battery life through the 3380bb9bceSjmc.Va hw.setperf 34aaeccf36Sderaadt.Xr sysctl 2 3583788af9Smkmechanism. 36*8c3133f8Sguenther.Pp 37*8c3133f8Sguenther.Nm 38*8c3133f8Sguentherreports the C-states offered by ACPI using the format 39*8c3133f8Sguenther.Dl C%d(%d@%d %s.%x@%#x) 40*8c3133f8Sguentherwhere the respective fields are the ACPI state, 41*8c3133f8Sguentherthe reported power consumption, 42*8c3133f8Sguentherthe reported latency, 43*8c3133f8Sguentherthe method, 44*8c3133f8Sguentherthe flags on the method, 45*8c3133f8Sguentherand the address for the method. 46*8c3133f8SguentherInapplicable or unspecified fields are elided. 47*8c3133f8SguentherIf the state won't be used for any reason then the entry will have a 48*8c3133f8Sguenther.Sq !\& 49*8c3133f8Sguentherprefix. 50*8c3133f8SguentherIf the state is the fallback state used when no valid C-state entries were 51*8c3133f8Sguentherfound then flags will be a 52*8c3133f8Sguenther.Sq !\& . 53*8c3133f8SguentherFor the 54*8c3133f8Sguenther.Va mwait 55*8c3133f8Sguenthermethod the address is the hints value for the instruction. 5683788af9Smk.Sh SEE ALSO 57aaeccf36Sderaadt.Xr sysctl 2 , 58561d69edSmk.Xr acpi 4 , 5983788af9Smk.Xr cpu 4 , 6083788af9Smk.Xr intro 4 , 6183788af9Smk.Xr apmd 8 , 6283788af9Smk.Xr sysctl 8 6383788af9Smk.Sh HISTORY 6483788af9SmkThe 6583788af9Smk.Nm 6683788af9Smkdriver first appeared in 6783788af9Smk.Ox 3.9 . 6883788af9Smk.Sh AUTHORS 6983788af9Smk.An -nosplit 7083788af9SmkThe 7183788af9Smk.Nm 7283788af9Smkdriver was written by 73e5cc2e7eSschwarze.An Marco Peereboom Aq Mt marco@openbsd.org . 740e2bb9c5SguentherCPU power state (C-state) support was added by 750193abd1Sguenther.An Philip Guenther Aq Mt guenther@openbsd.org . 76