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Improve the section on Cx states, documenting the removal of -1 as a

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valid value for cx_lowest.  To disable sleeping, use machdep.cpu_idle_hlt
instead.  Update the version of the ACPI spec we implement.

Approved by:	re (implicitly)
This commit is contained in:
Nate Lawson 2003-11-19 20:28:56 +00:00
parent 56a70eadf5
commit c25a3f8a7a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=122905
1 changed files with 9 additions and 2 deletions
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11
share/man/man4/acpi.4
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@ -342,13 +342,20 @@ The counters are reset when
is modified.
.It Va hw.acpi.cpu.cx_lowest
Zero-based index of the lowest CPU idle state to use.
A value of -1 disables ACPI CPU idle states.
A scheduling algorithm will select between 0...index for the state
to use during the next sleep.
To enable ACPI CPU idling control,
.Va machdep.cpu_idle_hlt
must be set to 1.
.It Va hw.acpi.cpu.cx_supported
List of supported CPU idle states and their transition latency
in microseconds.
Each state has a type, C1-3.
C1 is equivalent to the ia32 HLT instruction, C2 provides a deeper
sleep with the same semantics, and C3 provides the deepest sleep
but additionally requires bus mastering to be disabled.
Deeper sleeps provide more power savings but increased transition
latency when an interrupt occurs.
.El
.Sh COMPATIBILITY
ACPI is only found and supported on i386/ia32, ia64, and amd64.
@ -364,7 +371,7 @@ ACPI is only found and supported on i386/ia32, ia64, and amd64.
.%A "Microsoft Corporation"
.%A "Phoenix Technologies Ltd."
.%A "Toshiba Corporation"
.%D July 27 2000
.%D August 25, 2003
.%T "Advanced Configuration and Power Interface Specification"
.%O http://acpi.info/spec.htm
.Re