Implement Cx CPU idle states and updated throttling support.

* Use the cpu_idle_hook() to do idling for C1-C3.
* Use both _CST and the FADT to detect Cx states.
* Use both _PTC and P_CNT for controlling throttling.
* Add a notify handler to detect changes in _CST and _PSS
* Call the _INI function for each processor if present.  This will be
  done by ACPI-CA in the future.
* Fix a bug on SMP systems where CPUs will attach multiple times if the
  bus is rescan.
* Document new sysctls for controlling idling.

1 files changed, 25 insertions, 7 deletions

diff --git a/share/man/man4/acpi.4 b/share/man/man4/acpi.4
index 5761610..7dc7a73 100644
--- a/share/man/man4/acpi.4
+++ b/share/man/man4/acpi.4
@@ -309,12 +309,6 @@ Name of the DSDT table to load, if loading is enabled.
 Selectively disables portions of ACPI for debugging purposes.
 .It Va hint.acpi.0.disabled
 Disables all of ACPI.
-.It Va hw.acpi.cpu.performance_speed
-Sets the speed of the CPU, if it supports multiple speeds, while in
-the performance power profile.
-.It Va hw.acpi.cpu.economy_speed
-Sets the speed of the CPU, if it supports multiple speeds, while in
-the economy power profile.
 .It Va hw.acpi.ec.poll_timeout
 Delay in milliseconds to wait for the EC to respond.  Try increasing this
 number if you get the error 
@@ -332,8 +326,32 @@ Override the interrupt to use.
 .It Va hw.acpi.verbose
 Turn on verbose debugging information about what ACPI is doing.
 .El
+.Sh SYSCTLS
+.Bl -tag -width indent
+.It Va hw.acpi.cpu.performance_speed
+Sets the speed of the CPU, if it supports multiple speeds, while in
+the performance power profile.
+.It Va hw.acpi.cpu.economy_speed
+Sets the speed of the CPU, if it supports multiple speeds, while in
+the economy power profile.
+.It Va hw.acpi.cpu.cx_history
+Debugging information listing all sleep states and the number of
+long and short sleeps for each one.
+The counters are reset when
+.Va hw.acpi.cpu.cx_lowest
+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.
+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.
+.El
 .Sh COMPATIBILITY
-ACPI is only found/supported on i386/ia32, ia64 and amd64.
+ACPI is only found and supported on i386/ia32, ia64, and amd64.
 .Sh SEE ALSO
 .Xr loader.conf 5 ,
 .Xr acpiconf 8 ,