Advanced Configuration and Power Interface Specification

Processor Configuration and Control
Num
Processors
Index
Integer
(DWORD)
Integer
(DWORD)
The number of processors belonging to the domain for the particular C-state.
OSPM will not start performing power state transitions to a particular C-state
until this number of processors belonging to the same domain for the
particular C-state have been detected and started.
Indicates the index of the C-State entry in the _CST object for which the
dependency applies.
Given that the number or type of available C States may change dynamically, ACPI supports Notify
events on the processor object, with Notify events of type 0x81 causing OSPM to re-evaluate any
_CST objects residing under the particular processor object notified. On receipt of Notify events of
type 0x81, OSPM should re-evaluate any present _CSD objects also.
Example
This is an example usage of the _CSD structure in a Processor structure in the namespace. The
example represents a two processor configuration. The C1-type state can be independently entered
on each processor. For the C2-type state, there exists dependence between the two processors, such
that one processor transitioning to the C2-type state, causes the other processor to transition to the
C2-type state. A similar dependence exists for the C3-type state. OSPM will be required to
coordinate the C2 and C3 transitions between the two processors. Also OSPM can initiate a
transition on either processor to cause both to transition to the common target C-state.
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