Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
• I/O operation regions.
• Memory operation regions when accessing memory returned by the System Address Map
reporting interfaces.
2. OSPM must make Embedded Controller operation regions, accessed via the Embedded
Controllers described in ECDT, available before executing any control method. These operation
regions may become inaccessible after OSPM runs _REG(EmbeddedControl, 0).
Place _REG in the same scope as operation region declarations. The OS will run the _REG in a
given scope when the operation regions declared in that scope are available for use.
Example:
Scope(\_SB.PCI0) {
OperationRegion(OPR1, PCI_Config, ...)
Method(_REG, 2) {...}
// OSPM executes this when PCIO operation region handler
// status changes
Device(PCI1) {
Method(2) {...}
Device(ETH0) {
OperationRegion(OPR2, PCI_Config, ...)
Method(_REG,2) {...}
}
}
Device(ISA0) {
OperationRegion(OPR3, SystemI/O, ...)
Method(_REG, 2) {...} // OSPM executes this when ISAO operation region handler
// status changes
Device(EC0) {
Name(_HID, EISAID("PNP0C09"))
OperationRegion(OPR4, EmbeddedControl, ...)
Method(_REG, 2) {...} // OSPM executes this when EC operation region
// handler status changes
}
}
}
When the PCI0 operation region handler is ready, OSPM will run the _REG method declared in
PCI0 scope to indicate that PCI Config space operation region access is available within the PCI0
scope (in other words, OPR1 access is allowed). When the ISA0 operation handler is ready, OSPM
will run the _REG method in the ISA0 scope to indicate that the I/O space operation region access is
available within that scope (in other words, OPR3 access is allowed). Finally, when the Embedded
Controller operation region handler is ready, OSPM will run the _REG method in the EC0 scope to
indicate that EC space operation region access is available within the EC0 scope (in other words,
OPR4 access is allowed). It should be noted that PCI Config Space Operation Regions are ready as
soon the host controller or bridge controller has been programmed with a bus number. PCI1’s _REG
method would not be run until the PCI-PCI bridge has been properly configured. At the same time,
the OS will also run ETH0’s _REG method since its PCI Config Space would be also available. The
OS will again run ETH0’s _REG method when the ETH0 device is started. Also, when the host
controller or bridge controller is turned off or disabled, PCI Config Space Operation Regions for
child devices are no longer available. As such, ETH0’s _REG method will be run when it is turned
off and will again be run when PCI1 is turned off.
384 April, 2015 Version 6.0