Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
The _OSI method has one argument and one return value. The argument is an OS vendor defined
string representing a set of OS interfaces and behaviors or an ACPI defined string representing an
operating system and an ACPI feature group of the form, “OSVendorString-FeatureGroupString”.
Arguments: (1)
Arg0 – A String containing the OS interface / behavior compatibility string or the Feature Group
string, as defined in Table 5-165, or the “OS Vendor String Prefix – OS Vendor Specific String”. OS
Vendor String Prefixes are defined inTable 5-164
Return Value:
An Integer containing a Boolean that indicates whether the requested feature is supported:
0x0 –
0xFFFFFFFF –
The interface, behavior, or feature is not supported
The interface, behavior, or feature is supported
OSPM may indicate support for multiple OS interface / behavior strings if the operating system
supports the behaviors. For example, a newer version of an operating system may indicate support
for strings from all or some of the prior versions of that operating system.
_OSI provides the platform with the ability to support new operating system versions and their
associated features when they become available. OSPM can choose to expose new functionality
based on the _OSI argument string. That is, OSPM can use the strings passed into _OSI to ensure
compatibility between older platforms and newer operating systems by maintaining known
compatible behavior for a platform. As such, it is recommended that _OSI be evaluated by the
\_SB.INI control method so that platform compatible behavior or features are available early in
operating system initialization.
Since feature group functionality may be dependent on OSPM implementation, it may be required
that OS vendor-defined strings be checked before feature group strings.
Platform developers should consult OS vendor specific information for OS vendor defined strings
representing a set of OS interfaces and behaviors. ACPI defined strings representing an operating
system and an ACPI feature group are listed in the following tables.
Table 5-164 Operating System Vendor Strings
Operating System Vendor String Prefix
“FreeBSD”
“HP-UX”
Description
Free BSD
HP Unix Operating Environment
“Linux”
“OpenVMS”
“Windows”
GNU/Linux Operating system
HP OpenVMS Operating Environment
Microsoft Windows
Table 5-165 Feature Group Strings
Feature Group String
“Module Device”
Description
OSPM supports the declaration of module device (ACPI0004) in the
namespace and will enumerate objects under the module device scope.
270 April, 2015 Version 6.0