Patent Application
20060282651
This application relates to electronic computing, and more particularly to table management in Advanced Configuration and Power Interface (ACPI) computing systems.
ACPI is a specification that makes hardware status information available to an operating system in computers, including laptops, desktop, servers, etc. More information about ACPI may be found in the Advanced Configuration and Power Interface Specification, Revision 2.0a, Mar. 31, 2002, cooperatively defined by Compaq Computer Corporation, Intel Corporation, Microsoft Corporation, Phoenix Technologies Ltd., and Toshiba Corporation. The ACPI specification was developed to establish industry common interfaces enabling robust operating system (OS)-directed motherboard device configuration and power management of both devices and entire systems. ACPI is the key element in operating system-directed configuration and power management (OSPM).
ACPI is used in personal computers (PCs) running a variety of operating systems, such as Windows® available from Microsoft Corporation, Linux, available as open source form a variety of vendors, and HP-UX, available from Hewlett-Packard Company. ACPI also allows hardware resources to be manipulated. For example, ACPI assists in power management by allowing a computer system's peripherals to be powered on and off for improved power management. ACPI also allows the computer system to be turned on and off by external devices. For example, the touch of a mouse or the press of a key may wake up the computer system using ACPI.
ACPI implements both static and interpretable tables. At boot-up time, the system firmware (typically the BIOS, or Basic Input/Output System) constructs the static tables, which are consumed by the operating system. The interpretable tables include ACPI Machine Language (AML), which is compiled and then merged into the system firmware. The operating system reads the AML from the interpretable tables and executes the architected interfaces, using an ACPI interpreter. In this fashion, the operating system manipulates hardware resources.
ACPI uses several types of ACPI description tables including a Differentiated System Description Table (DSDT) and a Secondary System Description Table (SSDT). ACPI implements a single DSDT, which is part of a fixed system description. SSDTs are description tables that may be loaded after system boot. Base system support is provided in the DSDT and additional system options may be added on an as needed basis in the SSDTs.
The DSDT is loaded into a section of memory referred to as the ACPI Namespace when the computer system is booted. After the DSDT is loaded into the ACPI Namespace, each secondary description table with a unique OEM Table ID is loaded.
The ACPI namespace is a hierarchical tree structure in OS-controlled memory that contains named objects. These objects may be data objects, control method objects, bus/device package objects, etc. The BIOS determines which SSDTs will be exposed to the OS based on the hardware present when the computer is booted and the configuration desired by the user.
Modern computing systems may include a large number of ACPI tables. Adroit management of ACPI tables facilitates efficient operation.
In one embodiment a method of managing Advanced Configuration and Power Interface tables in a computer system comprises initializing a set, of Advanced Configuration and Power Interface tables including a plurality of secondary system description table tables in a memory; selecting an anchor table from the set of Advanced Configuration and Power Interface tables; and appending at least one secondary system description table to the anchor table.
Described herein are exemplary system and methods for managing ACPI tables in a computing system. The methods described herein may be embodied as logic instructions on a computer-readable medium. When executed on a processor, the logic instructions cause a general purpose computing device to be programmed as a special-purpose machine that implements the described methods. The processor, when configured by the logic instructions to execute the methods recited herein, constitutes structure for performing the described methods.
The particular embodiment of operating system 140 is not critical to the subject matter described herein. Operating system 140 may be embodied as a UNIX operating system or any derivative thereof (e.g., Linux, Solaris, etc.) or as a Windows® brand operating system.
Computing system 100 further includes a number of components to facilitate ACPI table management. Although the subject matter is with reference to ACPI table management, there is no intention to limit the claims to ACPI configuration systems. Rather, the subject matter describe herein may operate with and provide benefits with any operating system, architecture, and/or configuration management system.
Memory 130 includes an operating system 140 for managing operations of computer 108. In operation, one or more application modules 162 and/or libraries 164 executing on computer 108 make calls to the operating system 140 to execute one or more commands on the computer's processor. The operating system 140, in turn, invokes the services of system hardware 120 to execute the command(s). The operating system kernel 142 can be generally considered as one or more software modules that are responsible for performing many operating system functions.
In one embodiment, the kernel 142 interfaces with Operating System Power Management (OSPM) system code 144. The OSPM system code 144 comprises one or more software modules that may be a part of the operating system 105 and that may be used to modify the behavior of certain components of the computer system 100, typically to mange power consumption in accordance with pre-configured power conservation settings. The various device drivers 146 interface with and generally control the hardware installed in the computer system 100.
ACPI Driver/AML Interpreter 148 is a software module loaded during system start-up, which functions as an interface between the operating system 140 and an ACPI BIOS 154. ACPI Driver/AML Interpreter 148 populates an ACPI namespace 150 at system startup, loads description blocks from the system BIOS ACPI namespace at run time, handles certain general purpose events triggered by ACPI hardware, and passes other general purpose events to modules registered to handle those events, and the like.
A driver communicates with other drivers and the operating system components (e.g., an I/O manager or the kernel 142), for example in the Windows.RTM. 2000 operating system, by passing messages called I/O request packets (IRPs) up and down a “driver stack.” As will be understood by those skilled in the art, drivers for a particular hardware device may be “stacked” such that messages directed either down to the hardware device or back up to the operating system (or other program module) are passed through a chain of drivers in a driver stack before reaching their destination. An ACPI driver 148 may be inserted into a driver stack to add functionality to the hardware device.
In one embodiment, the ACPI driver 148 creates a filter Device Object (filter DO) or a Physical Device Object (PDO) in the driver stack for each device described in an ACPI namespace 150. If the device is capable of being enumerated by an element of another subsystem, such as a Plug-n-Play subsystem, that element of the other subsystem may create the PDO for the device and the ACPI driver 148 may put a filter DO on top of the PDO. The operating system 140 provides power management features to the device stack by means of these device objects.
The ACPI BIOS 154 refers to the portion of system firmware that is compatible with the ACPI specification. The ACPI BIOS 154 manages the boot-up process for the computing system 100 the machine and implements interfaces for power and configuration operations, such as, e.g., sleep, wake, and some restart operations. ACPI BIOS 154 contains definition blocks used to construct ACPI Tables 156 such as, e.g., the DSDT and the SSDT. Although the BIOS 158 and the ACPI BIOS 154 are illustrated as separate components in
The ACPI Tables 156 include a Root System Description Table (RSDT), a Differentiated System Description Table (DSDT) and one or more Secondary System Description Tables (SSDTs). These tables are described in greater detail below.
RSDT 215 includes a header and a plurality of entries including a reference (e.g., a pointer) to the Fixed ACPI Description Table (FACP) 220. The FACP 220 includes information used for power management and information that describes details of ACPI hardware registers. The FACP references the DSDT 225.
DSDT 225 includes a header and a differentiated definition block (DDB) that includes implementation and configuration information the operating system can use to perform power management, thermal management, or plug-and-play functionality of the base computer system. Other definition blocks may be provided to describe additional hardware devices.
The RSDT 215 also references one or more SSDTs 230-234. Each SSDT 230-234 includes a header that contains information about what the block contains. Each SSDT also includes a hardware data block that provides a description of hardware components in addition to the base computer system. Other definition blocks may be provided to describe additional ACPI devices.
Referring to
Operations 415-535 define a loop in which the separate SSDTs are appended to the anchor table. This reduces the number of SSDT pointers required to be maintained by the RSDT. If, at operation 415, there are more SSDTs to process, then control passes to operation 420, and the next SSDT is retrieved from the memory.
In the embodiment depicted in
If, at operation 415, there are more SSDTs, then operations 420-435 are executed on the next SSDT in memory. By contrast, if at operation 415 there are no more SSDTs in memory to process, then control passes to operation 440 and the checksum of the anchor table is updated. At operation 445 the anchor table is passed to the operating system.
Generally, various different general purpose or special purpose computing system configurations can be used. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
The functionality of the computers is embodied in many cases by computer-executable instructions, such as program modules, that are executed by the computers. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Tasks might also be performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media.
The instructions and/or program modules are stored at different times in the various computer-readable media that are either part of the computer or that can be read by the computer. Programs are typically distributed, for example, on floppy disks, CD-ROMs, DVD, or some form of communication media such as a modulated signal. From there, they are installed or loaded into the secondary memory of a computer. At execution, they are loaded at least partially into the computer's primary electronic memory. The invention described herein includes these and other various types of computer-readable media when such media contain instructions, programs, and/or modules for implementing the steps described below in conjunction with a microprocessor or other data processors. The invention also includes the computer itself when programmed according to the methods and techniques described below.
For purposes of illustration, programs and other executable program components such as the operating system are illustrated herein as discrete blocks, although it is recognized that such programs and components reside at various times in different storage components of the computer, and are executed by the data processor(s) of the computer.
With reference to
Computer 500 typically includes a variety of computer-readable media. Computer-readable media can be any available media that can be accessed by computer 500 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer-readable media may comprise computer storage media and communication media. “Computer storage media” includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 500. Communication media typically embodies computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network, fiber optic networks, or direct-wired connection and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media.
The system memory 506 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 510 and random access memory (RAM) 512. A basic input/output system 514 (BIOS), containing the basic routines that help to transfer information between elements within computer 500, such as during start-up, is typically stored in ROM 510. RAM 512 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 504. By way of example, and not limitation,
The computer 500 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, the computer system of
The drives and their associated computer storage media discussed above and illustrated in
The computer may operate in a networked environment using logical connections to one or more remote computers, such as a remote computing device 550. The remote computing device 550 may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to computer 500. The logical connections depicted in
When used in a LAN networking environment, the computer 500 is connected to the LAN 552 through a network interface or adapter 556. When used in a WAN networking environment, the computer 500 typically includes a modem 558 or other means for establishing communications over the Internet 554. The modem 558, which may be internal or external, may be connected to the system bus 506 via the I/O interface 542, or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer 500, or portions thereof, may be stored in the remote computing device 550. By way of example, and not limitation,
Moreover, some embodiments may be provided as computer program products, which may include a machine-readable or computer-readable medium having stored thereon instructions used to program a computer (or other electronic devices) to perform a process discussed herein. The machine-readable medium may include, but is not limited to, floppy diskettes, hard disk, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, erasable programmable ROMs (EPROMs), electrically EPROMs (EEPROMs), magnetic or optical cards, flash memory, or other suitable types of media or computer-readable media suitable for storing electronic instructions and/or data. Moreover, data discussed herein may be stored in a single database, multiple databases, or otherwise in select forms (such as in a table).
Additionally, some embodiments discussed herein may be downloaded as a computer program product, wherein the program may be transferred from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by way of data signals embodied in a carrier wave or other propagation medium via a communication link (e.g., a modem or network connection). Accordingly, herein, a carrier wave shall be regarded as comprising a machine-readable medium.
Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an implementation. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
