20 March 2012. Summary of changes for version 20120320:


This release is available at www.acpica.org/downloads.

The ACPI 5.0 specification is available at www.acpi.info.


1) ACPICA Core Subsystem:


Enhanced the sleep/wake interfaces to optionally execute the _GTS method (Going To Sleep) and the _BFS method (Back From Sleep). Windows apparently does not execute these methods, and therefore these methods are often untested. It has been seen on some systems where the execution of these methods causes errors and also prevents the machine from entering S5. It is therefore suggested that host operating systems do not execute these methods by default. In the future, perhaps these methods can be optionally executed based on the age of the system and/or what is the newest version of Windows that the BIOS asks for via _OSI. Changed interfaces: AcpiEnterSleepState and AcpileaveSleepStatePrep. See the ACPICA reference and Linux BZ 13041. Lin Ming.


Fixed a problem where the length of the local/common FADT was set too early. The local FADT table length cannot be set to the common length until the original length has been examined. There is code that checks the table length and sets various fields appropriately. This can affect older machines with early FADT versions. For example, this can cause inadvertent writes to the CST_CNT register. Julian Anastasov.


Fixed a mapping issue related to a physical table override. Use the deferred mapping mechanism for tables loaded via the physical override OSL interface. This allows for early mapping before the virtual memory manager is available. Thomas Renninger, Bob Moore.


Enhanced the automatic return-object repair code: Repair a common problem with predefined methods that are defined to return a variable-length Package of sub-objects. If there is only one sub-object, some BIOS ASL code mistakenly simply returns the single object instead of a Package with one sub-object. This new support will repair this error by wrapping a Package object around the original object, creating the correct and expected Package with one sub-object. Names that can be repaired in this manner include: _ALR, _CSD, _HPX, _MLS, _PLD, _PRT, _PSS, _TRT, _TSS, _BCL, _DOD, _FIX, and _Sx. ACPICA BZ 939.


Changed the exception code returned for invalid ACPI paths passed as parameters to external interfaces such as AcpiEvaluateObject. Was AE_BAD_PARAMETER, now is the more sensible AE_BAD_PATHNAME.


Example Code and Data Size: These are the sizes for the OS-independent acpica.lib produced by the Microsoft Visual C++ 9.0 32-bit compiler. The debug version of the code includes the debug output trace mechanism and has a much larger code and data size.


  Previous Release:

    Non-Debug Version:  93.0K Code, 25.0K Data, 118.0K Total

    Debug Version:     172.5K Code, 73.2K Data, 245.7K Total

  Current Release:

    Non-Debug Version:  92.9K Code, 25.0K Data, 117.9K Total

    Debug Version:     172.5K Code, 73.2K Data, 245.7K Total



2) iASL Compiler/Disassembler and Tools:


iASL: Added the infrastructure and initial implementation of a integrated C-like preprocessor. This will simplify BIOS development process by eliminating the need for a separate preprocessing step during builds. On Windows, it also eliminates the need to install a separate C compiler. ACPICA BZ 761. Some features including full #define() macro support are still under development. These preprocessor directives are supported:










    #pragma message



In addition, these new command line options are supported:

    -D <symbol> Define symbol for preprocessor use

    -li         Create preprocessed output file (*.i)

    -P          Preprocess only and create preprocessor output file (*.i)


Table Compiler: Fixed a problem where the equals operator within an expression did not work properly.


Updated iASL to use the current versions of Bison/Flex. Updated the Windows project file to invoke these tools from the standard location. ACPICA BZ 904. Versions supported:

    Flex for Windows:  V2.5.4

    Bison for Windows: V2.4.1