ACPICA version 20081031 released

[Moore, Robert]

31 October 2008. Summary of changes for version 20081031:

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

1) ACPI CA Core Subsystem:

Restructured the ACPICA header files into public/private. acpi.h now includes only the "public" acpica headers. All other acpica headers are "private" and should not be included by acpica users. One new file, accommon.h is used to include the commonly used private headers for acpica code generation. Future plans include moving all private headers to a new subdirectory.

Implemented an automatic Buffer->String return value conversion for predefined ACPI methods. For these methods (such as _BIF), added automatic conversion for return objects that are required to be a String, but a Buffer was found instead. This can happen when reading string battery data from an operation region, because it used to be difficult to convert the data from buffer to string from within the ASL. Ensures that the host OS is provided with a valid null-terminated string. Linux BZ 11822.

Updated the FACS waking vector interfaces. Split AcpiSetFirmwareWakingVector into two: one for the 32-bit vector, another for the 64-bit vector. This is required because the host OS must setup the wake much differently for each vector (real vs. protected mode, etc.) and the interface itself should not be deciding which vector to use. Also, eliminated the GetFirmwareWakingVector interface, as it served no purpose (only the firmware reads the vector, OS only writes the vector.) ACPICA BZ 731.

Implemented a mechanism to escape infinite AML While() loops. Added a loop counter to force exit from AML While loops if the count becomes too large. This can occur in poorly written AML when the hardware does not respond within a while loop and the loop does not implement a timeout. The maximum loop count is configurable. A new exception code is returned when a loop is broken, AE_AML_INFINITE_LOOP. Alexey Starikovskiy, Bob Moore.

Optimized the execution of AML While loops. Previously, a control state object was allocated and freed for each execution of the loop. The optimization is to simply reuse the control state for each iteration. This speeds up the raw loop execution time by about 5%.

Enhanced the implicit return mechanism. For Windows compatibility, return an implicit integer of value zero for methods that contain no executable code. Such methods are seen in the field as stubs (presumably), and can cause drivers to fail if they expect a return value. Lin Ming.

Allow multiple backslashes as root prefixes in namepaths. In a fully qualified namepath, allow multiple backslash prefixes. This can happen (and is seen in the field) because of the use of a double-backslash in strings (since backslash is the escape character) causing confusion. ACPICA BZ 739 Lin Ming.

Emit a warning if two different FACS or DSDT tables are discovered in the FADT. Checks if there are two valid but different addresses for the FACS and DSDT within the FADT (mismatch between the 32-bit and 64-bit fields.)

Consolidated the method argument count validation code. Merged the code that validates control method argument counts into the predefined validation module. Eliminates possible multiple warnings for incorrect argument counts.

Implemented ACPICA example code. Includes code for ACPICA initialization, handler installation, and calling a control method. Available at source/tools/examples.

Added a global pointer for FACS table to simplify internal FACS access. Use the global pointer instead of using AcpiGetTableByIndex for each FACS access. This simplifies the code for the Global Lock and the Firmware Waking Vector(s).

Example Code and Data Size: These are the sizes for the OS-independent acpica.lib produced by the Microsoft Visual C++ 6.0 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:  81.2K Code, 17.0K Data,  98.2K Total
    Debug Version:     155.8K Code, 49.1K Data, 204.9K Total
  Current Release:
    Non-Debug Version:  81.7K Code, 17.3K Data,  99.0K Total
    Debug Version:     156.4K Code, 49.4K Data, 205.8K Total

2) iASL Compiler/Disassembler and Tools:

iASL: Improved disassembly of external method calls. Added the -e option to allow the inclusion of additional ACPI tables to help with the disassembly of method invocations and the generation of external declarations during the disassembly. Certain external method invocations cannot be disassembled properly without the actual declaration of the method. Use the -e option to include the table where the external method(s) are actually declared. Most useful for disassembling SSDTs that make method calls back to the master DSDT. Lin Ming. Example: To disassemble an SSDT with calls to DSDT:  iasl -d -e dsdt.aml ssdt1.aml

iASL: Fix to allow references to aliases within ASL namepaths. Fixes a problem where the use of an alias within a namepath would result in a not found error or cause the compiler to fault. Also now allows forward references from the Alias operator itself. ACPICA BZ 738.