31 May 2018. Summary of changes for version 20180531:
This release is available at https://acpica.org/downloads
1) ACPICA kernel-resident Subsystem:
Implemented additional support to help ensure that a DSDT or SSDT is fully loaded even if errors are incurred during the load. The majority of the problems that are seen is the failure of individual AML operators that occur during execution of any module-level code (MLC) existing in the table. This support adds a mechanism to abort the current ASL statement (AML opcode), emit an error message, and to simply move on to the next opcode -- instead of aborting the entire table load. This is different than the execution of a control method where the entire method is aborted upon any error. The goal is to perform a very "best effort" to load the ACPI tables. The most common MLC errors that have been seen in the field are direct references to unresolved ASL/AML symbols (referenced directly without the use of the CondRefOf operator to validate the symbol). This new ACPICA behavior is now compatible with other ACPI implementations.
Interpreter: The Unload AML operator is no longer supported for the reasons below. An AE_NOT_IMPLEMENTED exception is returned.
1) A correct implementation on at least some hosts may not be possible.
2) Other ACPI implementations do not correctly/fully support it.
3) It requires host device driver support which is not known to exist.
(To properly support namespace unload out from underneath.)
4) This AML operator has never been seen in the field.
Parser: Added a debug option to dump AML parse sub-trees as they are being executed. Used with ACPI_DEBUG_PRINT, the enabling debug level is ACPI_DB_PARSE_TREES.
Debugger: Reduced the verbosity for errors incurred during table load and module-level code execution.
Completed an investigation into adding a namespace node "owner list" instead of the current "owner ID" associated with namespace nodes. This list would link together all nodes that are owned by an individual control method. The purpose would be to enhance control method execution by speeding up cleanup during method exit (all namespace nodes created by a method are deleted upon method termination.) Currently, the entire namespace must be searched for matching owner IDs if (and only if) the method creates named objects outside of the local scope. However, by far the most common case is that methods create objects locally, not outside the method scope. There is already an ACPICA optimization in place that only searches the entire namespace in the rare case of a method creating objects elsewhere in the namespace. Therefore, it is felt that the overhead of adding an additional pointer to each namespace node to implement the owner list makes this feature unnecessary.
2) iASL Compiler/Disassembler and Tools:
iASL, Disassembler, and Template generator: Implemented support for Revision D of the IORT table. Adds a new subtable that is used to specify SMMUv3 PMCGs. rmurphy-arm.
Disassembler: Restored correct table header validation for the "special" ACPI tables -- RSDP and FACS. These tables do not contain a standard ACPI table header and must be special-cased. This was a regression that has been present for apparently a long time.
AcpiExec: Reduced verbosity of the local exception handler implemented within acpiexec. This handler is invoked by ACPICA upon any exceptions generated during control method execution. A new option was added: -vh restores the original verbosity level if desired.
AcpiExec: Changed the default base from decimal to hex for the -x option (set debug level). This simplifies the use of this option and matches the behavior of the corresponding iASL -x option.
AcpiExec: Restored a force-exit on multiple control-c (sigint) interrupts. This allows program termination even if other issues cause the control-c to fail.
ASL test suite (ASLTS): Added tests for the recently implemented package element resolution mechanism that allows forward references to named objects from individual package elements (this mechanism provides compatibility with other ACPI implementations.)