acpidump — dump ACPI tables and ASL
acpidump [−d] [−t] [−h] [−v] [−f dsdt_input] [−o dsdt_output]
The acpidump utility analyzes ACPI tables in physical memory and can dump them to a file. In addition, acpidump can call iasl(8) to disassemble AML (ACPI Machine Language) found in these tables and dump them as ASL (ACPI Source Language) to stdout.
ACPI tables have an essential data block (the DSDT, Differentiated System Description Table) that includes information used on the kernel side such as detailed information about PnP hardware, procedures for controlling power management support, and so on. The acpidump utility can extract the DSDT data block from physical memory and store it into an output file and optionally also disassemble it. If any Secondary System Description Table (SSDT) entries exist, they will also be included in the output file and disassembly.
When acpidump is invoked without the −f option, it will read ACPI tables from physical memory via /dev/mem. First it searches for the RSDP (Root System Description Pointer), which has the signature "RSD PTR ", and then gets the RSDT (Root System Description Table), which includes a list of pointers to physical memory addresses for other tables. The RSDT itself and all other tables linked from RSDT are generically called SDTs (System Description Tables) and their header has a common format which consists of items such as Signature, Length, Revision, Checksum, OEMID, OEM Table ID, OEM Revision, Creator ID and Creator Revision. When invoked with the −t flag, the acpidump utility dumps contents of the following tables:
The RSDT contains a pointer to the physical memory address of the FACP (Fixed ACPI Description Table). The FACP defines static system information about power management support (ACPI Hardware Register Implementation) such as interrupt mode (INT_MODEL), SCI interrupt number, SMI command port (SMI_CMD) and the location of ACPI registers. The FACP also has a pointer to a physical memory address for the DSDT. While the other tables are fixed format, the DSDT consists of free-formatted AML data.
The following options are supported by acpidump:
Disassemble the DSDT into ASL using iasl(8) and print the results to stdout.
Dump the contents of the various fixed tables listed above.
Displays usage and exit.
Enable verbose messages.
Load the DSDT from the specified file instead of physical memory. Since only the DSDT is stored in the file, the −t flag may not be used with this option.
Store the DSDT data block from physical memory into the specified file.
This example dumps the DSDT from physical memory to foo.dsdt. It also prints the contents of various system tables and disassembles the AML contained in the DSDT to stdout, redirecting the output to foo.asl.
# acpidump -t -d -o foo.dsdt > foo.asl
This example reads a DSDT file and disassembles it to stdout. Verbose messages are enabled.
# acpidump -v -d -f foo.dsdt
The current implementation does not dump the BOOT structure or other miscellaneous tables.
Some contributions made by Chitoshi Ohsawa <ohsawa [AT] catv1.jp>, Takayasu IWANASHI <takayasu [AT] wendy.jp>, Yoshihiko SARUMARU <mistral [AT] imasy.jp>, Hiroki Sato <hrs [AT] FreeBSD.org>, Michael Lucas <mwlucas [AT] blackhelicopters.org> and Michael Smith <msmith [AT] FreeBSD.org>.
The acpidump utility first appeared in FreeBSD 5.0 and was rewritten to use iasl(8) for FreeBSD 5.2.
BSD October 4, 2004 BSD