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ACPIDUMP(8) System Manager's Manual ACPIDUMP(8)

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:

DMAR
 
DSDT
 
ECDT
 
FACS
 
FADT
 
HPET
 
LPIT
 
MADT
 
MCFG
 
NFIT
 
RSD PTR
 
RSDT
 
WDDT
 

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.
dsdt_input
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.
dsdt_output
Store the DSDT data block from physical memory into the specified file.

/dev/mem
 

If a developer requests a copy of your ASL, please use the following command to dump all tables and compress the result.

# acpidump -dt | gzip -c9 > my_computer.asl.gz

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

acpi(4), mem(4), acpiconf(8), acpidb(8), iasl(8)

The acpidump utility first appeared in FreeBSD 5.0 and was rewritten to use iasl(8) for FreeBSD 5.2.

Doug Rabson <dfr@FreeBSD.org>
Mitsuru IWASAKI <iwasaki@FreeBSD.org>
Yasuo YOKOYAMA <yokoyama@jp.FreeBSD.org>
Nate Lawson <njl@FreeBSD.org>

Some contributions made by Chitoshi Ohsawa <ohsawa@catv1.ccn-net.ne.jp>, Takayasu IWANASHI <takayasu@wendy.a.perfect-liberty.or.jp>, Yoshihiko SARUMARU <mistral@imasy.or.jp>, Hiroki Sato <hrs@FreeBSD.org>, Michael Lucas <mwlucas@blackhelicopters.org> and Michael Smith <msmith@FreeBSD.org>.

The current implementation does not dump the BOOT structure or other miscellaneous tables.

July 10, 2018 FreeBSD-12.0