ACPIDUMP(8) BSD System Manager's Manual ACPIDUMP(8)
acpidump -- dump ACPI tables and ASL
acpidump [-cdhstv] [-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 mem-
ory 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 Revi-
sion. When invoked with the -t flag, the acpidump utility dumps contents of the following
The RSDT contains a pointer to the physical memory address of the FACP (Fixed ACPI Descrip-
tion 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:
-c Dump unknown table data as characters instead of hex.
-d Disassemble the DSDT into ASL using iasl(8) and print the results to stdout.
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.
-h Displays usage and exit.
Store the DSDT data block from physical memory into the specified file.
-s Skip tables with bad checksums.
-t Dump the contents of the various fixed tables listed above.
-v Enable verbose messages.
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, redirect-
ing 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), amldb(8), iasl(8)
The acpidump utility first appeared in FreeBSD 5.0 and was rewritten to use iasl(8) for
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 <firstname.lastname@example.org>, Takayasu IWANASHI
<email@example.com>, Yoshihiko SARUMARU <firstname.lastname@example.org>, Hiroki
Sato <hrs@FreeBSD.org>, Michael Lucas <email@example.com> and Michael Smith
The current implementation does not dump some miscellaneous tables.
BSD February 17, 2011 BSD