[coreboot] DSDT Extraction

Stefan Reinauer stepan at coresystems.de
Mon Jun 8 01:12:37 CEST 2009

On 07.06.2009 15:47 Uhr, Morgan Reed wrote:
> Hi all,
>      As an aside to my earlier question, I'm currently looking at the
> Advanced ACPI stuff (i.e. pulling in the DSDT from the original BIOS).
> I've extracted the DSDT using the instructions from the wiki, i.e. cat
> /proc/acpi/dsdt > dsdt; iasl -d dsdt; iasl -tc dsdt.dsl;

We've been using the following script to dump ACPI information from a
running system.


rm -rf out
mkdir out
# walk through all ACPI tables with their addresses
# example:
#    RSDT @ 0xcf6794ba
# we can not just dump the tables by their names because some
# machines have double ACPI tables

acpidump | grep "@ 0x" | while read line
  NAME=$( echo `echo $line|cut -f1 -d@` )
  FNAME=$( echo $NAME | sed s/\ /_/g |sed s/\!/b/g )
  ADDR=$( echo `echo $line|cut -f2 -d@` )
  if [ "${!FNAME}" == "" ]; then
    eval $FNAME=0
    eval $FNAME=$(( ${!FNAME} + 1 ))
  printf "Processing table \"$NAME\" at $ADDR ... "
  printf "${!FNAME} tables of that kind found before.\n"

  # acpidump -s ${!FNAME} --table "$NAME" > out/$FNAME-$ADDR-${!FNAME}.txt
  acpidump -b -s ${!FNAME} --table "$NAME" > out/$FNAME-$ADDR-${!FNAME}.bin
  if [ "`file -b out/$FNAME-$ADDR-${!FNAME}.bin`" != "ASCII text" ]; then
    iasl -d out/$FNAME-$ADDR-${!FNAME}.bin &>/dev/null
    printf "Skipping $NAME because it was not dumped correctly.\n\n"


> Initially there are a few errors thrown by the compiler which I had to
> fix. Now, when I replace coreboot-v2/src/mainboard/via/epia-m/dsdt.c
> with it I get linker errors (section <section> [<fromaddr>-<toaddr>]
> overlaps section <section> [<fromaddr>-<toaddr>]), I expect this is to
> do with the DSDT from coreboot being ~1kB and the one from the dump
> being ~12kB.
> Anybody have any suggestions?

Yes. You should not use the vendor BIOS acpi tables. There might be
legal reasons against doing that, but more so technical reasons. These
tables will not do the right thing if you just plug them into coreboot,
even if you fix the compilation issues (that happen due to compiler
differences between the Microsoft and Intel ASL compiler). There are
very good ACPI implementations for some boards in the coreboot tree, and
they should give you enough hints on what to do and how.

I'd be interested though which parts you are actually missing in the
ACPI implementation of coreboot on the Epia-M, or why you are looking at
the vendor ACPI?

Best regards,


coresystems GmbH • Brahmsstr. 16 • D-79104 Freiburg i. Br.
      Tel.: +49 761 7668825 • Fax: +49 761 7664613
Email: info at coresystems.dehttp://www.coresystems.de/
Registergericht: Amtsgericht Freiburg • HRB 7656
Geschäftsführer: Stefan Reinauer • Ust-IdNr.: DE245674866

More information about the coreboot mailing list