[coreboot] DSDT Extraction

Morgan Reed morgan.s.reed at gmail.com
Mon Jun 8 15:22:30 CEST 2009

Just realised I omitted to CC the list.

On Mon, Jun 8, 2009 at 09:12, Stefan Reinauer<stepan at coresystems.de> wrote:
> We've been using the following script to dump ACPI information from a
> running system.
> #!/bin/bash
> 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
> do
>  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
>  else
>    eval $FNAME=$(( ${!FNAME} + 1 ))
>  fi
>  printf "Processing table \"$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
>  else
>    printf "Skipping $NAME because it was not dumped correctly.\n\n"
>  fi
> done

I'll try that out.

> 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.

Hmm, I'll have a poke around, any particular boards you suggest looking at?

> 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?

According to the tutorial at
<http://www.coreboot.org/VIA_EPIA-M#Advanced_ACPI> (and the comments
in via/epia-m/dsdt.asl) the only ACPI functionality in the epia-m tree
is very basic, supporting only the power button, interrupt routing and
basic power management (doesn't support all sleep states).

EDIT: further, soft power-off doesn't work, the system halts, the
drives spin down but the board does not power off.

Although now that I re-read some of the information it looks like the
article contradicts itself, down further it says that the dsdt.c
provided in the tree is ripped directly from the original BIOS
although it would seem that maybe the comment about it being extracted
from the BIOS only applies to the EPIA-M (not the EPIA-MII referenced

FWIW my board is an EPIA-MII not an EPIA-M.

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