[coreboot] 4 GB RAM failure on DBM690T target (690G/SB600)

Marc Jones marcj303 at gmail.com
Wed Jan 21 02:58:17 CET 2009

On Tue, Jan 20, 2009 at 6:50 PM, Carl-Daniel Hailfinger
<c-d.hailfinger.devel.2006 at gmx.net> wrote:
> On 20.01.2009 17:13, Rudolf Marek wrote:
>>> I'm not totally sure the ACPI code is hard coded to 1 GB. The default
>>> values in the ACPI code code correspond to 1 GB and there is some code
>>> which will calculate BIOS memory location from TOM and TOM2. I could not
>>> find any place where TOM and TOM2 are updated,
>> its in acpi-k8.c in amd directory. Its in ssdt table.
> Thanks. Unfortunately, the situation is more complicated on DBM690T.
> TOM (the top below 4 GB) is stored twice, once in the SSDT (modified
> automatically) and once in the DSDT (unmodified). TOM2 is only stored in
> the DSDT (unmodified). The (correct) value of TOM in the SSDT is ignored
> and the (incorrect) values of TOM/TOM2 in the DSDT are used.

This sounds like a oversite. Maybe the AMD BTDC guys can help.

More information about the coreboot mailing list