[coreboot] AMD DBM690T PowerNow table problems

Marc Jones marcj303 at gmail.com
Thu Jan 8 17:52:07 CET 2009

On Wed, Jan 7, 2009 at 7:34 PM, Carl-Daniel Hailfinger
<c-d.hailfinger.devel.2006 at gmx.net> wrote:
> On 06.01.2009 17:47, Marc Jones wrote:
>> On Mon, Jan 5, 2009 at 6:36 PM, Bao, Zheng <Zheng.Bao at amd.com> wrote:
>>> If fid_multiplier is 0, it doesn't seem to have any sense. So I agree.
>>> Acked-by: zheng bao <zheng.bao at amd.com>
>> I also fixed this in acpi_tables.c Pistachio.
>> r 3847
> Thanks!
> The Linux kernel powernow-k8 driver doesn't complain anymore, but now
> the machine will lock up or reboot once I put some load on it.
> Blacklisting the powernow-k8 driver avoids the issue, but that makes
> frequency scaling impossible.
> AFAICS the standard cpu frequency governor is ondemand and it scales the
> frequency down from 1800 MHz to 1000 Mhz. That seems to work fine, but
> scaling up again will cause the lockups/reboots. By the way, coreboot
> reports a BIST failure after such reboots. Not nice.
> Rudolf's PowerNow tables had entries for 1000/1600/1800 MHz. The
> proprietary BIOS and coreboot only have entries for 1000/1800 MHz.
> According to the docs, scaling from 1000 MHz to 1800 MHz can't be done
> in a single step. Is that maybe the reason for the problems I'm seeing?

Can you dump the current tables or can you not get that far before a
crash? The entries are end points and the driver takes care of the
stepping that needs to be done to get to those points. We need to
check that the table generated the correct vid setting for the fid. It
is well described in the bkdg section 10.6.


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