[coreboot] AMD DBM690T PowerNow table problems

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Thu Jan 8 03:34:18 CET 2009

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

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?



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