[Bug 364156] Re: powernow-k8: BIOS does not provide ACPI -PSS objects in a way that Linux understands

[Tom Pringle]

I see this problem on all 6 AMD machines I work with on a regular basis.
CPU frequency scaling is disabled.  Most of these machines have the log
message

                                 [Firmware Bug]: powernow-k8: No
compatible ACPI _PSS objects found.

These machines are configured with motherboards from various vendors
using various AMD / NVIDIA chipsets.  The common factor is the K8 / K10
cpu architecture and the Linux kernel (2.6.28 and .31 possibly earlier
as well).

The problem is most acute on the recently released IBM thinkpad edge
notebook which boots both Window7 and Ubuntu 10.04.  In windows it
appears to run at a much lower temperature.  Based on this observation I
assume frequency scaling is working in Windows so it is hard to
understand how the lack of frequency scaling in Ubuntu could be a BIOS
bug.  Given the pervasiveness of the problem in Linux and the
observation that Windows seems to scale CPU frequency, isn't this
problem more likely to be a Linux kernel issue.  Or does windows somehow
workaround the BIOS bug.  If so perhaps there is workaround that could
be applied in the linux kernel.

more attachments to follow

** Attachment added: "acpidump.txt"
   http://launchpadlibrarian.net/38553264/acpidump.txt

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powernow-k8: BIOS does not provide ACPI -PSS objects in a way that Linux understands
https://bugs.launchpad.net/bugs/364156
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