7.10 support of new AMD PowerNow! (family 0x11 and beyond)

Tim Gardner tim.gardner at canonical.com
Thu Jan 24 15:44:16 UTC 2008

Langsdorf, Mark wrote:
>>> In late November, I submitted a few patches to this list
>>> for consideration in an Ubuntu 7.10 update release.  The
>>> purpose was to provide support for PowerNow! in AMD's
>>> forthcoming Family 0x11 processors.  There was a short
>>> patch submittted on 11/27 that addressed Family 0x11
>>> parts, and a much larger patch on 11/29 that handled all
>>> future AMD parts.
>>> There was never much discussion of them that I saw, and
>>> so I don't know which, if either, was adapted.  Linux
>>> PowerNow! support of family 0x11 parts is becoming 
>>> important to some of our OEMs, so I'm trying to determine
>>> what the Ubuntu kernel community did.  Would someone 
>>> please enlighten me?
>> Mark - We have reviewed the November patch, but see some problems with
>> it. It appears to change the default behavior of the 
>> function, which we are loath to do in a security update.
> There were 2 November patches: a small one that addresses 0x11
> only, and a larger one that addresses all future families.
> I'm not sure how either patch changes the default behavior.
> Would you explain?
> * The small patch adjusts the calculation of frequency from
> the Frequency ID based on the family number.  This is necessary
> to get PowerNow! working on 0x11 parts, since the 0x10 calculation
> returns the incorrect frequency and the driver assumes there is
> an ACPI error.
> * The large patch removes Frequency ID (fid) from the driver 
> altogether, because fid is not part of the architectural
> definition and is not guaranteed to be supported on future
> parts.
>> I also do not see this patch upstream in 2.6.24-rc8. Why not?
> The small one was superceded by the large patch.  The majority
> of the large patch code (and the more relevant portion) is in
> 2.6.24-rc8 as far as I can tell.  I'll go nag Dave Jones about
> getting the rest of the patch in.  The full patch is in
> 2.6.24-rc8-mm1.
> -Mark Langsdorf
> Operating System Research Center
Mark - I've applied the small patch, but it appears the larger patch
that you mentioned was not submitted to the mailing list. I have it
indirectly from Matt Domsch (and others) that the frequency calculation
patch is the right thing to do. This change will show up only in the
Gutsy security update kernel.

Matt - Please confirm since I have not spoken to you directly on this issue.



Tim Gardner tim.gardner at ubuntu.com

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