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    SubjectRe: Cleanups for powernow-k8
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    On Tue, Jan 13, 2004 at 04:37:13PM -0600, paul.devriendt@amd.com wrote:

    > I have a totally new driver, that I am hoping to release within about
    > a month. (I did target the end of the year, but I got distracted on
    > some other stuff). The new driver :
    > - uses ACPI to figure out the available p-states. I have seen a *lot*
    > of buggy BIOSs where the PSB/PST info is wrong or missing,
    > - uses ACPI to handle battery / mains power transitions,
    > and some other clean ups.

    IMHO, a cpufreq driver have to not do things like that. It's up to
    a common library made eventually by ACPI folks to go. And AFAIK
    Dominik do make some patch for that. There is not only the K8 that
    can benefit from what you want to add (K7, Pentium M,...).

    > I would appreciate some advice on a question ... should I leave the old
    > non-ACPI capability there for those people who do not want to enable ACPI
    > in the kernel ? If so, is this a big ifdef, or is there a better way to do
    > it ? Or should I just say that it is dependent on ACPI, got to have ACPI ?

    Still IMHO, people that want to disable ACPI, but want to be able to
    lower the frequency of their processor don't know what they loose. The
    ACPI C-state, for which ACPI provide a good way to save powers in the
    idle loop today. But, I have seen broken BIOS, or bug in the current
    ACPI implentation, that do not permit to enable ACPI under Linux, so
    unless those issues are resolved, there may be still a need to support
    legacy configuration.

    BTW, an other drawback for only ACPI config. I have a K7 mobile
    for which I do have only 5 P-state on the ACPI side, instead
    of 9 as reported by the legacy method. One of the P-state is
    also broken (the VID is too high). I can't say of the 'quality'
    of BIOS made for the K8 architecture, but it should be possible
    that you get more appropriate information via the legacy table than
    the one provided by ACPI.. One solution may be a setup at kernel
    boot in order to configure the powernow-k8 with legacy method even
    if ACPI is enabled, or even a DMI quirk if such (broken) platform are
    known.


    --
    Ducrot Bruno

    -- Which is worse: ignorance or apathy?
    -- Don't know. Don't care.
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