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    SubjectRe: 2.6.22-rc1-mm1 [cannot change thermal trip points]
    Hi!

    > > > ACPI: thermal trip points are read-only
    > >
    > > What was the rationale? Can we get this one reverted?
    > >
    > > Some machines (HP omnibook xe3) have broken trip points -- too high --
    > > so machine will overheat and trigger hw shutdown before starting
    > > passive cooling.
    > >
    > > That's really broken, and write to trip points is reasonable way to
    > > 'fix' that. (I'd understand if you only ever let trip points to
    > > decrease... but otoh root should be able to shoot himself....)
    >
    > No, writing trip-points is neither a fix, nor it is reasonable.
    > It is a workaround at best, and it is a dangerous and mis-leading hack.
    >
    > The OS has no capability to actually change the ACPI trip points
    > that are used by the BIOS. Changing the OS copy of them
    > to make the user think that trip events will actually
    > happen when the temperature crosses the OS copy is crazy.

    Aha... wait. It seemed to work for me when I enabled thermal
    polling...

    Slowing cpu down / shutdown / turn the fan on is done in the os after
    all. Should we just start polling temperatures when user writes custom
    trip points?

    > If there are systems with broken thermals and the
    > ACPI thermal control needs and over-ride to turn
    > on the fan, then that is fine -- but using
    > fake trip-points and giving the user the impression
    > that they are real is not viable.

    They become real when we fake _TSP, too, ..?
    Pavel

    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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