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    SubjectRe: 2.6.31-rc2+: Interrupts enabled after cpufreq_suspend
    On Sat, Jul 11, 2009 at 08:23:37AM +1000, Ben Herrenschmidt wrote:
    > On Fri, 2009-07-10 at 15:25 -0400, Dave Jones wrote:
    > > The answer seems to be in 42d4dc3f4e1ec1396371aac89d0dccfdd977191b
    > > which introduced all this code to work around some failure that only happens
    > > on PPC...
    > >
    > > [PATCH] Add suspend method to cpufreq core
    > >
    > > In order to properly fix some issues with cpufreq vs. sleep on
    > > PowerBooks, I had to add a suspend callback to the pmac_cpufreq driver.
    > > I must force a switch to full speed before sleep and I switch back to
    > > previous speed on resume.
    > >
    > >
    > > Ben, is there something better we can do here ?
    > >
    > > I really don't want to add an #ifdef __powerpc__ to core code if we can help it.
    > > I'd rather we didn't call into driver guts at all from the suspend path.
    > Wait a minute ... having a suspend/resume method in cpufreq is one
    > thing, having it muck around with SMP is another :-) The ppc code
    > doesn't do that.
    > There's nothing fundamentally "fail" in requiring a switch to a given
    > frequency before suspend. I don't know what kind of major FAIL the K8
    > code is doing here though :-)

    The fail part comes from the fact that interrupts get reenabled.
    And that's something that can easily happen out of our control if
    we call into acpi_cpufreq's ->get method for example, so powernow-k8 isn't
    the sole reason.

    > I'm happy instead of #ifdef's however to push the logic into the ppc
    > driver, or use a flag that the ppc driver sets to enable that logic.



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