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    SubjectRe: [PATCH] Dynamic tick, version 050127-1
    * Zwane Mwaikambo <zwane@arm.linux.org.uk> [050204 09:54]:
    > On Fri, 4 Feb 2005, Tony Lindgren wrote:
    >
    > > * Zwane Mwaikambo <zwane@arm.linux.org.uk> [050204 09:31]:
    > > > On Fri, 4 Feb 2005, Tony Lindgren wrote:
    > > >
    > > > > Yes, it's safer to keep the timer periodic, although it's
    > > > > used for oneshot purposes for the skips. If the timer interrupt
    > > > > got missed for some reason, the system would be able to recover when
    > > > > it's in periodic mode.
    > > > >
    > > > > And with some timers, we can do the reprogramming faster, as we just
    > > > > need to load the new value.
    > > > >
    > > > > I could not figure out how to disable the interrupts for PIT
    > > > > when local APIC is used and the ticks to skip is longer than PIT
    > > > > would allow. So I just changed the mode temporarily to disable it.
    > > > >
    > > > > Does anybody know if there's a way to stop PIT interrupts while
    > > > > keeping it in the periodic mode?
    > > >
    > > > disable_irq(0) ?
    > >
    > > Then the problem is that the CPU does not stay in sleep but wakes to
    > > the first PIT interrupt AFAIK.
    >
    > I do not understand, do you want to disable the PIT from interrupting the
    > processor and enable it interrupting at a later time?

    Yes, that right. PIT max skip ticks = 54 and local APIC timer > 1000.
    PIT interrupt needs to be disabled to stay in sleep for over 54 ticks.

    But I think you're right, disable_irq(0) should do the trick :)

    Hmmm, we should be able to keep PIT irq disabled all the time when using
    local APIC timer. I'll play with it a bit.

    Tony
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