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    SubjectRe: [RFC][PATCH 2/3]i386,x86-64 Handle missing local APIC timer interrupts on C3 state
    On Fri, 9 Dec 2005, Venkatesh Pallipadi wrote:

    > On Fri, Dec 09, 2005 at 12:06:35AM -0800, Zwane Mwaikambo wrote:
    > > On Thu, 8 Dec 2005, Venkatesh Pallipadi wrote:
    > >
    > > > Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
    > > > disable local APIC timer and switch to using a broadcast from external timer
    > > > interrupt (IRQ 0).
    > > >
    > > > +void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
    > > > +void switch_APIC_timer_to_ipi(void *cpumask);
    > > > +void switch_ipi_to_APIC_timer(void *cpumask);
    > >
    > > When is this used?
    >
    > +void smp_send_timer_broadcast_ipi(struct pt_regs *regs);
    > This is called by the IRQ0 timer interrupt handler, to check whether any CPUs
    > have enrolled for this broadcast.
    >
    > +void switch_APIC_timer_to_ipi(void *cpumask);
    > Called by acpi processor driver when it find out that a particular CPU can
    > support C3 state (and it is an Intel CPU).
    >
    > +void switch_ipi_to_APIC_timer(void *cpumask);
    > Called by acpi processor driver again to reset to APIC_timer when C3 is not
    > supported by the CPU.

    Well i was more curious as to where in the patchset the
    switch_ipi_to_APIC_timer is used;

    zwane@montezuma linux-2.6-hg-x86_64 {0:1} grep switch_ipi_to_APIC_timer /tmp/patch[1234]
    /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask);
    /tmp/patch2:+void switch_ipi_to_APIC_timer(void *cpumask)
    /tmp/patch2:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
    /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask)
    /tmp/patch4:+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
    /tmp/patch4:+void switch_ipi_to_APIC_timer(void *cpumask);

    Or will it only be used in future?

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