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    Subject[patch -mm 02/28] ACPI: Move timer broadcast and pmtimer access before C3 arbiter shutdown
    From: Udo A. Steinberg <us15@os.inf.tu-dresden.de>

    The chipset doc for IHC4 tells us:

    1.In general, software should not attempt any non-posted accesses during
    arbiter disable except to the ICH4's power management registers. This implies
    that interrupt handlers for any unmasked hardware interrupts and SMI/NMI should
    check ARB_DIS status before reading from ICH devices.

    So it's not a good idea to access ICH devices after arbiter shut down.

    Signed-off-by: Udo A. Steinberg <us15@os.inf.tu-dresden.de>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: Len Brown <lenb@kernel.org>

    ---
    drivers/acpi/processor_idle.c | 7 ++++++-
    1 file changed, 6 insertions(+), 1 deletion(-)

    Index: linux-2.6.22-rc4-mm/drivers/acpi/processor_idle.c
    ===================================================================
    --- linux-2.6.22-rc4-mm.orig/drivers/acpi/processor_idle.c 2007-06-23 14:38:57.000000000 +0200
    +++ linux-2.6.22-rc4-mm/drivers/acpi/processor_idle.c 2007-06-23 14:38:57.000000000 +0200
    @@ -978,6 +978,12 @@ static int acpi_idle_enter_c3(struct cpu
    return 0;
    }

    + /*
    + * Must be done before busmaster disable as we might need to
    + * access HPET !
    + */
    + acpi_state_timer_broadcast(pr, cx, 1);
    +
    /* disable bus master */
    if (pr->flags.bm_check) {
    spin_lock(&c3_lock);
    @@ -997,7 +1003,6 @@ static int acpi_idle_enter_c3(struct cpu

    /* Get start time (ticks) */
    t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
    - acpi_state_timer_broadcast(pr, cx, 1);
    acpi_idle_do_entry(cx);
    t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);

    --

    -
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