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    SubjectRe: [PATCH] ACPI: Move timer broadcast and pmtimer access before C3 arbiter shutdown
    On Wed, 06 Jun 2007 11:37:53 +0200 Thomas Gleixner <tglx@linutronix.de> wrote:

    > From: Udo A. Steinberg <us15@os.inf.tu-dresden.de>
    >
    > The chip set doc for IHC4 says:
    >
    > 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>
    >
    > ---
    > drivers/acpi/processor_idle.c | 9 +++++----
    > 1 file changed, 5 insertions(+), 4 deletions(-)
    >
    > Index: linux-2.6.22-rc4/drivers/acpi/processor_idle.c
    > ===================================================================
    > --- linux-2.6.22-rc4.orig/drivers/acpi/processor_idle.c 2007-06-06 11:47:21.000000000 +0200
    > +++ linux-2.6.22-rc4/drivers/acpi/processor_idle.c 2007-06-06 11:48:21.000000000 +0200
    > @@ -488,6 +488,11 @@ static void acpi_processor_idle(void)
    >
    > case ACPI_STATE_C3:
    >
    > + /* Get start time (ticks) */
    > + t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
    > + /* Handle timer broadcast before bus arbiter shutdown ! */
    > + acpi_state_timer_broadcast(pr, cx, 1);
    > +
    > if (pr->flags.bm_check) {
    > if (atomic_inc_return(&c3_cpu_count) ==
    > num_online_cpus()) {
    > @@ -502,10 +507,7 @@ static void acpi_processor_idle(void)
    > ACPI_FLUSH_CPU_CACHE();
    > }
    >
    > - /* Get start time (ticks) */
    > - t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
    > /* Invoke C3 */
    > - acpi_state_timer_broadcast(pr, cx, 1);
    > acpi_cstate_enter(cx);
    > /* Get end time (ticks) */
    > t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);

    hm, this needs a bit of help to get it to work against Len's current tree.

    However, if by "non-posted accesses" you're referring to that inl(), how
    come the second one which was left in place isn't also a problem?

    -
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