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    Subject[patch 01/26] ACPI: disable lower idle C-states across suspend/resume
    2.6.22-stable review patch.  If anyone has any objections, please let us
    know.

    ------------------
    From: Thomas Gleixner <tglx@linutronix.de>

    changeset b04e7bdb984e3b7f62fb7f44146a529f88cc7639 from mainline.

    device_suspend() calls ACPI suspend functions, which seems to have undesired
    side effects on lower idle C-states. It took me some time to realize that
    especially the VAIO BIOSes (both Andrews jinxed UP and my elfstruck SMP one)
    show this effect. I'm quite sure that other bug reports against suspend/resume
    about turning the system into a brick have the same root cause.

    After fishing in the dark for quite some time, I realized that removing the ACPI
    processor module before suspend (this removes the lower C-state functionality)
    made the problem disappear. Interestingly enough the propability of having a
    bricked box is influenced by various factors (interrupts, size of the ram image,
    ...). Even adding a bunch of printks in the wrong places made the problem go
    away. The previous periodic tick implementation simply pampered over the
    problem, which explains why the dyntick / clockevents changes made this more
    prominent.

    We avoid complex functionality during the boot process and we have to do the
    same during suspend/resume. It is a similar scenario and equaly fragile.

    Add suspend / resume functions to the ACPI processor code and disable the lower
    idle C-states across suspend/resume. Fall back to the default idle
    implementation (halt) instead.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Tested-by: Andrew Morton <akpm@linux-foundation.org>
    Cc: Len Brown <lenb@kernel.org>
    Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
    Cc: Rafael J. Wysocki <rjw@sisk.pl>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    drivers/acpi/processor_core.c | 2 ++
    drivers/acpi/processor_idle.c | 19 ++++++++++++++++++-
    include/acpi/processor.h | 2 ++
    3 files changed, 22 insertions(+), 1 deletion(-)

    --- a/drivers/acpi/processor_core.c
    +++ b/drivers/acpi/processor_core.c
    @@ -93,6 +93,8 @@ static struct acpi_driver acpi_processor
    .add = acpi_processor_add,
    .remove = acpi_processor_remove,
    .start = acpi_processor_start,
    + .suspend = acpi_processor_suspend,
    + .resume = acpi_processor_resume,
    },
    };

    --- a/drivers/acpi/processor_idle.c
    +++ b/drivers/acpi/processor_idle.c
    @@ -324,6 +324,23 @@ static void acpi_state_timer_broadcast(s

    #endif

    +/*
    + * Suspend / resume control
    + */
    +static int acpi_idle_suspend;
    +
    +int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
    +{
    + acpi_idle_suspend = 1;
    + return 0;
    +}
    +
    +int acpi_processor_resume(struct acpi_device * device)
    +{
    + acpi_idle_suspend = 0;
    + return 0;
    +}
    +
    static void acpi_processor_idle(void)
    {
    struct acpi_processor *pr = NULL;
    @@ -354,7 +371,7 @@ static void acpi_processor_idle(void)
    }

    cx = pr->power.state;
    - if (!cx) {
    + if (!cx || acpi_idle_suspend) {
    if (pm_idle_save)
    pm_idle_save();
    else
    --- a/include/acpi/processor.h
    +++ b/include/acpi/processor.h
    @@ -279,6 +279,8 @@ int acpi_processor_power_init(struct acp
    int acpi_processor_cst_has_changed(struct acpi_processor *pr);
    int acpi_processor_power_exit(struct acpi_processor *pr,
    struct acpi_device *device);
    +int acpi_processor_suspend(struct acpi_device * device, pm_message_t state);
    +int acpi_processor_resume(struct acpi_device * device);

    /* in processor_thermal.c */
    int acpi_processor_get_limit_info(struct acpi_processor *pr);
    --
    -
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