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    SubjectRe: [PATCH v1] Input: tegra-kbc - report wakeup key for some platforms.
    Hi Rakesh,

    On Thu, Dec 01, 2011 at 01:09:59PM -0800, Rakesh Iyer wrote:
    > Hello Dmitry.
    >
    > Sorry for the wrap issue, my Outlook does not seem to obey the settings.
    >
    > I wanted to explain the tegra system resume path implementation so I can justify
    > why I am doing this complicated fix and why I feel it will guarantee the resume
    > is due to keypress.
    >
    > The tegra wake resume code is registered as a syscore ops.
    > When the system is resumed due to a wake event, the suspend_enter (after wakeup)
    > routine will invoke the tegra syscoreops_resume method and that routine will propagate
    > the wake event to the individual ISR's through genirq.
    > If kbc was wake source, kbc_isr will be invoked in this execution path.
    >
    > If system is resumed due to other reason, the tegra_syscoreops_resume code will not
    > find the event.

    Consider the following sequence:

    1. Something other than keyboard generates wakeup event
    2. It's IRQ fires up and gets serviced
    3. System starts resuming devices
    4. User presses a key on the keypad while it is still suspended _and_
    registered as a wakeup source
    5. Keypad's ISR runs as well and you decide that KEY_POWER should be
    reported even though keypad wasn't the real reason the system
    woke up.

    Is this scenario not possible?

    Thanks.

    --
    Dmitry


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