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    SubjectRe: [PATCH] ACPI Suspend: Enable ACPI during resume if SCI_EN is not set
    applied to acpi-test.

    thanks,
    -Len

    On Sat, 4 Oct 2008, Rafael J. Wysocki wrote:

    > From: Rafael J. Wysocki <rjw@sisk.pl>
    >
    > ACPI Suspend: Enable ACPI during resume if SCI_EN is not set
    >
    > On some machines, like for example MSI Wind U100, the BIOS doesn't
    > enable ACPI before returning control to the OS, which sometimes
    > causes resume to fail. This is against the ACPI specification,
    > which clearly states that "When the platform is waking from an S1, S2
    > or S3 state, OSPM assumes the hardware is already in the ACPI mode
    > and will not issue an ACPI_ENABLE", but it won't hurt to check the
    > SCI_EN bit and enable ACPI during resume from S3 if this bit is not
    > set.
    >
    > Fortunately, we already have acpi_enable() for that, so use it in the
    > resume code path, before executing _BFS, in analogy with the
    > resume-from-hibernation code path.
    >
    > NOTE: We aren't supposed to set SCI_EN directly, because it's owned
    > by the hardware.
    >
    > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
    > ---
    > drivers/acpi/sleep/main.c | 2 ++
    > 1 file changed, 2 insertions(+)
    >
    > Index: linux-2.6/drivers/acpi/sleep/main.c
    > ===================================================================
    > --- linux-2.6.orig/drivers/acpi/sleep/main.c
    > +++ linux-2.6/drivers/acpi/sleep/main.c
    > @@ -200,6 +200,8 @@ static int acpi_suspend_enter(suspend_st
    > break;
    > }
    >
    > + /* If ACPI is not enabled by the BIOS, we need to enable it here. */
    > + acpi_enable();
    > /* Reprogram control registers and execute _BFS */
    > acpi_leave_sleep_state_prep(acpi_state);
    >
    >


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