Comment 125 for bug 532374

For users who either won't or can't upgrade their BIOS, a workaround for this problem has been included upstream in kernel 2.6.34-rc7, and also cc'd to the stable kernel branch (meaning 2.6.33 and possibly 2.6.32). from the changelog:

commit 07bedca29b0973f36a6b6db36936deed367164ed
Author: Alex Chiang
Date: Tue Apr 20 08:03:14 2010 -0600

    ACPI: DMI init_set_sci_en_on_resume for multiple Lenovo ThinkPads

    Multiple Lenovo ThinkPad models with Intel Core i5/i7 CPUs can
    successfully suspend/resume once, and then hang on the second s/r
    cycle.

    We got confirmation that this was due to a BIOS defect. The BIOS
    did not properly set SCI_EN coming out of S3. The BIOS guys
    hinted that The Other Leading OS ignores the fact that hardware
    owns the bit and sets it manually.

    In any case, an existing DMI table exists for machines where this
    defect is a known problem. Lenovo promise to fix their BIOS, but
    for folks who either won't or can't upgrade their BIOS, allow
    Linux to workaround the issue.

    https://bugzilla.kernel.org/show_bug.cgi?id=15407
    https://bugs.launchpad.net/ubuntu/+source/linux/+bug/532374

    Confirmed by numerous testers in the launchpad bug that using
    acpi_sleep=sci_force_enable fixes the issue. We add the machines
    to acpisleep_dmi_table[] to automatically enable this workaround.

    Cc: <email address hidden>
    Cc: Colin King
    Signed-off-by: Alex Chiang
    Signed-off-by: Len Brown