Comment 30 for bug 1178131

The bisect of commits to Kernel 3.0.0-16.28 .. 30.0.0-16.29 produced the following result. I dont understand what that means but it will hopefully provide the informations you need to continue debugging or fix the bug:

df89d48a8cbdc23578397c6e62d5c9c9e630c610 is the first bad commit
commit df89d48a8cbdc23578397c6e62d5c9c9e630c610
Author: Matthew Garrett <email address hidden>
Date: Thu Nov 10 16:38:33 2011 -0500

    PCI: Rework ASPM disable code

    BugLink: http://bugs.launchpad.net/bugs/927848

    commit 3c076351c4027a56d5005a39a0b518a4ba393ce2 upstream.

    Right now we forcibly clear ASPM state on all devices if the BIOS indicates
    that the feature isn't supported. Based on the Microsoft presentation
    "PCI Express In Depth for Windows Vista and Beyond", I'm starting to think
    that this may be an error. The implication is that unless the platform
    grants full control via _OSC, Windows will not touch any PCIe features -
    including ASPM. In that case clearing ASPM state would be an error unless
    the platform has granted us that control.

    This patch reworks the ASPM disabling code such that the actual clearing
    of state is triggered by a successful handoff of PCIe control to the OS.
    The general ASPM code undergoes some changes in order to ensure that the
    ability to clear the bits isn't overridden by ASPM having already been
    disabled. Further, this theoretically now allows for situations where
    only a subset of PCIe roots hand over control, leaving the others in the
    BIOS state.

    It's difficult to know for sure that this is the right thing to do -
    there's zero public documentation on the interaction between all of these
    components. But enough vendors enable ASPM on platforms and then set this
    bit that it seems likely that they're expecting the OS to leave them alone.

    Measured to save around 5W on an idle Thinkpad X220.

    Signed-off-by: Matthew Garrett <email address hidden>
    Signed-off-by: Jesse Barnes <email address hidden>
    Signed-off-by: Greg Kroah-Hartman <email address hidden>
    Signed-off-by: Tim Gardner <email address hidden>

:040000 040000 2ae424c4b73d5552809986f7116ba347b4fb1a90 04a4a42154f00a9c3a47ec3f787e424437b06183 M drivers
:040000 040000 72de932be7dafa9fa5712bc854a332850c0a79ac 94d1f2df9527e35ddc9d6489c2de6545fad4c764 M include