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    Subject[PATCH 3.2 009/199] PCI: Check for PME in targeted sleep state
    3.2.87-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Alan Stern <stern@rowland.harvard.edu>

    commit 6496ebd7edf446fccf8266a1a70ffcb64252593e upstream.

    One some systems, the firmware does not allow certain PCI devices to be put
    in deep D-states. This can cause problems for wakeup signalling, if the
    device does not support PME# in the deepest allowed suspend state. For
    example, Pierre reports that on his system, ACPI does not permit his xHCI
    host controller to go into D3 during runtime suspend -- but D3 is the only
    state in which the controller can generate PME# signals. As a result, the
    controller goes into runtime suspend but never wakes up, so it doesn't work
    properly. USB devices plugged into the controller are never detected.

    If the device relies on PME# for wakeup signals but is not capable of
    generating PME# in the target state, the PCI core should accurately report
    that it cannot do wakeup from runtime suspend. This patch modifies the
    pci_dev_run_wake() routine to add this check.

    Reported-by: Pierre de Villemereuil <flyos@mailoo.org>
    Tested-by: Pierre de Villemereuil <flyos@mailoo.org>
    Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    CC: Lukas Wunner <lukas@wunner.de>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    drivers/pci/pci.c | 4 ++++
    1 file changed, 4 insertions(+)

    --- a/drivers/pci/pci.c
    +++ b/drivers/pci/pci.c
    @@ -1763,6 +1763,10 @@ bool pci_dev_run_wake(struct pci_dev *de
    if (!dev->pme_support)
    return false;

    + /* PME-capable in principle, but not from the intended sleep state */
    + if (!pci_pme_capable(dev, pci_target_state(dev)))
    + return false;
    +
    while (bus->parent) {
    struct pci_dev *bridge = bus->self;

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