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    Subject[PATCH v1 2/9] PCI/PM: Clear PCIe PME Status bit in core, not PCIe port driver
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    Date
    From: Bjorn Helgaas <bhelgaas@google.com>

    fe31e69740ed ("PCI/PCIe: Clear Root PME Status bits early during system
    resume") added a .resume_noirq() callback to the PCIe port driver to clear
    the PME Status bit during resume to work around a BIOS issue.

    The BIOS evidently enabled PME interrupts for ACPI-based runtime wakeups
    but did not clear the PME Status bit during resume, which meant PMEs after
    resume did not trigger interrupts because PME Status did not transition
    from cleared to set.

    The fix was in the PCIe port driver, so it worked when CONFIG_PCIEPORTBUS
    was set. But I think we *always* want the fix because the platform may use
    PME interrupts even if Linux is built without the PCIe port driver.

    Move the fix from the port driver to the PCI core so we can work around
    this "PME doesn't work after waking from a sleep state" issue regardless of
    CONFIG_PCIEPORTBUS.

    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    ---
    drivers/pci/pci-driver.c | 14 ++++++++++++++
    drivers/pci/pcie/portdrv_pci.c | 15 ---------------
    2 files changed, 14 insertions(+), 15 deletions(-)

    diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
    index 3bed6beda051..bf0704b75f79 100644
    --- a/drivers/pci/pci-driver.c
    +++ b/drivers/pci/pci-driver.c
    @@ -525,6 +525,18 @@ static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
    pci_fixup_device(pci_fixup_resume_early, pci_dev);
    }

    +static void pcie_resume_early(struct pci_dev *pci_dev)
    +{
    + /*
    + * Some BIOSes forget to clear Root PME Status bits after system wakeup
    + * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
    + * bits now just in case (shouldn't hurt).
    + */
    + if (pci_is_pcie(pci_dev) &&
    + pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT)
    + pcie_clear_root_pme_status(pci_dev);
    +}
    +
    /*
    * Default "suspend" method for devices that have no driver provided suspend,
    * or not even a driver at all (second part).
    @@ -873,6 +885,8 @@ static int pci_pm_resume_noirq(struct device *dev)
    if (pci_has_legacy_pm_support(pci_dev))
    return pci_legacy_resume_early(dev);

    + pcie_resume_early(pci_dev);
    +
    if (drv && drv->pm && drv->pm->resume_noirq)
    error = drv->pm->resume_noirq(dev);

    diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
    index 4413dd85e923..f91afd09e356 100644
    --- a/drivers/pci/pcie/portdrv_pci.c
    +++ b/drivers/pci/pcie/portdrv_pci.c
    @@ -62,20 +62,6 @@ static int pcie_portdrv_restore_config(struct pci_dev *dev)
    }

    #ifdef CONFIG_PM
    -static int pcie_port_resume_noirq(struct device *dev)
    -{
    - struct pci_dev *pdev = to_pci_dev(dev);
    -
    - /*
    - * Some BIOSes forget to clear Root PME Status bits after system wakeup
    - * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
    - * bits now just in case (shouldn't hurt).
    - */
    - if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT)
    - pcie_clear_root_pme_status(pdev);
    - return 0;
    -}
    -
    static int pcie_port_runtime_suspend(struct device *dev)
    {
    return to_pci_dev(dev)->bridge_d3 ? 0 : -EBUSY;
    @@ -103,7 +89,6 @@ static const struct dev_pm_ops pcie_portdrv_pm_ops = {
    .thaw = pcie_port_device_resume,
    .poweroff = pcie_port_device_suspend,
    .restore = pcie_port_device_resume,
    - .resume_noirq = pcie_port_resume_noirq,
    .runtime_suspend = pcie_port_runtime_suspend,
    .runtime_resume = pcie_port_runtime_resume,
    .runtime_idle = pcie_port_runtime_idle,
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