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    Subject[PATCH 4.17 115/220] PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume
    Date
    4.17-stable review patch.  If anyone has any objections, please let me know.

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

    From: Mika Westerberg <mika.westerberg@linux.intel.com>

    commit 13c65840feab8109194f9490c9870587173cb29d upstream.

    After a suspend/resume cycle the Presence Detect or Data Link Layer Status
    Changed bits might be set. If we don't clear them those events will not
    fire anymore and nothing happens for instance when a device is now
    hot-unplugged.

    Fix this by clearing those bits in a newly introduced function
    pcie_reenable_notification(). This should be fine because immediately
    after, we check if the adapter is still present by reading directly from
    the status register.

    Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/pci/hotplug/pciehp.h | 2 +-
    drivers/pci/hotplug/pciehp_core.c | 2 +-
    drivers/pci/hotplug/pciehp_hpc.c | 13 ++++++++++++-
    3 files changed, 14 insertions(+), 3 deletions(-)

    --- a/drivers/pci/hotplug/pciehp.h
    +++ b/drivers/pci/hotplug/pciehp.h
    @@ -121,7 +121,7 @@ struct controller *pcie_init(struct pcie
    int pcie_init_notification(struct controller *ctrl);
    int pciehp_enable_slot(struct slot *p_slot);
    int pciehp_disable_slot(struct slot *p_slot);
    -void pcie_enable_notification(struct controller *ctrl);
    +void pcie_reenable_notification(struct controller *ctrl);
    int pciehp_power_on_slot(struct slot *slot);
    void pciehp_power_off_slot(struct slot *slot);
    void pciehp_get_power_status(struct slot *slot, u8 *status);
    --- a/drivers/pci/hotplug/pciehp_core.c
    +++ b/drivers/pci/hotplug/pciehp_core.c
    @@ -283,7 +283,7 @@ static int pciehp_resume(struct pcie_dev
    ctrl = get_service_data(dev);

    /* reinitialize the chipset's event detection logic */
    - pcie_enable_notification(ctrl);
    + pcie_reenable_notification(ctrl);

    slot = ctrl->slot;

    --- a/drivers/pci/hotplug/pciehp_hpc.c
    +++ b/drivers/pci/hotplug/pciehp_hpc.c
    @@ -659,7 +659,7 @@ static irqreturn_t pcie_isr(int irq, voi
    return handled;
    }

    -void pcie_enable_notification(struct controller *ctrl)
    +static void pcie_enable_notification(struct controller *ctrl)
    {
    u16 cmd, mask;

    @@ -697,6 +697,17 @@ void pcie_enable_notification(struct con
    pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, cmd);
    }

    +void pcie_reenable_notification(struct controller *ctrl)
    +{
    + /*
    + * Clear both Presence and Data Link Layer Changed to make sure
    + * those events still fire after we have re-enabled them.
    + */
    + pcie_capability_write_word(ctrl->pcie->port, PCI_EXP_SLTSTA,
    + PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC);
    + pcie_enable_notification(ctrl);
    +}
    +
    static void pcie_disable_notification(struct controller *ctrl)
    {
    u16 mask;

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