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    SubjectRe: [PATCH] PCI / PM: Check device_may_wakeup() in pci_enable_wake()
    On Wed, May 09, 2018 at 12:18:32AM +0200, Rafael J. Wysocki wrote:
    > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    >
    > Commit 0847684cfc5f0 (PCI / PM: Simplify device wakeup settings code)
    > went too far and dropped the device_may_wakeup() check from
    > pci_enable_wake() which causes wakeup to be enabled during system
    > suspend, hibernation or shutdown for some PCI devices that are not
    > allowed by user space to wake up the system from sleep (or power off).
    >
    > As a result of this excessive power is drawn by some of the affected
    > systems while in sleep states or off.
    >
    > Restore the device_may_wakeup() check in pci_enable_wake(), but make
    > sure that the PCI bus type's runtime suspend callback will not call
    > device_may_wakeup() which is about system wakeup from sleep and not
    > about device wakeup from runtime suspend.
    >
    > Fixes: 0847684cfc5f0 (PCI / PM: Simplify device wakeup settings code)
    > Reported-by: Joseph Salisbury <joseph.salisbury@canonical.com>
    > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

    Acked-by: Bjorn Helgaas <bhelgaas@google.com>

    0847684cfc5f0 appeared in v4.13, which raises the question of whether
    this problem is important enough for a stable backport. Up to you :)

    > ---
    > drivers/pci/pci.c | 29 +++++++++++++++++++++++------
    > 1 file changed, 23 insertions(+), 6 deletions(-)
    >
    > Index: linux-pm/drivers/pci/pci.c
    > ===================================================================
    > --- linux-pm.orig/drivers/pci/pci.c
    > +++ linux-pm/drivers/pci/pci.c
    > @@ -1910,7 +1910,7 @@ void pci_pme_active(struct pci_dev *dev,
    > EXPORT_SYMBOL(pci_pme_active);
    >
    > /**
    > - * pci_enable_wake - enable PCI device as wakeup event source
    > + * __pci_enable_wake - enable PCI device as wakeup event source
    > * @dev: PCI device affected
    > * @state: PCI state from which device will issue wakeup events
    > * @enable: True to enable event generation; false to disable
    > @@ -1928,7 +1928,7 @@ EXPORT_SYMBOL(pci_pme_active);
    > * Error code depending on the platform is returned if both the platform and
    > * the native mechanism fail to enable the generation of wake-up events
    > */
    > -int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable)
    > +static int __pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable)
    > {
    > int ret = 0;
    >
    > @@ -1969,6 +1969,23 @@ int pci_enable_wake(struct pci_dev *dev,
    >
    > return ret;
    > }
    > +
    > +/**
    > + * pci_enable_wake - change wakeup settings for a PCI device
    > + * @pci_dev: Target device
    > + * @state: PCI state from which device will issue wakeup events
    > + * @enable: Whether or not to enable event generation
    > + *
    > + * If @enable is set, check device_may_wakeup() for the device before calling
    > + * __pci_enable_wake() for it.
    > + */
    > +int pci_enable_wake(struct pci_dev *pci_dev, pci_power_t state, bool enable)
    > +{
    > + if (enable && !device_may_wakeup(&pci_dev->dev))
    > + return -EINVAL;
    > +
    > + return __pci_enable_wake(pci_dev, state, enable);
    > +}
    > EXPORT_SYMBOL(pci_enable_wake);
    >
    > /**
    > @@ -1981,9 +1998,9 @@ EXPORT_SYMBOL(pci_enable_wake);
    > * should not be called twice in a row to enable wake-up due to PCI PM vs ACPI
    > * ordering constraints.
    > *
    > - * This function only returns error code if the device is not capable of
    > - * generating PME# from both D3_hot and D3_cold, and the platform is unable to
    > - * enable wake-up power for it.
    > + * This function only returns error code if the device is not allowed to wake
    > + * up the system from sleep or it is not capable of generating PME# from both
    > + * D3_hot and D3_cold and the platform is unable to enable wake-up power for it.
    > */
    > int pci_wake_from_d3(struct pci_dev *dev, bool enable)
    > {
    > @@ -2114,7 +2131,7 @@ int pci_finish_runtime_suspend(struct pc
    >
    > dev->runtime_d3cold = target_state == PCI_D3cold;
    >
    > - pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));
    > + __pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));
    >
    > error = pci_set_power_state(dev, target_state);
    >
    >

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