[PATCH 1/5] PCI/PM: Disable device wakeups when halting or powering off system

[Mario Limonciello (AMD)]

PCI devices can be configured as wakeup sources from low power states.
However, when the system is powering off such wakeups are not expected
and may lead to spurious behavior.

ACPI r6.5, section 16.1.5 notes:

    "Hardware does allow a transition to S0 due to power button press
     or a Remote Start."

This implies that wakeups from PCI devices should not be relied upon
in these states. To align with this expectation and avoid unintended
wakeups, disable device wakeup capability during these transitions.

Tested-by: Eric Naim <dnaim@xxxxxxxxxxx>
Signed-off-by: Mario Limonciello (AMD) <superm1@xxxxxxxxxx>
---
 drivers/pci/pci-driver.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 2bfefd8db5260..a43ee7bbfb3f5 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1166,6 +1166,9 @@ static int pci_pm_poweroff(struct device *dev)
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
 
+	if (device_may_wakeup(dev) && system_state == SYSTEM_POWER_OFF)
+		device_set_wakeup_enable(dev, false);
+
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_suspend(dev, PMSG_HIBERNATE);
 
-- 
2.43.0