[PATCH v7 05/12] PCI/PM: Disable device wakeups when halting or powering off system

["Mario Limonciello (AMD)" <superm1@kernel.org>]

PCI devices can be configured as wakeup sources from low power states.
However, when the system is halting or 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@cachyos.org>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
---
v7:
 * Reword title
 * Reword commit
v5:
 * Re-order
 * Add tags
v4:
 * https://lore.kernel.org/linux-pci/20250616175019.3471583-1-superm1@kernel.org/
---
 drivers/pci/pci-driver.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 63665240ae87f..f201d298d7173 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1139,6 +1139,10 @@ 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_HALT || 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