In subject, s|PCI: PM:|PCI/PM:| to follow previous practice. On Sun, Aug 17, 2025 at 09:00:55PM -0500, Mario Limonciello (AMD) wrote: > PCI devices can be programmed as a wakeup source from low power states > by sysfs. However when using the S4 flow to go into S5 these wakeup > sources should be disabled to avoid what users would perceive as > spurious wakeup events.
Is the "can be programmed vis sysfs" part relevant here? I think S4 and S5 are ACPI sleep states not applicable to all platforms. Is it relevant that we got here via ACPI? I assume non-ACPI systems can also exercise this path. Is there a way to describe this scenario in a way that would apply to all systems? I'm not sure what "using the S4 flow to go in to S5" means. It would be nice to have a spec reference or some sort of rationale for the requirement to disable all wakeup sources in SYSTEM_HALT and SYSTEM_POWER_OFF. > Tested-by: Eric Naim <dn...@cachyos.org> > Signed-off-by: Mario Limonciello (AMD) <supe...@kernel.org> > --- > v5: > * Re-order > * Add tags > v4: > * > https://lore.kernel.org/linux-pci/20250616175019.3471583-1-supe...@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); I guess the suggestion is that we can't wake up at all from SYSTEM_HALT or SYSTEM_POWER_OFF? Would both be considered S5? Does this mean we need a physical power button push to start up again? I guess ACPI r6.5, sec 16.1.5 kind of suggests that: "hardware does allow a transition to S0 due to power button press or a Remote Start." > if (pci_has_legacy_pm_support(pci_dev)) > return pci_legacy_suspend(dev, PMSG_HIBERNATE); > > -- > 2.43.0 >
