| Message ID | 20190625102942.27740-4-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | PCI / ACPI: Handle sibling devices sharing power resources | expand |
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index b782acac26c5..2abe0eeafb53 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -902,6 +902,7 @@ static void pci_acpi_setup(struct device *dev) device_wakeup_enable(dev); acpi_pci_wakeup(pci_dev, false); + acpi_device_power_add_dependent(adev, dev); } static void pci_acpi_cleanup(struct device *dev) @@ -914,6 +915,7 @@ static void pci_acpi_cleanup(struct device *dev) pci_acpi_remove_pm_notifier(adev); if (adev->wakeup.flags.valid) { + acpi_device_power_remove_dependent(adev, dev); if (pci_dev->bridge_d3) device_wakeup_disable(dev);
If otherwise unrelated PCI devices share ACPI power resources turning them on causes the devices to enter D0uninitialized power state which may cause problems. For example in Intel Ice Lake two root ports (RP0 and RP1), Thunderbolt controller (NHI) and xHCI controller all share power resources as can be ween in the topology below where power resources are marked with []: Host bridge | +- RP0 ---\ +- RP1 ---|--+--> [TBT] +- NHI --/ | | | | v +- xHCI --> [D3C] In a situation where all devices sharing the power resources are in D3cold (the power resources are turned off) and for example the Thunderbolt controller is runtime resumed resulting that the power resources are turned on. This means that the other devices sharing them (RP0, RP1 and xHCI) are transitioned into D0uninitialized state. If they were configured to trigger wake (PME) on a certain event that configuration gets lost after reset so we would need to re-initialize them to get the wakeup working as expected again. To do so we would need to runtime resume all of them to make sure their registers get restored properly before we can runtime suspend them again. Since we just added concept of "_PR0 dependent device" we can solve this by calling the relevant add/remove functions when the PCI device is bind to its ACPI representation. If it has power resources the PCI device will be added as dependent device to them and runtime resumed whenever they are physically turned on. This should make sure PCI core can reconfigure wakes after the device is transitioned into D0uninitialized. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- drivers/pci/pci-acpi.c | 2 ++ 1 file changed, 2 insertions(+)