On Fri, Jul 21, 2017 at 11:30:24PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > The acpi_pci_propagate_wakeup() routine is there to handle cases in > which PCI bridges (or PCIe ports) are expected to signal wakeup > for devices below them, but currently it doesn't do that correctly. > > The problem is that acpi_pci_propagate_wakeup() uses > acpi_pm_set_device_wakeup() for bridges and if that routine is > called for multiple times to disable wakeup for the same device, > it will disable it on the first invocation and the next calls > will have no effect (it works analogously when called to enable > wakeup, but that is not a problem). > > Now, say acpi_pci_propagate_wakeup() has been called for two > different devices under the same bridge and it has called > acpi_pm_set_device_wakeup() for that bridge each time. The > bridge is now enabled to generate wakeup signals. Next, > suppose that one of the devices below it resumes and > acpi_pci_propagate_wakeup() is called to disable wakeup for that > device. It will then call acpi_pm_set_device_wakeup() for the bridge > and that will effectively disable remote wakeup for all devices under > it even though some of them may still be suspended and remote wakeup > may be expected to work for them. > > To address this (arguably theoretical) issue, allow > wakeup.enable_count under struct acpi_device to grow beyond 1 in > certain situations. In particular, allow that to happen in > acpi_pci_propagate_wakeup() when wakeup is enabled or disabled > for PCI bridges, so that wakeup is actually disabled for the > bridge when all devices under it resume and not when just one > of them does that. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
