PCI/ACPI: Notify PCI devices when their power resource is turned on

This patch reduces power consumption by allowing idle devices to go to a
low power state after another device on the same power resource has been
awakened.

A power resource may be shared by multiple devices.  When all devices
sharing a power resource are put into D3_COLD state, the power resource
will be turned off.  When one of the devices is awakened, the power
resource will be turned on and all devices sharing it will be powered on to
D0uninitialized state.  These devices should be resumed, so that they have
the opportunity to go to low power state later.

[bhelgaas: changelog]
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/acpi/pci_bind.c b/drivers/acpi/pci_bind.c
index 2ef04098cc1d5f4d01942d3e4de79014c4911efe..f1ea71c80ab65cb0eb9706bab94b3056d4d6c683 100644 (file)
--- a/drivers/acpi/pci_bind.c
+++ b/drivers/acpi/pci_bind.c
@@ -45,6 +45,7 @@ static int acpi_pci_unbind(struct acpi_device *device)
 
        device_set_run_wake(&dev->dev, false);
        pci_acpi_remove_pm_notifier(device);
+       acpi_power_resource_unregister_device(&dev->dev, device->handle);
 
        if (!dev->subordinate)
                goto out;
@@ -71,6 +72,7 @@ static int acpi_pci_bind(struct acpi_device *device)
                return 0;
 
        pci_acpi_add_pm_notifier(device, dev);
+       acpi_power_resource_register_device(&dev->dev, device->handle);
        if (device->wakeup.flags.run_wake)
                device_set_run_wake(&dev->dev, true);