-/*
- * Devices on USB hub ports have only one "suspend" state, corresponding
- * to ACPI D2, "may cause the device to lose some context".
- * State transitions include:
- *
- * - suspend, resume ... when the VBUS power link stays live
- * - suspend, disconnect ... VBUS lost
- *
- * Once VBUS drop breaks the circuit, the port it's using has to go through
- * normal re-enumeration procedures, starting with enabling VBUS power.
- * Other than re-initializing the hub (plug/unplug, except for root hubs),
- * Linux (2.6) currently has NO mechanisms to initiate that: no khubd
- * timer, no SRP, no requests through sysfs.
- *
- * If CONFIG_USB_SUSPEND isn't enabled, devices only really suspend when
- * the root hub for their bus goes into global suspend ... so we don't
- * (falsely) update the device power state to say it suspended.
- */
-static int __usb_port_suspend (struct usb_device *udev, int port1)
-{
- int status = 0;
-
- /* caller owns the udev device lock */
- if (port1 < 0)
- return port1;
-
- /* we change the device's upstream USB link,
- * but root hubs have no upstream USB link.
- */
- if (udev->parent)
- status = hub_port_suspend(hdev_to_hub(udev->parent), port1,
- udev);
- else {
- dev_dbg(&udev->dev, "usb %ssuspend\n",
- udev->auto_pm ? "auto-" : "");
- usb_set_device_state(udev, USB_STATE_SUSPENDED);
- }
- return status;
-}
-
-/*
- * usb_port_suspend - suspend a usb device's upstream port
- * @udev: device that's no longer in active use
- * Context: must be able to sleep; device not locked; pm locks held
- *
- * Suspends a USB device that isn't in active use, conserving power.
- * Devices may wake out of a suspend, if anything important happens,
- * using the remote wakeup mechanism. They may also be taken out of
- * suspend by the host, using usb_port_resume(). It's also routine
- * to disconnect devices while they are suspended.
- *
- * This only affects the USB hardware for a device; its interfaces
- * (and, for hubs, child devices) must already have been suspended.
- *
- * Suspending OTG devices may trigger HNP, if that's been enabled
- * between a pair of dual-role devices. That will change roles, such
- * as from A-Host to A-Peripheral or from B-Host back to B-Peripheral.
- *
- * Returns 0 on success, else negative errno.
- */
-int usb_port_suspend(struct usb_device *udev)
-{
- return __usb_port_suspend(udev, udev->portnum);
-}
-