#ifdef CONFIG_USB_SUSPEND
/*
+ * usb_port_suspend - suspend a usb device's upstream port
+ * @udev: device that's no longer in active use, not a root hub
+ * 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.
+ *
* Selective port suspend reduces power; most suspended devices draw
* less than 500 uA. It's also used in OTG, along with remote wakeup.
* All devices below the suspended port are also suspended.
* also support "remote wakeup", where the device can activate the USB
* tree above them to deliver data, such as a keypress or packet. In
* some cases, this wakes the USB host.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * Returns 0 on success, else negative errno.
*/
-static int hub_port_suspend(struct usb_hub *hub, int port1,
- struct usb_device *udev)
+int usb_port_suspend(struct usb_device *udev)
{
- int status;
+ struct usb_hub *hub = hdev_to_hub(udev->parent);
+ int port1 = udev->portnum;
+ int status;
// dev_dbg(hub->intfdev, "suspend port %d\n", port1);
NULL, 0,
USB_CTRL_SET_TIMEOUT);
if (status)
- dev_dbg(&udev->dev,
- "won't remote wakeup, status %d\n",
- status);
+ dev_dbg(&udev->dev, "won't remote wakeup, status %d\n",
+ status);
}
/* see 7.1.7.6 */
status = set_port_feature(hub->hdev, port1, USB_PORT_FEAT_SUSPEND);
if (status) {
- dev_dbg(hub->intfdev,
- "can't suspend port %d, status %d\n",
- port1, status);
+ dev_dbg(hub->intfdev, "can't suspend port %d, status %d\n",
+ port1, status);
/* paranoia: "should not happen" */
(void) usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
USB_REQ_CLEAR_FEATURE, USB_RECIP_DEVICE,
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.
- *
- * 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.
- *
- * Returns 0 on success, else negative errno.
- */
-int usb_port_suspend(struct usb_device *udev)
-{
- int status = 0;
-
- status = hub_port_suspend(hdev_to_hub(udev->parent),
- udev->portnum, udev);
- return status;
-}
-
/*
* If the USB "suspend" state is in use (rather than "global suspend"),
* many devices will be individually taken out of suspend state using
if (status >= 0)
status = (status == 2 ? 0 : -ENODEV);
- if (status)
- dev_dbg(&udev->dev,
- "gone after usb resume? status %d\n",
- status);
- else if (udev->actconfig) {
+ if (status) {
+ dev_dbg(&udev->dev, "gone after usb resume? status %d\n",
+ status);
+ } else if (udev->actconfig) {
le16_to_cpus(&devstatus);
if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) {
status = usb_control_msg(udev,
return status;
}
-static int
-hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
+/*
+ * usb_port_resume - re-activate a suspended usb device's upstream port
+ * @udev: device to re-activate, not a root hub
+ * Context: must be able to sleep; device not locked; pm locks held
+ *
+ * This will re-activate the suspended device, increasing power usage
+ * while letting drivers communicate again with its endpoints.
+ * USB resume explicitly guarantees that the power session between
+ * the host and the device is the same as it was when the device
+ * suspended.
+ *
+ * Returns 0 on success, else negative errno.
+ */
+int usb_port_resume(struct usb_device *udev)
{
- int status;
- u16 portchange, portstatus;
+ struct usb_hub *hub = hdev_to_hub(udev->parent);
+ int port1 = udev->portnum;
+ int status;
+ u16 portchange, portstatus;
/* Skip the initial Clear-Suspend step for a remote wakeup */
status = hub_port_status(hub, port1, &portstatus, &portchange);
status = clear_port_feature(hub->hdev,
port1, USB_PORT_FEAT_SUSPEND);
if (status) {
- dev_dbg(hub->intfdev,
- "can't resume port %d, status %d\n",
- port1, status);
+ dev_dbg(hub->intfdev, "can't resume port %d, status %d\n",
+ port1, status);
} else {
/* drive resume for at least 20 msec */
dev_dbg(&udev->dev, "usb %sresume\n",
status = finish_port_resume(udev);
}
}
- if (status < 0)
+ if (status < 0) {
+ dev_dbg(&udev->dev, "can't resume, status %d\n", status);
hub_port_logical_disconnect(hub, port1);
+ }
clear_bit(port1, hub->busy_bits);
if (!hub->hdev->parent && !hub->busy_bits[0])
return status;
}
-/*
- * usb_port_resume - re-activate a suspended usb device's upstream port
- * @udev: device to re-activate
- * Context: must be able to sleep; device not locked; pm locks held
- *
- * This will re-activate the suspended device, increasing power usage
- * while letting drivers communicate again with its endpoints.
- * USB resume explicitly guarantees that the power session between
- * the host and the device is the same as it was when the device
- * suspended.
- *
- * Returns 0 on success, else negative errno.
- */
-int usb_port_resume(struct usb_device *udev)
-{
- int status;
-
- status = hub_port_resume(hdev_to_hub(udev->parent),
- udev->portnum, udev);
- if (status < 0)
- dev_dbg(&udev->dev, "can't resume, status %d\n", status);
- return status;
-}
-
static int remote_wakeup(struct usb_device *udev)
{
int status = 0;
return 0;
}
-static inline int
-finish_port_resume(struct usb_device *udev)
-{
- return 0;
-}
-
-static inline int
-hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
-{
- return 0;
-}
-
int usb_port_resume(struct usb_device *udev)
{
return 0;
projects / linux-2.6 / commitdiff