USB: autosuspend code consolidation
This patch (as813) gathers together common code for USB interface
autosuspend/autoresume.
It also adds some simple checking at the time an autosuspend request
is made, to see whether the request will fail. This way we don't
add a workqueue entry when it would end up doing nothing.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 401d76f..ca0e40e 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -940,6 +940,36 @@
return status;
}
+/* Internal routine to check whether we may autosuspend a device. */
+static int autosuspend_check(struct usb_device *udev)
+{
+ int i;
+ struct usb_interface *intf;
+
+ /* For autosuspend, fail fast if anything is in use.
+ * Also fail if any interfaces require remote wakeup but it
+ * isn't available. */
+ udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
+ if (udev->pm_usage_cnt > 0)
+ return -EBUSY;
+ if (udev->actconfig) {
+ for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
+ intf = udev->actconfig->interface[i];
+ if (!is_active(intf))
+ continue;
+ if (intf->pm_usage_cnt > 0)
+ return -EBUSY;
+ if (intf->needs_remote_wakeup &&
+ !udev->do_remote_wakeup) {
+ dev_dbg(&udev->dev, "remote wakeup needed "
+ "for autosuspend\n");
+ return -EOPNOTSUPP;
+ }
+ }
+ }
+ return 0;
+}
+
/**
* usb_suspend_both - suspend a USB device and its interfaces
* @udev: the usb_device to suspend
@@ -991,28 +1021,10 @@
udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
- /* For autosuspend, fail fast if anything is in use.
- * Also fail if any interfaces require remote wakeup but it
- * isn't available. */
if (udev->auto_pm) {
- if (udev->pm_usage_cnt > 0)
- return -EBUSY;
- if (udev->actconfig) {
- for (; i < udev->actconfig->desc.bNumInterfaces; i++) {
- intf = udev->actconfig->interface[i];
- if (!is_active(intf))
- continue;
- if (intf->pm_usage_cnt > 0)
- return -EBUSY;
- if (intf->needs_remote_wakeup &&
- !udev->do_remote_wakeup) {
- dev_dbg(&udev->dev,
- "remote wakeup needed for autosuspend\n");
- return -EOPNOTSUPP;
- }
- }
- i = 0;
- }
+ status = autosuspend_check(udev);
+ if (status < 0)
+ return status;
}
/* Suspend all the interfaces and then udev itself */
@@ -1151,7 +1163,7 @@
{
usb_pm_lock(udev);
udev->pm_usage_cnt -= dec_usage_cnt;
- if (udev->pm_usage_cnt <= 0)
+ if (autosuspend_check(udev) == 0)
queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
USB_AUTOSUSPEND_DELAY);
usb_pm_unlock(udev);
@@ -1200,6 +1212,33 @@
return status;
}
+/* Internal routine to adjust an interface's usage counter and change
+ * its device's autosuspend state.
+ */
+static int usb_autopm_do_interface(struct usb_interface *intf,
+ int inc_usage_cnt)
+{
+ struct usb_device *udev = interface_to_usbdev(intf);
+ int status = 0;
+
+ usb_pm_lock(udev);
+ if (intf->condition == USB_INTERFACE_UNBOUND)
+ status = -ENODEV;
+ else {
+ intf->pm_usage_cnt += inc_usage_cnt;
+ if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {
+ udev->auto_pm = 1;
+ status = usb_resume_both(udev);
+ if (status != 0)
+ intf->pm_usage_cnt -= inc_usage_cnt;
+ } else if (inc_usage_cnt <= 0 && autosuspend_check(udev) == 0)
+ queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
+ USB_AUTOSUSPEND_DELAY);
+ }
+ usb_pm_unlock(udev);
+ return status;
+}
+
/**
* usb_autopm_put_interface - decrement a USB interface's PM-usage counter
* @intf: the usb_interface whose counter should be decremented
@@ -1233,17 +1272,11 @@
*/
void usb_autopm_put_interface(struct usb_interface *intf)
{
- struct usb_device *udev = interface_to_usbdev(intf);
+ int status;
- usb_pm_lock(udev);
- if (intf->condition != USB_INTERFACE_UNBOUND &&
- --intf->pm_usage_cnt <= 0) {
- queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
- USB_AUTOSUSPEND_DELAY);
- }
- usb_pm_unlock(udev);
- // dev_dbg(&intf->dev, "%s: cnt %d\n",
- // __FUNCTION__, intf->pm_usage_cnt);
+ status = usb_autopm_do_interface(intf, -1);
+ // dev_dbg(&intf->dev, "%s: status %d cnt %d\n",
+ // __FUNCTION__, status, intf->pm_usage_cnt);
}
EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
@@ -1280,20 +1313,9 @@
*/
int usb_autopm_get_interface(struct usb_interface *intf)
{
- struct usb_device *udev = interface_to_usbdev(intf);
- int status;
+ int status;
- usb_pm_lock(udev);
- if (intf->condition == USB_INTERFACE_UNBOUND)
- status = -ENODEV;
- else {
- ++intf->pm_usage_cnt;
- udev->auto_pm = 1;
- status = usb_resume_both(udev);
- if (status != 0)
- --intf->pm_usage_cnt;
- }
- usb_pm_unlock(udev);
+ status = usb_autopm_do_interface(intf, 1);
// dev_dbg(&intf->dev, "%s: status %d cnt %d\n",
// __FUNCTION__, status, intf->pm_usage_cnt);
return status;