modifications to new generic autosuspend code

Hi Alan,

here are the changes I made to adapt the HID suspend code to the new
model. Basically I just changed the simple flag to a callback that allows
to know whether the flag has been checked and allow several independently
removable sources of business.

	Regards
		Oliver

--------

--- linux-2.6.20/drivers/usb/core/driver.c	2007-02-06 14:14:48.000000000 +0100
+++ linux-stern/drivers/usb/core/driver.c	2007-02-15 16:04:57.000000000 +0100
@@ -942,21 +942,48 @@
 
 #ifdef	CONFIG_USB_SUSPEND
 
+static int is_interface_busy(struct usb_interface *intf)
+{
+	struct usb_driver *drv = to_usb_driver(intf->dev.driver);
+
+	if (!drv)
+		return 0;
+	if (!drv->check_busy)
+		return 0;
+
+	return (drv->check_busy)(intf);
+}
+
 /* Internal routine to check whether we may autosuspend a device. */
-static int autosuspend_check(struct usb_device *udev)
+static int autosuspend_check(struct usb_device *udev, int starting)
 {
 	int			i;
+	unsigned		delay;
 	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. */
+	/* For autosuspend, fail fast if anything is in use or autosuspend
+	 * is disabled.  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->autosuspend_delay)
+		return -EPERM;
+
+	/* starting is non-zero when the autosuspend timer is first started,
+	 * in which case we should return the maximum delay needed.
+	 * It is zero when the timer expires, in which case we should return
+	 * 0 if it is okay to autosuspend now, otherwise the next timer
+	 * delay value.
+	 */
+	delay = (starting ? udev->autosuspend_delay : 0);
+
 	if (udev->actconfig) {
 		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
 			intf = udev->actconfig->interface[i];
+			if (!intf->autosuspend_delay)
+				return -EPERM;
 			if (!is_active(intf))
 				continue;
 			if (intf->pm_usage_cnt > 0)
@@ -967,6 +994,29 @@
 						"for autosuspend\n");
 				return -EOPNOTSUPP;
 			}
+			if (starting || is_interface_busy(intf))
+				delay = max(delay, intf->autosuspend_delay);
+		}
+	}
+	return delay;
+}
+
+/* Internal routine to check whether we need to autoresume a device. */
+static int autosuspend_recheck(struct usb_device *udev)
+{
+	int			i;
+	struct usb_interface	*intf;
+
+	/* There's a race between the test of the USB_IF_DEVICE_BUSY flag
+	 * above and the completion of an URB (when a driver would set the
+	 * flag).  If the flag gets set after the decision to start an
+	 * autosuspend has been made, we need to go back and autoresume
+	 * the device. */
+	if (udev->actconfig) {
+		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
+			intf = udev->actconfig->interface[i];
+			if (is_interface_busy(intf))
+				return 1;
 		}
 	}
 	return 0;
--- linux-2.6.20/include/linux/usb.h	2007-02-06 14:14:57.000000000 +0100
+++ linux-stern/include/linux/usb.h	2007-02-15 13:41:21.000000000 +0100
@@ -804,6 +812,8 @@
 	void (*pre_reset) (struct usb_interface *intf);
 	void (*post_reset) (struct usb_interface *intf);
 
+	int (*check_busy) (struct usb_interface *intf);
+
 	const struct usb_device_id *id_table;
 
 	struct usb_dynids dynids;

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