1 files changed, 287 insertions, 365 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index a1c1a11dd9be..f7b337feb3ea 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -31,9 +31,16 @@
 #include "hcd.h"
 #include "hub.h"
 
+#ifdef	CONFIG_USB_PERSIST
+#define	USB_PERSIST	1
+#else
+#define	USB_PERSIST	0
+#endif
+
 struct usb_hub {
 	struct device		*intfdev;	/* the "interface" device */
 	struct usb_device	*hdev;
+	struct kref		kref;
 	struct urb		*urb;		/* for interrupt polling pipe */
 
 	/* buffer for urb ... with extra space in case of babble */
@@ -66,6 +73,7 @@ struct usb_hub {
 	unsigned		limited_power:1;
 	unsigned		quiescing:1;
 	unsigned		activating:1;
+	unsigned		disconnected:1;
 
 	unsigned		has_indicators:1;
 	u8			indicator[USB_MAXCHILDREN];
@@ -321,7 +329,7 @@ static void kick_khubd(struct usb_hub *hub)
 	to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
 
 	spin_lock_irqsave(&hub_event_lock, flags);
-	if (list_empty(&hub->event_list)) {
+	if (!hub->disconnected & list_empty(&hub->event_list)) {
 		list_add_tail(&hub->event_list, &hub_event_list);
 		wake_up(&khubd_wait);
 	}
@@ -330,6 +338,7 @@ static void kick_khubd(struct usb_hub *hub)
 
 void usb_kick_khubd(struct usb_device *hdev)
 {
+	/* FIXME: What if hdev isn't bound to the hub driver? */
 	kick_khubd(hdev_to_hub(hdev));
 }
 
@@ -400,9 +409,10 @@ static void hub_tt_kevent (struct work_struct *work)
 	struct usb_hub		*hub =
 		container_of(work, struct usb_hub, tt.kevent);
 	unsigned long		flags;
+	int			limit = 100;
 
 	spin_lock_irqsave (&hub->tt.lock, flags);
-	while (!list_empty (&hub->tt.clear_list)) {
+	while (--limit && !list_empty (&hub->tt.clear_list)) {
 		struct list_head	*temp;
 		struct usb_tt_clear	*clear;
 		struct usb_device	*hdev = hub->hdev;
@@ -550,48 +560,68 @@ static int hub_hub_status(struct usb_hub *hub,
 static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
 {
 	struct usb_device *hdev = hub->hdev;
-	int ret;
+	int ret = 0;
 
-	if (hdev->children[port1-1] && set_state) {
+	if (hdev->children[port1-1] && set_state)
 		usb_set_device_state(hdev->children[port1-1],
 				USB_STATE_NOTATTACHED);
-	}
-	ret = clear_port_feature(hdev, port1, USB_PORT_FEAT_ENABLE);
+	if (!hub->error)
+		ret = clear_port_feature(hdev, port1, USB_PORT_FEAT_ENABLE);
 	if (ret)
 		dev_err(hub->intfdev, "cannot disable port %d (err = %d)\n",
-			port1, ret);
-
+				port1, ret);
 	return ret;
 }
 
+/*
+ * Disable a port and mark a logical connnect-change event, so that some
+ * time later khubd will disconnect() any existing usb_device on the port
+ * and will re-enumerate if there actually is a device attached.
+ */
+static void hub_port_logical_disconnect(struct usb_hub *hub, int port1)
+{
+	dev_dbg(hub->intfdev, "logical disconnect on port %d\n", port1);
+	hub_port_disable(hub, port1, 1);
+
+	/* FIXME let caller ask to power down the port:
+	 *  - some devices won't enumerate without a VBUS power cycle
+	 *  - SRP saves power that way
+	 *  - ... new call, TBD ...
+	 * That's easy if this hub can switch power per-port, and
+	 * khubd reactivates the port later (timer, SRP, etc).
+	 * Powerdown must be optional, because of reset/DFU.
+	 */
+
+	set_bit(port1, hub->change_bits);
+ 	kick_khubd(hub);
+}
 
 /* caller has locked the hub device */
-static void hub_pre_reset(struct usb_interface *intf)
+static int hub_pre_reset(struct usb_interface *intf)
 {
 	struct usb_hub *hub = usb_get_intfdata(intf);
 	struct usb_device *hdev = hub->hdev;
-	int port1;
+	int i;
 
-	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
-		if (hdev->children[port1 - 1]) {
-			usb_disconnect(&hdev->children[port1 - 1]);
-			if (hub->error == 0)
-				hub_port_disable(hub, port1, 0);
-		}
+	/* Disconnect all the children */
+	for (i = 0; i < hdev->maxchild; ++i) {
+		if (hdev->children[i])
+			usb_disconnect(&hdev->children[i]);
 	}
 	hub_quiesce(hub);
+	return 0;
 }
 
 /* caller has locked the hub device */
-static void hub_post_reset(struct usb_interface *intf)
+static int hub_post_reset(struct usb_interface *intf)
 {
 	struct usb_hub *hub = usb_get_intfdata(intf);
 
-	hub_activate(hub);
 	hub_power_on(hub);
+	hub_activate(hub);
+	return 0;
 }
 
-
 static int hub_configure(struct usb_hub *hub,
 	struct usb_endpoint_descriptor *endpoint)
 {
@@ -845,43 +875,42 @@ fail:
 	return ret;
 }
 
+static void hub_release(struct kref *kref)
+{
+	struct usb_hub *hub = container_of(kref, struct usb_hub, kref);
+
+	usb_put_intf(to_usb_interface(hub->intfdev));
+	kfree(hub);
+}
+
 static unsigned highspeed_hubs;
 
 static void hub_disconnect(struct usb_interface *intf)
 {
 	struct usb_hub *hub = usb_get_intfdata (intf);
-	struct usb_device *hdev;
+
+	/* Take the hub off the event list and don't let it be added again */
+	spin_lock_irq(&hub_event_lock);
+	list_del_init(&hub->event_list);
+	hub->disconnected = 1;
+	spin_unlock_irq(&hub_event_lock);
 
 	/* Disconnect all children and quiesce the hub */
 	hub->error = 0;
 	hub_pre_reset(intf);
 
 	usb_set_intfdata (intf, NULL);
-	hdev = hub->hdev;
 
-	if (hdev->speed == USB_SPEED_HIGH)
+	if (hub->hdev->speed == USB_SPEED_HIGH)
 		highspeed_hubs--;
 
 	usb_free_urb(hub->urb);
-	hub->urb = NULL;
-
-	spin_lock_irq(&hub_event_lock);
-	list_del_init(&hub->event_list);
-	spin_unlock_irq(&hub_event_lock);
-
 	kfree(hub->descriptor);
-	hub->descriptor = NULL;
-
 	kfree(hub->status);
-	hub->status = NULL;
-
-	if (hub->buffer) {
-		usb_buffer_free(hdev, sizeof(*hub->buffer), hub->buffer,
-				hub->buffer_dma);
-		hub->buffer = NULL;
-	}
+	usb_buffer_free(hub->hdev, sizeof(*hub->buffer), hub->buffer,
+			hub->buffer_dma);
 
-	kfree(hub);
+	kref_put(&hub->kref, hub_release);
 }
 
 static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
@@ -929,10 +958,12 @@ descriptor_error:
 		return -ENOMEM;
 	}
 
+	kref_init(&hub->kref);
 	INIT_LIST_HEAD(&hub->event_list);
 	hub->intfdev = &intf->dev;
 	hub->hdev = hdev;
 	INIT_DELAYED_WORK(&hub->leds, led_work);
+	usb_get_intf(intf);
 
 	usb_set_intfdata (intf, hub);
 	intf->needs_remote_wakeup = 1;
@@ -982,49 +1013,6 @@ hub_ioctl(struct usb_interface *intf, unsigned int code, void *user_data)
 }
 
 
-/* grab device/port lock, returning index of that port (zero based).
- * protects the upstream link used by this device from concurrent
- * tree operations like suspend, resume, reset, and disconnect, which
- * apply to everything downstream of a given port.
- */
-static int locktree(struct usb_device *udev)
-{
-	int			t;
-	struct usb_device	*hdev;
-
-	if (!udev)
-		return -ENODEV;
-
-	/* root hub is always the first lock in the series */
-	hdev = udev->parent;
-	if (!hdev) {
-		usb_lock_device(udev);
-		return 0;
-	}
-
-	/* on the path from root to us, lock everything from
-	 * top down, dropping parent locks when not needed
-	 */
-	t = locktree(hdev);
-	if (t < 0)
-		return t;
-
-	/* everything is fail-fast once disconnect
-	 * processing starts
-	 */
-	if (udev->state == USB_STATE_NOTATTACHED) {
-		usb_unlock_device(hdev);
-		return -ENODEV;
-	}
-
-	/* when everyone grabs locks top->bottom,
-	 * non-overlapping work may be concurrent
-	 */
-	usb_lock_device(udev);
-	usb_unlock_device(hdev);
-	return udev->portnum;
-}
-
 static void recursively_mark_NOTATTACHED(struct usb_device *udev)
 {
 	int i;
@@ -1089,46 +1077,6 @@ void usb_set_device_state(struct usb_device *udev,
 	spin_unlock_irqrestore(&device_state_lock, flags);
 }
 
-
-#ifdef	CONFIG_PM
-
-/**
- * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
- * @rhdev: struct usb_device for the root hub
- *
- * The USB host controller driver calls this function when its root hub
- * is resumed and Vbus power has been interrupted or the controller
- * has been reset.  The routine marks all the children of the root hub
- * as NOTATTACHED and marks logical connect-change events on their ports.
- */
-void usb_root_hub_lost_power(struct usb_device *rhdev)
-{
-	struct usb_hub *hub;
-	int port1;
-	unsigned long flags;
-
-	dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
-
-	/* Make sure no potential wakeup events get lost,
-	 * by forcing the root hub to be resumed.
-	 */
-	rhdev->dev.power.prev_state.event = PM_EVENT_ON;
-
-	spin_lock_irqsave(&device_state_lock, flags);
-	hub = hdev_to_hub(rhdev);
-	for (port1 = 1; port1 <= rhdev->maxchild; ++port1) {
-		if (rhdev->children[port1 - 1]) {
-			recursively_mark_NOTATTACHED(
-					rhdev->children[port1 - 1]);
-			set_bit(port1, hub->change_bits);
-		}
-	}
-	spin_unlock_irqrestore(&device_state_lock, flags);
-}
-EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
-
-#endif	/* CONFIG_PM */
-
 static void choose_address(struct usb_device *udev)
 {
 	int		devnum;
@@ -1269,7 +1217,6 @@ static inline void show_string(struct usb_device *udev, char *id, char *string)
 
 #ifdef	CONFIG_USB_OTG
 #include "otg_whitelist.h"
-static int __usb_port_suspend(struct usb_device *, int port1);
 #endif
 
 /**
@@ -1375,11 +1322,11 @@ int usb_new_device(struct usb_device *udev)
 		 * (Includes HNP test device.)
 		 */
 		if (udev->bus->b_hnp_enable || udev->bus->is_b_host) {
-			err = __usb_port_suspend(udev, udev->bus->otg_port);
+			err = usb_port_suspend(udev);
 			if (err < 0)
 				dev_dbg(&udev->dev, "HNP fail, %d\n", err);
 		}
-		err = -ENODEV;
+		err = -ENOTSUPP;
 		goto fail;
 	}
 #endif
@@ -1478,9 +1425,9 @@ static int hub_port_wait_reset(struct usb_hub *hub, int port1,
 		if (!(portstatus & USB_PORT_STAT_CONNECTION))
 			return -ENOTCONN;
 
-		/* bomb out completely if something weird happened */
+		/* bomb out completely if the connection bounced */
 		if ((portchange & USB_PORT_STAT_C_CONNECTION))
-			return -EINVAL;
+			return -ENOTCONN;
 
 		/* if we`ve finished resetting, then break out of the loop */
 		if (!(portstatus & USB_PORT_STAT_RESET) &&
@@ -1559,34 +1506,24 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
 	return status;
 }
 
-/*
- * Disable a port and mark a logical connnect-change event, so that some
- * time later khubd will disconnect() any existing usb_device on the port
- * and will re-enumerate if there actually is a device attached.
- */
-static void hub_port_logical_disconnect(struct usb_hub *hub, int port1)
-{
-	dev_dbg(hub->intfdev, "logical disconnect on port %d\n", port1);
-	hub_port_disable(hub, port1, 1);
-
-	/* FIXME let caller ask to power down the port:
-	 *  - some devices won't enumerate without a VBUS power cycle
-	 *  - SRP saves power that way
-	 *  - ... new call, TBD ...
-	 * That's easy if this hub can switch power per-port, and
-	 * khubd reactivates the port later (timer, SRP, etc).
-	 * Powerdown must be optional, because of reset/DFU.
-	 */
-
-	set_bit(port1, hub->change_bits);
- 	kick_khubd(hub);
-}
-
 #ifdef	CONFIG_PM
 
 #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.
@@ -1595,11 +1532,35 @@ static void hub_port_logical_disconnect(struct usb_hub *hub, int port1)
  * 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);
 
@@ -1616,17 +1577,15 @@ static int hub_port_suspend(struct usb_hub *hub, int 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,
@@ -1644,85 +1603,24 @@ static int hub_port_suspend(struct usb_hub *hub, int port1,
 }
 
 /*
- * 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);
-}
-
-/*
  * If the USB "suspend" state is in use (rather than "global suspend"),
  * many devices will be individually taken out of suspend state using
- * special" resume" signaling.  These routines kick in shortly after
+ * special "resume" signaling.  This routine kicks in shortly after
  * hardware resume signaling is finished, either because of selective
  * resume (by host) or remote wakeup (by device) ... now see what changed
  * in the tree that's rooted at this device.
+ *
+ * If @udev->reset_resume is set then the device is reset before the
+ * status check is done.
  */
 static int finish_port_resume(struct usb_device *udev)
 {
-	int	status;
+	int	status = 0;
 	u16	devstatus;
 
 	/* caller owns the udev device lock */
-	dev_dbg(&udev->dev, "finish resume\n");
+	dev_dbg(&udev->dev, "finish %sresume\n",
+			udev->reset_resume ? "reset-" : "");
 
 	/* usb ch9 identifies four variants of SUSPENDED, based on what
 	 * state the device resumes to.  Linux currently won't see the
@@ -1733,22 +1631,31 @@ static int finish_port_resume(struct usb_device *udev)
 			? USB_STATE_CONFIGURED
 			: USB_STATE_ADDRESS);
 
+	/* 10.5.4.5 says not to reset a suspended port if the attached
+	 * device is enabled for remote wakeup.  Hence the reset
+	 * operation is carried out here, after the port has been
+	 * resumed.
+	 */
+	if (udev->reset_resume)
+		status = usb_reset_device(udev);
+
  	/* 10.5.4.5 says be sure devices in the tree are still there.
  	 * For now let's assume the device didn't go crazy on resume,
 	 * and device drivers will know about any resume quirks.
 	 */
-	status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
-	if (status >= 0)
-		status = (status == 2 ? 0 : -ENODEV);
+	if (status == 0) {
+		devstatus = 0;
+		status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
+		if (status >= 0)
+			status = (status > 0 ? 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))
-				&& udev->parent) {
+		if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) {
 			status = usb_control_msg(udev,
 					usb_sndctrlpipe(udev, 0),
 					USB_REQ_CLEAR_FEATURE,
@@ -1761,19 +1668,52 @@ static int finish_port_resume(struct usb_device *udev)
 					"wakeup, status %d\n", status);
 		}
 		status = 0;
-
-	} else if (udev->devnum <= 0) {
-		dev_dbg(&udev->dev, "bogus resume!\n");
-		status = -EINVAL;
 	}
 	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.
+ *
+ * If CONFIG_USB_PERSIST and @udev->reset_resume are both set then this
+ * routine won't check that the port is still enabled.  Furthermore,
+ * if @udev->reset_resume is set then finish_port_resume() above will
+ * reset @udev.  The end result is that a broken power session can be
+ * recovered and @udev will appear to persist across a loss of VBUS power.
+ *
+ * For example, if a host controller doesn't maintain VBUS suspend current
+ * during a system sleep or is reset when the system wakes up, all the USB
+ * power sessions below it will be broken.  This is especially troublesome
+ * for mass-storage devices containing mounted filesystems, since the
+ * device will appear to have disconnected and all the memory mappings
+ * to it will be lost.  Using the USB_PERSIST facility, the device can be
+ * made to appear as if it had not disconnected.
+ *
+ * This facility is inherently dangerous.  Although usb_reset_device()
+ * makes every effort to insure that the same device is present after the
+ * reset as before, it cannot provide a 100% guarantee.  Furthermore it's
+ * quite possible for a device to remain unaltered but its media to be
+ * changed.  If the user replaces a flash memory card while the system is
+ * asleep, he will have only himself to blame when the filesystem on the
+ * new card is corrupted and the system crashes.
+ *
+ * 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;
+	unsigned	mask_flags, want_flags;
 
 	/* Skip the initial Clear-Suspend step for a remote wakeup */
 	status = hub_port_status(hub, port1, &portstatus, &portchange);
@@ -1788,30 +1728,31 @@ hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
 	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 */
-		if (udev)
-			dev_dbg(&udev->dev, "usb %sresume\n",
-					udev->auto_pm ? "auto-" : "");
+		dev_dbg(&udev->dev, "usb %sresume\n",
+				udev->auto_pm ? "auto-" : "");
 		msleep(25);
 
-#define LIVE_FLAGS	( USB_PORT_STAT_POWER \
-			| USB_PORT_STAT_ENABLE \
-			| USB_PORT_STAT_CONNECTION)
-
 		/* Virtual root hubs can trigger on GET_PORT_STATUS to
 		 * stop resume signaling.  Then finish the resume
 		 * sequence.
 		 */
 		status = hub_port_status(hub, port1, &portstatus, &portchange);
-SuspendCleared:
-		if (status < 0
-				|| (portstatus & LIVE_FLAGS) != LIVE_FLAGS
-				|| (portstatus & USB_PORT_STAT_SUSPEND) != 0
-				) {
+
+ SuspendCleared:
+		if (USB_PERSIST && udev->reset_resume)
+			want_flags = USB_PORT_STAT_POWER
+					| USB_PORT_STAT_CONNECTION;
+		else
+			want_flags = USB_PORT_STAT_POWER
+					| USB_PORT_STAT_CONNECTION
+					| USB_PORT_STAT_ENABLE;
+		mask_flags = want_flags | USB_PORT_STAT_SUSPEND;
+
+		if (status < 0 || (portstatus & mask_flags) != want_flags) {
 			dev_dbg(hub->intfdev,
 				"port %d status %04x.%04x after resume, %d\n",
 				port1, portchange, portstatus, status);
@@ -1823,51 +1764,19 @@ SuspendCleared:
 						USB_PORT_FEAT_C_SUSPEND);
 			/* TRSMRCY = 10 msec */
 			msleep(10);
-			if (udev)
-				status = finish_port_resume(udev);
 		}
 	}
-	if (status < 0)
-		hub_port_logical_disconnect(hub, port1);
 
 	clear_bit(port1, hub->busy_bits);
 	if (!hub->hdev->parent && !hub->busy_bits[0])
 		usb_enable_root_hub_irq(hub->hdev->bus);
 
-	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;
-
-	/* we change the device's upstream USB link,
-	 * but root hubs have no upstream USB link.
-	 */
-	if (udev->parent) {
-		// NOTE this fails if parent is also suspended...
-		status = hub_port_resume(hdev_to_hub(udev->parent),
-				udev->portnum, udev);
-	} else {
-		dev_dbg(&udev->dev, "usb %sresume\n",
-				udev->auto_pm ? "auto-" : "");
+	if (status == 0)
 		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);
+	}
 	return status;
 }
 
@@ -1894,21 +1803,16 @@ int usb_port_suspend(struct usb_device *udev)
 	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;
+	int status = 0;
+
+	/* However we may need to do a reset-resume */
+	if (udev->reset_resume) {
+		dev_dbg(&udev->dev, "reset-resume\n");
+		status = usb_reset_device(udev);
+	}
+	return status;
 }
 
 static inline int remote_wakeup(struct usb_device *udev)
@@ -1923,7 +1827,6 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
 	struct usb_hub		*hub = usb_get_intfdata (intf);
 	struct usb_device	*hdev = hub->hdev;
 	unsigned		port1;
-	int			status = 0;
 
 	/* fail if children aren't already suspended */
 	for (port1 = 1; port1 <= hdev->maxchild; port1++) {
@@ -1949,49 +1852,75 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
 
 	/* stop khubd and related activity */
 	hub_quiesce(hub);
-
-	/* "global suspend" of the downstream HC-to-USB interface */
-	if (!hdev->parent) {
-		status = hcd_bus_suspend(hdev->bus);
-		if (status != 0) {
-			dev_dbg(&hdev->dev, "'global' suspend %d\n", status);
-			hub_activate(hub);
-		}
-	}
-	return status;
+	return 0;
 }
 
 static int hub_resume(struct usb_interface *intf)
 {
 	struct usb_hub		*hub = usb_get_intfdata (intf);
-	struct usb_device	*hdev = hub->hdev;
-	int			status;
 
 	dev_dbg(&intf->dev, "%s\n", __FUNCTION__);
 
-	/* "global resume" of the downstream HC-to-USB interface */
-	if (!hdev->parent) {
-		struct usb_bus	*bus = hdev->bus;
-		if (bus) {
-			status = hcd_bus_resume (bus);
-			if (status) {
-				dev_dbg(&intf->dev, "'global' resume %d\n",
-					status);
-				return status;
+	/* tell khubd to look for changes on this hub */
+	hub_activate(hub);
+	return 0;
+}
+
+static int hub_reset_resume(struct usb_interface *intf)
+{
+	struct usb_hub *hub = usb_get_intfdata(intf);
+	struct usb_device *hdev = hub->hdev;
+	int port1;
+
+	hub_power_on(hub);
+
+	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
+		struct usb_device *child = hdev->children[port1-1];
+
+		if (child) {
+
+			/* For "USB_PERSIST"-enabled children we must
+			 * mark the child device for reset-resume and
+			 * turn off the connect-change status to prevent
+			 * khubd from disconnecting it later.
+			 */
+			if (USB_PERSIST && child->persist_enabled) {
+				child->reset_resume = 1;
+				clear_port_feature(hdev, port1,
+						USB_PORT_FEAT_C_CONNECTION);
+
+			/* Otherwise we must disconnect the child,
+			 * but as we may not lock the child device here
+			 * we have to do a "logical" disconnect.
+			 */
+			} else {
+				hub_port_logical_disconnect(hub, port1);
 			}
-		} else
-			return -EOPNOTSUPP;
-		if (status == 0) {
-			/* TRSMRCY = 10 msec */
-			msleep(10);
 		}
 	}
 
-	/* tell khubd to look for changes on this hub */
 	hub_activate(hub);
 	return 0;
 }
 
+/**
+ * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
+ * @rhdev: struct usb_device for the root hub
+ *
+ * The USB host controller driver calls this function when its root hub
+ * is resumed and Vbus power has been interrupted or the controller
+ * has been reset.  The routine marks @rhdev as having lost power.  When
+ * the hub driver is resumed it will take notice; if CONFIG_USB_PERSIST
+ * is enabled then it will carry out power-session recovery, otherwise
+ * it will disconnect all the child devices.
+ */
+void usb_root_hub_lost_power(struct usb_device *rhdev)
+{
+	dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
+	rhdev->reset_resume = 1;
+}
+EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
+
 #else	/* CONFIG_PM */
 
 static inline int remote_wakeup(struct usb_device *udev)
@@ -1999,8 +1928,9 @@ static inline int remote_wakeup(struct usb_device *udev)
 	return 0;
 }
 
-#define hub_suspend NULL
-#define hub_resume NULL
+#define hub_suspend		NULL
+#define hub_resume		NULL
+#define hub_reset_resume	NULL
 #endif
 
 
@@ -2463,19 +2393,6 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 		return;
 	}
 
-#ifdef  CONFIG_USB_SUSPEND
-	/* If something is connected, but the port is suspended, wake it up. */
-	if (portstatus & USB_PORT_STAT_SUSPEND) {
-		status = hub_port_resume(hub, port1, NULL);
-		if (status < 0) {
-			dev_dbg(hub_dev,
-				"can't clear suspend on port %d; %d\n",
-				port1, status);
-			goto done;
-		}
-	}
-#endif
-
 	for (i = 0; i < SET_CONFIG_TRIES; i++) {
 		struct usb_device *udev;
 
@@ -2586,7 +2503,7 @@ loop:
 		ep0_reinit(udev);
 		release_address(udev);
 		usb_put_dev(udev);
-		if (status == -ENOTCONN)
+		if ((status == -ENOTCONN) || (status == -ENOTSUPP))
 			break;
 	}
  
@@ -2627,10 +2544,12 @@ static void hub_events(void)
 		list_del_init(tmp);
 
 		hub = list_entry(tmp, struct usb_hub, event_list);
-		hdev = hub->hdev;
-		intf = to_usb_interface(hub->intfdev);
-		hub_dev = &intf->dev;
+		kref_get(&hub->kref);
+		spin_unlock_irq(&hub_event_lock);
 
+		hdev = hub->hdev;
+		hub_dev = hub->intfdev;
+		intf = to_usb_interface(hub_dev);
 		dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
 				hdev->state, hub->descriptor
 					? hub->descriptor->bNbrPorts
@@ -2639,16 +2558,10 @@ static void hub_events(void)
 				(u16) hub->change_bits[0],
 				(u16) hub->event_bits[0]);
 
-		usb_get_intf(intf);
-		spin_unlock_irq(&hub_event_lock);
-
 		/* Lock the device, then check to see if we were
 		 * disconnected while waiting for the lock to succeed. */
-		if (locktree(hdev) < 0) {
-			usb_put_intf(intf);
-			continue;
-		}
-		if (hub != usb_get_intfdata(intf))
+		usb_lock_device(hdev);
+		if (unlikely(hub->disconnected))
 			goto loop;
 
 		/* If the hub has died, clean up after it */
@@ -2811,13 +2724,14 @@ loop_autopm:
 			usb_autopm_enable(intf);
 loop:
 		usb_unlock_device(hdev);
-		usb_put_intf(intf);
+		kref_put(&hub->kref, hub_release);
 
         } /* end while (1) */
 }
 
 static int hub_thread(void *__unused)
 {
+	set_freezable();
 	do {
 		hub_events();
 		wait_event_interruptible(khubd_wait,
@@ -2846,6 +2760,7 @@ static struct usb_driver hub_driver = {
 	.disconnect =	hub_disconnect,
 	.suspend =	hub_suspend,
 	.resume =	hub_resume,
+	.reset_resume =	hub_reset_resume,
 	.pre_reset =	hub_pre_reset,
 	.post_reset =	hub_post_reset,
 	.ioctl =	hub_ioctl,
@@ -2948,6 +2863,11 @@ static int config_descriptors_changed(struct usb_device *udev)
  * this from a driver probe() routine after downloading new firmware.
  * For calls that might not occur during probe(), drivers should lock
  * the device using usb_lock_device_for_reset().
+ *
+ * Locking exception: This routine may also be called from within an
+ * autoresume handler.  Such usage won't conflict with other tasks
+ * holding the device lock because these tasks should always call
+ * usb_autopm_resume_device(), thereby preventing any unwanted autoresume.
  */
 int usb_reset_device(struct usb_device *udev)
 {
@@ -2978,7 +2898,7 @@ int usb_reset_device(struct usb_device *udev)
 		 * Other endpoints will be handled by re-enumeration. */
 		ep0_reinit(udev);
 		ret = hub_port_init(parent_hub, udev, port1, i);
-		if (ret >= 0)
+		if (ret >= 0 || ret == -ENOTCONN || ret == -ENODEV)
 			break;
 	}
 	clear_bit(port1, parent_hub->busy_bits);
@@ -3094,6 +3014,7 @@ int usb_reset_composite_device(struct usb_device *udev,
 				drv = to_usb_driver(cintf->dev.driver);
 				if (drv->pre_reset)
 					(drv->pre_reset)(cintf);
+	/* FIXME: Unbind if pre_reset returns an error or isn't defined */
 			}
 		}
 	}
@@ -3112,6 +3033,7 @@ int usb_reset_composite_device(struct usb_device *udev,
 				drv = to_usb_driver(cintf->dev.driver);
 				if (drv->post_reset)
 					(drv->post_reset)(cintf);
+	/* FIXME: Unbind if post_reset returns an error or isn't defined */
 			}
 			if (cintf != iface)
 				up(&cintf->dev.sem);