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32 results

hw_irq.h

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  • hub.c 81.81 KiB
    /*
     * USB hub driver.
     *
     * (C) Copyright 1999 Linus Torvalds
     * (C) Copyright 1999 Johannes Erdfelt
     * (C) Copyright 1999 Gregory P. Smith
     * (C) Copyright 2001 Brad Hards (bhards@bigpond.net.au)
     *
     */
    
    #include <linux/config.h>
    #ifdef CONFIG_USB_DEBUG
    	#define DEBUG
    #else
    	#undef DEBUG
    #endif
    #include <linux/kernel.h>
    #include <linux/errno.h>
    #include <linux/module.h>
    #include <linux/moduleparam.h>
    #include <linux/completion.h>
    #include <linux/sched.h>
    #include <linux/list.h>
    #include <linux/slab.h>
    #include <linux/smp_lock.h>
    #include <linux/ioctl.h>
    #include <linux/usb.h>
    #include <linux/usbdevice_fs.h>
    #include <linux/kthread.h>
    
    #include <asm/semaphore.h>
    #include <asm/uaccess.h>
    #include <asm/byteorder.h>
    
    #include "usb.h"
    #include "hcd.h"
    #include "hub.h"
    
    /* Protect struct usb_device->state and ->children members
     * Note: Both are also protected by ->serialize, except that ->state can
     * change to USB_STATE_NOTATTACHED even when the semaphore isn't held. */
    static DEFINE_SPINLOCK(device_state_lock);
    
    /* khubd's worklist and its lock */
    static DEFINE_SPINLOCK(hub_event_lock);
    static LIST_HEAD(hub_event_list);	/* List of hubs needing servicing */
    
    /* Wakes up khubd */
    static DECLARE_WAIT_QUEUE_HEAD(khubd_wait);
    
    static struct task_struct *khubd_task;
    
    /* cycle leds on hubs that aren't blinking for attention */
    static int blinkenlights = 0;
    module_param (blinkenlights, bool, S_IRUGO);
    MODULE_PARM_DESC (blinkenlights, "true to cycle leds on hubs");
    
    /*
     * As of 2.6.10 we introduce a new USB device initialization scheme which
     * closely resembles the way Windows works.  Hopefully it will be compatible
     * with a wider range of devices than the old scheme.  However some previously
     * working devices may start giving rise to "device not accepting address"
     * errors; if that happens the user can try the old scheme by adjusting the
     * following module parameters.
     *
     * For maximum flexibility there are two boolean parameters to control the
     * hub driver's behavior.  On the first initialization attempt, if the
     * "old_scheme_first" parameter is set then the old scheme will be used,
     * otherwise the new scheme is used.  If that fails and "use_both_schemes"
     * is set, then the driver will make another attempt, using the other scheme.
     */
    static int old_scheme_first = 0;
    module_param(old_scheme_first, bool, S_IRUGO | S_IWUSR);
    MODULE_PARM_DESC(old_scheme_first,
    		 "start with the old device initialization scheme");
    
    static int use_both_schemes = 1;
    module_param(use_both_schemes, bool, S_IRUGO | S_IWUSR);
    MODULE_PARM_DESC(use_both_schemes,
    		"try the other device initialization scheme if the "
    		"first one fails");
    
    
    #ifdef	DEBUG
    static inline char *portspeed (int portstatus)
    {
    	if (portstatus & (1 << USB_PORT_FEAT_HIGHSPEED))
        		return "480 Mb/s";
    	else if (portstatus & (1 << USB_PORT_FEAT_LOWSPEED))
    		return "1.5 Mb/s";
    	else
    		return "12 Mb/s";
    }
    #endif
    
    /* Note that hdev or one of its children must be locked! */
    static inline struct usb_hub *hdev_to_hub(struct usb_device *hdev)
    {
    	return usb_get_intfdata(hdev->actconfig->interface[0]);
    }
    
    /* USB 2.0 spec Section 11.24.4.5 */
    static int get_hub_descriptor(struct usb_device *hdev, void *data, int size)
    {
    	int i, ret;
    
    	for (i = 0; i < 3; i++) {
    		ret = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
    			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
    			USB_DT_HUB << 8, 0, data, size,
    			USB_CTRL_GET_TIMEOUT);
    		if (ret >= (USB_DT_HUB_NONVAR_SIZE + 2))
    			return ret;
    	}
    	return -EINVAL;
    }
    
    /*
     * USB 2.0 spec Section 11.24.2.1
     */
    static int clear_hub_feature(struct usb_device *hdev, int feature)
    {
    	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
    		USB_REQ_CLEAR_FEATURE, USB_RT_HUB, feature, 0, NULL, 0, 1000);
    }
    
    /*
     * USB 2.0 spec Section 11.24.2.2
     */
    static int clear_port_feature(struct usb_device *hdev, int port1, int feature)
    {
    	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
    		USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature, port1,
    		NULL, 0, 1000);
    }
    
    /*
     * USB 2.0 spec Section 11.24.2.13
     */
    static int set_port_feature(struct usb_device *hdev, int port1, int feature)
    {
    	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
    		USB_REQ_SET_FEATURE, USB_RT_PORT, feature, port1,
    		NULL, 0, 1000);
    }
    
    /*
     * USB 2.0 spec Section 11.24.2.7.1.10 and table 11-7
     * for info about using port indicators
     */
    static void set_port_led(
    	struct usb_hub *hub,
    	int port1,
    	int selector
    )
    {
    	int status = set_port_feature(hub->hdev, (selector << 8) | port1,
    			USB_PORT_FEAT_INDICATOR);
    	if (status < 0)
    		dev_dbg (hub->intfdev,
    			"port %d indicator %s status %d\n",
    			port1,
    			({ char *s; switch (selector) {
    			case HUB_LED_AMBER: s = "amber"; break;
    			case HUB_LED_GREEN: s = "green"; break;
    			case HUB_LED_OFF: s = "off"; break;
    			case HUB_LED_AUTO: s = "auto"; break;
    			default: s = "??"; break;
    			}; s; }),
    			status);
    }
    
    #define	LED_CYCLE_PERIOD	((2*HZ)/3)
    
    static void led_work (void *__hub)
    {
    	struct usb_hub		*hub = __hub;
    	struct usb_device	*hdev = hub->hdev;
    	unsigned		i;
    	unsigned		changed = 0;
    	int			cursor = -1;
    
    	if (hdev->state != USB_STATE_CONFIGURED || hub->quiescing)
    		return;
    
    	for (i = 0; i < hub->descriptor->bNbrPorts; i++) {
    		unsigned	selector, mode;
    
    		/* 30%-50% duty cycle */
    
    		switch (hub->indicator[i]) {
    		/* cycle marker */
    		case INDICATOR_CYCLE:
    			cursor = i;
    			selector = HUB_LED_AUTO;
    			mode = INDICATOR_AUTO;
    			break;
    		/* blinking green = sw attention */
    		case INDICATOR_GREEN_BLINK:
    			selector = HUB_LED_GREEN;
    			mode = INDICATOR_GREEN_BLINK_OFF;
    			break;
    		case INDICATOR_GREEN_BLINK_OFF:
    			selector = HUB_LED_OFF;
    			mode = INDICATOR_GREEN_BLINK;
    			break;
    		/* blinking amber = hw attention */
    		case INDICATOR_AMBER_BLINK:
    			selector = HUB_LED_AMBER;
    			mode = INDICATOR_AMBER_BLINK_OFF;
    			break;
    		case INDICATOR_AMBER_BLINK_OFF:
    			selector = HUB_LED_OFF;
    			mode = INDICATOR_AMBER_BLINK;
    			break;
    		/* blink green/amber = reserved */
    		case INDICATOR_ALT_BLINK:
    			selector = HUB_LED_GREEN;
    			mode = INDICATOR_ALT_BLINK_OFF;
    			break;
    		case INDICATOR_ALT_BLINK_OFF:
    			selector = HUB_LED_AMBER;
    			mode = INDICATOR_ALT_BLINK;
    			break;
    		default:
    			continue;
    		}
    		if (selector != HUB_LED_AUTO)
    			changed = 1;
    		set_port_led(hub, i + 1, selector);
    		hub->indicator[i] = mode;
    	}
    	if (!changed && blinkenlights) {
    		cursor++;
    		cursor %= hub->descriptor->bNbrPorts;
    		set_port_led(hub, cursor + 1, HUB_LED_GREEN);
    		hub->indicator[cursor] = INDICATOR_CYCLE;
    		changed++;
    	}
    	if (changed)
    		schedule_delayed_work(&hub->leds, LED_CYCLE_PERIOD);
    }
    
    /* use a short timeout for hub/port status fetches */
    #define	USB_STS_TIMEOUT		1000
    #define	USB_STS_RETRIES		5
    
    /*
     * USB 2.0 spec Section 11.24.2.6
     */
    static int get_hub_status(struct usb_device *hdev,
    		struct usb_hub_status *data)
    {
    	int i, status = -ETIMEDOUT;
    
    	for (i = 0; i < USB_STS_RETRIES && status == -ETIMEDOUT; i++) {
    		status = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
    			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
    			data, sizeof(*data), USB_STS_TIMEOUT);
    	}
    	return status;
    }
    
    /*
     * USB 2.0 spec Section 11.24.2.7
     */
    static int get_port_status(struct usb_device *hdev, int port1,
    		struct usb_port_status *data)
    {
    	int i, status = -ETIMEDOUT;
    
    	for (i = 0; i < USB_STS_RETRIES && status == -ETIMEDOUT; i++) {
    		status = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
    			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port1,
    			data, sizeof(*data), USB_STS_TIMEOUT);
    	}
    	return status;
    }
    
    static void kick_khubd(struct usb_hub *hub)
    {
    	unsigned long	flags;
    
    	spin_lock_irqsave(&hub_event_lock, flags);
    	if (list_empty(&hub->event_list)) {
    		list_add_tail(&hub->event_list, &hub_event_list);
    		wake_up(&khubd_wait);
    	}
    	spin_unlock_irqrestore(&hub_event_lock, flags);
    }
    
    void usb_kick_khubd(struct usb_device *hdev)
    {
    	kick_khubd(hdev_to_hub(hdev));
    }
    
    
    /* completion function, fires on port status changes and various faults */
    static void hub_irq(struct urb *urb, struct pt_regs *regs)
    {
    	struct usb_hub *hub = (struct usb_hub *)urb->context;
    	int status;
    	int i;
    	unsigned long bits;
    
    	switch (urb->status) {
    	case -ENOENT:		/* synchronous unlink */
    	case -ECONNRESET:	/* async unlink */
    	case -ESHUTDOWN:	/* hardware going away */
    		return;
    
    	default:		/* presumably an error */
    		/* Cause a hub reset after 10 consecutive errors */
    		dev_dbg (hub->intfdev, "transfer --> %d\n", urb->status);
    		if ((++hub->nerrors < 10) || hub->error)
    			goto resubmit;
    		hub->error = urb->status;
    		/* FALL THROUGH */
    	
    	/* let khubd handle things */
    	case 0:			/* we got data:  port status changed */
    		bits = 0;
    		for (i = 0; i < urb->actual_length; ++i)
    			bits |= ((unsigned long) ((*hub->buffer)[i]))
    					<< (i*8);
    		hub->event_bits[0] = bits;
    		break;
    	}
    
    	hub->nerrors = 0;
    
    	/* Something happened, let khubd figure it out */
    	kick_khubd(hub);
    
    resubmit:
    	if (hub->quiescing)
    		return;
    
    	if ((status = usb_submit_urb (hub->urb, GFP_ATOMIC)) != 0
    			&& status != -ENODEV && status != -EPERM)
    		dev_err (hub->intfdev, "resubmit --> %d\n", status);
    }
    
    /* USB 2.0 spec Section 11.24.2.3 */
    static inline int
    hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt)
    {
    	return usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
    			       HUB_CLEAR_TT_BUFFER, USB_RT_PORT, devinfo,
    			       tt, NULL, 0, 1000);
    }
    
    /*
     * enumeration blocks khubd for a long time. we use keventd instead, since
     * long blocking there is the exception, not the rule.  accordingly, HCDs
     * talking to TTs must queue control transfers (not just bulk and iso), so
     * both can talk to the same hub concurrently.
     */
    static void hub_tt_kevent (void *arg)
    {
    	struct usb_hub		*hub = arg;
    	unsigned long		flags;
    
    	spin_lock_irqsave (&hub->tt.lock, flags);
    	while (!list_empty (&hub->tt.clear_list)) {
    		struct list_head	*temp;
    		struct usb_tt_clear	*clear;
    		struct usb_device	*hdev = hub->hdev;
    		int			status;
    
    		temp = hub->tt.clear_list.next;
    		clear = list_entry (temp, struct usb_tt_clear, clear_list);
    		list_del (&clear->clear_list);
    
    		/* drop lock so HCD can concurrently report other TT errors */
    		spin_unlock_irqrestore (&hub->tt.lock, flags);
    		status = hub_clear_tt_buffer (hdev, clear->devinfo, clear->tt);
    		spin_lock_irqsave (&hub->tt.lock, flags);
    
    		if (status)
    			dev_err (&hdev->dev,
    				"clear tt %d (%04x) error %d\n",
    				clear->tt, clear->devinfo, status);
    		kfree(clear);
    	}
    	spin_unlock_irqrestore (&hub->tt.lock, flags);
    }
    
    /**
     * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub
     * @udev: the device whose split transaction failed
     * @pipe: identifies the endpoint of the failed transaction
     *
     * High speed HCDs use this to tell the hub driver that some split control or
     * bulk transaction failed in a way that requires clearing internal state of
     * a transaction translator.  This is normally detected (and reported) from
     * interrupt context.
     *
     * It may not be possible for that hub to handle additional full (or low)
     * speed transactions until that state is fully cleared out.
     */
    void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
    {
    	struct usb_tt		*tt = udev->tt;
    	unsigned long		flags;
    	struct usb_tt_clear	*clear;
    
    	/* we've got to cope with an arbitrary number of pending TT clears,
    	 * since each TT has "at least two" buffers that can need it (and
    	 * there can be many TTs per hub).  even if they're uncommon.
    	 */
    	if ((clear = kmalloc (sizeof *clear, SLAB_ATOMIC)) == NULL) {
    		dev_err (&udev->dev, "can't save CLEAR_TT_BUFFER state\n");
    		/* FIXME recover somehow ... RESET_TT? */
    		return;
    	}
    
    	/* info that CLEAR_TT_BUFFER needs */
    	clear->tt = tt->multi ? udev->ttport : 1;
    	clear->devinfo = usb_pipeendpoint (pipe);
    	clear->devinfo |= udev->devnum << 4;
    	clear->devinfo |= usb_pipecontrol (pipe)
    			? (USB_ENDPOINT_XFER_CONTROL << 11)
    			: (USB_ENDPOINT_XFER_BULK << 11);
    	if (usb_pipein (pipe))
    		clear->devinfo |= 1 << 15;
    	
    	/* tell keventd to clear state for this TT */
    	spin_lock_irqsave (&tt->lock, flags);
    	list_add_tail (&clear->clear_list, &tt->clear_list);
    	schedule_work (&tt->kevent);
    	spin_unlock_irqrestore (&tt->lock, flags);
    }
    
    static void hub_power_on(struct usb_hub *hub)
    {
    	int port1;
    
    	/* if hub supports power switching, enable power on each port */
    	if ((hub->descriptor->wHubCharacteristics & HUB_CHAR_LPSM) < 2) {
    		dev_dbg(hub->intfdev, "enabling power on all ports\n");
    		for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
    			set_port_feature(hub->hdev, port1,
    					USB_PORT_FEAT_POWER);
    	}
    
    	/* Wait for power to be enabled */
    	msleep(hub->descriptor->bPwrOn2PwrGood * 2);
    }
    
    static void hub_quiesce(struct usb_hub *hub)
    {
    	/* stop khubd and related activity */
    	hub->quiescing = 1;
    	usb_kill_urb(hub->urb);
    	if (hub->has_indicators)
    		cancel_delayed_work(&hub->leds);
    	if (hub->has_indicators || hub->tt.hub)
    		flush_scheduled_work();
    }
    
    static void hub_activate(struct usb_hub *hub)
    {
    	int	status;
    
    	hub->quiescing = 0;
    	hub->activating = 1;
    	status = usb_submit_urb(hub->urb, GFP_NOIO);
    	if (status < 0)
    		dev_err(hub->intfdev, "activate --> %d\n", status);
    	if (hub->has_indicators && blinkenlights)
    		schedule_delayed_work(&hub->leds, LED_CYCLE_PERIOD);
    
    	/* scan all ports ASAP */
    	kick_khubd(hub);
    }
    
    static int hub_hub_status(struct usb_hub *hub,
    		u16 *status, u16 *change)
    {
    	int ret;
    
    	ret = get_hub_status(hub->hdev, &hub->status->hub);
    	if (ret < 0)
    		dev_err (hub->intfdev,
    			"%s failed (err = %d)\n", __FUNCTION__, ret);
    	else {
    		*status = le16_to_cpu(hub->status->hub.wHubStatus);
    		*change = le16_to_cpu(hub->status->hub.wHubChange); 
    		ret = 0;
    	}
    	return ret;
    }
    
    static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
    {
    	struct usb_device *hdev = hub->hdev;
    	int ret;
    
    	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 (ret)
    		dev_err(hub->intfdev, "cannot disable port %d (err = %d)\n",
    			port1, ret);
    
    	return ret;
    }
    
    static int hub_configure(struct usb_hub *hub,
    	struct usb_endpoint_descriptor *endpoint)
    {
    	struct usb_device *hdev = hub->hdev;
    	struct device *hub_dev = hub->intfdev;
    	u16 hubstatus, hubchange;
    	unsigned int pipe;
    	int maxp, ret;
    	char *message;
    
    	hub->buffer = usb_buffer_alloc(hdev, sizeof(*hub->buffer), GFP_KERNEL,
    			&hub->buffer_dma);
    	if (!hub->buffer) {
    		message = "can't allocate hub irq buffer";
    		ret = -ENOMEM;
    		goto fail;
    	}
    
    	hub->status = kmalloc(sizeof(*hub->status), GFP_KERNEL);
    	if (!hub->status) {
    		message = "can't kmalloc hub status buffer";
    		ret = -ENOMEM;
    		goto fail;
    	}
    
    	hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL);
    	if (!hub->descriptor) {
    		message = "can't kmalloc hub descriptor";
    		ret = -ENOMEM;
    		goto fail;
    	}
    
    	/* Request the entire hub descriptor.
    	 * hub->descriptor can handle USB_MAXCHILDREN ports,
    	 * but the hub can/will return fewer bytes here.
    	 */
    	ret = get_hub_descriptor(hdev, hub->descriptor,
    			sizeof(*hub->descriptor));
    	if (ret < 0) {
    		message = "can't read hub descriptor";
    		goto fail;
    	} else if (hub->descriptor->bNbrPorts > USB_MAXCHILDREN) {
    		message = "hub has too many ports!";
    		ret = -ENODEV;
    		goto fail;
    	}
    
    	hdev->maxchild = hub->descriptor->bNbrPorts;
    	dev_info (hub_dev, "%d port%s detected\n", hdev->maxchild,
    		(hdev->maxchild == 1) ? "" : "s");
    
    	le16_to_cpus(&hub->descriptor->wHubCharacteristics);
    
    	if (hub->descriptor->wHubCharacteristics & HUB_CHAR_COMPOUND) {
    		int	i;
    		char	portstr [USB_MAXCHILDREN + 1];
    
    		for (i = 0; i < hdev->maxchild; i++)
    			portstr[i] = hub->descriptor->DeviceRemovable
    				    [((i + 1) / 8)] & (1 << ((i + 1) % 8))
    				? 'F' : 'R';
    		portstr[hdev->maxchild] = 0;
    		dev_dbg(hub_dev, "compound device; port removable status: %s\n", portstr);
    	} else
    		dev_dbg(hub_dev, "standalone hub\n");
    
    	switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_LPSM) {
    		case 0x00:
    			dev_dbg(hub_dev, "ganged power switching\n");
    			break;
    		case 0x01:
    			dev_dbg(hub_dev, "individual port power switching\n");
    			break;
    		case 0x02:
    		case 0x03:
    			dev_dbg(hub_dev, "no power switching (usb 1.0)\n");
    			break;
    	}
    
    	switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_OCPM) {
    		case 0x00:
    			dev_dbg(hub_dev, "global over-current protection\n");
    			break;
    		case 0x08:
    			dev_dbg(hub_dev, "individual port over-current protection\n");
    			break;
    		case 0x10:
    		case 0x18:
    			dev_dbg(hub_dev, "no over-current protection\n");
                            break;
    	}
    
    	spin_lock_init (&hub->tt.lock);
    	INIT_LIST_HEAD (&hub->tt.clear_list);
    	INIT_WORK (&hub->tt.kevent, hub_tt_kevent, hub);
    	switch (hdev->descriptor.bDeviceProtocol) {
    		case 0:
    			break;
    		case 1:
    			dev_dbg(hub_dev, "Single TT\n");
    			hub->tt.hub = hdev;
    			break;
    		case 2:
    			ret = usb_set_interface(hdev, 0, 1);
    			if (ret == 0) {
    				dev_dbg(hub_dev, "TT per port\n");
    				hub->tt.multi = 1;
    			} else
    				dev_err(hub_dev, "Using single TT (err %d)\n",
    					ret);
    			hub->tt.hub = hdev;
    			break;
    		default:
    			dev_dbg(hub_dev, "Unrecognized hub protocol %d\n",
    				hdev->descriptor.bDeviceProtocol);
    			break;
    	}
    
    	/* Note 8 FS bit times == (8 bits / 12000000 bps) ~= 666ns */
    	switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_TTTT) {
    		case HUB_TTTT_8_BITS:
    			if (hdev->descriptor.bDeviceProtocol != 0) {
    				hub->tt.think_time = 666;
    				dev_dbg(hub_dev, "TT requires at most %d "
    						"FS bit times (%d ns)\n",
    					8, hub->tt.think_time);
    			}
    			break;
    		case HUB_TTTT_16_BITS:
    			hub->tt.think_time = 666 * 2;
    			dev_dbg(hub_dev, "TT requires at most %d "
    					"FS bit times (%d ns)\n",
    				16, hub->tt.think_time);
    			break;
    		case HUB_TTTT_24_BITS:
    			hub->tt.think_time = 666 * 3;
    			dev_dbg(hub_dev, "TT requires at most %d "
    					"FS bit times (%d ns)\n",
    				24, hub->tt.think_time);
    			break;
    		case HUB_TTTT_32_BITS:
    			hub->tt.think_time = 666 * 4;
    			dev_dbg(hub_dev, "TT requires at most %d "
    					"FS bit times (%d ns)\n",
    				32, hub->tt.think_time);
    			break;
    	}
    
    	/* probe() zeroes hub->indicator[] */
    	if (hub->descriptor->wHubCharacteristics & HUB_CHAR_PORTIND) {
    		hub->has_indicators = 1;
    		dev_dbg(hub_dev, "Port indicators are supported\n");
    	}
    
    	dev_dbg(hub_dev, "power on to power good time: %dms\n",
    		hub->descriptor->bPwrOn2PwrGood * 2);
    
    	/* power budgeting mostly matters with bus-powered hubs,
    	 * and battery-powered root hubs (may provide just 8 mA).
    	 */
    	ret = usb_get_status(hdev, USB_RECIP_DEVICE, 0, &hubstatus);
    	if (ret < 0) {
    		message = "can't get hub status";
    		goto fail;
    	}
    	le16_to_cpus(&hubstatus);
    	if (hdev == hdev->bus->root_hub) {
    		struct usb_hcd *hcd =
    				container_of(hdev->bus, struct usb_hcd, self);
    
    		hub->power_budget = min(500u, hcd->power_budget) / 2;
    	} else if ((hubstatus & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
    		dev_dbg(hub_dev, "hub controller current requirement: %dmA\n",
    			hub->descriptor->bHubContrCurrent);
    		hub->power_budget = (501 - hub->descriptor->bHubContrCurrent)
    					/ 2;
    	}
    	if (hub->power_budget)
    		dev_dbg(hub_dev, "%dmA bus power budget for children\n",
    			hub->power_budget * 2);
    
    
    	ret = hub_hub_status(hub, &hubstatus, &hubchange);
    	if (ret < 0) {
    		message = "can't get hub status";
    		goto fail;
    	}
    
    	/* local power status reports aren't always correct */
    	if (hdev->actconfig->desc.bmAttributes & USB_CONFIG_ATT_SELFPOWER)
    		dev_dbg(hub_dev, "local power source is %s\n",
    			(hubstatus & HUB_STATUS_LOCAL_POWER)
    			? "lost (inactive)" : "good");
    
    	if ((hub->descriptor->wHubCharacteristics & HUB_CHAR_OCPM) == 0)
    		dev_dbg(hub_dev, "%sover-current condition exists\n",
    			(hubstatus & HUB_STATUS_OVERCURRENT) ? "" : "no ");
    
    	/* set up the interrupt endpoint */
    	pipe = usb_rcvintpipe(hdev, endpoint->bEndpointAddress);
    	maxp = usb_maxpacket(hdev, pipe, usb_pipeout(pipe));
    
    	if (maxp > sizeof(*hub->buffer))
    		maxp = sizeof(*hub->buffer);
    
    	hub->urb = usb_alloc_urb(0, GFP_KERNEL);
    	if (!hub->urb) {
    		message = "couldn't allocate interrupt urb";
    		ret = -ENOMEM;
    		goto fail;
    	}
    
    	usb_fill_int_urb(hub->urb, hdev, pipe, *hub->buffer, maxp, hub_irq,
    		hub, endpoint->bInterval);
    	hub->urb->transfer_dma = hub->buffer_dma;
    	hub->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
    
    	/* maybe cycle the hub leds */
    	if (hub->has_indicators && blinkenlights)
    		hub->indicator [0] = INDICATOR_CYCLE;
    
    	hub_power_on(hub);
    	hub_activate(hub);
    	return 0;
    
    fail:
    	dev_err (hub_dev, "config failed, %s (err %d)\n",
    			message, ret);
    	/* hub_disconnect() frees urb and descriptor */
    	return ret;
    }
    
    static unsigned highspeed_hubs;
    
    /* Called after the hub driver is unbound from a hub with children */
    static void hub_remove_children_work(void *__hub)
    {
    	struct usb_hub		*hub = __hub;
    	struct usb_device	*hdev = hub->hdev;
    	int			i;
    
    	kfree(hub);
    
    	usb_lock_device(hdev);
    	for (i = 0; i < hdev->maxchild; ++i) {
    		if (hdev->children[i])
    			usb_disconnect(&hdev->children[i]);
    	}
    	usb_unlock_device(hdev);
    	usb_put_dev(hdev);
    }
    
    static void hub_disconnect(struct usb_interface *intf)
    {
    	struct usb_hub *hub = usb_get_intfdata (intf);
    	struct usb_device *hdev;
    	int n, port1;
    
    	usb_set_intfdata (intf, NULL);
    	hdev = hub->hdev;
    
    	if (hdev->speed == USB_SPEED_HIGH)
    		highspeed_hubs--;
    
    	hub_quiesce(hub);
    	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;
    	}
    
    	/* If there are any children then this is an unbind only, not a
    	 * physical disconnection.  The active ports must be disabled
    	 * and later on we must call usb_disconnect().  We can't call
    	 * it now because we may not hold the hub's device lock.
    	 */
    	n = 0;
    	for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
    		if (hdev->children[port1 - 1]) {
    			++n;
    			hub_port_disable(hub, port1, 1);
    		}
    	}
    
    	if (n == 0)
    		kfree(hub);
    	else {
    		/* Reuse the hub->leds work_struct for our own purposes */
    		INIT_WORK(&hub->leds, hub_remove_children_work, hub);
    		schedule_work(&hub->leds);
    		usb_get_dev(hdev);
    	}
    }
    
    static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
    {
    	struct usb_host_interface *desc;
    	struct usb_endpoint_descriptor *endpoint;
    	struct usb_device *hdev;
    	struct usb_hub *hub;
    
    	desc = intf->cur_altsetting;
    	hdev = interface_to_usbdev(intf);
    
    	/* Some hubs have a subclass of 1, which AFAICT according to the */
    	/*  specs is not defined, but it works */
    	if ((desc->desc.bInterfaceSubClass != 0) &&
    	    (desc->desc.bInterfaceSubClass != 1)) {
    descriptor_error:
    		dev_err (&intf->dev, "bad descriptor, ignoring hub\n");
    		return -EIO;
    	}
    
    	/* Multiple endpoints? What kind of mutant ninja-hub is this? */
    	if (desc->desc.bNumEndpoints != 1)
    		goto descriptor_error;
    
    	endpoint = &desc->endpoint[0].desc;
    
    	/* Output endpoint? Curiouser and curiouser.. */
    	if (!(endpoint->bEndpointAddress & USB_DIR_IN))
    		goto descriptor_error;
    
    	/* If it's not an interrupt endpoint, we'd better punt! */
    	if ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
    			!= USB_ENDPOINT_XFER_INT)
    		goto descriptor_error;
    
    	/* We found a hub */
    	dev_info (&intf->dev, "USB hub found\n");
    
    	hub = kmalloc(sizeof(*hub), GFP_KERNEL);
    	if (!hub) {
    		dev_dbg (&intf->dev, "couldn't kmalloc hub struct\n");
    		return -ENOMEM;
    	}
    
    	memset(hub, 0, sizeof(*hub));
    
    	INIT_LIST_HEAD(&hub->event_list);
    	hub->intfdev = &intf->dev;
    	hub->hdev = hdev;
    	INIT_WORK(&hub->leds, led_work, hub);
    
    	usb_set_intfdata (intf, hub);
    
    	if (hdev->speed == USB_SPEED_HIGH)
    		highspeed_hubs++;
    
    	if (hub_configure(hub, endpoint) >= 0)
    		return 0;
    
    	hub_disconnect (intf);
    	return -ENODEV;
    }
    
    static int
    hub_ioctl(struct usb_interface *intf, unsigned int code, void *user_data)
    {
    	struct usb_device *hdev = interface_to_usbdev (intf);
    
    	/* assert ifno == 0 (part of hub spec) */
    	switch (code) {
    	case USBDEVFS_HUB_PORTINFO: {
    		struct usbdevfs_hub_portinfo *info = user_data;
    		int i;
    
    		spin_lock_irq(&device_state_lock);
    		if (hdev->devnum <= 0)
    			info->nports = 0;
    		else {
    			info->nports = hdev->maxchild;
    			for (i = 0; i < info->nports; i++) {
    				if (hdev->children[i] == NULL)
    					info->port[i] = 0;
    				else
    					info->port[i] =
    						hdev->children[i]->devnum;
    			}
    		}
    		spin_unlock_irq(&device_state_lock);
    
    		return info->nports + 1;
    		}
    
    	default:
    		return -ENOSYS;
    	}
    }
    
    /* caller has locked the hub device */
    static void hub_pre_reset(struct usb_hub *hub)
    {
    	struct usb_device *hdev = hub->hdev;
    	int i;
    
    	for (i = 0; i < hdev->maxchild; ++i) {
    		if (hdev->children[i])
    			usb_disconnect(&hdev->children[i]);
    	}
    	hub_quiesce(hub);
    }
    
    /* caller has locked the hub device */
    static void hub_post_reset(struct usb_hub *hub)
    {
    	hub_activate(hub);
    	hub_power_on(hub);
    }
    
    
    /* 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;
    	for (t = 0; t < hdev->maxchild; t++) {
    		if (hdev->children[t] == udev) {
    			/* everything is fail-fast once disconnect
    			 * processing starts
    			 */
    			if (udev->state == USB_STATE_NOTATTACHED)
    				break;
    
    			/* when everyone grabs locks top->bottom,
    			 * non-overlapping work may be concurrent
    			 */
    			down(&udev->serialize);
    			up(&hdev->serialize);
    			return t + 1;
    		}
    	}
    	usb_unlock_device(hdev);
    	return -ENODEV;
    }
    
    static void recursively_mark_NOTATTACHED(struct usb_device *udev)
    {
    	int i;
    
    	for (i = 0; i < udev->maxchild; ++i) {
    		if (udev->children[i])
    			recursively_mark_NOTATTACHED(udev->children[i]);
    	}
    	udev->state = USB_STATE_NOTATTACHED;
    }
    
    /**
     * usb_set_device_state - change a device's current state (usbcore, hcds)
     * @udev: pointer to device whose state should be changed
     * @new_state: new state value to be stored
     *
     * udev->state is _not_ fully protected by the device lock.  Although
     * most transitions are made only while holding the lock, the state can
     * can change to USB_STATE_NOTATTACHED at almost any time.  This
     * is so that devices can be marked as disconnected as soon as possible,
     * without having to wait for any semaphores to be released.  As a result,
     * all changes to any device's state must be protected by the
     * device_state_lock spinlock.
     *
     * Once a device has been added to the device tree, all changes to its state
     * should be made using this routine.  The state should _not_ be set directly.
     *
     * If udev->state is already USB_STATE_NOTATTACHED then no change is made.
     * Otherwise udev->state is set to new_state, and if new_state is
     * USB_STATE_NOTATTACHED then all of udev's descendants' states are also set
     * to USB_STATE_NOTATTACHED.
     */
    void usb_set_device_state(struct usb_device *udev,
    		enum usb_device_state new_state)
    {
    	unsigned long flags;
    
    	spin_lock_irqsave(&device_state_lock, flags);
    	if (udev->state == USB_STATE_NOTATTACHED)
    		;	/* do nothing */
    	else if (new_state != USB_STATE_NOTATTACHED)
    		udev->state = new_state;
    	else
    		recursively_mark_NOTATTACHED(udev);
    	spin_unlock_irqrestore(&device_state_lock, flags);
    }
    EXPORT_SYMBOL(usb_set_device_state);
    
    
    static void choose_address(struct usb_device *udev)
    {
    	int		devnum;
    	struct usb_bus	*bus = udev->bus;
    
    	/* If khubd ever becomes multithreaded, this will need a lock */
    
    	/* Try to allocate the next devnum beginning at bus->devnum_next. */
    	devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
    			bus->devnum_next);
    	if (devnum >= 128)
    		devnum = find_next_zero_bit(bus->devmap.devicemap, 128, 1);
    
    	bus->devnum_next = ( devnum >= 127 ? 1 : devnum + 1);
    
    	if (devnum < 128) {
    		set_bit(devnum, bus->devmap.devicemap);
    		udev->devnum = devnum;
    	}
    }
    
    static void release_address(struct usb_device *udev)
    {
    	if (udev->devnum > 0) {
    		clear_bit(udev->devnum, udev->bus->devmap.devicemap);
    		udev->devnum = -1;
    	}
    }
    
    /**
     * usb_disconnect - disconnect a device (usbcore-internal)
     * @pdev: pointer to device being disconnected
     * Context: !in_interrupt ()
     *
     * Something got disconnected. Get rid of it and all of its children.
     *
     * If *pdev is a normal device then the parent hub must already be locked.
     * If *pdev is a root hub then this routine will acquire the
     * usb_bus_list_lock on behalf of the caller.
     *
     * Only hub drivers (including virtual root hub drivers for host
     * controllers) should ever call this.
     *
     * This call is synchronous, and may not be used in an interrupt context.
     */
    void usb_disconnect(struct usb_device **pdev)
    {
    	struct usb_device	*udev = *pdev;
    	int			i;
    
    	if (!udev) {
    		pr_debug ("%s nodev\n", __FUNCTION__);
    		return;
    	}
    
    	/* mark the device as inactive, so any further urb submissions for
    	 * this device (and any of its children) will fail immediately.
    	 * this quiesces everyting except pending urbs.
    	 */
    	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
    
    	/* lock the bus list on behalf of HCDs unregistering their root hubs */
    	if (!udev->parent) {
    		down(&usb_bus_list_lock);
    		usb_lock_device(udev);
    	} else
    		down(&udev->serialize);
    
    	dev_info (&udev->dev, "USB disconnect, address %d\n", udev->devnum);
    
    	/* Free up all the children before we remove this device */
    	for (i = 0; i < USB_MAXCHILDREN; i++) {
    		if (udev->children[i])
    			usb_disconnect(&udev->children[i]);
    	}
    
    	/* deallocate hcd/hardware state ... nuking all pending urbs and
    	 * cleaning up all state associated with the current configuration
    	 * so that the hardware is now fully quiesced.
    	 */
    	usb_disable_device(udev, 0);
    
    	/* Free the device number, remove the /proc/bus/usb entry and
    	 * the sysfs attributes, and delete the parent's children[]
    	 * (or root_hub) pointer.
    	 */
    	dev_dbg (&udev->dev, "unregistering device\n");
    	release_address(udev);
    	usbfs_remove_device(udev);
    	usbdev_remove(udev);
    	usb_remove_sysfs_dev_files(udev);
    
    	/* Avoid races with recursively_mark_NOTATTACHED() */
    	spin_lock_irq(&device_state_lock);
    	*pdev = NULL;
    	spin_unlock_irq(&device_state_lock);
    
    	if (!udev->parent) {
    		usb_unlock_device(udev);
    		up(&usb_bus_list_lock);
    	} else
    		up(&udev->serialize);
    
    	device_unregister(&udev->dev);
    }
    
    static int choose_configuration(struct usb_device *udev)
    {
    	int c, i;
    
    	/* NOTE: this should interact with hub power budgeting */
    
    	c = udev->config[0].desc.bConfigurationValue;
    	if (udev->descriptor.bNumConfigurations != 1) {
    		for (i = 0; i < udev->descriptor.bNumConfigurations; i++) {
    			struct usb_interface_descriptor	*desc;
    
    			/* heuristic:  Linux is more likely to have class
    			 * drivers, so avoid vendor-specific interfaces.
    			 */
    			desc = &udev->config[i].intf_cache[0]
    					->altsetting->desc;
    			if (desc->bInterfaceClass == USB_CLASS_VENDOR_SPEC)
    				continue;
    			/* COMM/2/all is CDC ACM, except 0xff is MSFT RNDIS.
    			 * MSFT needs this to be the first config; never use
    			 * it as the default unless Linux has host-side RNDIS.
    			 * A second config would ideally be CDC-Ethernet, but
    			 * may instead be the "vendor specific" CDC subset
    			 * long used by ARM Linux for sa1100 or pxa255.
    			 */
    			if (desc->bInterfaceClass == USB_CLASS_COMM
    					&& desc->bInterfaceSubClass == 2
    					&& desc->bInterfaceProtocol == 0xff) {
    				c = udev->config[1].desc.bConfigurationValue;
    				continue;
    			}
    			c = udev->config[i].desc.bConfigurationValue;
    			break;
    		}
    		dev_info(&udev->dev,
    			"configuration #%d chosen from %d choices\n",
    			c, udev->descriptor.bNumConfigurations);
    	}
    	return c;
    }
    
    #ifdef DEBUG
    static void show_string(struct usb_device *udev, char *id, char *string)
    {
    	if (!string)
    		return;
    	dev_printk(KERN_INFO, &udev->dev, "%s: %s\n", id, string);
    }
    
    #else
    static inline void show_string(struct usb_device *udev, char *id, char *string)
    {}
    #endif
    
    static void get_string(struct usb_device *udev, char **string, int index)
    {
    	char *buf;
    
    	if (!index)
    		return;
    	buf = kmalloc(256, GFP_KERNEL);
    	if (!buf)
    		return;
    	if (usb_string(udev, index, buf, 256) > 0)
    		*string = buf;
    	else
    		kfree(buf);
    }
    
    
    #ifdef	CONFIG_USB_OTG
    #include "otg_whitelist.h"
    #endif
    
    /**
     * usb_new_device - perform initial device setup (usbcore-internal)
     * @udev: newly addressed device (in ADDRESS state)
     *
     * This is called with devices which have been enumerated, but not yet
     * configured.  The device descriptor is available, but not descriptors
     * for any device configuration.  The caller must have locked udev and
     * either the parent hub (if udev is a normal device) or else the
     * usb_bus_list_lock (if udev is a root hub).  The parent's pointer to
     * udev has already been installed, but udev is not yet visible through
     * sysfs or other filesystem code.
     *
     * Returns 0 for success (device is configured and listed, with its
     * interfaces, in sysfs); else a negative errno value.
     *
     * This call is synchronous, and may not be used in an interrupt context.
     *
     * Only the hub driver should ever call this; root hub registration
     * uses it indirectly.
     */
    int usb_new_device(struct usb_device *udev)
    {
    	int err;
    	int c;
    
    	err = usb_get_configuration(udev);
    	if (err < 0) {
    		dev_err(&udev->dev, "can't read configurations, error %d\n",
    			err);
    		goto fail;
    	}
    
    	/* read the standard strings and cache them if present */
    	get_string(udev, &udev->product, udev->descriptor.iProduct);
    	get_string(udev, &udev->manufacturer, udev->descriptor.iManufacturer);
    	get_string(udev, &udev->serial, udev->descriptor.iSerialNumber);
    
    	/* Tell the world! */
    	dev_dbg(&udev->dev, "new device strings: Mfr=%d, Product=%d, "
    			"SerialNumber=%d\n",
    			udev->descriptor.iManufacturer,
    			udev->descriptor.iProduct,
    			udev->descriptor.iSerialNumber);
    	show_string(udev, "Product", udev->product);
    	show_string(udev, "Manufacturer", udev->manufacturer);
    	show_string(udev, "SerialNumber", udev->serial);
    
    #ifdef	CONFIG_USB_OTG
    	/*
    	 * OTG-aware devices on OTG-capable root hubs may be able to use SRP,
    	 * to wake us after we've powered off VBUS; and HNP, switching roles
    	 * "host" to "peripheral".  The OTG descriptor helps figure this out.
    	 */
    	if (!udev->bus->is_b_host
    			&& udev->config
    			&& udev->parent == udev->bus->root_hub) {
    		struct usb_otg_descriptor	*desc = 0;
    		struct usb_bus			*bus = udev->bus;
    
    		/* descriptor may appear anywhere in config */
    		if (__usb_get_extra_descriptor (udev->rawdescriptors[0],
    					le16_to_cpu(udev->config[0].desc.wTotalLength),
    					USB_DT_OTG, (void **) &desc) == 0) {
    			if (desc->bmAttributes & USB_OTG_HNP) {
    				unsigned		port1;
    				struct usb_device	*root = udev->parent;
    				
    				for (port1 = 1; port1 <= root->maxchild;
    						port1++) {
    					if (root->children[port1-1] == udev)
    						break;
    				}
    
    				dev_info(&udev->dev,
    					"Dual-Role OTG device on %sHNP port\n",
    					(port1 == bus->otg_port)
    						? "" : "non-");
    
    				/* enable HNP before suspend, it's simpler */
    				if (port1 == bus->otg_port)
    					bus->b_hnp_enable = 1;
    				err = usb_control_msg(udev,
    					usb_sndctrlpipe(udev, 0),
    					USB_REQ_SET_FEATURE, 0,
    					bus->b_hnp_enable
    						? USB_DEVICE_B_HNP_ENABLE
    						: USB_DEVICE_A_ALT_HNP_SUPPORT,
    					0, NULL, 0, USB_CTRL_SET_TIMEOUT);
    				if (err < 0) {
    					/* OTG MESSAGE: report errors here,
    					 * customize to match your product.
    					 */
    					dev_info(&udev->dev,
    						"can't set HNP mode; %d\n",
    						err);
    					bus->b_hnp_enable = 0;
    				}
    			}
    		}
    	}
    
    	if (!is_targeted(udev)) {
    
    		/* Maybe it can talk to us, though we can't talk to it.
    		 * (Includes HNP test device.)
    		 */
    		if (udev->bus->b_hnp_enable || udev->bus->is_b_host) {
    			static int __usb_suspend_device (struct usb_device *,
    						int port1, pm_message_t state);
    			err = __usb_suspend_device(udev,
    					udev->bus->otg_port,
    					PMSG_SUSPEND);
    			if (err < 0)
    				dev_dbg(&udev->dev, "HNP fail, %d\n", err);
    		}
    		err = -ENODEV;
    		goto fail;
    	}
    #endif
    
    	/* put device-specific files into sysfs */
    	err = device_add (&udev->dev);
    	if (err) {
    		dev_err(&udev->dev, "can't device_add, error %d\n", err);
    		goto fail;
    	}
    	usb_create_sysfs_dev_files (udev);
    
    	/* choose and set the configuration. that registers the interfaces
    	 * with the driver core, and lets usb device drivers bind to them.
    	 */
    	c = choose_configuration(udev);
    	if (c < 0)
    		dev_warn(&udev->dev,
    				"can't choose an initial configuration\n");
    	else {
    		err = usb_set_configuration(udev, c);
    		if (err) {
    			dev_err(&udev->dev, "can't set config #%d, error %d\n",
    					c, err);
    			usb_remove_sysfs_dev_files(udev);
    			device_del(&udev->dev);
    			goto fail;
    		}
    	}
    
    	/* USB device state == configured ... usable */
    
    	/* add a /proc/bus/usb entry */
    	usbdev_add(udev);
    	usbfs_add_device(udev);
    	return 0;
    
    fail:
    	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
    	return err;
    }
    
    
    static int hub_port_status(struct usb_hub *hub, int port1,
    			       u16 *status, u16 *change)
    {
    	int ret;
    
    	ret = get_port_status(hub->hdev, port1, &hub->status->port);
    	if (ret < 0)
    		dev_err (hub->intfdev,
    			"%s failed (err = %d)\n", __FUNCTION__, ret);
    	else {
    		*status = le16_to_cpu(hub->status->port.wPortStatus);
    		*change = le16_to_cpu(hub->status->port.wPortChange); 
    		ret = 0;
    	}
    	return ret;
    }
    
    #define PORT_RESET_TRIES	5
    #define SET_ADDRESS_TRIES	2
    #define GET_DESCRIPTOR_TRIES	2
    #define SET_CONFIG_TRIES	(2 * (use_both_schemes + 1))
    #define USE_NEW_SCHEME(i)	((i) / 2 == old_scheme_first)
    
    #define HUB_ROOT_RESET_TIME	50	/* times are in msec */
    #define HUB_SHORT_RESET_TIME	10
    #define HUB_LONG_RESET_TIME	200
    #define HUB_RESET_TIMEOUT	500
    
    static int hub_port_wait_reset(struct usb_hub *hub, int port1,
    				struct usb_device *udev, unsigned int delay)
    {
    	int delay_time, ret;
    	u16 portstatus;
    	u16 portchange;
    
    	for (delay_time = 0;
    			delay_time < HUB_RESET_TIMEOUT;
    			delay_time += delay) {
    		/* wait to give the device a chance to reset */
    		msleep(delay);
    
    		/* read and decode port status */
    		ret = hub_port_status(hub, port1, &portstatus, &portchange);
    		if (ret < 0)
    			return ret;
    
    		/* Device went away? */
    		if (!(portstatus & USB_PORT_STAT_CONNECTION))
    			return -ENOTCONN;
    
    		/* bomb out completely if something weird happened */
    		if ((portchange & USB_PORT_STAT_C_CONNECTION))
    			return -EINVAL;
    
    		/* if we`ve finished resetting, then break out of the loop */
    		if (!(portstatus & USB_PORT_STAT_RESET) &&
    		    (portstatus & USB_PORT_STAT_ENABLE)) {
    			if (portstatus & USB_PORT_STAT_HIGH_SPEED)
    				udev->speed = USB_SPEED_HIGH;
    			else if (portstatus & USB_PORT_STAT_LOW_SPEED)
    				udev->speed = USB_SPEED_LOW;
    			else
    				udev->speed = USB_SPEED_FULL;
    			return 0;
    		}
    
    		/* switch to the long delay after two short delay failures */
    		if (delay_time >= 2 * HUB_SHORT_RESET_TIME)
    			delay = HUB_LONG_RESET_TIME;
    
    		dev_dbg (hub->intfdev,
    			"port %d not reset yet, waiting %dms\n",
    			port1, delay);
    	}
    
    	return -EBUSY;
    }
    
    static int hub_port_reset(struct usb_hub *hub, int port1,
    				struct usb_device *udev, unsigned int delay)
    {
    	int i, status;
    
    	/* Reset the port */
    	for (i = 0; i < PORT_RESET_TRIES; i++) {
    		status = set_port_feature(hub->hdev,
    				port1, USB_PORT_FEAT_RESET);
    		if (status)
    			dev_err(hub->intfdev,
    					"cannot reset port %d (err = %d)\n",
    					port1, status);
    		else {
    			status = hub_port_wait_reset(hub, port1, udev, delay);
    			if (status && status != -ENOTCONN)
    				dev_dbg(hub->intfdev,
    						"port_wait_reset: err = %d\n",
    						status);
    		}
    
    		/* return on disconnect or reset */
    		switch (status) {
    		case 0:
    			/* TRSTRCY = 10 ms */
    			msleep(10);
    			/* FALL THROUGH */
    		case -ENOTCONN:
    		case -ENODEV:
    			clear_port_feature(hub->hdev,
    				port1, USB_PORT_FEAT_C_RESET);
    			/* FIXME need disconnect() for NOTATTACHED device */
    			usb_set_device_state(udev, status
    					? USB_STATE_NOTATTACHED
    					: USB_STATE_DEFAULT);
    			return status;
    		}
    
    		dev_dbg (hub->intfdev,
    			"port %d not enabled, trying reset again...\n",
    			port1);
    		delay = HUB_LONG_RESET_TIME;
    	}
    
    	dev_err (hub->intfdev,
    		"Cannot enable port %i.  Maybe the USB cable is bad?\n",
    		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
    	 *  - usb_suspend_device(dev, PMSG_SUSPEND)
    	 * 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_USB_SUSPEND
    
    /*
     * 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.
     *
     * Devices leave suspend state when the host wakes them up.  Some devices
     * 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.
     */
    static int hub_port_suspend(struct usb_hub *hub, int port1,
    		struct usb_device *udev)
    {
    	int	status;
    
    	// dev_dbg(hub->intfdev, "suspend port %d\n", port1);
    
    	/* enable remote wakeup when appropriate; this lets the device
    	 * wake up the upstream hub (including maybe the root hub).
    	 *
    	 * NOTE:  OTG devices may issue remote wakeup (or SRP) even when
    	 * we don't explicitly enable it here.
    	 */
    	if (udev->actconfig
    			// && FIXME (remote wakeup enabled on this bus)
    			// ... currently assuming it's always appropriate
    			&& (udev->actconfig->desc.bmAttributes
    				& USB_CONFIG_ATT_WAKEUP) != 0) {
    		status = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
    				USB_REQ_SET_FEATURE, USB_RECIP_DEVICE,
    				USB_DEVICE_REMOTE_WAKEUP, 0,
    				NULL, 0,
    				USB_CTRL_SET_TIMEOUT);
    		if (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);
    		/* paranoia:  "should not happen" */
    		(void) usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
    				USB_REQ_CLEAR_FEATURE, USB_RECIP_DEVICE,
    				USB_DEVICE_REMOTE_WAKEUP, 0,
    				NULL, 0,
    				USB_CTRL_SET_TIMEOUT);
    	} else {
    		/* device has up to 10 msec to fully suspend */
    		dev_dbg(&udev->dev, "usb suspend\n");
    		usb_set_device_state(udev, USB_STATE_SUSPENDED);
    		msleep(10);
    	}
    	return status;
    }
    
    /*
     * 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.
     */
    static int __usb_suspend_device (struct usb_device *udev, int port1,
    				 pm_message_t state)
    {
    	int	status;
    
    	/* caller owns the udev device lock */
    	if (port1 < 0)
    		return port1;
    
    	if (udev->state == USB_STATE_SUSPENDED
    			|| udev->state == USB_STATE_NOTATTACHED) {
    		return 0;
    	}
    
    	/* suspend interface drivers; if this is a hub, it
    	 * suspends the child devices
    	 */
    	if (udev->actconfig) {
    		int	i;
    
    		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
    			struct usb_interface	*intf;
    			struct usb_driver	*driver;
    
    			intf = udev->actconfig->interface[i];
    			if (state.event <= intf->dev.power.power_state.event)
    				continue;
    			if (!intf->dev.driver)
    				continue;
    			driver = to_usb_driver(intf->dev.driver);
    
    			if (driver->suspend) {
    				status = driver->suspend(intf, state);
    				if (intf->dev.power.power_state.event != state.event
    						|| status)
    					dev_err(&intf->dev,
    						"suspend %d fail, code %d\n",
    						state.event, status);
    			}
    
    			/* only drivers with suspend() can ever resume();
    			 * and after power loss, even they won't.
    			 * bus_rescan_devices() can rebind drivers later.
    			 *
    			 * FIXME the PM core self-deadlocks when unbinding
    			 * drivers during suspend/resume ... everything grabs
    			 * dpm_sem (not a spinlock, ugh).  we want to unbind,
    			 * since we know every driver's probe/disconnect works
    			 * even for drivers that can't suspend.
    			 */
    			if (!driver->suspend || state.event > PM_EVENT_FREEZE) {
    #if 1
    				dev_warn(&intf->dev, "resume is unsafe!\n");
    #else
    				down_write(&usb_bus_type.rwsem);
    				device_release_driver(&intf->dev);
    				up_write(&usb_bus_type.rwsem);
    #endif
    			}
    		}
    	}
    
    	/*
    	 * FIXME this needs port power off call paths too, to help force
    	 * USB into the "generic" PM model.  At least for devices on
    	 * ports that aren't using ganged switching (usually root hubs).
    	 *
    	 * NOTE: SRP-capable links should adopt more aggressive poweroff
    	 * policies (when HNP doesn't apply) once we have mechanisms to
    	 * turn power back on!  (Likely not before 2.7...)
    	 */
    	if (state.event > PM_EVENT_FREEZE) {
    		dev_warn(&udev->dev, "no poweroff yet, suspending instead\n");
    	}
    
    	/* "global suspend" of the HC-to-USB interface (root hub), or
    	 * "selective suspend" of just one hub-device link.
    	 */
    	if (!udev->parent) {
    		struct usb_bus	*bus = udev->bus;
    		if (bus && bus->op->hub_suspend) {
    			status = bus->op->hub_suspend (bus);
    			if (status == 0) {
    				dev_dbg(&udev->dev, "usb suspend\n");
    				usb_set_device_state(udev,
    						USB_STATE_SUSPENDED);
    			}
    		} else
    			status = -EOPNOTSUPP;
    	} else
    		status = hub_port_suspend(hdev_to_hub(udev->parent), port1,
    				udev);
    
    	if (status == 0)
    		udev->dev.power.power_state = state;
    	return status;
    }
    
    /**
     * usb_suspend_device - suspend a usb device
     * @udev: device that's no longer in active use
     * @state: PMSG_SUSPEND to suspend
     * Context: must be able to sleep; device not locked
     *
     * 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_resume_device().  It's also routine
     * to disconnect devices while they are 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_suspend_device(struct usb_device *udev, pm_message_t state)
    {
    	int	port1, status;
    
    	port1 = locktree(udev);
    	if (port1 < 0)
    		return port1;
    
    	status = __usb_suspend_device(udev, port1, state);
    	usb_unlock_device(udev);
    	return status;
    }
    
    /*
     * 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.
     */
    static int finish_port_resume(struct usb_device *udev)
    {
    	int	status;
    	u16	devstatus;
    
    	/* caller owns the udev device lock */
    	dev_dbg(&udev->dev, "usb resume\n");
    
    	/* usb ch9 identifies four variants of SUSPENDED, based on what
    	 * state the device resumes to.  Linux currently won't see the
    	 * first two on the host side; they'd be inside hub_port_init()
    	 * during many timeouts, but khubd can't suspend until later.
    	 */
    	usb_set_device_state(udev, udev->actconfig
    			? USB_STATE_CONFIGURED
    			: USB_STATE_ADDRESS);
    	udev->dev.power.power_state = PMSG_ON;
    
     	/* 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)
    		dev_dbg(&udev->dev,
    			"gone after usb resume? status %d\n",
    			status);
    	else if (udev->actconfig) {
    		unsigned	i;
    
    		le16_to_cpus(&devstatus);
    		if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) {
    			status = usb_control_msg(udev,
    					usb_sndctrlpipe(udev, 0),
    					USB_REQ_CLEAR_FEATURE,
    						USB_RECIP_DEVICE,
    					USB_DEVICE_REMOTE_WAKEUP, 0,
    					NULL, 0,
    					USB_CTRL_SET_TIMEOUT);
    			if (status) {
    				dev_dbg(&udev->dev, "disable remote "
    					"wakeup, status %d\n", status);
    				status = 0;
    			}
    		}
    
    		/* resume interface drivers; if this is a hub, it
    		 * resumes the child devices
    		 */
    		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
    			struct usb_interface	*intf;
    			struct usb_driver	*driver;
    
    			intf = udev->actconfig->interface[i];
    			if (intf->dev.power.power_state.event == PM_EVENT_ON)
    				continue;
    			if (!intf->dev.driver) {
    				/* FIXME maybe force to alt 0 */
    				continue;
    			}
    			driver = to_usb_driver(intf->dev.driver);
    
    			/* bus_rescan_devices() may rebind drivers */
    			if (!driver->resume)
    				continue;
    
    			/* can we do better than just logging errors? */
    			status = driver->resume(intf);
    			if (intf->dev.power.power_state.event != PM_EVENT_ON
    					|| status)
    				dev_dbg(&intf->dev,
    					"resume fail, state %d code %d\n",
    					intf->dev.power.power_state.event, 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)
    {
    	int	status;
    
    	// dev_dbg(hub->intfdev, "resume port %d\n", port1);
    
    	/* see 7.1.7.7; affects power usage, but not budgeting */
    	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);
    	} else {
    		u16		devstatus;
    		u16		portchange;
    
    		/* drive resume for at least 20 msec */
    		if (udev)
    			dev_dbg(&udev->dev, "RESUME\n");
    		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.
    		 */
    		devstatus = portchange = 0;
    		status = hub_port_status(hub, port1,
    				&devstatus, &portchange);
    		if (status < 0
    				|| (devstatus & LIVE_FLAGS) != LIVE_FLAGS
    				|| (devstatus & USB_PORT_STAT_SUSPEND) != 0
    				) {
    			dev_dbg(hub->intfdev,
    				"port %d status %04x.%04x after resume, %d\n",
    				port1, portchange, devstatus, status);
    		} else {
    			/* TRSMRCY = 10 msec */
    			msleep(10);
    			if (udev)
    				status = finish_port_resume(udev);
    		}
    	}
    	if (status < 0)
    		hub_port_logical_disconnect(hub, port1);
    
    	return status;
    }
    
    static int hub_resume (struct usb_interface *intf);
    
    /**
     * usb_resume_device - re-activate a suspended usb device
     * @udev: device to re-activate
     * Context: must be able to sleep; device not locked
     *
     * 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_resume_device(struct usb_device *udev)
    {
    	int	port1, status;
    
    	port1 = locktree(udev);
    	if (port1 < 0)
    		return port1;
    
    	/* "global resume" of the HC-to-USB interface (root hub), or
    	 * selective resume of one hub-to-device port
    	 */
    	if (!udev->parent) {
    		struct usb_bus	*bus = udev->bus;
    		if (bus && bus->op->hub_resume) {
    			status = bus->op->hub_resume (bus);
    		} else
    			status = -EOPNOTSUPP;
    		if (status == 0) {
    			dev_dbg(&udev->dev, "usb resume\n");
    			/* TRSMRCY = 10 msec */
    			msleep(10);
    			usb_set_device_state (udev, USB_STATE_CONFIGURED);
    			udev->dev.power.power_state = PMSG_ON;
    			status = hub_resume (udev
    					->actconfig->interface[0]);
    		}
    	} else if (udev->state == USB_STATE_SUSPENDED) {
    		// NOTE this fails if parent is also suspended...
    		status = hub_port_resume(hdev_to_hub(udev->parent),
    				port1, udev);
    	} else {
    		status = 0;
    	}
    	if (status < 0) {
    		dev_dbg(&udev->dev, "can't resume, status %d\n",
    			status);
    	}
    
    	usb_unlock_device(udev);
    
    	/* rebind drivers that had no suspend() */
    	if (status == 0) {
    		usb_lock_all_devices();
    		bus_rescan_devices(&usb_bus_type);
    		usb_unlock_all_devices();
    	}
    	return status;
    }
    
    static int remote_wakeup(struct usb_device *udev)
    {
    	int	status = 0;
    
    	/* don't repeat RESUME sequence if this device
    	 * was already woken up by some other task
    	 */
    	down(&udev->serialize);
    	if (udev->state == USB_STATE_SUSPENDED) {
    		dev_dbg(&udev->dev, "RESUME (wakeup)\n");
    		/* TRSMRCY = 10 msec */
    		msleep(10);
    		status = finish_port_resume(udev);
    	}
    	up(&udev->serialize);
    	return status;
    }
    
    static int hub_suspend(struct usb_interface *intf, pm_message_t state)
    {
    	struct usb_hub		*hub = usb_get_intfdata (intf);
    	struct usb_device	*hdev = hub->hdev;
    	unsigned		port1;
    	int			status;
    
    	/* stop khubd and related activity */
    	hub_quiesce(hub);
    
    	/* then suspend every port */
    	for (port1 = 1; port1 <= hdev->maxchild; port1++) {
    		struct usb_device	*udev;
    
    		udev = hdev->children [port1-1];
    		if (!udev)
    			continue;
    		down(&udev->serialize);
    		status = __usb_suspend_device(udev, port1, state);
    		up(&udev->serialize);
    		if (status < 0)
    			dev_dbg(&intf->dev, "suspend port %d --> %d\n",
    				port1, status);
    	}
    
    	intf->dev.power.power_state = state;
    	return 0;
    }
    
    static int hub_resume(struct usb_interface *intf)
    {
    	struct usb_device	*hdev = interface_to_usbdev(intf);
    	struct usb_hub		*hub = usb_get_intfdata (intf);
    	unsigned		port1;
    	int			status;
    
    	if (intf->dev.power.power_state.event == PM_EVENT_ON)
    		return 0;
    
    	for (port1 = 1; port1 <= hdev->maxchild; port1++) {
    		struct usb_device	*udev;
    		u16			portstat, portchange;
    
    		udev = hdev->children [port1-1];
    		status = hub_port_status(hub, port1, &portstat, &portchange);
    		if (status == 0) {
    			if (portchange & USB_PORT_STAT_C_SUSPEND) {
    				clear_port_feature(hdev, port1,
    					USB_PORT_FEAT_C_SUSPEND);
    				portchange &= ~USB_PORT_STAT_C_SUSPEND;
    			}
    
    			/* let khubd handle disconnects etc */
    			if (portchange)
    				continue;
    		}
    
    		if (!udev || status < 0)
    			continue;
    		down (&udev->serialize);
    		if (portstat & USB_PORT_STAT_SUSPEND)
    			status = hub_port_resume(hub, port1, udev);
    		else {
    			status = finish_port_resume(udev);
    			if (status < 0) {
    				dev_dbg(&intf->dev, "resume port %d --> %d\n",
    					port1, status);
    				hub_port_logical_disconnect(hub, port1);
    			}
    		}
    		up(&udev->serialize);
    	}
    	intf->dev.power.power_state = PMSG_ON;
    
    	hub->resume_root_hub = 0;
    	hub_activate(hub);
    	return 0;
    }
    
    void usb_resume_root_hub(struct usb_device *hdev)
    {
    	struct usb_hub *hub = hdev_to_hub(hdev);
    
    	hub->resume_root_hub = 1;
    	kick_khubd(hub);
    }
    
    #else	/* !CONFIG_USB_SUSPEND */
    
    int usb_suspend_device(struct usb_device *udev, pm_message_t state)
    {
    	return 0;
    }
    
    int usb_resume_device(struct usb_device *udev)
    {
    	return 0;
    }
    
    #define	hub_suspend		NULL
    #define	hub_resume		NULL
    #define	remote_wakeup(x)	0
    
    #endif	/* CONFIG_USB_SUSPEND */
    
    EXPORT_SYMBOL(usb_suspend_device);
    EXPORT_SYMBOL(usb_resume_device);
    
    
    
    /* USB 2.0 spec, 7.1.7.3 / fig 7-29:
     *
     * Between connect detection and reset signaling there must be a delay
     * of 100ms at least for debounce and power-settling.  The corresponding
     * timer shall restart whenever the downstream port detects a disconnect.
     * 
     * Apparently there are some bluetooth and irda-dongles and a number of
     * low-speed devices for which this debounce period may last over a second.
     * Not covered by the spec - but easy to deal with.
     *
     * This implementation uses a 1500ms total debounce timeout; if the
     * connection isn't stable by then it returns -ETIMEDOUT.  It checks
     * every 25ms for transient disconnects.  When the port status has been
     * unchanged for 100ms it returns the port status.
     */
    
    #define HUB_DEBOUNCE_TIMEOUT	1500
    #define HUB_DEBOUNCE_STEP	  25
    #define HUB_DEBOUNCE_STABLE	 100
    
    static int hub_port_debounce(struct usb_hub *hub, int port1)
    {
    	int ret;
    	int total_time, stable_time = 0;
    	u16 portchange, portstatus;
    	unsigned connection = 0xffff;
    
    	for (total_time = 0; ; total_time += HUB_DEBOUNCE_STEP) {
    		ret = hub_port_status(hub, port1, &portstatus, &portchange);
    		if (ret < 0)
    			return ret;
    
    		if (!(portchange & USB_PORT_STAT_C_CONNECTION) &&
    		     (portstatus & USB_PORT_STAT_CONNECTION) == connection) {
    			stable_time += HUB_DEBOUNCE_STEP;
    			if (stable_time >= HUB_DEBOUNCE_STABLE)
    				break;
    		} else {
    			stable_time = 0;
    			connection = portstatus & USB_PORT_STAT_CONNECTION;
    		}
    
    		if (portchange & USB_PORT_STAT_C_CONNECTION) {
    			clear_port_feature(hub->hdev, port1,
    					USB_PORT_FEAT_C_CONNECTION);
    		}
    
    		if (total_time >= HUB_DEBOUNCE_TIMEOUT)
    			break;
    		msleep(HUB_DEBOUNCE_STEP);
    	}
    
    	dev_dbg (hub->intfdev,
    		"debounce: port %d: total %dms stable %dms status 0x%x\n",
    		port1, total_time, stable_time, portstatus);
    
    	if (stable_time < HUB_DEBOUNCE_STABLE)
    		return -ETIMEDOUT;
    	return portstatus;
    }
    
    static void ep0_reinit(struct usb_device *udev)
    {
    	usb_disable_endpoint(udev, 0 + USB_DIR_IN);
    	usb_disable_endpoint(udev, 0 + USB_DIR_OUT);
    	udev->ep_in[0] = udev->ep_out[0] = &udev->ep0;
    }
    
    #define usb_sndaddr0pipe()	(PIPE_CONTROL << 30)
    #define usb_rcvaddr0pipe()	((PIPE_CONTROL << 30) | USB_DIR_IN)
    
    static int hub_set_address(struct usb_device *udev)
    {
    	int retval;
    
    	if (udev->devnum == 0)
    		return -EINVAL;
    	if (udev->state == USB_STATE_ADDRESS)
    		return 0;
    	if (udev->state != USB_STATE_DEFAULT)
    		return -EINVAL;
    	retval = usb_control_msg(udev, usb_sndaddr0pipe(),
    		USB_REQ_SET_ADDRESS, 0, udev->devnum, 0,
    		NULL, 0, USB_CTRL_SET_TIMEOUT);
    	if (retval == 0) {
    		usb_set_device_state(udev, USB_STATE_ADDRESS);
    		ep0_reinit(udev);
    	}
    	return retval;
    }
    
    /* Reset device, (re)assign address, get device descriptor.
     * Device connection must be stable, no more debouncing needed.
     * Returns device in USB_STATE_ADDRESS, except on error.
     *
     * If this is called for an already-existing device (as part of
     * usb_reset_device), the caller must own the device lock.  For a
     * newly detected device that is not accessible through any global
     * pointers, it's not necessary to lock the device.
     */
    static int
    hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
    		int retry_counter)
    {
    	static DECLARE_MUTEX(usb_address0_sem);
    
    	struct usb_device	*hdev = hub->hdev;
    	int			i, j, retval;
    	unsigned		delay = HUB_SHORT_RESET_TIME;
    	enum usb_device_speed	oldspeed = udev->speed;
    
    	/* root hub ports have a slightly longer reset period
    	 * (from USB 2.0 spec, section 7.1.7.5)
    	 */
    	if (!hdev->parent) {
    		delay = HUB_ROOT_RESET_TIME;
    		if (port1 == hdev->bus->otg_port)
    			hdev->bus->b_hnp_enable = 0;
    	}
    
    	/* Some low speed devices have problems with the quick delay, so */
    	/*  be a bit pessimistic with those devices. RHbug #23670 */
    	if (oldspeed == USB_SPEED_LOW)
    		delay = HUB_LONG_RESET_TIME;
    
    	down(&usb_address0_sem);
    
    	/* Reset the device; full speed may morph to high speed */
    	retval = hub_port_reset(hub, port1, udev, delay);
    	if (retval < 0)		/* error or disconnect */
    		goto fail;
    				/* success, speed is known */
    	retval = -ENODEV;
    
    	if (oldspeed != USB_SPEED_UNKNOWN && oldspeed != udev->speed) {
    		dev_dbg(&udev->dev, "device reset changed speed!\n");
    		goto fail;
    	}
    	oldspeed = udev->speed;
      
    	/* USB 2.0 section 5.5.3 talks about ep0 maxpacket ...
    	 * it's fixed size except for full speed devices.
    	 */
    	switch (udev->speed) {
    	case USB_SPEED_HIGH:		/* fixed at 64 */
    		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
    		break;
    	case USB_SPEED_FULL:		/* 8, 16, 32, or 64 */
    		/* to determine the ep0 maxpacket size, try to read
    		 * the device descriptor to get bMaxPacketSize0 and
    		 * then correct our initial guess.
    		 */
    		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
    		break;
    	case USB_SPEED_LOW:		/* fixed at 8 */
    		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(8);
    		break;
    	default:
    		goto fail;
    	}
     
    	dev_info (&udev->dev,
    			"%s %s speed USB device using %s and address %d\n",
    			(udev->config) ? "reset" : "new",
    			({ char *speed; switch (udev->speed) {
    			case USB_SPEED_LOW:	speed = "low";	break;
    			case USB_SPEED_FULL:	speed = "full";	break;
    			case USB_SPEED_HIGH:	speed = "high";	break;
    			default: 		speed = "?";	break;
    			}; speed;}),
    			udev->bus->controller->driver->name,
    			udev->devnum);
    
    	/* Set up TT records, if needed  */
    	if (hdev->tt) {
    		udev->tt = hdev->tt;
    		udev->ttport = hdev->ttport;
    	} else if (udev->speed != USB_SPEED_HIGH
    			&& hdev->speed == USB_SPEED_HIGH) {
    		udev->tt = &hub->tt;
    		udev->ttport = port1;
    	}
     
    	/* Why interleave GET_DESCRIPTOR and SET_ADDRESS this way?
    	 * Because device hardware and firmware is sometimes buggy in
    	 * this area, and this is how Linux has done it for ages.
    	 * Change it cautiously.
    	 *
    	 * NOTE:  If USE_NEW_SCHEME() is true we will start by issuing
    	 * a 64-byte GET_DESCRIPTOR request.  This is what Windows does,
    	 * so it may help with some non-standards-compliant devices.
    	 * Otherwise we start with SET_ADDRESS and then try to read the
    	 * first 8 bytes of the device descriptor to get the ep0 maxpacket
    	 * value.
    	 */
    	for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
    		if (USE_NEW_SCHEME(retry_counter)) {
    			struct usb_device_descriptor *buf;
    			int r = 0;
    
    #define GET_DESCRIPTOR_BUFSIZE	64
    			buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO);
    			if (!buf) {
    				retval = -ENOMEM;
    				continue;
    			}
    
    			/* Use a short timeout the first time through,
    			 * so that recalcitrant full-speed devices with
    			 * 8- or 16-byte ep0-maxpackets won't slow things
    			 * down tremendously by NAKing the unexpectedly
    			 * early status stage.  Also, retry on all errors;
    			 * some devices are flakey.
    			 */
    			for (j = 0; j < 3; ++j) {
    				buf->bMaxPacketSize0 = 0;
    				r = usb_control_msg(udev, usb_rcvaddr0pipe(),
    					USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
    					USB_DT_DEVICE << 8, 0,
    					buf, GET_DESCRIPTOR_BUFSIZE,
    					(i ? USB_CTRL_GET_TIMEOUT : 1000));
    				switch (buf->bMaxPacketSize0) {
    				case 8: case 16: case 32: case 64:
    					if (buf->bDescriptorType ==
    							USB_DT_DEVICE) {
    						r = 0;
    						break;
    					}
    					/* FALL THROUGH */
    				default:
    					if (r == 0)
    						r = -EPROTO;
    					break;
    				}
    				if (r == 0)
    					break;
    			}
    			udev->descriptor.bMaxPacketSize0 =
    					buf->bMaxPacketSize0;
    			kfree(buf);
    
    			retval = hub_port_reset(hub, port1, udev, delay);
    			if (retval < 0)		/* error or disconnect */
    				goto fail;
    			if (oldspeed != udev->speed) {
    				dev_dbg(&udev->dev,
    					"device reset changed speed!\n");
    				retval = -ENODEV;
    				goto fail;
    			}
    			if (r) {
    				dev_err(&udev->dev, "device descriptor "
    						"read/%s, error %d\n",
    						"64", r);
    				retval = -EMSGSIZE;
    				continue;
    			}
    #undef GET_DESCRIPTOR_BUFSIZE
    		}
    
    		for (j = 0; j < SET_ADDRESS_TRIES; ++j) {
    			retval = hub_set_address(udev);
    			if (retval >= 0)
    				break;
    			msleep(200);
    		}
    		if (retval < 0) {
    			dev_err(&udev->dev,
    				"device not accepting address %d, error %d\n",
    				udev->devnum, retval);
    			goto fail;
    		}
     
    		/* cope with hardware quirkiness:
    		 *  - let SET_ADDRESS settle, some device hardware wants it
    		 *  - read ep0 maxpacket even for high and low speed,
      		 */
    		msleep(10);
    		if (USE_NEW_SCHEME(retry_counter))
    			break;
    
    		retval = usb_get_device_descriptor(udev, 8);
    		if (retval < 8) {
    			dev_err(&udev->dev, "device descriptor "
    					"read/%s, error %d\n",
    					"8", retval);
    			if (retval >= 0)
    				retval = -EMSGSIZE;
    		} else {
    			retval = 0;
    			break;
    		}
    	}
    	if (retval)
    		goto fail;
    
    	i = udev->descriptor.bMaxPacketSize0;
    	if (le16_to_cpu(udev->ep0.desc.wMaxPacketSize) != i) {
    		if (udev->speed != USB_SPEED_FULL ||
    				!(i == 8 || i == 16 || i == 32 || i == 64)) {
    			dev_err(&udev->dev, "ep0 maxpacket = %d\n", i);
    			retval = -EMSGSIZE;
    			goto fail;
    		}
    		dev_dbg(&udev->dev, "ep0 maxpacket = %d\n", i);
    		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(i);
    		ep0_reinit(udev);
    	}
      
    	retval = usb_get_device_descriptor(udev, USB_DT_DEVICE_SIZE);
    	if (retval < (signed)sizeof(udev->descriptor)) {
    		dev_err(&udev->dev, "device descriptor read/%s, error %d\n",
    			"all", retval);
    		if (retval >= 0)
    			retval = -ENOMSG;
    		goto fail;
    	}
    
    	retval = 0;
    
    fail:
    	if (retval)
    		hub_port_disable(hub, port1, 0);
    	up(&usb_address0_sem);
    	return retval;
    }
    
    static void
    check_highspeed (struct usb_hub *hub, struct usb_device *udev, int port1)
    {
    	struct usb_qualifier_descriptor	*qual;
    	int				status;
    
    	qual = kmalloc (sizeof *qual, SLAB_KERNEL);
    	if (qual == NULL)
    		return;
    
    	status = usb_get_descriptor (udev, USB_DT_DEVICE_QUALIFIER, 0,
    			qual, sizeof *qual);
    	if (status == sizeof *qual) {
    		dev_info(&udev->dev, "not running at top speed; "
    			"connect to a high speed hub\n");
    		/* hub LEDs are probably harder to miss than syslog */
    		if (hub->has_indicators) {
    			hub->indicator[port1-1] = INDICATOR_GREEN_BLINK;
    			schedule_work (&hub->leds);
    		}
    	}
    	kfree(qual);
    }
    
    static unsigned
    hub_power_remaining (struct usb_hub *hub)
    {
    	struct usb_device *hdev = hub->hdev;
    	int remaining;
    	unsigned i;
    
    	remaining = hub->power_budget;
    	if (!remaining)		/* self-powered */
    		return 0;
    
    	for (i = 0; i < hdev->maxchild; i++) {
    		struct usb_device	*udev = hdev->children[i];
    		int			delta, ceiling;
    
    		if (!udev)
    			continue;
    
    		/* 100mA per-port ceiling, or 8mA for OTG ports */
    		if (i != (udev->bus->otg_port - 1) || hdev->parent)
    			ceiling = 50;
    		else
    			ceiling = 4;
    
    		if (udev->actconfig)
    			delta = udev->actconfig->desc.bMaxPower;
    		else
    			delta = ceiling;
    		// dev_dbg(&udev->dev, "budgeted %dmA\n", 2 * delta);
    		if (delta > ceiling)
    			dev_warn(&udev->dev, "%dmA over %dmA budget!\n",
    				2 * (delta - ceiling), 2 * ceiling);
    		remaining -= delta;
    	}
    	if (remaining < 0) {
    		dev_warn(hub->intfdev,
    			"%dmA over power budget!\n",
    			-2 * remaining);
    		remaining = 0;
    	}
    	return remaining;
    }
    
    /* Handle physical or logical connection change events.
     * This routine is called when:
     * 	a port connection-change occurs;
     *	a port enable-change occurs (often caused by EMI);
     *	usb_reset_device() encounters changed descriptors (as from
     *		a firmware download)
     * caller already locked the hub
     */
    static void hub_port_connect_change(struct usb_hub *hub, int port1,
    					u16 portstatus, u16 portchange)
    {
    	struct usb_device *hdev = hub->hdev;
    	struct device *hub_dev = hub->intfdev;
    	int status, i;
     
    	dev_dbg (hub_dev,
    		"port %d, status %04x, change %04x, %s\n",
    		port1, portstatus, portchange, portspeed (portstatus));
    
    	if (hub->has_indicators) {
    		set_port_led(hub, port1, HUB_LED_AUTO);
    		hub->indicator[port1-1] = INDICATOR_AUTO;
    	}
     
    	/* Disconnect any existing devices under this port */
    	if (hdev->children[port1-1])
    		usb_disconnect(&hdev->children[port1-1]);
    	clear_bit(port1, hub->change_bits);
    
    #ifdef	CONFIG_USB_OTG
    	/* during HNP, don't repeat the debounce */
    	if (hdev->bus->is_b_host)
    		portchange &= ~USB_PORT_STAT_C_CONNECTION;
    #endif
    
    	if (portchange & USB_PORT_STAT_C_CONNECTION) {
    		status = hub_port_debounce(hub, port1);
    		if (status < 0) {
    			dev_err (hub_dev,
    				"connect-debounce failed, port %d disabled\n",
    				port1);
    			goto done;
    		}
    		portstatus = status;
    	}
    
    	/* Return now if nothing is connected */
    	if (!(portstatus & USB_PORT_STAT_CONNECTION)) {
    
    		/* maybe switch power back on (e.g. root hub was reset) */
    		if ((hub->descriptor->wHubCharacteristics
    					& HUB_CHAR_LPSM) < 2
    				&& !(portstatus & (1 << USB_PORT_FEAT_POWER)))
    			set_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
     
    		if (portstatus & USB_PORT_STAT_ENABLE)
      			goto done;
    		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;
    
    		/* reallocate for each attempt, since references
    		 * to the previous one can escape in various ways
    		 */
    		udev = usb_alloc_dev(hdev, hdev->bus, port1);
    		if (!udev) {
    			dev_err (hub_dev,
    				"couldn't allocate port %d usb_device\n",
    				port1);
    			goto done;
    		}
    
    		usb_set_device_state(udev, USB_STATE_POWERED);
    		udev->speed = USB_SPEED_UNKNOWN;
     
    		/* set the address */
    		choose_address(udev);
    		if (udev->devnum <= 0) {
    			status = -ENOTCONN;	/* Don't retry */
    			goto loop;
    		}
    
    		/* reset and get descriptor */
    		status = hub_port_init(hub, udev, port1, i);
    		if (status < 0)
    			goto loop;
    
    		/* consecutive bus-powered hubs aren't reliable; they can
    		 * violate the voltage drop budget.  if the new child has
    		 * a "powered" LED, users should notice we didn't enable it
    		 * (without reading syslog), even without per-port LEDs
    		 * on the parent.
    		 */
    		if (udev->descriptor.bDeviceClass == USB_CLASS_HUB
    				&& hub->power_budget) {
    			u16	devstat;
    
    			status = usb_get_status(udev, USB_RECIP_DEVICE, 0,
    					&devstat);
    			if (status < 0) {
    				dev_dbg(&udev->dev, "get status %d ?\n", status);
    				goto loop_disable;
    			}
    			cpu_to_le16s(&devstat);
    			if ((devstat & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
    				dev_err(&udev->dev,
    					"can't connect bus-powered hub "
    					"to this port\n");
    				if (hub->has_indicators) {
    					hub->indicator[port1-1] =
    						INDICATOR_AMBER_BLINK;
    					schedule_work (&hub->leds);
    				}
    				status = -ENOTCONN;	/* Don't retry */
    				goto loop_disable;
    			}
    		}
     
    		/* check for devices running slower than they could */
    		if (le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0200
    				&& udev->speed == USB_SPEED_FULL
    				&& highspeed_hubs != 0)
    			check_highspeed (hub, udev, port1);
    
    		/* Store the parent's children[] pointer.  At this point
    		 * udev becomes globally accessible, although presumably
    		 * no one will look at it until hdev is unlocked.
    		 */
    		down (&udev->serialize);
    		status = 0;
    
    		/* We mustn't add new devices if the parent hub has
    		 * been disconnected; we would race with the
    		 * recursively_mark_NOTATTACHED() routine.
    		 */
    		spin_lock_irq(&device_state_lock);
    		if (hdev->state == USB_STATE_NOTATTACHED)
    			status = -ENOTCONN;
    		else
    			hdev->children[port1-1] = udev;
    		spin_unlock_irq(&device_state_lock);
    
    		/* Run it through the hoops (find a driver, etc) */
    		if (!status) {
    			status = usb_new_device(udev);
    			if (status) {
    				spin_lock_irq(&device_state_lock);
    				hdev->children[port1-1] = NULL;
    				spin_unlock_irq(&device_state_lock);
    			}
    		}
    
    		up (&udev->serialize);
    		if (status)
    			goto loop_disable;
    
    		status = hub_power_remaining(hub);
    		if (status)
    			dev_dbg(hub_dev,
    				"%dmA power budget left\n",
    				2 * status);
    
    		return;
    
    loop_disable:
    		hub_port_disable(hub, port1, 1);
    loop:
    		ep0_reinit(udev);
    		release_address(udev);
    		usb_put_dev(udev);
    		if (status == -ENOTCONN)
    			break;
    	}
     
    done:
    	hub_port_disable(hub, port1, 1);
    }
    
    static void hub_events(void)
    {
    	struct list_head *tmp;
    	struct usb_device *hdev;
    	struct usb_interface *intf;
    	struct usb_hub *hub;
    	struct device *hub_dev;
    	u16 hubstatus;
    	u16 hubchange;
    	u16 portstatus;
    	u16 portchange;
    	int i, ret;
    	int connect_change;
    
    	/*
    	 *  We restart the list every time to avoid a deadlock with
    	 * deleting hubs downstream from this one. This should be
    	 * safe since we delete the hub from the event list.
    	 * Not the most efficient, but avoids deadlocks.
    	 */
    	while (1) {
    
    		/* Grab the first entry at the beginning of the list */
    		spin_lock_irq(&hub_event_lock);
    		if (list_empty(&hub_event_list)) {
    			spin_unlock_irq(&hub_event_lock);
    			break;
    		}
    
    		tmp = hub_event_list.next;
    		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;
    
    		dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
    				hdev->state, hub->descriptor
    					? hub->descriptor->bNbrPorts
    					: 0,
    				/* NOTE: expects max 15 ports... */
    				(u16) hub->change_bits[0],
    				(u16) hub->event_bits[0]);
    
    		usb_get_intf(intf);
    		i = hub->resume_root_hub;
    		spin_unlock_irq(&hub_event_lock);
    
    		/* Is this is a root hub wanting to be resumed? */
    		if (i)
    			usb_resume_device(hdev);
    
    		/* 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))
    			goto loop;
    
    		/* If the hub has died, clean up after it */
    		if (hdev->state == USB_STATE_NOTATTACHED) {
    			hub_pre_reset(hub);
    			goto loop;
    		}
    
    		/* If this is an inactive or suspended hub, do nothing */
    		if (hub->quiescing)
    			goto loop;
    
    		if (hub->error) {
    			dev_dbg (hub_dev, "resetting for error %d\n",
    				hub->error);
    
    			ret = usb_reset_device(hdev);
    			if (ret) {
    				dev_dbg (hub_dev,
    					"error resetting hub: %d\n", ret);
    				goto loop;
    			}
    
    			hub->nerrors = 0;
    			hub->error = 0;
    		}
    
    		/* deal with port status changes */
    		for (i = 1; i <= hub->descriptor->bNbrPorts; i++) {
    			if (test_bit(i, hub->busy_bits))
    				continue;
    			connect_change = test_bit(i, hub->change_bits);
    			if (!test_and_clear_bit(i, hub->event_bits) &&
    					!connect_change && !hub->activating)
    				continue;
    
    			ret = hub_port_status(hub, i,
    					&portstatus, &portchange);
    			if (ret < 0)
    				continue;
    
    			if (hub->activating && !hdev->children[i-1] &&
    					(portstatus &
    						USB_PORT_STAT_CONNECTION))
    				connect_change = 1;
    
    			if (portchange & USB_PORT_STAT_C_CONNECTION) {
    				clear_port_feature(hdev, i,
    					USB_PORT_FEAT_C_CONNECTION);
    				connect_change = 1;
    			}
    
    			if (portchange & USB_PORT_STAT_C_ENABLE) {
    				if (!connect_change)
    					dev_dbg (hub_dev,
    						"port %d enable change, "
    						"status %08x\n",
    						i, portstatus);
    				clear_port_feature(hdev, i,
    					USB_PORT_FEAT_C_ENABLE);
    
    				/*
    				 * EM interference sometimes causes badly
    				 * shielded USB devices to be shutdown by
    				 * the hub, this hack enables them again.
    				 * Works at least with mouse driver. 
    				 */
    				if (!(portstatus & USB_PORT_STAT_ENABLE)
    				    && !connect_change
    				    && hdev->children[i-1]) {
    					dev_err (hub_dev,
    					    "port %i "
    					    "disabled by hub (EMI?), "
    					    "re-enabling...\n",
    						i);
    					connect_change = 1;
    				}
    			}
    
    			if (portchange & USB_PORT_STAT_C_SUSPEND) {
    				clear_port_feature(hdev, i,
    					USB_PORT_FEAT_C_SUSPEND);
    				if (hdev->children[i-1]) {
    					ret = remote_wakeup(hdev->
    							children[i-1]);
    					if (ret < 0)
    						connect_change = 1;
    				} else {
    					ret = -ENODEV;
    					hub_port_disable(hub, i, 1);
    				}
    				dev_dbg (hub_dev,
    					"resume on port %d, status %d\n",
    					i, ret);
    			}
    			
    			if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
    				dev_err (hub_dev,
    					"over-current change on port %d\n",
    					i);
    				clear_port_feature(hdev, i,
    					USB_PORT_FEAT_C_OVER_CURRENT);
    				hub_power_on(hub);
    			}
    
    			if (portchange & USB_PORT_STAT_C_RESET) {
    				dev_dbg (hub_dev,
    					"reset change on port %d\n",
    					i);
    				clear_port_feature(hdev, i,
    					USB_PORT_FEAT_C_RESET);
    			}
    
    			if (connect_change)
    				hub_port_connect_change(hub, i,
    						portstatus, portchange);
    		} /* end for i */
    
    		/* deal with hub status changes */
    		if (test_and_clear_bit(0, hub->event_bits) == 0)
    			;	/* do nothing */
    		else if (hub_hub_status(hub, &hubstatus, &hubchange) < 0)
    			dev_err (hub_dev, "get_hub_status failed\n");
    		else {
    			if (hubchange & HUB_CHANGE_LOCAL_POWER) {
    				dev_dbg (hub_dev, "power change\n");
    				clear_hub_feature(hdev, C_HUB_LOCAL_POWER);
    			}
    			if (hubchange & HUB_CHANGE_OVERCURRENT) {
    				dev_dbg (hub_dev, "overcurrent change\n");
    				msleep(500);	/* Cool down */
    				clear_hub_feature(hdev, C_HUB_OVER_CURRENT);
                            	hub_power_on(hub);
    			}
    		}
    
    		hub->activating = 0;
    
    		/* If this is a root hub, tell the HCD it's okay to
    		 * re-enable port-change interrupts now. */
    		if (!hdev->parent)
    			usb_enable_root_hub_irq(hdev->bus);
    
    loop:
    		usb_unlock_device(hdev);
    		usb_put_intf(intf);
    
            } /* end while (1) */
    }
    
    static int hub_thread(void *__unused)
    {
    	do {
    		hub_events();
    		wait_event_interruptible(khubd_wait,
    				!list_empty(&hub_event_list) ||
    				kthread_should_stop());
    		try_to_freeze();
    	} while (!kthread_should_stop() || !list_empty(&hub_event_list));
    
    	pr_debug("%s: khubd exiting\n", usbcore_name);
    	return 0;
    }
    
    static struct usb_device_id hub_id_table [] = {
        { .match_flags = USB_DEVICE_ID_MATCH_DEV_CLASS,
          .bDeviceClass = USB_CLASS_HUB},
        { .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS,
          .bInterfaceClass = USB_CLASS_HUB},
        { }						/* Terminating entry */
    };
    
    MODULE_DEVICE_TABLE (usb, hub_id_table);
    
    static struct usb_driver hub_driver = {
    	.owner =	THIS_MODULE,
    	.name =		"hub",
    	.probe =	hub_probe,
    	.disconnect =	hub_disconnect,
    	.suspend =	hub_suspend,
    	.resume =	hub_resume,
    	.ioctl =	hub_ioctl,
    	.id_table =	hub_id_table,
    };
    
    int usb_hub_init(void)
    {
    	if (usb_register(&hub_driver) < 0) {
    		printk(KERN_ERR "%s: can't register hub driver\n",
    			usbcore_name);
    		return -1;
    	}
    
    	khubd_task = kthread_run(hub_thread, NULL, "khubd");
    	if (!IS_ERR(khubd_task))
    		return 0;
    
    	/* Fall through if kernel_thread failed */
    	usb_deregister(&hub_driver);
    	printk(KERN_ERR "%s: can't start khubd\n", usbcore_name);
    
    	return -1;
    }
    
    void usb_hub_cleanup(void)
    {
    	kthread_stop(khubd_task);
    
    	/*
    	 * Hub resources are freed for us by usb_deregister. It calls
    	 * usb_driver_purge on every device which in turn calls that
    	 * devices disconnect function if it is using this driver.
    	 * The hub_disconnect function takes care of releasing the
    	 * individual hub resources. -greg
    	 */
    	usb_deregister(&hub_driver);
    } /* usb_hub_cleanup() */
    
    static int config_descriptors_changed(struct usb_device *udev)
    {
    	unsigned			index;
    	unsigned			len = 0;
    	struct usb_config_descriptor	*buf;
    
    	for (index = 0; index < udev->descriptor.bNumConfigurations; index++) {
    		if (len < le16_to_cpu(udev->config[index].desc.wTotalLength))
    			len = le16_to_cpu(udev->config[index].desc.wTotalLength);
    	}
    	buf = kmalloc (len, SLAB_KERNEL);
    	if (buf == NULL) {
    		dev_err(&udev->dev, "no mem to re-read configs after reset\n");
    		/* assume the worst */
    		return 1;
    	}
    	for (index = 0; index < udev->descriptor.bNumConfigurations; index++) {
    		int length;
    		int old_length = le16_to_cpu(udev->config[index].desc.wTotalLength);
    
    		length = usb_get_descriptor(udev, USB_DT_CONFIG, index, buf,
    				old_length);
    		if (length < old_length) {
    			dev_dbg(&udev->dev, "config index %d, error %d\n",
    					index, length);
    			break;
    		}
    		if (memcmp (buf, udev->rawdescriptors[index], old_length)
    				!= 0) {
    			dev_dbg(&udev->dev, "config index %d changed (#%d)\n",
    				index, buf->bConfigurationValue);
    			break;
    		}
    	}
    	kfree(buf);
    	return index != udev->descriptor.bNumConfigurations;
    }
    
    /**
     * usb_reset_device - perform a USB port reset to reinitialize a device
     * @udev: device to reset (not in SUSPENDED or NOTATTACHED state)
     *
     * WARNING - don't reset any device unless drivers for all of its
     * interfaces are expecting that reset!  Maybe some driver->reset()
     * method should eventually help ensure sufficient cooperation.
     *
     * Do a port reset, reassign the device's address, and establish its
     * former operating configuration.  If the reset fails, or the device's
     * descriptors change from their values before the reset, or the original
     * configuration and altsettings cannot be restored, a flag will be set
     * telling khubd to pretend the device has been disconnected and then
     * re-connected.  All drivers will be unbound, and the device will be
     * re-enumerated and probed all over again.
     *
     * Returns 0 if the reset succeeded, -ENODEV if the device has been
     * flagged for logical disconnection, or some other negative error code
     * if the reset wasn't even attempted.
     *
     * The caller must own the device lock.  For example, it's safe to use
     * 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().
     */
    int usb_reset_device(struct usb_device *udev)
    {
    	struct usb_device		*parent_hdev = udev->parent;
    	struct usb_hub			*parent_hub;
    	struct usb_device_descriptor	descriptor = udev->descriptor;
    	struct usb_hub			*hub = NULL;
    	int 				i, ret = 0, port1 = -1;
    
    	if (udev->state == USB_STATE_NOTATTACHED ||
    			udev->state == USB_STATE_SUSPENDED) {
    		dev_dbg(&udev->dev, "device reset not allowed in state %d\n",
    				udev->state);
    		return -EINVAL;
    	}
    
    	if (!parent_hdev) {
    		/* this requires hcd-specific logic; see OHCI hc_restart() */
    		dev_dbg(&udev->dev, "%s for root hub!\n", __FUNCTION__);
    		return -EISDIR;
    	}
    
    	for (i = 0; i < parent_hdev->maxchild; i++)
    		if (parent_hdev->children[i] == udev) {
    			port1 = i + 1;
    			break;
    		}
    
    	if (port1 < 0) {
    		/* If this ever happens, it's very bad */
    		dev_err(&udev->dev, "Can't locate device's port!\n");
    		return -ENOENT;
    	}
    	parent_hub = hdev_to_hub(parent_hdev);
    
    	/* If we're resetting an active hub, take some special actions */
    	if (udev->actconfig &&
    			udev->actconfig->interface[0]->dev.driver ==
    				&hub_driver.driver &&
    			(hub = hdev_to_hub(udev)) != NULL) {
    		hub_pre_reset(hub);
    	}
    
    	set_bit(port1, parent_hub->busy_bits);
    	for (i = 0; i < SET_CONFIG_TRIES; ++i) {
    
    		/* ep0 maxpacket size may change; let the HCD know about it.
    		 * Other endpoints will be handled by re-enumeration. */
    		ep0_reinit(udev);
    		ret = hub_port_init(parent_hub, udev, port1, i);
    		if (ret >= 0)
    			break;
    	}
    	clear_bit(port1, parent_hub->busy_bits);
    	if (ret < 0)
    		goto re_enumerate;
     
    	/* Device might have changed firmware (DFU or similar) */
    	if (memcmp(&udev->descriptor, &descriptor, sizeof descriptor)
    			|| config_descriptors_changed (udev)) {
    		dev_info(&udev->dev, "device firmware changed\n");
    		udev->descriptor = descriptor;	/* for disconnect() calls */
    		goto re_enumerate;
      	}
      
    	if (!udev->actconfig)
    		goto done;
    
    	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
    			USB_REQ_SET_CONFIGURATION, 0,
    			udev->actconfig->desc.bConfigurationValue, 0,
    			NULL, 0, USB_CTRL_SET_TIMEOUT);
    	if (ret < 0) {
    		dev_err(&udev->dev,
    			"can't restore configuration #%d (error=%d)\n",
    			udev->actconfig->desc.bConfigurationValue, ret);
    		goto re_enumerate;
      	}
    	usb_set_device_state(udev, USB_STATE_CONFIGURED);
    
    	for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
    		struct usb_interface *intf = udev->actconfig->interface[i];
    		struct usb_interface_descriptor *desc;
    
    		/* set_interface resets host side toggle even
    		 * for altsetting zero.  the interface may have no driver.
    		 */
    		desc = &intf->cur_altsetting->desc;
    		ret = usb_set_interface(udev, desc->bInterfaceNumber,
    			desc->bAlternateSetting);
    		if (ret < 0) {
    			dev_err(&udev->dev, "failed to restore interface %d "
    				"altsetting %d (error=%d)\n",
    				desc->bInterfaceNumber,
    				desc->bAlternateSetting,
    				ret);
    			goto re_enumerate;
    		}
    	}
    
    done:
    	if (hub)
    		hub_post_reset(hub);
    	return 0;
     
    re_enumerate:
    	hub_port_logical_disconnect(parent_hub, port1);
    	return -ENODEV;
    }