V4L/DVB (8145a): USB Video Class driver

This driver supports video input devices compliant with the USB Video Class
specification. This means lots of currently manufactured webcams, and probably
most of the future ones.

Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 1955 insertions, 0 deletions

diff --git a/drivers/media/video/uvc/uvc_driver.c b/drivers/media/video/uvc/uvc_driver.c
new file mode 100644
index 000000000000..60ced589f898
--- /dev/null
+++ b/drivers/media/video/uvc/uvc_driver.c
@@ -0,0 +1,1955 @@
+/*
+ *      uvc_driver.c  --  USB Video Class driver
+ *
+ *      Copyright (C) 2005-2008
+ *          Laurent Pinchart (laurent.pinchart@skynet.be)
+ *
+ *      This program is free software; you can redistribute it and/or modify
+ *      it under the terms of the GNU General Public License as published by
+ *      the Free Software Foundation; either version 2 of the License, or
+ *      (at your option) any later version.
+ *
+ */
+
+/*
+ * This driver aims to support video input devices compliant with the 'USB
+ * Video Class' specification.
+ *
+ * The driver doesn't support the deprecated v4l1 interface. It implements the
+ * mmap capture method only, and doesn't do any image format conversion in
+ * software. If your user-space application doesn't support YUYV or MJPEG, fix
+ * it :-). Please note that the MJPEG data have been stripped from their
+ * Huffman tables (DHT marker), you will need to add it back if your JPEG
+ * codec can't handle MJPEG data.
+ */
+
+#include <linux/kernel.h>
+#include <linux/version.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/videodev2.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <asm/atomic.h>
+
+#include <media/v4l2-common.h>
+
+#include "uvcvideo.h"
+
+#define DRIVER_AUTHOR		"Laurent Pinchart <laurent.pinchart@skynet.be>"
+#define DRIVER_DESC		"USB Video Class driver"
+#ifndef DRIVER_VERSION
+#define DRIVER_VERSION		"v0.1.0"
+#endif
+
+static unsigned int uvc_quirks_param;
+unsigned int uvc_trace_param;
+
+/* ------------------------------------------------------------------------
+ * Control, formats, ...
+ */
+
+static struct uvc_format_desc uvc_fmts[] = {
+	{
+		.name		= "YUV 4:2:2 (YUYV)",
+		.guid		= UVC_GUID_FORMAT_YUY2,
+		.fcc		= V4L2_PIX_FMT_YUYV,
+	},
+	{
+		.name		= "YUV 4:2:0 (NV12)",
+		.guid		= UVC_GUID_FORMAT_NV12,
+		.fcc		= V4L2_PIX_FMT_NV12,
+	},
+	{
+		.name		= "MJPEG",
+		.guid		= UVC_GUID_FORMAT_MJPEG,
+		.fcc		= V4L2_PIX_FMT_MJPEG,
+	},
+	{
+		.name		= "YVU 4:2:0 (YV12)",
+		.guid		= UVC_GUID_FORMAT_YV12,
+		.fcc		= V4L2_PIX_FMT_YVU420,
+	},
+	{
+		.name		= "YUV 4:2:0 (I420)",
+		.guid		= UVC_GUID_FORMAT_I420,
+		.fcc		= V4L2_PIX_FMT_YUV420,
+	},
+	{
+		.name		= "YUV 4:2:2 (UYVY)",
+		.guid		= UVC_GUID_FORMAT_UYVY,
+		.fcc		= V4L2_PIX_FMT_UYVY,
+	},
+	{
+		.name		= "Greyscale",
+		.guid		= UVC_GUID_FORMAT_Y800,
+		.fcc		= V4L2_PIX_FMT_GREY,
+	},
+	{
+		.name		= "RGB Bayer",
+		.guid		= UVC_GUID_FORMAT_BY8,
+		.fcc		= V4L2_PIX_FMT_SBGGR8,
+	},
+};
+
+/* ------------------------------------------------------------------------
+ * Utility functions
+ */
+
+struct usb_host_endpoint *uvc_find_endpoint(struct usb_host_interface *alts,
+		__u8 epaddr)
+{
+	struct usb_host_endpoint *ep;
+	unsigned int i;
+
+	for (i = 0; i < alts->desc.bNumEndpoints; ++i) {
+		ep = &alts->endpoint[i];
+		if (ep->desc.bEndpointAddress == epaddr)
+			return ep;
+	}
+
+	return NULL;
+}
+
+static struct uvc_format_desc *uvc_format_by_guid(const __u8 guid[16])
+{
+	unsigned int len = ARRAY_SIZE(uvc_fmts);
+	unsigned int i;
+
+	for (i = 0; i < len; ++i) {
+		if (memcmp(guid, uvc_fmts[i].guid, 16) == 0)
+			return &uvc_fmts[i];
+	}
+
+	return NULL;
+}
+
+static __u32 uvc_colorspace(const __u8 primaries)
+{
+	static const __u8 colorprimaries[] = {
+		0,
+		V4L2_COLORSPACE_SRGB,
+		V4L2_COLORSPACE_470_SYSTEM_M,
+		V4L2_COLORSPACE_470_SYSTEM_BG,
+		V4L2_COLORSPACE_SMPTE170M,
+		V4L2_COLORSPACE_SMPTE240M,
+	};
+
+	if (primaries < ARRAY_SIZE(colorprimaries))
+		return colorprimaries[primaries];
+
+	return 0;
+}
+
+/* Simplify a fraction using a simple continued fraction decomposition. The
+ * idea here is to convert fractions such as 333333/10000000 to 1/30 using
+ * 32 bit arithmetic only. The algorithm is not perfect and relies upon two
+ * arbitrary parameters to remove non-significative terms from the simple
+ * continued fraction decomposition. Using 8 and 333 for n_terms and threshold
+ * respectively seems to give nice results.
+ */
+void uvc_simplify_fraction(uint32_t *numerator, uint32_t *denominator,
+		unsigned int n_terms, unsigned int threshold)
+{
+	uint32_t *an;
+	uint32_t x, y, r;
+	unsigned int i, n;
+
+	an = kmalloc(n_terms * sizeof *an, GFP_KERNEL);
+	if (an == NULL)
+		return;
+
+	/* Convert the fraction to a simple continued fraction. See
+	 * http://mathforum.org/dr.math/faq/faq.fractions.html
+	 * Stop if the current term is bigger than or equal to the given
+	 * threshold.
+	 */
+	x = *numerator;
+	y = *denominator;
+
+	for (n = 0; n < n_terms && y != 0; ++n) {
+		an[n] = x / y;
+		if (an[n] >= threshold) {
+			if (n < 2)
+				n++;
+			break;
+		}
+
+		r = x - an[n] * y;
+		x = y;
+		y = r;
+	}
+
+	/* Expand the simple continued fraction back to an integer fraction. */
+	x = 0;
+	y = 1;
+
+	for (i = n; i > 0; --i) {
+		r = y;
+		y = an[i-1] * y + x;
+		x = r;
+	}
+
+	*numerator = y;
+	*denominator = x;
+	kfree(an);
+}
+
+/* Convert a fraction to a frame interval in 100ns multiples. The idea here is
+ * to compute numerator / denominator * 10000000 using 32 bit fixed point
+ * arithmetic only.
+ */
+uint32_t uvc_fraction_to_interval(uint32_t numerator, uint32_t denominator)
+{
+	uint32_t multiplier;
+
+	/* Saturate the result if the operation would overflow. */
+	if (denominator == 0 ||
+	    numerator/denominator >= ((uint32_t)-1)/10000000)
+		return (uint32_t)-1;
+
+	/* Divide both the denominator and the multiplier by two until
+	 * numerator * multiplier doesn't overflow. If anyone knows a better
+	 * algorithm please let me know.
+	 */
+	multiplier = 10000000;
+	while (numerator > ((uint32_t)-1)/multiplier) {
+		multiplier /= 2;
+		denominator /= 2;
+	}
+
+	return denominator ? numerator * multiplier / denominator : 0;
+}
+
+/* ------------------------------------------------------------------------
+ * Terminal and unit management
+ */
+
+static struct uvc_entity *uvc_entity_by_id(struct uvc_device *dev, int id)
+{
+	struct uvc_entity *entity;
+
+	list_for_each_entry(entity, &dev->entities, list) {
+		if (entity->id == id)
+			return entity;
+	}
+
+	return NULL;
+}
+
+static struct uvc_entity *uvc_entity_by_reference(struct uvc_device *dev,
+	int id, struct uvc_entity *entity)
+{
+	unsigned int i;
+
+	if (entity == NULL)
+		entity = list_entry(&dev->entities, struct uvc_entity, list);
+
+	list_for_each_entry_continue(entity, &dev->entities, list) {
+		switch (UVC_ENTITY_TYPE(entity)) {
+		case TT_STREAMING:
+			if (entity->output.bSourceID == id)
+				return entity;
+			break;
+
+		case VC_PROCESSING_UNIT:
+			if (entity->processing.bSourceID == id)
+				return entity;
+			break;
+
+		case VC_SELECTOR_UNIT:
+			for (i = 0; i < entity->selector.bNrInPins; ++i)
+				if (entity->selector.baSourceID[i] == id)
+					return entity;
+			break;
+
+		case VC_EXTENSION_UNIT:
+			for (i = 0; i < entity->extension.bNrInPins; ++i)
+				if (entity->extension.baSourceID[i] == id)
+					return entity;
+			break;
+		}
+	}
+
+	return NULL;
+}
+
+/* ------------------------------------------------------------------------
+ * Descriptors handling
+ */
+
+static int uvc_parse_format(struct uvc_device *dev,
+	struct uvc_streaming *streaming, struct uvc_format *format,
+	__u32 **intervals, unsigned char *buffer, int buflen)
+{
+	struct usb_interface *intf = streaming->intf;
+	struct usb_host_interface *alts = intf->cur_altsetting;
+	struct uvc_format_desc *fmtdesc;
+	struct uvc_frame *frame;
+	const unsigned char *start = buffer;
+	unsigned int interval;
+	unsigned int i, n;
+	__u8 ftype;
+
+	format->type = buffer[2];
+	format->index = buffer[3];
+
+	switch (buffer[2]) {
+	case VS_FORMAT_UNCOMPRESSED:
+	case VS_FORMAT_FRAME_BASED:
+		if (buflen < 27) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+			       "interface %d FORMAT error\n",
+			       dev->udev->devnum,
+			       alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		/* Find the format descriptor from its GUID. */
+		fmtdesc = uvc_format_by_guid(&buffer[5]);
+
+		if (fmtdesc != NULL) {
+			strncpy(format->name, fmtdesc->name,
+				sizeof format->name);
+			format->fcc = fmtdesc->fcc;
+		} else {
+			uvc_printk(KERN_INFO, "Unknown video format "
+				UVC_GUID_FORMAT "\n",
+				UVC_GUID_ARGS(&buffer[5]));
+			snprintf(format->name, sizeof format->name,
+				UVC_GUID_FORMAT, UVC_GUID_ARGS(&buffer[5]));
+			format->fcc = 0;
+		}
+
+		format->bpp = buffer[21];
+		if (buffer[2] == VS_FORMAT_UNCOMPRESSED) {
+			ftype = VS_FRAME_UNCOMPRESSED;
+		} else {
+			ftype = VS_FRAME_FRAME_BASED;
+			if (buffer[27])
+				format->flags = UVC_FMT_FLAG_COMPRESSED;
+		}
+		break;
+
+	case VS_FORMAT_MJPEG:
+		if (buflen < 11) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+			       "interface %d FORMAT error\n",
+			       dev->udev->devnum,
+			       alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		strncpy(format->name, "MJPEG", sizeof format->name);
+		format->fcc = V4L2_PIX_FMT_MJPEG;
+		format->flags = UVC_FMT_FLAG_COMPRESSED;
+		format->bpp = 0;
+		ftype = VS_FRAME_MJPEG;
+		break;
+
+	case VS_FORMAT_DV:
+		if (buflen < 9) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+			       "interface %d FORMAT error\n",
+			       dev->udev->devnum,
+			       alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		switch (buffer[8] & 0x7f) {
+		case 0:
+			strncpy(format->name, "SD-DV", sizeof format->name);
+			break;
+		case 1:
+			strncpy(format->name, "SDL-DV", sizeof format->name);
+			break;
+		case 2:
+			strncpy(format->name, "HD-DV", sizeof format->name);
+			break;
+		default:
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+			       "interface %d: unknown DV format %u\n",
+			       dev->udev->devnum,
+			       alts->desc.bInterfaceNumber, buffer[8]);
+			return -EINVAL;
+		}
+
+		strncat(format->name, buffer[8] & (1 << 7) ? " 60Hz" : " 50Hz",
+			sizeof format->name);
+
+		format->fcc = V4L2_PIX_FMT_DV;
+		format->flags = UVC_FMT_FLAG_COMPRESSED | UVC_FMT_FLAG_STREAM;
+		format->bpp = 0;
+		ftype = 0;
+
+		/* Create a dummy frame descriptor. */
+		frame = &format->frame[0];
+		memset(&format->frame[0], 0, sizeof format->frame[0]);
+		frame->bFrameIntervalType = 1;
+		frame->dwDefaultFrameInterval = 1;
+		frame->dwFrameInterval = *intervals;
+		*(*intervals)++ = 1;
+		format->nframes = 1;
+		break;
+
+	case VS_FORMAT_MPEG2TS:
+	case VS_FORMAT_STREAM_BASED:
+		/* Not supported yet. */
+	default:
+		uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+		       "interface %d unsupported format %u\n",
+		       dev->udev->devnum, alts->desc.bInterfaceNumber,
+		       buffer[2]);
+		return -EINVAL;
+	}
+
+	uvc_trace(UVC_TRACE_DESCR, "Found format %s.\n", format->name);
+
+	buflen -= buffer[0];
+	buffer += buffer[0];
+
+	/* Parse the frame descriptors. Only uncompressed, MJPEG and frame
+	 * based formats have frame descriptors.
+	 */
+	while (buflen > 2 && buffer[2] == ftype) {
+		frame = &format->frame[format->nframes];
+
+		if (ftype != VS_FRAME_FRAME_BASED)
+			n = buflen > 25 ? buffer[25] : 0;
+		else
+			n = buflen > 21 ? buffer[21] : 0;
+
+		n = n ? n : 3;
+
+		if (buflen < 26 + 4*n) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+			       "interface %d FRAME error\n", dev->udev->devnum,
+			       alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		frame->bFrameIndex = buffer[3];
+		frame->bmCapabilities = buffer[4];
+		frame->wWidth = le16_to_cpup((__le16 *)&buffer[5]);
+		frame->wHeight = le16_to_cpup((__le16 *)&buffer[7]);
+		frame->dwMinBitRate = le32_to_cpup((__le32 *)&buffer[9]);
+		frame->dwMaxBitRate = le32_to_cpup((__le32 *)&buffer[13]);
+		if (ftype != VS_FRAME_FRAME_BASED) {
+			frame->dwMaxVideoFrameBufferSize =
+				le32_to_cpup((__le32 *)&buffer[17]);
+			frame->dwDefaultFrameInterval =
+				le32_to_cpup((__le32 *)&buffer[21]);
+			frame->bFrameIntervalType = buffer[25];
+		} else {
+			frame->dwMaxVideoFrameBufferSize = 0;
+			frame->dwDefaultFrameInterval =
+				le32_to_cpup((__le32 *)&buffer[17]);
+			frame->bFrameIntervalType = buffer[21];
+		}
+		frame->dwFrameInterval = *intervals;
+
+		/* Several UVC chipsets screw up dwMaxVideoFrameBufferSize
+		 * completely. Observed behaviours range from setting the
+		 * value to 1.1x the actual frame size of hardwiring the
+		 * 16 low bits to 0. This results in a higher than necessary
+		 * memory usage as well as a wrong image size information. For
+		 * uncompressed formats this can be fixed by computing the
+		 * value from the frame size.
+		 */
+		if (!(format->flags & UVC_FMT_FLAG_COMPRESSED))
+			frame->dwMaxVideoFrameBufferSize = format->bpp
+				* frame->wWidth * frame->wHeight / 8;
+
+		/* Some bogus devices report dwMinFrameInterval equal to
+		 * dwMaxFrameInterval and have dwFrameIntervalStep set to
+		 * zero. Setting all null intervals to 1 fixes the problem and
+		 * some other divisions by zero which could happen.
+		 */
+		for (i = 0; i < n; ++i) {
+			interval = le32_to_cpup((__le32 *)&buffer[26+4*i]);
+			*(*intervals)++ = interval ? interval : 1;
+		}
+
+		/* Make sure that the default frame interval stays between
+		 * the boundaries.
+		 */
+		n -= frame->bFrameIntervalType ? 1 : 2;
+		frame->dwDefaultFrameInterval =
+			min(frame->dwFrameInterval[n],
+			    max(frame->dwFrameInterval[0],
+				frame->dwDefaultFrameInterval));
+
+		uvc_trace(UVC_TRACE_DESCR, "- %ux%u (%u.%u fps)\n",
+			frame->wWidth, frame->wHeight,
+			10000000/frame->dwDefaultFrameInterval,
+			(100000000/frame->dwDefaultFrameInterval)%10);
+
+		format->nframes++;
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	if (buflen > 2 && buffer[2] == VS_STILL_IMAGE_FRAME) {
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	if (buflen > 2 && buffer[2] == VS_COLORFORMAT) {
+		if (buflen < 6) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
+			       "interface %d COLORFORMAT error\n",
+			       dev->udev->devnum,
+			       alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		format->colorspace = uvc_colorspace(buffer[3]);
+
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	return buffer - start;
+}
+
+static int uvc_parse_streaming(struct uvc_device *dev,
+	struct usb_interface *intf)
+{
+	struct uvc_streaming *streaming = NULL;
+	struct uvc_format *format;
+	struct uvc_frame *frame;
+	struct usb_host_interface *alts = &intf->altsetting[0];
+	unsigned char *_buffer, *buffer = alts->extra;
+	int _buflen, buflen = alts->extralen;
+	unsigned int nformats = 0, nframes = 0, nintervals = 0;
+	unsigned int size, i, n, p;
+	__u32 *interval;
+	__u16 psize;
+	int ret = -EINVAL;
+
+	if (intf->cur_altsetting->desc.bInterfaceSubClass
+		!= SC_VIDEOSTREAMING) {
+		uvc_trace(UVC_TRACE_DESCR, "device %d interface %d isn't a "
+			"video streaming interface\n", dev->udev->devnum,
+			intf->altsetting[0].desc.bInterfaceNumber);
+		return -EINVAL;
+	}
+
+	if (usb_driver_claim_interface(&uvc_driver.driver, intf, dev)) {
+		uvc_trace(UVC_TRACE_DESCR, "device %d interface %d is already "
+			"claimed\n", dev->udev->devnum,
+			intf->altsetting[0].desc.bInterfaceNumber);
+		return -EINVAL;
+	}
+
+	streaming = kzalloc(sizeof *streaming, GFP_KERNEL);
+	if (streaming == NULL) {
+		usb_driver_release_interface(&uvc_driver.driver, intf);
+		return -EINVAL;
+	}
+
+	mutex_init(&streaming->mutex);
+	streaming->intf = usb_get_intf(intf);
+	streaming->intfnum = intf->cur_altsetting->desc.bInterfaceNumber;
+
+	/* The Pico iMage webcam has its class-specific interface descriptors
+	 * after the endpoint descriptors.
+	 */
+	if (buflen == 0) {
+		for (i = 0; i < alts->desc.bNumEndpoints; ++i) {
+			struct usb_host_endpoint *ep = &alts->endpoint[i];
+
+			if (ep->extralen == 0)
+				continue;
+
+			if (ep->extralen > 2 &&
+			    ep->extra[1] == USB_DT_CS_INTERFACE) {
+				uvc_trace(UVC_TRACE_DESCR, "trying extra data "
+					"from endpoint %u.\n", i);
+				buffer = alts->endpoint[i].extra;
+				buflen = alts->endpoint[i].extralen;
+				break;
+			}
+		}
+	}
+
+	/* Skip the standard interface descriptors. */
+	while (buflen > 2 && buffer[1] != USB_DT_CS_INTERFACE) {
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	if (buflen <= 2) {
+		uvc_trace(UVC_TRACE_DESCR, "no class-specific streaming "
+			"interface descriptors found.\n");
+		goto error;
+	}
+
+	/* Parse the header descriptor. */
+	if (buffer[2] == VS_OUTPUT_HEADER) {
+		uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming interface "
+			"%d OUTPUT HEADER descriptor is not supported.\n",
+			dev->udev->devnum, alts->desc.bInterfaceNumber);
+		goto error;
+	} else if (buffer[2] == VS_INPUT_HEADER) {
+		p = buflen >= 5 ? buffer[3] : 0;
+		n = buflen >= 12 ? buffer[12] : 0;
+
+		if (buflen < 13 + p*n || buffer[2] != VS_INPUT_HEADER) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming "
+				"interface %d INPUT HEADER descriptor is "
+				"invalid.\n", dev->udev->devnum,
+				alts->desc.bInterfaceNumber);
+			goto error;
+		}
+
+		streaming->header.bNumFormats = p;
+		streaming->header.bEndpointAddress = buffer[6];
+		streaming->header.bmInfo = buffer[7];
+		streaming->header.bTerminalLink = buffer[8];
+		streaming->header.bStillCaptureMethod = buffer[9];
+		streaming->header.bTriggerSupport = buffer[10];
+		streaming->header.bTriggerUsage = buffer[11];
+		streaming->header.bControlSize = n;
+
+		streaming->header.bmaControls = kmalloc(p*n, GFP_KERNEL);
+		if (streaming->header.bmaControls == NULL) {
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		memcpy(streaming->header.bmaControls, &buffer[13], p*n);
+	} else {
+		uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming interface "
+			"%d HEADER descriptor not found.\n", dev->udev->devnum,
+			alts->desc.bInterfaceNumber);
+		goto error;
+	}
+
+	buflen -= buffer[0];
+	buffer += buffer[0];
+
+	_buffer = buffer;
+	_buflen = buflen;
+
+	/* Count the format and frame descriptors. */
+	while (_buflen > 2) {
+		switch (_buffer[2]) {
+		case VS_FORMAT_UNCOMPRESSED:
+		case VS_FORMAT_MJPEG:
+		case VS_FORMAT_FRAME_BASED:
+			nformats++;
+			break;
+
+		case VS_FORMAT_DV:
+			/* DV format has no frame descriptor. We will create a
+			 * dummy frame descriptor with a dummy frame interval.
+			 */
+			nformats++;
+			nframes++;
+			nintervals++;
+			break;
+
+		case VS_FORMAT_MPEG2TS:
+		case VS_FORMAT_STREAM_BASED:
+			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming "
+				"interface %d FORMAT %u is not supported.\n",
+				dev->udev->devnum,
+				alts->desc.bInterfaceNumber, _buffer[2]);
+			break;
+
+		case VS_FRAME_UNCOMPRESSED:
+		case VS_FRAME_MJPEG:
+			nframes++;
+			if (_buflen > 25)
+				nintervals += _buffer[25] ? _buffer[25] : 3;
+			break;
+
+		case VS_FRAME_FRAME_BASED:
+			nframes++;
+			if (_buflen > 21)
+				nintervals += _buffer[21] ? _buffer[21] : 3;
+			break;
+		}
+
+		_buflen -= _buffer[0];
+		_buffer += _buffer[0];
+	}
+
+	if (nformats == 0) {
+		uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming interface "
+			"%d has no supported formats defined.\n",
+			dev->udev->devnum, alts->desc.bInterfaceNumber);
+		goto error;
+	}
+
+	size = nformats * sizeof *format + nframes * sizeof *frame
+	     + nintervals * sizeof *interval;
+	format = kzalloc(size, GFP_KERNEL);
+	if (format == NULL) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	frame = (struct uvc_frame *)&format[nformats];
+	interval = (__u32 *)&frame[nframes];
+
+	streaming->format = format;
+	streaming->nformats = nformats;
+
+	/* Parse the format descriptors. */
+	while (buflen > 2) {
+		switch (buffer[2]) {
+		case VS_FORMAT_UNCOMPRESSED:
+		case VS_FORMAT_MJPEG:
+		case VS_FORMAT_DV:
+		case VS_FORMAT_FRAME_BASED:
+			format->frame = frame;
+			ret = uvc_parse_format(dev, streaming, format,
+				&interval, buffer, buflen);
+			if (ret < 0)
+				goto error;
+
+			frame += format->nframes;
+			format++;
+
+			buflen -= ret;
+			buffer += ret;
+			continue;
+
+		default:
+			break;
+		}
+
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	/* Parse the alternate settings to find the maximum bandwidth. */
+	for (i = 0; i < intf->num_altsetting; ++i) {
+		struct usb_host_endpoint *ep;
+		alts = &intf->altsetting[i];
+		ep = uvc_find_endpoint(alts,
+				streaming->header.bEndpointAddress);
+		if (ep == NULL)
+			continue;
+
+		psize = le16_to_cpu(ep->desc.wMaxPacketSize);
+		psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
+		if (psize > streaming->maxpsize)
+			streaming->maxpsize = psize;
+	}
+
+	list_add_tail(&streaming->list, &dev->streaming);
+	return 0;
+
+error:
+	usb_driver_release_interface(&uvc_driver.driver, intf);
+	usb_put_intf(intf);
+	kfree(streaming->format);
+	kfree(streaming->header.bmaControls);
+	kfree(streaming);
+	return ret;
+}
+
+/* Parse vendor-specific extensions. */
+static int uvc_parse_vendor_control(struct uvc_device *dev,
+	const unsigned char *buffer, int buflen)
+{
+	struct usb_device *udev = dev->udev;
+	struct usb_host_interface *alts = dev->intf->cur_altsetting;
+	struct uvc_entity *unit;
+	unsigned int n, p;
+	int handled = 0;
+
+	switch (le16_to_cpu(dev->udev->descriptor.idVendor)) {
+	case 0x046d:		/* Logitech */
+		if (buffer[1] != 0x41 || buffer[2] != 0x01)
+			break;
+
+		/* Logitech implements several vendor specific functions
+		 * through vendor specific extension units (LXU).
+		 *
+		 * The LXU descriptors are similar to XU descriptors
+		 * (see "USB Device Video Class for Video Devices", section
+		 * 3.7.2.6 "Extension Unit Descriptor") with the following
+		 * differences:
+		 *
+		 * ----------------------------------------------------------
+		 * 0		bLength		1	 Number
+		 *	Size of this descriptor, in bytes: 24+p+n*2
+		 * ----------------------------------------------------------
+		 * 23+p+n	bmControlsType	N	Bitmap
+		 * 	Individual bits in the set are defined:
+		 * 	0: Absolute
+		 * 	1: Relative
+		 *
+		 * 	This bitset is mapped exactly the same as bmControls.
+		 * ----------------------------------------------------------
+		 * 23+p+n*2	bReserved	1	Boolean
+		 * ----------------------------------------------------------
+		 * 24+p+n*2	iExtension	1	Index
+		 *	Index of a string descriptor that describes this
+		 *	extension unit.
+		 * ----------------------------------------------------------
+		 */
+		p = buflen >= 22 ? buffer[21] : 0;
+		n = buflen >= 25 + p ? buffer[22+p] : 0;
+
+		if (buflen < 25 + p + 2*n) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d EXTENSION_UNIT error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			break;
+		}
+
+		unit = kzalloc(sizeof *unit + p + 2*n, GFP_KERNEL);
+		if (unit == NULL)
+			return -ENOMEM;
+
+		unit->id = buffer[3];
+		unit->type = VC_EXTENSION_UNIT;
+		memcpy(unit->extension.guidExtensionCode, &buffer[4], 16);
+		unit->extension.bNumControls = buffer[20];
+		unit->extension.bNrInPins =
+			le16_to_cpup((__le16 *)&buffer[21]);
+		unit->extension.baSourceID = (__u8 *)unit + sizeof *unit;
+		memcpy(unit->extension.baSourceID, &buffer[22], p);
+		unit->extension.bControlSize = buffer[22+p];
+		unit->extension.bmControls = (__u8 *)unit + sizeof *unit + p;
+		unit->extension.bmControlsType = (__u8 *)unit + sizeof *unit
+					       + p + n;
+		memcpy(unit->extension.bmControls, &buffer[23+p], 2*n);
+
+		if (buffer[24+p+2*n] != 0)
+			usb_string(udev, buffer[24+p+2*n], unit->name,
+				   sizeof unit->name);
+		else
+			sprintf(unit->name, "Extension %u", buffer[3]);
+
+		list_add_tail(&unit->list, &dev->entities);
+		handled = 1;
+		break;
+	}
+
+	return handled;
+}
+
+static int uvc_parse_standard_control(struct uvc_device *dev,
+	const unsigned char *buffer, int buflen)
+{
+	struct usb_device *udev = dev->udev;
+	struct uvc_entity *unit, *term;
+	struct usb_interface *intf;
+	struct usb_host_interface *alts = dev->intf->cur_altsetting;
+	unsigned int i, n, p, len;
+	__u16 type;
+
+	switch (buffer[2]) {
+	case VC_HEADER:
+		n = buflen >= 12 ? buffer[11] : 0;
+
+		if (buflen < 12 || buflen < 12 + n) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d HEADER error\n", udev->devnum,
+				alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		dev->uvc_version = le16_to_cpup((__le16 *)&buffer[3]);
+		dev->clock_frequency = le32_to_cpup((__le32 *)&buffer[7]);
+
+		/* Parse all USB Video Streaming interfaces. */
+		for (i = 0; i < n; ++i) {
+			intf = usb_ifnum_to_if(udev, buffer[12+i]);
+			if (intf == NULL) {
+				uvc_trace(UVC_TRACE_DESCR, "device %d "
+					"interface %d doesn't exists\n",
+					udev->devnum, i);
+				continue;
+			}
+
+			uvc_parse_streaming(dev, intf);
+		}
+		break;
+
+	case VC_INPUT_TERMINAL:
+		if (buflen < 8) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d INPUT_TERMINAL error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		/* Make sure the terminal type MSB is not null, otherwise it
+		 * could be confused with a unit.
+		 */
+		type = le16_to_cpup((__le16 *)&buffer[4]);
+		if ((type & 0xff00) == 0) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d INPUT_TERMINAL %d has invalid "
+				"type 0x%04x, skipping\n", udev->devnum,
+				alts->desc.bInterfaceNumber,
+				buffer[3], type);
+			return 0;
+		}
+
+		n = 0;
+		p = 0;
+		len = 8;
+
+		if (type == ITT_CAMERA) {
+			n = buflen >= 15 ? buffer[14] : 0;
+			len = 15;
+
+		} else if (type == ITT_MEDIA_TRANSPORT_INPUT) {
+			n = buflen >= 9 ? buffer[8] : 0;
+			p = buflen >= 10 + n ? buffer[9+n] : 0;
+			len = 10;
+		}
+
+		if (buflen < len + n + p) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d INPUT_TERMINAL error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		term = kzalloc(sizeof *term + n + p, GFP_KERNEL);
+		if (term == NULL)
+			return -ENOMEM;
+
+		term->id = buffer[3];
+		term->type = type | UVC_TERM_INPUT;
+
+		if (UVC_ENTITY_TYPE(term) == ITT_CAMERA) {
+			term->camera.bControlSize = n;
+			term->camera.bmControls = (__u8 *)term + sizeof *term;
+			term->camera.wObjectiveFocalLengthMin =
+				le16_to_cpup((__le16 *)&buffer[8]);
+			term->camera.wObjectiveFocalLengthMax =
+				le16_to_cpup((__le16 *)&buffer[10]);
+			term->camera.wOcularFocalLength =
+				le16_to_cpup((__le16 *)&buffer[12]);
+			memcpy(term->camera.bmControls, &buffer[15], n);
+		} else if (UVC_ENTITY_TYPE(term) == ITT_MEDIA_TRANSPORT_INPUT) {
+			term->media.bControlSize = n;
+			term->media.bmControls = (__u8 *)term + sizeof *term;
+			term->media.bTransportModeSize = p;
+			term->media.bmTransportModes = (__u8 *)term
+						     + sizeof *term + n;
+			memcpy(term->media.bmControls, &buffer[9], n);
+			memcpy(term->media.bmTransportModes, &buffer[10+n], p);
+		}
+
+		if (buffer[7] != 0)
+			usb_string(udev, buffer[7], term->name,
+				   sizeof term->name);
+		else if (UVC_ENTITY_TYPE(term) == ITT_CAMERA)
+			sprintf(term->name, "Camera %u", buffer[3]);
+		else if (UVC_ENTITY_TYPE(term) == ITT_MEDIA_TRANSPORT_INPUT)
+			sprintf(term->name, "Media %u", buffer[3]);
+		else
+			sprintf(term->name, "Input %u", buffer[3]);
+
+		list_add_tail(&term->list, &dev->entities);
+		break;
+
+	case VC_OUTPUT_TERMINAL:
+		if (buflen < 9) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d OUTPUT_TERMINAL error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		/* Make sure the terminal type MSB is not null, otherwise it
+		 * could be confused with a unit.
+		 */
+		type = le16_to_cpup((__le16 *)&buffer[4]);
+		if ((type & 0xff00) == 0) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d OUTPUT_TERMINAL %d has invalid "
+				"type 0x%04x, skipping\n", udev->devnum,
+				alts->desc.bInterfaceNumber, buffer[3], type);
+			return 0;
+		}
+
+		term = kzalloc(sizeof *term, GFP_KERNEL);
+		if (term == NULL)
+			return -ENOMEM;
+
+		term->id = buffer[3];
+		term->type = type | UVC_TERM_OUTPUT;
+		term->output.bSourceID = buffer[7];
+
+		if (buffer[8] != 0)
+			usb_string(udev, buffer[8], term->name,
+				   sizeof term->name);
+		else
+			sprintf(term->name, "Output %u", buffer[3]);
+
+		list_add_tail(&term->list, &dev->entities);
+		break;
+
+	case VC_SELECTOR_UNIT:
+		p = buflen >= 5 ? buffer[4] : 0;
+
+		if (buflen < 5 || buflen < 6 + p) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d SELECTOR_UNIT error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		unit = kzalloc(sizeof *unit + p, GFP_KERNEL);
+		if (unit == NULL)
+			return -ENOMEM;
+
+		unit->id = buffer[3];
+		unit->type = buffer[2];
+		unit->selector.bNrInPins = buffer[4];
+		unit->selector.baSourceID = (__u8 *)unit + sizeof *unit;
+		memcpy(unit->selector.baSourceID, &buffer[5], p);
+
+		if (buffer[5+p] != 0)
+			usb_string(udev, buffer[5+p], unit->name,
+				   sizeof unit->name);
+		else
+			sprintf(unit->name, "Selector %u", buffer[3]);
+
+		list_add_tail(&unit->list, &dev->entities);
+		break;
+
+	case VC_PROCESSING_UNIT:
+		n = buflen >= 8 ? buffer[7] : 0;
+		p = dev->uvc_version >= 0x0110 ? 10 : 9;
+
+		if (buflen < p + n) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d PROCESSING_UNIT error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		unit = kzalloc(sizeof *unit + n, GFP_KERNEL);
+		if (unit == NULL)
+			return -ENOMEM;
+
+		unit->id = buffer[3];
+		unit->type = buffer[2];
+		unit->processing.bSourceID = buffer[4];
+		unit->processing.wMaxMultiplier =
+			le16_to_cpup((__le16 *)&buffer[5]);
+		unit->processing.bControlSize = buffer[7];
+		unit->processing.bmControls = (__u8 *)unit + sizeof *unit;
+		memcpy(unit->processing.bmControls, &buffer[8], n);
+		if (dev->uvc_version >= 0x0110)
+			unit->processing.bmVideoStandards = buffer[9+n];
+
+		if (buffer[8+n] != 0)
+			usb_string(udev, buffer[8+n], unit->name,
+				   sizeof unit->name);
+		else
+			sprintf(unit->name, "Processing %u", buffer[3]);
+
+		list_add_tail(&unit->list, &dev->entities);
+		break;
+
+	case VC_EXTENSION_UNIT:
+		p = buflen >= 22 ? buffer[21] : 0;
+		n = buflen >= 24 + p ? buffer[22+p] : 0;
+
+		if (buflen < 24 + p + n) {
+			uvc_trace(UVC_TRACE_DESCR, "device %d videocontrol "
+				"interface %d EXTENSION_UNIT error\n",
+				udev->devnum, alts->desc.bInterfaceNumber);
+			return -EINVAL;
+		}
+
+		unit = kzalloc(sizeof *unit + p + n, GFP_KERNEL);
+		if (unit == NULL)
+			return -ENOMEM;
+
+		unit->id = buffer[3];
+		unit->type = buffer[2];
+		memcpy(unit->extension.guidExtensionCode, &buffer[4], 16);
+		unit->extension.bNumControls = buffer[20];
+		unit->extension.bNrInPins =
+			le16_to_cpup((__le16 *)&buffer[21]);
+		unit->extension.baSourceID = (__u8 *)unit + sizeof *unit;
+		memcpy(unit->extension.baSourceID, &buffer[22], p);
+		unit->extension.bControlSize = buffer[22+p];
+		unit->extension.bmControls = (__u8 *)unit + sizeof *unit + p;
+		memcpy(unit->extension.bmControls, &buffer[23+p], n);
+
+		if (buffer[23+p+n] != 0)
+			usb_string(udev, buffer[23+p+n], unit->name,
+				   sizeof unit->name);
+		else
+			sprintf(unit->name, "Extension %u", buffer[3]);
+
+		list_add_tail(&unit->list, &dev->entities);
+		break;
+
+	default:
+		uvc_trace(UVC_TRACE_DESCR, "Found an unknown CS_INTERFACE "
+			"descriptor (%u)\n", buffer[2]);
+		break;
+	}
+
+	return 0;
+}
+
+static int uvc_parse_control(struct uvc_device *dev)
+{
+	struct usb_host_interface *alts = dev->intf->cur_altsetting;
+	unsigned char *buffer = alts->extra;
+	int buflen = alts->extralen;
+	int ret;
+
+	/* Parse the default alternate setting only, as the UVC specification
+	 * defines a single alternate setting, the default alternate setting
+	 * zero.
+	 */
+
+	while (buflen > 2) {
+		if (uvc_parse_vendor_control(dev, buffer, buflen) ||
+		    buffer[1] != USB_DT_CS_INTERFACE)
+			goto next_descriptor;
+
+		if ((ret = uvc_parse_standard_control(dev, buffer, buflen)) < 0)
+			return ret;
+
+next_descriptor:
+		buflen -= buffer[0];
+		buffer += buffer[0];
+	}
+
+	/* Check if the optional status endpoint is present. */
+	if (alts->desc.bNumEndpoints == 1) {
+		struct usb_host_endpoint *ep = &alts->endpoint[0];
+		struct usb_endpoint_descriptor *desc = &ep->desc;
+
+		if (usb_endpoint_is_int_in(desc) &&
+		    le16_to_cpu(desc->wMaxPacketSize) >= 8 &&
+		    desc->bInterval != 0) {
+			uvc_trace(UVC_TRACE_DESCR, "Found a Status endpoint "
+				"(addr %02x).\n", desc->bEndpointAddress);
+			dev->int_ep = ep;
+		}
+	}
+
+	return 0;
+}
+
+/* ------------------------------------------------------------------------
+ * USB probe and disconnect
+ */
+
+/*
+ * Unregister the video devices.
+ */
+static void uvc_unregister_video(struct uvc_device *dev)
+{
+	if (dev->video.vdev) {
+		if (dev->video.vdev->minor == -1)
+			video_device_release(dev->video.vdev);
+		else
+			video_unregister_device(dev->video.vdev);
+		dev->video.vdev = NULL;
+	}
+}
+
+/*
+ * Scan the UVC descriptors to locate a chain starting at an Output Terminal
+ * and containing the following units:
+ *
+ * - a USB Streaming Output Terminal
+ * - zero or one Processing Unit
+ * - zero, one or mode single-input Selector Units
+ * - zero or one multiple-input Selector Units, provided all inputs are
+ *   connected to input terminals
+ * - zero, one or mode single-input Extension Units
+ * - one Camera Input Terminal, or one or more External terminals.
+ *
+ * A side forward scan is made on each detected entity to check for additional
+ * extension units.
+ */
+static int uvc_scan_chain_entity(struct uvc_video_device *video,
+	struct uvc_entity *entity)
+{
+	switch (UVC_ENTITY_TYPE(entity)) {
+	case VC_EXTENSION_UNIT:
+		if (uvc_trace_param & UVC_TRACE_PROBE)
+			printk(" <- XU %d", entity->id);
+
+		if (entity->extension.bNrInPins != 1) {
+			uvc_trace(UVC_TRACE_DESCR, "Extension unit %d has more "
+				"than 1 input pin.\n", entity->id);
+			return -1;
+		}
+
+		list_add_tail(&entity->chain, &video->extensions);
+		break;
+
+	case VC_PROCESSING_UNIT:
+		if (uvc_trace_param & UVC_TRACE_PROBE)
+			printk(" <- PU %d", entity->id);
+
+		if (video->processing != NULL) {
+			uvc_trace(UVC_TRACE_DESCR, "Found multiple "
+				"Processing Units in chain.\n");
+			return -1;
+		}
+
+		video->processing = entity;
+		break;
+
+	case VC_SELECTOR_UNIT:
+		if (uvc_trace_param & UVC_TRACE_PROBE)
+			printk(" <- SU %d", entity->id);
+
+		/* Single-input selector units are ignored. */
+		if (entity->selector.bNrInPins == 1)
+			break;
+
+		if (video->selector != NULL) {
+			uvc_trace(UVC_TRACE_DESCR, "Found multiple Selector "
+				"Units in chain.\n");
+			return -1;
+		}
+
+		video->selector = entity;
+		break;
+
+	case ITT_VENDOR_SPECIFIC:
+	case ITT_CAMERA:
+	case ITT_MEDIA_TRANSPORT_INPUT:
+		if (uvc_trace_param & UVC_TRACE_PROBE)
+			printk(" <- IT %d\n", entity->id);
+
+		list_add_tail(&entity->chain, &video->iterms);
+		break;
+
+	default:
+		uvc_trace(UVC_TRACE_DESCR, "Unsupported entity type "
+			"0x%04x found in chain.\n", UVC_ENTITY_TYPE(entity));
+		return -1;
+	}
+
+	return 0;
+}
+
+static int uvc_scan_chain_forward(struct uvc_video_device *video,
+	struct uvc_entity *entity, struct uvc_entity *prev)
+{
+	struct uvc_entity *forward;
+	int found;
+
+	/* Forward scan */
+	forward = NULL;
+	found = 0;
+
+	while (1) {
+		forward = uvc_entity_by_reference(video->dev, entity->id,
+			forward);
+		if (forward == NULL)
+			break;
+
+		if (UVC_ENTITY_TYPE(forward) != VC_EXTENSION_UNIT ||
+		    forward == prev)
+			continue;
+
+		if (forward->extension.bNrInPins != 1) {
+			uvc_trace(UVC_TRACE_DESCR, "Extension unit %d has"
+				"more than 1 input pin.\n", entity->id);
+			return -1;
+		}
+
+		list_add_tail(&forward->chain, &video->extensions);
+		if (uvc_trace_param & UVC_TRACE_PROBE) {
+			if (!found)
+				printk(" (-> XU");
+
+			printk(" %d", forward->id);
+			found = 1;
+		}
+	}
+	if (found)
+		printk(")");
+
+	return 0;
+}
+
+static int uvc_scan_chain_backward(struct uvc_video_device *video,
+	struct uvc_entity *entity)
+{
+	struct uvc_entity *term;
+	int id = -1, i;
+
+	switch (UVC_ENTITY_TYPE(entity)) {
+	case VC_EXTENSION_UNIT:
+		id = entity->extension.baSourceID[0];
+		break;
+
+	case VC_PROCESSING_UNIT:
+		id = entity->processing.bSourceID;
+		break;
+
+	case VC_SELECTOR_UNIT:
+		/* Single-input selector units are ignored. */
+		if (entity->selector.bNrInPins == 1) {
+			id = entity->selector.baSourceID[0];
+			break;
+		}
+
+		if (uvc_trace_param & UVC_TRACE_PROBE)
+			printk(" <- IT");
+
+		video->selector = entity;
+		for (i = 0; i < entity->selector.bNrInPins; ++i) {
+			id = entity->selector.baSourceID[i];
+			term = uvc_entity_by_id(video->dev, id);
+			if (term == NULL || !UVC_ENTITY_IS_ITERM(term)) {
+				uvc_trace(UVC_TRACE_DESCR, "Selector unit %d "
+					"input %d isn't connected to an "
+					"input terminal\n", entity->id, i);
+				return -1;
+			}
+
+			if (uvc_trace_param & UVC_TRACE_PROBE)
+				printk(" %d", term->id);
+
+			list_add_tail(&term->chain, &video->iterms);
+			uvc_scan_chain_forward(video, term, entity);
+		}
+
+		if (uvc_trace_param & UVC_TRACE_PROBE)
+			printk("\n");
+
+		id = 0;
+		break;
+	}
+
+	return id;
+}
+
+static int uvc_scan_chain(struct uvc_video_device *video)
+{
+	struct uvc_entity *entity, *prev;
+	int id;
+
+	entity = video->oterm;
+	uvc_trace(UVC_TRACE_PROBE, "Scanning UVC chain: OT %d", entity->id);
+	id = entity->output.bSourceID;
+	while (id != 0) {
+		prev = entity;
+		entity = uvc_entity_by_id(video->dev, id);
+		if (entity == NULL) {
+			uvc_trace(UVC_TRACE_DESCR, "Found reference to "
+				"unknown entity %d.\n", id);
+			return -1;
+		}
+
+		/* Process entity */
+		if (uvc_scan_chain_entity(video, entity) < 0)
+			return -1;
+
+		/* Forward scan */
+		if (uvc_scan_chain_forward(video, entity, prev) < 0)
+			return -1;
+
+		/* Stop when a terminal is found. */
+		if (!UVC_ENTITY_IS_UNIT(entity))
+			break;
+
+		/* Backward scan */
+		id = uvc_scan_chain_backward(video, entity);
+		if (id < 0)
+			return id;
+	}
+
+	/* Initialize the video buffers queue. */
+	uvc_queue_init(&video->queue);
+
+	return 0;
+}
+
+/*
+ * Register the video devices.
+ *
+ * The driver currently supports a single video device per control interface
+ * only. The terminal and units must match the following structure:
+ *
+ * ITT_CAMERA -> VC_PROCESSING_UNIT -> VC_EXTENSION_UNIT{0,n} -> TT_STREAMING
+ *
+ * The Extension Units, if present, must have a single input pin. The
+ * Processing Unit and Extension Units can be in any order. Additional
+ * Extension Units connected to the main chain as single-unit branches are
+ * also supported.
+ */
+static int uvc_register_video(struct uvc_device *dev)
+{
+	struct video_device *vdev;
+	struct uvc_entity *term;
+	int found = 0, ret;
+
+	/* Check if the control interface matches the structure we expect. */
+	list_for_each_entry(term, &dev->entities, list) {
+		struct uvc_streaming *streaming;
+
+		if (UVC_ENTITY_TYPE(term) != TT_STREAMING)
+			continue;
+
+		memset(&dev->video, 0, sizeof dev->video);
+		mutex_init(&dev->video.ctrl_mutex);
+		INIT_LIST_HEAD(&dev->video.iterms);
+		INIT_LIST_HEAD(&dev->video.extensions);
+		dev->video.oterm = term;
+		dev->video.dev = dev;
+		if (uvc_scan_chain(&dev->video) < 0)
+			continue;
+
+		list_for_each_entry(streaming, &dev->streaming, list) {
+			if (streaming->header.bTerminalLink == term->id) {
+				dev->video.streaming = streaming;
+				found = 1;
+				break;
+			}
+		}
+
+		if (found)
+			break;
+	}
+
+	if (!found) {
+		uvc_printk(KERN_INFO, "No valid video chain found.\n");
+		return -1;
+	}
+
+	if (uvc_trace_param & UVC_TRACE_PROBE) {
+		uvc_printk(KERN_INFO, "Found a valid video chain (");
+		list_for_each_entry(term, &dev->video.iterms, chain) {
+			printk("%d", term->id);
+			if (term->chain.next != &dev->video.iterms)
+				printk(",");
+		}
+		printk(" -> %d).\n", dev->video.oterm->id);
+	}
+
+	/* Initialize the streaming interface with default streaming
+	 * parameters.
+	 */
+	if ((ret = uvc_video_init(&dev->video)) < 0) {
+		uvc_printk(KERN_ERR, "Failed to initialize the device "
+			"(%d).\n", ret);
+		return ret;
+	}
+
+	/* Register the device with V4L. */
+	vdev = video_device_alloc();
+	if (vdev == NULL)
+		return -1;
+
+	/* We already hold a reference to dev->udev. The video device will be
+	 * unregistered before the reference is released, so we don't need to
+	 * get another one.
+	 */
+	vdev->dev = &dev->intf->dev;
+	vdev->type = 0;
+	vdev->type2 = 0;
+	vdev->minor = -1;
+	vdev->fops = &uvc_fops;
+	vdev->release = video_device_release;
+	strncpy(vdev->name, dev->name, sizeof vdev->name);
+
+	/* Set the driver data before calling video_register_device, otherwise
+	 * uvc_v4l2_open might race us.
+	 *
+	 * FIXME: usb_set_intfdata hasn't been called so far. Is that a
+	 * 	  problem ? Does any function which could be called here get
+	 * 	  a pointer to the usb_interface ?
+	 */
+	dev->video.vdev = vdev;
+	video_set_drvdata(vdev, &dev->video);
+
+	if (video_register_device(vdev, VFL_TYPE_GRABBER, -1) < 0) {
+		dev->video.vdev = NULL;
+		video_device_release(vdev);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Delete the UVC device.
+ *
+ * Called by the kernel when the last reference to the uvc_device structure
+ * is released.
+ *
+ * Unregistering the video devices is done here because every opened instance
+ * must be closed before the device can be unregistered. An alternative would
+ * have been to use another reference count for uvc_v4l2_open/uvc_release, and
+ * unregister the video devices on disconnect when that reference count drops
+ * to zero.
+ *
+ * As this function is called after or during disconnect(), all URBs have
+ * already been canceled by the USB core. There is no need to kill the
+ * interrupt URB manually.
+ */
+void uvc_delete(struct kref *kref)
+{
+	struct uvc_device *dev = container_of(kref, struct uvc_device, kref);
+	struct list_head *p, *n;
+
+	/* Unregister the video device */
+	uvc_unregister_video(dev);
+	usb_put_intf(dev->intf);
+	usb_put_dev(dev->udev);
+
+	uvc_status_cleanup(dev);
+	uvc_ctrl_cleanup_device(dev);
+
+	list_for_each_safe(p, n, &dev->entities) {
+		struct uvc_entity *entity;
+		entity = list_entry(p, struct uvc_entity, list);
+		kfree(entity);
+	}
+
+	list_for_each_safe(p, n, &dev->streaming) {
+		struct uvc_streaming *streaming;
+		streaming = list_entry(p, struct uvc_streaming, list);
+		usb_driver_release_interface(&uvc_driver.driver,
+			streaming->intf);
+		usb_put_intf(streaming->intf);
+		kfree(streaming->format);
+		kfree(streaming->header.bmaControls);
+		kfree(streaming);
+	}
+
+	kfree(dev);
+}
+
+static int uvc_probe(struct usb_interface *intf,
+		     const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct uvc_device *dev;
+	int ret;
+
+	if (id->idVendor && id->idProduct)
+		uvc_trace(UVC_TRACE_PROBE, "Probing known UVC device %s "
+				"(%04x:%04x)\n", udev->devpath, id->idVendor,
+				id->idProduct);
+	else
+		uvc_trace(UVC_TRACE_PROBE, "Probing generic UVC device %s\n",
+				udev->devpath);
+
+	/* Allocate memory for the device and initialize it */
+	if ((dev = kzalloc(sizeof *dev, GFP_KERNEL)) == NULL)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&dev->entities);
+	INIT_LIST_HEAD(&dev->streaming);
+	kref_init(&dev->kref);
+
+	dev->udev = usb_get_dev(udev);
+	dev->intf = usb_get_intf(intf);
+	dev->intfnum = intf->cur_altsetting->desc.bInterfaceNumber;
+	dev->quirks = id->driver_info | uvc_quirks_param;
+
+	if (udev->product != NULL)
+		strncpy(dev->name, udev->product, sizeof dev->name);
+	else
+		snprintf(dev->name, sizeof dev->name,
+			"UVC Camera (%04x:%04x)",
+			le16_to_cpu(udev->descriptor.idVendor),
+			le16_to_cpu(udev->descriptor.idProduct));
+
+	/* Parse the Video Class control descriptor */
+	if (uvc_parse_control(dev) < 0) {
+		uvc_trace(UVC_TRACE_PROBE, "Unable to parse UVC "
+			"descriptors.\n");
+		goto error;
+	}
+
+	uvc_printk(KERN_INFO, "Found UVC %u.%02u device %s (%04x:%04x)\n",
+		dev->uvc_version >> 8, dev->uvc_version & 0xff,
+		udev->product ? udev->product : "<unnamed>",
+		le16_to_cpu(udev->descriptor.idVendor),
+		le16_to_cpu(udev->descriptor.idProduct));
+
+	if (uvc_quirks_param != 0) {
+		uvc_printk(KERN_INFO, "Forcing device quirks 0x%x by module "
+			"parameter for testing purpose.\n", uvc_quirks_param);
+		uvc_printk(KERN_INFO, "Please report required quirks to the "
+			"linux-uvc-devel mailing list.\n");
+	}
+
+	/* Initialize controls */
+	if (uvc_ctrl_init_device(dev) < 0)
+		goto error;
+
+	/* Register the video devices */
+	if (uvc_register_video(dev) < 0)
+		goto error;
+
+	/* Save our data pointer in the interface data */
+	usb_set_intfdata(intf, dev);
+
+	/* Initialize the interrupt URB */
+	if ((ret = uvc_status_init(dev)) < 0) {
+		uvc_printk(KERN_INFO, "Unable to initialize the status "
+			"endpoint (%d), status interrupt will not be "
+			"supported.\n", ret);
+	}
+
+	uvc_trace(UVC_TRACE_PROBE, "UVC device initialized.\n");
+	return 0;
+
+error:
+	kref_put(&dev->kref, uvc_delete);
+	return -ENODEV;
+}
+
+static void uvc_disconnect(struct usb_interface *intf)
+{
+	struct uvc_device *dev = usb_get_intfdata(intf);
+
+	/* Set the USB interface data to NULL. This can be done outside the
+	 * lock, as there's no other reader.
+	 */
+	usb_set_intfdata(intf, NULL);
+
+	if (intf->cur_altsetting->desc.bInterfaceSubClass == SC_VIDEOSTREAMING)
+		return;
+
+	/* uvc_v4l2_open() might race uvc_disconnect(). A static driver-wide
+	 * lock is needed to prevent uvc_disconnect from releasing its
+	 * reference to the uvc_device instance after uvc_v4l2_open() received
+	 * the pointer to the device (video_devdata) but before it got the
+	 * chance to increase the reference count (kref_get).
+	 */
+	mutex_lock(&uvc_driver.open_mutex);
+
+	dev->state |= UVC_DEV_DISCONNECTED;
+	kref_put(&dev->kref, uvc_delete);
+
+	mutex_unlock(&uvc_driver.open_mutex);
+}
+
+static int uvc_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct uvc_device *dev = usb_get_intfdata(intf);
+
+	uvc_trace(UVC_TRACE_SUSPEND, "Suspending interface %u\n",
+		intf->cur_altsetting->desc.bInterfaceNumber);
+
+	/* Controls are cached on the fly so they don't need to be saved. */
+	if (intf->cur_altsetting->desc.bInterfaceSubClass == SC_VIDEOCONTROL)
+		return uvc_status_suspend(dev);
+
+	if (dev->video.streaming->intf != intf) {
+		uvc_trace(UVC_TRACE_SUSPEND, "Suspend: video streaming USB "
+				"interface mismatch.\n");
+		return -EINVAL;
+	}
+
+	return uvc_video_suspend(&dev->video);
+}
+
+static int uvc_resume(struct usb_interface *intf)
+{
+	struct uvc_device *dev = usb_get_intfdata(intf);
+	int ret;
+
+	uvc_trace(UVC_TRACE_SUSPEND, "Resuming interface %u\n",
+		intf->cur_altsetting->desc.bInterfaceNumber);
+
+	if (intf->cur_altsetting->desc.bInterfaceSubClass == SC_VIDEOCONTROL) {
+		if ((ret = uvc_ctrl_resume_device(dev)) < 0)
+			return ret;
+
+		return uvc_status_resume(dev);
+	}
+
+	if (dev->video.streaming->intf != intf) {
+		uvc_trace(UVC_TRACE_SUSPEND, "Resume: video streaming USB "
+				"interface mismatch.\n");
+		return -EINVAL;
+	}
+
+	return uvc_video_resume(&dev->video);
+}
+
+/* ------------------------------------------------------------------------
+ * Driver initialization and cleanup
+ */
+
+/*
+ * The Logitech cameras listed below have their interface class set to
+ * VENDOR_SPEC because they don't announce themselves as UVC devices, even
+ * though they are compliant.
+ */
+static struct usb_device_id uvc_ids[] = {
+	/* ALi M5606 (Clevo M540SR) */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x0402,
+	  .idProduct		= 0x5606,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Creative Live! Optia */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x041e,
+	  .idProduct		= 0x4057,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Microsoft Lifecam NX-6000 */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x045e,
+	  .idProduct		= 0x00f8,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Microsoft Lifecam VX-7000 */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x045e,
+	  .idProduct		= 0x0723,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Logitech Quickcam Fusion */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x046d,
+	  .idProduct		= 0x08c1,
+	  .bInterfaceClass	= USB_CLASS_VENDOR_SPEC,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0 },
+	/* Logitech Quickcam Orbit MP */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x046d,
+	  .idProduct		= 0x08c2,
+	  .bInterfaceClass	= USB_CLASS_VENDOR_SPEC,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0 },
+	/* Logitech Quickcam Pro for Notebook */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x046d,
+	  .idProduct		= 0x08c3,
+	  .bInterfaceClass	= USB_CLASS_VENDOR_SPEC,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0 },
+	/* Logitech Quickcam Pro 5000 */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x046d,
+	  .idProduct		= 0x08c5,
+	  .bInterfaceClass	= USB_CLASS_VENDOR_SPEC,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0 },
+	/* Logitech Quickcam OEM Dell Notebook */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x046d,
+	  .idProduct		= 0x08c6,
+	  .bInterfaceClass	= USB_CLASS_VENDOR_SPEC,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0 },
+	/* Logitech Quickcam OEM Cisco VT Camera II */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x046d,
+	  .idProduct		= 0x08c7,
+	  .bInterfaceClass	= USB_CLASS_VENDOR_SPEC,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0 },
+	/* Apple Built-In iSight */
+	{ .match_flags          = USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x05ac,
+	  .idProduct		= 0x8501,
+	  .bInterfaceClass      = USB_CLASS_VIDEO,
+	  .bInterfaceSubClass   = 1,
+	  .bInterfaceProtocol   = 0,
+	  .driver_info 		= UVC_QUIRK_PROBE_MINMAX
+				| UVC_QUIRK_BUILTIN_ISIGHT },
+	/* Genesys Logic USB 2.0 PC Camera */
+	{ .match_flags          = USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor             = 0x05e3,
+	  .idProduct            = 0x0505,
+	  .bInterfaceClass      = USB_CLASS_VIDEO,
+	  .bInterfaceSubClass   = 1,
+	  .bInterfaceProtocol   = 0,
+	  .driver_info          = UVC_QUIRK_STREAM_NO_FID },
+	/* Silicon Motion SM371 */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x090c,
+	  .idProduct		= 0xb371,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* MT6227 */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x0e8d,
+	  .idProduct		= 0x0004,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Syntek (HP Spartan) */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x174f,
+	  .idProduct		= 0x5212,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_STREAM_NO_FID },
+	/* Syntek (Asus U3S) */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x174f,
+	  .idProduct		= 0x8a33,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_STREAM_NO_FID },
+	/* Ecamm Pico iMage */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x18cd,
+	  .idProduct		= 0xcafe,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_EXTRAFIELDS },
+	/* Bodelin ProScopeHR */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_DEV_HI
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x19ab,
+	  .idProduct		= 0x1000,
+	  .bcdDevice_hi		= 0x0126,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_STATUS_INTERVAL },
+	/* SiGma Micro USB Web Camera */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x1c4f,
+	  .idProduct		= 0x3000,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX
+				| UVC_QUIRK_IGNORE_SELECTOR_UNIT},
+	/* Acer OEM Webcam - Unknown vendor */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x5986,
+	  .idProduct		= 0x0100,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Packard Bell OEM Webcam */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x5986,
+	  .idProduct		= 0x0101,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Acer Crystal Eye webcam */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x5986,
+	  .idProduct		= 0x0102,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Acer OrbiCam - Unknown vendor */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x5986,
+	  .idProduct		= 0x0200,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_PROBE_MINMAX },
+	/* Generic USB Video Class */
+	{ USB_INTERFACE_INFO(USB_CLASS_VIDEO, 1, 0) },
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, uvc_ids);
+
+struct uvc_driver uvc_driver = {
+	.driver = {
+		.name		= "uvcvideo",
+		.probe		= uvc_probe,
+		.disconnect	= uvc_disconnect,
+		.suspend	= uvc_suspend,
+		.resume		= uvc_resume,
+		.id_table	= uvc_ids,
+		.supports_autosuspend = 1,
+	},
+};
+
+static int __init uvc_init(void)
+{
+	int result;
+
+	INIT_LIST_HEAD(&uvc_driver.devices);
+	INIT_LIST_HEAD(&uvc_driver.controls);
+	mutex_init(&uvc_driver.open_mutex);
+	mutex_init(&uvc_driver.ctrl_mutex);
+
+	uvc_ctrl_init();
+
+	result = usb_register(&uvc_driver.driver);
+	if (result == 0)
+		printk(KERN_INFO DRIVER_DESC " (" DRIVER_VERSION ")\n");
+	return result;
+}
+
+static void __exit uvc_cleanup(void)
+{
+	usb_deregister(&uvc_driver.driver);
+}
+
+module_init(uvc_init);
+module_exit(uvc_cleanup);
+
+module_param_named(quirks, uvc_quirks_param, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(quirks, "Forced device quirks");
+module_param_named(trace, uvc_trace_param, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(trace, "Trace level bitmask");
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRIVER_VERSION);