[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / usb / gadget / uvc_video.c

/*
 *	uvc_video.c  --  USB Video Class Gadget driver
 *
 *	Copyright (C) 2009-2010
 *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 *
 *	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.
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include <media/v4l2-dev.h>

#include "uvc.h"
#include "uvc_queue.h"

/* --------------------------------------------------------------------------
 * Video codecs
 */

static int
uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
		u8 *data, int len)
{
	data[0] = 2;
	data[1] = UVC_STREAM_EOH | video->fid;

	if (buf->bytesused - video->queue.buf_used <= len - 2)
		data[1] |= UVC_STREAM_EOF;

	return 2;
}

static int
uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
		u8 *data, int len)
{
	struct uvc_video_queue *queue = &video->queue;
	unsigned int nbytes;
	void *mem;

	/* Copy video data to the USB buffer. */
	mem = buf->mem + queue->buf_used;
	nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);

	memcpy(data, mem, nbytes);
	queue->buf_used += nbytes;

	return nbytes;
}

static void
uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
		struct uvc_buffer *buf)
{
	void *mem = req->buf;
	int len = video->req_size;
	int ret;

	/* Add a header at the beginning of the payload. */
	if (video->payload_size == 0) {
		ret = uvc_video_encode_header(video, buf, mem, len);
		video->payload_size += ret;
		mem += ret;
		len -= ret;
	}

	/* Process video data. */
	len = min((int)(video->max_payload_size - video->payload_size), len);
	ret = uvc_video_encode_data(video, buf, mem, len);

	video->payload_size += ret;
	len -= ret;

	req->length = video->req_size - len;
	req->zero = video->payload_size == video->max_payload_size;

	if (buf->bytesused == video->queue.buf_used) {
		video->queue.buf_used = 0;
		buf->state = UVC_BUF_STATE_DONE;
		uvc_queue_next_buffer(&video->queue, buf);
		video->fid ^= UVC_STREAM_FID;

		video->payload_size = 0;
	}

	if (video->payload_size == video->max_payload_size ||
	    buf->bytesused == video->queue.buf_used)
		video->payload_size = 0;
}

static void
uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
		struct uvc_buffer *buf)
{
	void *mem = req->buf;
	int len = video->req_size;
	int ret;

	/* Add the header. */
	ret = uvc_video_encode_header(video, buf, mem, len);
	mem += ret;
	len -= ret;

	/* Process video data. */
	ret = uvc_video_encode_data(video, buf, mem, len);
	len -= ret;

	req->length = video->req_size - len;

	if (buf->bytesused == video->queue.buf_used) {
		video->queue.buf_used = 0;
		buf->state = UVC_BUF_STATE_DONE;
		uvc_queue_next_buffer(&video->queue, buf);
		video->fid ^= UVC_STREAM_FID;
	}
}

/* --------------------------------------------------------------------------
 * Request handling
 */

/*
 * I somehow feel that synchronisation won't be easy to achieve here. We have
 * three events that control USB requests submission:
 *
 * - USB request completion: the completion handler will resubmit the request
 *   if a video buffer is available.
 *
 * - USB interface setting selection: in response to a SET_INTERFACE request,
 *   the handler will start streaming if a video buffer is available and if
 *   video is not currently streaming.
 *
 * - V4L2 buffer queueing: the driver will start streaming if video is not
 *   currently streaming.
 *
 * Race conditions between those 3 events might lead to deadlocks or other
 * nasty side effects.
 *
 * The "video currently streaming" condition can't be detected by the irqqueue
 * being empty, as a request can still be in flight. A separate "queue paused"
 * flag is thus needed.
 *
 * The paused flag will be set when we try to retrieve the irqqueue head if the
 * queue is empty, and cleared when we queue a buffer.
 *
 * The USB request completion handler will get the buffer at the irqqueue head
 * under protection of the queue spinlock. If the queue is empty, the streaming
 * paused flag will be set. Right after releasing the spinlock a userspace
 * application can queue a buffer. The flag will then cleared, and the ioctl
 * handler will restart the video stream.
 */
static void
uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct uvc_video *video = req->context;
	struct uvc_video_queue *queue = &video->queue;
	struct uvc_buffer *buf;
	unsigned long flags;
	int ret;

	switch (req->status) {
	case 0:
		break;

	case -ESHUTDOWN:	/* disconnect from host. */
		printk(KERN_INFO "VS request cancelled.\n");
		uvc_queue_cancel(queue, 1);
		goto requeue;

	default:
		printk(KERN_INFO "VS request completed with status %d.\n",
			req->status);
		uvc_queue_cancel(queue, 0);
		goto requeue;
	}

	spin_lock_irqsave(&video->queue.irqlock, flags);
	buf = uvc_queue_head(&video->queue);
	if (buf == NULL) {
		spin_unlock_irqrestore(&video->queue.irqlock, flags);
		goto requeue;
	}

	video->encode(req, video, buf);

	if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) {
		printk(KERN_INFO "Failed to queue request (%d).\n", ret);
		usb_ep_set_halt(ep);
		spin_unlock_irqrestore(&video->queue.irqlock, flags);
		goto requeue;
	}
	spin_unlock_irqrestore(&video->queue.irqlock, flags);

	return;

requeue:
	spin_lock_irqsave(&video->req_lock, flags);
	list_add_tail(&req->list, &video->req_free);
	spin_unlock_irqrestore(&video->req_lock, flags);
}

static int
uvc_video_free_requests(struct uvc_video *video)
{
	unsigned int i;

	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
		if (video->req[i]) {
			usb_ep_free_request(video->ep, video->req[i]);
			video->req[i] = NULL;
		}

		if (video->req_buffer[i]) {
			kfree(video->req_buffer[i]);
			video->req_buffer[i] = NULL;
		}
	}

	INIT_LIST_HEAD(&video->req_free);
	video->req_size = 0;
	return 0;
}

static int
uvc_video_alloc_requests(struct uvc_video *video)
{
	unsigned int req_size;
	unsigned int i;
	int ret = -ENOMEM;

	BUG_ON(video->req_size);

	req_size = video->ep->maxpacket
		 * max_t(unsigned int, video->ep->maxburst, 1)
		 * (video->ep->mult);

	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
		video->req_buffer[i] = kmalloc(req_size, GFP_KERNEL);
		if (video->req_buffer[i] == NULL)
			goto error;

		video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
		if (video->req[i] == NULL)
			goto error;

		video->req[i]->buf = video->req_buffer[i];
		video->req[i]->length = 0;
		video->req[i]->complete = uvc_video_complete;
		video->req[i]->context = video;

		list_add_tail(&video->req[i]->list, &video->req_free);
	}

	video->req_size = req_size;

	return 0;

error:
	uvc_video_free_requests(video);
	return ret;
}

/* --------------------------------------------------------------------------
 * Video streaming
 */

/*
 * uvc_video_pump - Pump video data into the USB requests
 *
 * This function fills the available USB requests (listed in req_free) with
 * video data from the queued buffers.
 */
static int
uvc_video_pump(struct uvc_video *video)
{
	struct usb_request *req;
	struct uvc_buffer *buf;
	unsigned long flags;
	int ret;

	/* FIXME TODO Race between uvc_video_pump and requests completion
	 * handler ???
	 */

	while (1) {
		/* Retrieve the first available USB request, protected by the
		 * request lock.
		 */
		spin_lock_irqsave(&video->req_lock, flags);
		if (list_empty(&video->req_free)) {
			spin_unlock_irqrestore(&video->req_lock, flags);
			return 0;
		}
		req = list_first_entry(&video->req_free, struct usb_request,
					list);
		list_del(&req->list);
		spin_unlock_irqrestore(&video->req_lock, flags);

		/* Retrieve the first available video buffer and fill the
		 * request, protected by the video queue irqlock.
		 */
		spin_lock_irqsave(&video->queue.irqlock, flags);
		buf = uvc_queue_head(&video->queue);
		if (buf == NULL) {
			spin_unlock_irqrestore(&video->queue.irqlock, flags);
			break;
		}

		video->encode(req, video, buf);

		/* Queue the USB request */
		ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
		if (ret < 0) {
			printk(KERN_INFO "Failed to queue request (%d)\n", ret);
			usb_ep_set_halt(video->ep);
			spin_unlock_irqrestore(&video->queue.irqlock, flags);
			break;
		}
		spin_unlock_irqrestore(&video->queue.irqlock, flags);
	}

	spin_lock_irqsave(&video->req_lock, flags);
	list_add_tail(&req->list, &video->req_free);
	spin_unlock_irqrestore(&video->req_lock, flags);
	return 0;
}

/*
 * Enable or disable the video stream.
 */
static int
uvc_video_enable(struct uvc_video *video, int enable)
{
	unsigned int i;
	int ret;

	if (video->ep == NULL) {
		printk(KERN_INFO "Video enable failed, device is "
			"uninitialized.\n");
		return -ENODEV;
	}

	if (!enable) {
		for (i = 0; i < UVC_NUM_REQUESTS; ++i)
			usb_ep_dequeue(video->ep, video->req[i]);

		uvc_video_free_requests(video);
		uvc_queue_enable(&video->queue, 0);
		return 0;
	}

	if ((ret = uvc_queue_enable(&video->queue, 1)) < 0)
		return ret;

	if ((ret = uvc_video_alloc_requests(video)) < 0)
		return ret;

	if (video->max_payload_size) {
		video->encode = uvc_video_encode_bulk;
		video->payload_size = 0;
	} else
		video->encode = uvc_video_encode_isoc;

	return uvc_video_pump(video);
}

/*
 * Initialize the UVC video stream.
 */
static int
uvc_video_init(struct uvc_video *video)
{
	INIT_LIST_HEAD(&video->req_free);
	spin_lock_init(&video->req_lock);

	video->fcc = V4L2_PIX_FMT_YUYV;
	video->bpp = 16;
	video->width = 320;
	video->height = 240;
	video->imagesize = 320 * 240 * 2;

	/* Initialize the video buffers queue. */
	uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT);
	return 0;
}
Commit	Line	Data
cdda479f LP	1	/*
	2	* uvc_video.c -- USB Video Class Gadget driver
	3	*
	4	* Copyright (C) 2009-2010
	5	* Laurent Pinchart (laurent.pinchart@ideasonboard.com)
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
cdda479f LP	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/device.h>
	15	#include <linux/errno.h>
	16	#include <linux/usb/ch9.h>
	17	#include <linux/usb/gadget.h>
	18
	19	#include <media/v4l2-dev.h>
	20
	21	#include "uvc.h"
	22	#include "uvc_queue.h"
	23
	24	/* --------------------------------------------------------------------------
	25	* Video codecs
	26	*/
	27
	28	static int
	29	uvc_video_encode_header(struct uvc_video video, struct uvc_buffer buf,
	30	u8 *data, int len)
	31	{
	32	data[0] = 2;
	33	data[1] = UVC_STREAM_EOH \| video->fid;
	34
d6925225	35	if (buf->bytesused - video->queue.buf_used <= len - 2)
cdda479f LP	36	data[1] \|= UVC_STREAM_EOF;
	37
	38	return 2;
	39	}
	40
	41	static int
	42	uvc_video_encode_data(struct uvc_video video, struct uvc_buffer buf,
	43	u8 *data, int len)
	44	{
	45	struct uvc_video_queue *queue = &video->queue;
	46	unsigned int nbytes;
	47	void *mem;
	48
	49	/* Copy video data to the USB buffer. */
d6925225 BS	50	mem = buf->mem + queue->buf_used;
d6925225 BS	51	nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
cdda479f LP	52
	53	memcpy(data, mem, nbytes);
	54	queue->buf_used += nbytes;
	55
	56	return nbytes;
	57	}
	58
	59	static void
	60	uvc_video_encode_bulk(struct usb_request req, struct uvc_video video,
	61	struct uvc_buffer *buf)
	62	{
	63	void *mem = req->buf;
	64	int len = video->req_size;
	65	int ret;
	66
	67	/* Add a header at the beginning of the payload. */
	68	if (video->payload_size == 0) {
	69	ret = uvc_video_encode_header(video, buf, mem, len);
	70	video->payload_size += ret;
	71	mem += ret;
	72	len -= ret;
	73	}
	74
	75	/* Process video data. */
	76	len = min((int)(video->max_payload_size - video->payload_size), len);
	77	ret = uvc_video_encode_data(video, buf, mem, len);
	78
	79	video->payload_size += ret;
	80	len -= ret;
	81
	82	req->length = video->req_size - len;
	83	req->zero = video->payload_size == video->max_payload_size;
	84
d6925225	85	if (buf->bytesused == video->queue.buf_used) {
cdda479f LP	86	video->queue.buf_used = 0;
	87	buf->state = UVC_BUF_STATE_DONE;
	88	uvc_queue_next_buffer(&video->queue, buf);
	89	video->fid ^= UVC_STREAM_FID;
	90
	91	video->payload_size = 0;
	92	}
	93
	94	if (video->payload_size == video->max_payload_size \|\|
d6925225	95	buf->bytesused == video->queue.buf_used)
cdda479f LP	96	video->payload_size = 0;
	97	}
	98
	99	static void
	100	uvc_video_encode_isoc(struct usb_request req, struct uvc_video video,
	101	struct uvc_buffer *buf)
	102	{
	103	void *mem = req->buf;
	104	int len = video->req_size;
	105	int ret;
	106
	107	/* Add the header. */
	108	ret = uvc_video_encode_header(video, buf, mem, len);
	109	mem += ret;
	110	len -= ret;
	111
	112	/* Process video data. */
	113	ret = uvc_video_encode_data(video, buf, mem, len);
	114	len -= ret;
	115
	116	req->length = video->req_size - len;
	117
d6925225	118	if (buf->bytesused == video->queue.buf_used) {
cdda479f LP	119	video->queue.buf_used = 0;
	120	buf->state = UVC_BUF_STATE_DONE;
	121	uvc_queue_next_buffer(&video->queue, buf);
	122	video->fid ^= UVC_STREAM_FID;
	123	}
	124	}
	125
	126	/* --------------------------------------------------------------------------
	127	* Request handling
	128	*/
	129
	130	/*
	131	* I somehow feel that synchronisation won't be easy to achieve here. We have
	132	* three events that control USB requests submission:
	133	*
	134	* - USB request completion: the completion handler will resubmit the request
	135	* if a video buffer is available.
	136	*
	137	* - USB interface setting selection: in response to a SET_INTERFACE request,
	138	* the handler will start streaming if a video buffer is available and if
	139	* video is not currently streaming.
	140	*
	141	* - V4L2 buffer queueing: the driver will start streaming if video is not
	142	* currently streaming.
	143	*
	144	* Race conditions between those 3 events might lead to deadlocks or other
	145	* nasty side effects.
	146	*
	147	* The "video currently streaming" condition can't be detected by the irqqueue
	148	* being empty, as a request can still be in flight. A separate "queue paused"
	149	* flag is thus needed.
	150	*
	151	* The paused flag will be set when we try to retrieve the irqqueue head if the
	152	* queue is empty, and cleared when we queue a buffer.
	153	*
	154	* The USB request completion handler will get the buffer at the irqqueue head
	155	* under protection of the queue spinlock. If the queue is empty, the streaming
	156	* paused flag will be set. Right after releasing the spinlock a userspace
	157	* application can queue a buffer. The flag will then cleared, and the ioctl
	158	* handler will restart the video stream.
	159	*/
	160	static void
	161	uvc_video_complete(struct usb_ep ep, struct usb_request req)
	162	{
	163	struct uvc_video *video = req->context;
d6925225	164	struct uvc_video_queue *queue = &video->queue;
cdda479f LP	165	struct uvc_buffer *buf;
	166	unsigned long flags;
	167	int ret;
	168
	169	switch (req->status) {
	170	case 0:
	171	break;
	172
d6925225	173	case -ESHUTDOWN: /* disconnect from host. */
cdda479f	174	printk(KERN_INFO "VS request cancelled.\n");
d6925225	175	uvc_queue_cancel(queue, 1);
cdda479f LP	176	goto requeue;
	177
	178	default:
	179	printk(KERN_INFO "VS request completed with status %d.\n",
	180	req->status);
d6925225	181	uvc_queue_cancel(queue, 0);
cdda479f LP	182	goto requeue;
	183	}
	184
	185	spin_lock_irqsave(&video->queue.irqlock, flags);
	186	buf = uvc_queue_head(&video->queue);
	187	if (buf == NULL) {
	188	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	189	goto requeue;
	190	}
	191
	192	video->encode(req, video, buf);
	193
	194	if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) {
	195	printk(KERN_INFO "Failed to queue request (%d).\n", ret);
	196	usb_ep_set_halt(ep);
	197	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	198	goto requeue;
	199	}
	200	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	201
	202	return;
	203
	204	requeue:
	205	spin_lock_irqsave(&video->req_lock, flags);
	206	list_add_tail(&req->list, &video->req_free);
	207	spin_unlock_irqrestore(&video->req_lock, flags);
	208	}
	209
	210	static int
	211	uvc_video_free_requests(struct uvc_video *video)
	212	{
	213	unsigned int i;
	214
	215	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
	216	if (video->req[i]) {
	217	usb_ep_free_request(video->ep, video->req[i]);
	218	video->req[i] = NULL;
	219	}
	220
	221	if (video->req_buffer[i]) {
	222	kfree(video->req_buffer[i]);
	223	video->req_buffer[i] = NULL;
	224	}
	225	}
	226
	227	INIT_LIST_HEAD(&video->req_free);
	228	video->req_size = 0;
	229	return 0;
	230	}
	231
	232	static int
	233	uvc_video_alloc_requests(struct uvc_video *video)
	234	{
326b0e61	235	unsigned int req_size;
cdda479f LP	236	unsigned int i;
	237	int ret = -ENOMEM;
	238
	239	BUG_ON(video->req_size);
	240
326b0e61 BS	241	req_size = video->ep->maxpacket
326b0e61 BS	242	* max_t(unsigned int, video->ep->maxburst, 1)
7b1a80c8	243	* (video->ep->mult);
326b0e61	244
cdda479f	245	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
326b0e61	246	video->req_buffer[i] = kmalloc(req_size, GFP_KERNEL);
cdda479f LP	247	if (video->req_buffer[i] == NULL)
	248	goto error;
	249
	250	video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
	251	if (video->req[i] == NULL)
	252	goto error;
	253
	254	video->req[i]->buf = video->req_buffer[i];
	255	video->req[i]->length = 0;
cdda479f LP	256	video->req[i]->complete = uvc_video_complete;
	257	video->req[i]->context = video;
	258
	259	list_add_tail(&video->req[i]->list, &video->req_free);
	260	}
	261
326b0e61 BS	262	video->req_size = req_size;
326b0e61 BS	263
cdda479f LP	264	return 0;
	265
	266	error:
	267	uvc_video_free_requests(video);
	268	return ret;
	269	}
	270
	271	/* --------------------------------------------------------------------------
	272	* Video streaming
	273	*/
	274
	275	/*
	276	* uvc_video_pump - Pump video data into the USB requests
	277	*
	278	* This function fills the available USB requests (listed in req_free) with
	279	* video data from the queued buffers.
	280	*/
5d9955f8	281	static int
cdda479f LP	282	uvc_video_pump(struct uvc_video *video)
	283	{
	284	struct usb_request *req;
	285	struct uvc_buffer *buf;
	286	unsigned long flags;
	287	int ret;
	288
	289	/* FIXME TODO Race between uvc_video_pump and requests completion
	290	* handler ???
	291	*/
	292
	293	while (1) {
	294	/* Retrieve the first available USB request, protected by the
	295	* request lock.
	296	*/
	297	spin_lock_irqsave(&video->req_lock, flags);
	298	if (list_empty(&video->req_free)) {
	299	spin_unlock_irqrestore(&video->req_lock, flags);
	300	return 0;
	301	}
	302	req = list_first_entry(&video->req_free, struct usb_request,
	303	list);
	304	list_del(&req->list);
	305	spin_unlock_irqrestore(&video->req_lock, flags);
	306
	307	/* Retrieve the first available video buffer and fill the
	308	* request, protected by the video queue irqlock.
	309	*/
	310	spin_lock_irqsave(&video->queue.irqlock, flags);
	311	buf = uvc_queue_head(&video->queue);
	312	if (buf == NULL) {
	313	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	314	break;
	315	}
	316
	317	video->encode(req, video, buf);
	318
	319	/* Queue the USB request */
6854bcdc CR	320	ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
6854bcdc CR	321	if (ret < 0) {
cdda479f LP	322	printk(KERN_INFO "Failed to queue request (%d)\n", ret);
	323	usb_ep_set_halt(video->ep);
	324	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	325	break;
	326	}
	327	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	328	}
	329
	330	spin_lock_irqsave(&video->req_lock, flags);
	331	list_add_tail(&req->list, &video->req_free);
	332	spin_unlock_irqrestore(&video->req_lock, flags);
	333	return 0;
	334	}
	335
	336	/*
	337	* Enable or disable the video stream.
	338	*/
5d9955f8	339	static int
cdda479f LP	340	uvc_video_enable(struct uvc_video *video, int enable)
	341	{
	342	unsigned int i;
	343	int ret;
	344
	345	if (video->ep == NULL) {
	346	printk(KERN_INFO "Video enable failed, device is "
	347	"uninitialized.\n");
	348	return -ENODEV;
	349	}
	350
	351	if (!enable) {
	352	for (i = 0; i < UVC_NUM_REQUESTS; ++i)
	353	usb_ep_dequeue(video->ep, video->req[i]);
	354
	355	uvc_video_free_requests(video);
	356	uvc_queue_enable(&video->queue, 0);
	357	return 0;
	358	}
	359
	360	if ((ret = uvc_queue_enable(&video->queue, 1)) < 0)
	361	return ret;
	362
	363	if ((ret = uvc_video_alloc_requests(video)) < 0)
	364	return ret;
	365
	366	if (video->max_payload_size) {
	367	video->encode = uvc_video_encode_bulk;
	368	video->payload_size = 0;
	369	} else
	370	video->encode = uvc_video_encode_isoc;
	371
	372	return uvc_video_pump(video);
	373	}
	374
	375	/*
	376	* Initialize the UVC video stream.
	377	*/
5d9955f8	378	static int
cdda479f LP	379	uvc_video_init(struct uvc_video *video)
	380	{
	381	INIT_LIST_HEAD(&video->req_free);
	382	spin_lock_init(&video->req_lock);
	383
	384	video->fcc = V4L2_PIX_FMT_YUYV;
	385	video->bpp = 16;
	386	video->width = 320;
	387	video->height = 240;
	388	video->imagesize = 320 * 240 * 2;
	389
	390	/* Initialize the video buffers queue. */
	391	uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT);
	392	return 0;
	393	}
	394