1 files changed, 934 insertions, 0 deletions

diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
new file mode 100644
index 000000000000..6faf1fb21614
--- /dev/null
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -0,0 +1,934 @@
+/*
+ *      uvc_video.c  --  USB Video Class driver - Video handling
+ *
+ *      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.
+ *
+ */
+
+#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 <asm/unaligned.h>
+
+#include <media/v4l2-common.h>
+
+#include "uvcvideo.h"
+
+/* ------------------------------------------------------------------------
+ * UVC Controls
+ */
+
+static int __uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
+                        __u8 intfnum, __u8 cs, void *data, __u16 size,
+                        int timeout)
+{
+        __u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+        unsigned int pipe;
+        int ret;
+
+        pipe = (query & 0x80) ? usb_rcvctrlpipe(dev->udev, 0)
+                              : usb_sndctrlpipe(dev->udev, 0);
+        type |= (query & 0x80) ? USB_DIR_IN : USB_DIR_OUT;
+
+        ret = usb_control_msg(dev->udev, pipe, query, type, cs << 8,
+                        unit << 8 | intfnum, data, size, timeout);
+
+        if (ret != size) {
+                uvc_printk(KERN_ERR, "Failed to query (%u) UVC control %u "
+                        "(unit %u) : %d (exp. %u).\n", query, cs, unit, ret,
+                        size);
+                return -EIO;
+        }
+
+        return 0;
+}
+
+int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
+                        __u8 intfnum, __u8 cs, void *data, __u16 size)
+{
+        return __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,
+                                UVC_CTRL_CONTROL_TIMEOUT);
+}
+
+static void uvc_fixup_buffer_size(struct uvc_video_device *video,
+        struct uvc_streaming_control *ctrl)
+{
+        struct uvc_format *format;
+        struct uvc_frame *frame;
+
+        if (ctrl->bFormatIndex <= 0 ||
+            ctrl->bFormatIndex > video->streaming->nformats)
+                return;
+
+        format = &video->streaming->format[ctrl->bFormatIndex - 1];
+
+        if (ctrl->bFrameIndex <= 0 ||
+            ctrl->bFrameIndex > format->nframes)
+                return;
+
+        frame = &format->frame[ctrl->bFrameIndex - 1];
+
+        if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) ||
+             (ctrl->dwMaxVideoFrameSize == 0 &&
+              video->dev->uvc_version < 0x0110))
+                ctrl->dwMaxVideoFrameSize =
+                        frame->dwMaxVideoFrameBufferSize;
+}
+
+static int uvc_get_video_ctrl(struct uvc_video_device *video,
+        struct uvc_streaming_control *ctrl, int probe, __u8 query)
+{
+        __u8 data[34];
+        __u8 size;
+        int ret;
+
+        size = video->dev->uvc_version >= 0x0110 ? 34 : 26;
+        ret = __uvc_query_ctrl(video->dev, query, 0, video->streaming->intfnum,
+                probe ? VS_PROBE_CONTROL : VS_COMMIT_CONTROL, &data, size,
+                UVC_CTRL_STREAMING_TIMEOUT);
+
+        if (ret < 0)
+                return ret;
+
+        ctrl->bmHint = le16_to_cpup((__le16 *)&data[0]);
+        ctrl->bFormatIndex = data[2];
+        ctrl->bFrameIndex = data[3];
+        ctrl->dwFrameInterval = le32_to_cpup((__le32 *)&data[4]);
+        ctrl->wKeyFrameRate = le16_to_cpup((__le16 *)&data[8]);
+        ctrl->wPFrameRate = le16_to_cpup((__le16 *)&data[10]);
+        ctrl->wCompQuality = le16_to_cpup((__le16 *)&data[12]);
+        ctrl->wCompWindowSize = le16_to_cpup((__le16 *)&data[14]);
+        ctrl->wDelay = le16_to_cpup((__le16 *)&data[16]);
+        ctrl->dwMaxVideoFrameSize =
+                le32_to_cpu(get_unaligned((__le32 *)&data[18]));
+        ctrl->dwMaxPayloadTransferSize =
+                le32_to_cpu(get_unaligned((__le32 *)&data[22]));
+
+        if (size == 34) {
+                ctrl->dwClockFrequency =
+                        le32_to_cpu(get_unaligned((__le32 *)&data[26]));
+                ctrl->bmFramingInfo = data[30];
+                ctrl->bPreferedVersion = data[31];
+                ctrl->bMinVersion = data[32];
+                ctrl->bMaxVersion = data[33];
+        } else {
+                ctrl->dwClockFrequency = video->dev->clock_frequency;
+                ctrl->bmFramingInfo = 0;
+                ctrl->bPreferedVersion = 0;
+                ctrl->bMinVersion = 0;
+                ctrl->bMaxVersion = 0;
+        }
+
+        /* Some broken devices return a null or wrong dwMaxVideoFrameSize.
+         * Try to get the value from the format and frame descriptor.
+         */
+        uvc_fixup_buffer_size(video, ctrl);
+
+        return 0;
+}
+
+int uvc_set_video_ctrl(struct uvc_video_device *video,
+        struct uvc_streaming_control *ctrl, int probe)
+{
+        __u8 data[34];
+        __u8 size;
+
+        size = video->dev->uvc_version >= 0x0110 ? 34 : 26;
+        memset(data, 0, sizeof data);
+
+        *(__le16 *)&data[0] = cpu_to_le16(ctrl->bmHint);
+        data[2] = ctrl->bFormatIndex;
+        data[3] = ctrl->bFrameIndex;
+        *(__le32 *)&data[4] = cpu_to_le32(ctrl->dwFrameInterval);
+        *(__le16 *)&data[8] = cpu_to_le16(ctrl->wKeyFrameRate);
+        *(__le16 *)&data[10] = cpu_to_le16(ctrl->wPFrameRate);
+        *(__le16 *)&data[12] = cpu_to_le16(ctrl->wCompQuality);
+        *(__le16 *)&data[14] = cpu_to_le16(ctrl->wCompWindowSize);
+        *(__le16 *)&data[16] = cpu_to_le16(ctrl->wDelay);
+        /* Note: Some of the fields below are not required for IN devices (see
+         * UVC spec, 4.3.1.1), but we still copy them in case support for OUT
+         * devices is added in the future. */
+        put_unaligned(cpu_to_le32(ctrl->dwMaxVideoFrameSize),
+                (__le32 *)&data[18]);
+        put_unaligned(cpu_to_le32(ctrl->dwMaxPayloadTransferSize),
+                (__le32 *)&data[22]);
+
+        if (size == 34) {
+                put_unaligned(cpu_to_le32(ctrl->dwClockFrequency),
+                        (__le32 *)&data[26]);
+                data[30] = ctrl->bmFramingInfo;
+                data[31] = ctrl->bPreferedVersion;
+                data[32] = ctrl->bMinVersion;
+                data[33] = ctrl->bMaxVersion;
+        }
+
+        return __uvc_query_ctrl(video->dev, SET_CUR, 0,
+                video->streaming->intfnum,
+                probe ? VS_PROBE_CONTROL : VS_COMMIT_CONTROL, &data, size,
+                UVC_CTRL_STREAMING_TIMEOUT);
+}
+
+int uvc_probe_video(struct uvc_video_device *video,
+        struct uvc_streaming_control *probe)
+{
+        struct uvc_streaming_control probe_min, probe_max;
+        __u16 bandwidth;
+        unsigned int i;
+        int ret;
+
+        mutex_lock(&video->streaming->mutex);
+
+        /* Perform probing. The device should adjust the requested values
+         * according to its capabilities. However, some devices, namely the
+         * first generation UVC Logitech webcams, don't implement the Video
+         * Probe control properly, and just return the needed bandwidth. For
+         * that reason, if the needed bandwidth exceeds the maximum available
+         * bandwidth, try to lower the quality.
+         */
+        if ((ret = uvc_set_video_ctrl(video, probe, 1)) < 0)
+                goto done;
+
+        /* Get the minimum and maximum values for compression settings. */
+        if (!(video->dev->quirks & UVC_QUIRK_PROBE_MINMAX)) {
+                ret = uvc_get_video_ctrl(video, &probe_min, 1, GET_MIN);
+                if (ret < 0)
+                        goto done;
+                ret = uvc_get_video_ctrl(video, &probe_max, 1, GET_MAX);
+                if (ret < 0)
+                        goto done;
+
+                probe->wCompQuality = probe_max.wCompQuality;
+        }
+
+        for (i = 0; i < 2; ++i) {
+                if ((ret = uvc_set_video_ctrl(video, probe, 1)) < 0 ||
+                    (ret = uvc_get_video_ctrl(video, probe, 1, GET_CUR)) < 0)
+                        goto done;
+
+                if (video->streaming->intf->num_altsetting == 1)
+                        break;
+
+                bandwidth = probe->dwMaxPayloadTransferSize;
+                if (bandwidth <= video->streaming->maxpsize)
+                        break;
+
+                if (video->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
+                        ret = -ENOSPC;
+                        goto done;
+                }
+
+                /* TODO: negotiate compression parameters */
+                probe->wKeyFrameRate = probe_min.wKeyFrameRate;
+                probe->wPFrameRate = probe_min.wPFrameRate;
+                probe->wCompQuality = probe_max.wCompQuality;
+                probe->wCompWindowSize = probe_min.wCompWindowSize;
+        }
+
+done:
+        mutex_unlock(&video->streaming->mutex);
+        return ret;
+}
+
+/* ------------------------------------------------------------------------
+ * Video codecs
+ */
+
+/* Values for bmHeaderInfo (Video and Still Image Payload Headers, 2.4.3.3) */
+#define UVC_STREAM_EOH  (1 << 7)
+#define UVC_STREAM_ERR  (1 << 6)
+#define UVC_STREAM_STI  (1 << 5)
+#define UVC_STREAM_RES  (1 << 4)
+#define UVC_STREAM_SCR  (1 << 3)
+#define UVC_STREAM_PTS  (1 << 2)
+#define UVC_STREAM_EOF  (1 << 1)
+#define UVC_STREAM_FID  (1 << 0)
+
+/* Video payload decoding is handled by uvc_video_decode_start(),
+ * uvc_video_decode_data() and uvc_video_decode_end().
+ *
+ * uvc_video_decode_start is called with URB data at the start of a bulk or
+ * isochronous payload. It processes header data and returns the header size
+ * in bytes if successful. If an error occurs, it returns a negative error
+ * code. The following error codes have special meanings.
+ *
+ * - EAGAIN informs the caller that the current video buffer should be marked
+ *   as done, and that the function should be called again with the same data
+ *   and a new video buffer. This is used when end of frame conditions can be
+ *   reliably detected at the beginning of the next frame only.
+ *
+ * If an error other than -EAGAIN is returned, the caller will drop the current
+ * payload. No call to uvc_video_decode_data and uvc_video_decode_end will be
+ * made until the next payload. -ENODATA can be used to drop the current
+ * payload if no other error code is appropriate.
+ *
+ * uvc_video_decode_data is called for every URB with URB data. It copies the
+ * data to the video buffer.
+ *
+ * uvc_video_decode_end is called with header data at the end of a bulk or
+ * isochronous payload. It performs any additional header data processing and
+ * returns 0 or a negative error code if an error occured. As header data have
+ * already been processed by uvc_video_decode_start, this functions isn't
+ * required to perform sanity checks a second time.
+ *
+ * For isochronous transfers where a payload is always transfered in a single
+ * URB, the three functions will be called in a row.
+ *
+ * To let the decoder process header data and update its internal state even
+ * when no video buffer is available, uvc_video_decode_start must be prepared
+ * to be called with a NULL buf parameter. uvc_video_decode_data and
+ * uvc_video_decode_end will never be called with a NULL buffer.
+ */
+static int uvc_video_decode_start(struct uvc_video_device *video,
+                struct uvc_buffer *buf, const __u8 *data, int len)
+{
+        __u8 fid;
+
+        /* Sanity checks:
+         * - packet must be at least 2 bytes long
+         * - bHeaderLength value must be at least 2 bytes (see above)
+         * - bHeaderLength value can't be larger than the packet size.
+         */
+        if (len < 2 || data[0] < 2 || data[0] > len)
+                return -EINVAL;
+
+        /* Skip payloads marked with the error bit ("error frames"). */
+        if (data[1] & UVC_STREAM_ERR) {
+                uvc_trace(UVC_TRACE_FRAME, "Dropping payload (error bit "
+                          "set).\n");
+                return -ENODATA;
+        }
+
+        fid = data[1] & UVC_STREAM_FID;
+
+        /* Store the payload FID bit and return immediately when the buffer is
+         * NULL.
+         */
+        if (buf == NULL) {
+                video->last_fid = fid;
+                return -ENODATA;
+        }
+
+        /* Synchronize to the input stream by waiting for the FID bit to be
+         * toggled when the the buffer state is not UVC_BUF_STATE_ACTIVE.
+         * queue->last_fid is initialized to -1, so the first isochronous
+         * frame will always be in sync.
+         *
+         * If the device doesn't toggle the FID bit, invert video->last_fid
+         * when the EOF bit is set to force synchronisation on the next packet.
+         */
+        if (buf->state != UVC_BUF_STATE_ACTIVE) {
+                if (fid == video->last_fid) {
+                        uvc_trace(UVC_TRACE_FRAME, "Dropping payload (out of "
+                                "sync).\n");
+                        if ((video->dev->quirks & UVC_QUIRK_STREAM_NO_FID) &&
+                            (data[1] & UVC_STREAM_EOF))
+                                video->last_fid ^= UVC_STREAM_FID;
+                        return -ENODATA;
+                }
+
+                /* TODO: Handle PTS and SCR. */
+                buf->state = UVC_BUF_STATE_ACTIVE;
+        }
+
+        /* Mark the buffer as done if we're at the beginning of a new frame.
+         * End of frame detection is better implemented by checking the EOF
+         * bit (FID bit toggling is delayed by one frame compared to the EOF
+         * bit), but some devices don't set the bit at end of frame (and the
+         * last payload can be lost anyway). We thus must check if the FID has
+         * been toggled.
+         *
+         * queue->last_fid is initialized to -1, so the first isochronous
+         * frame will never trigger an end of frame detection.
+         *
+         * Empty buffers (bytesused == 0) don't trigger end of frame detection
+         * as it doesn't make sense to return an empty buffer. This also
+         * avoids detecting and of frame conditions at FID toggling if the
+         * previous payload had the EOF bit set.
+         */
+        if (fid != video->last_fid && buf->buf.bytesused != 0) {
+                uvc_trace(UVC_TRACE_FRAME, "Frame complete (FID bit "
+                                "toggled).\n");
+                buf->state = UVC_BUF_STATE_DONE;
+                return -EAGAIN;
+        }
+
+        video->last_fid = fid;
+
+        return data[0];
+}
+
+static void uvc_video_decode_data(struct uvc_video_device *video,
+                struct uvc_buffer *buf, const __u8 *data, int len)
+{
+        struct uvc_video_queue *queue = &video->queue;
+        unsigned int maxlen, nbytes;
+        void *mem;
+
+        if (len <= 0)
+                return;
+
+        /* Copy the video data to the buffer. */
+        maxlen = buf->buf.length - buf->buf.bytesused;
+        mem = queue->mem + buf->buf.m.offset + buf->buf.bytesused;
+        nbytes = min((unsigned int)len, maxlen);
+        memcpy(mem, data, nbytes);
+        buf->buf.bytesused += nbytes;
+
+        /* Complete the current frame if the buffer size was exceeded. */
+        if (len > maxlen) {
+                uvc_trace(UVC_TRACE_FRAME, "Frame complete (overflow).\n");
+                buf->state = UVC_BUF_STATE_DONE;
+        }
+}
+
+static void uvc_video_decode_end(struct uvc_video_device *video,
+                struct uvc_buffer *buf, const __u8 *data, int len)
+{
+        /* Mark the buffer as done if the EOF marker is set. */
+        if (data[1] & UVC_STREAM_EOF && buf->buf.bytesused != 0) {
+                uvc_trace(UVC_TRACE_FRAME, "Frame complete (EOF found).\n");
+                if (data[0] == len)
+                        uvc_trace(UVC_TRACE_FRAME, "EOF in empty payload.\n");
+                buf->state = UVC_BUF_STATE_DONE;
+                if (video->dev->quirks & UVC_QUIRK_STREAM_NO_FID)
+                        video->last_fid ^= UVC_STREAM_FID;
+        }
+}
+
+/* ------------------------------------------------------------------------
+ * URB handling
+ */
+
+/*
+ * Completion handler for video URBs.
+ */
+static void uvc_video_decode_isoc(struct urb *urb,
+        struct uvc_video_device *video, struct uvc_buffer *buf)
+{
+        u8 *mem;
+        int ret, i;
+
+        for (i = 0; i < urb->number_of_packets; ++i) {
+                if (urb->iso_frame_desc[i].status < 0) {
+                        uvc_trace(UVC_TRACE_FRAME, "USB isochronous frame "
+                                "lost (%d).\n", urb->iso_frame_desc[i].status);
+                        continue;
+                }
+
+                /* Decode the payload header. */
+                mem = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
+                do {
+                        ret = uvc_video_decode_start(video, buf, mem,
+                                urb->iso_frame_desc[i].actual_length);
+                        if (ret == -EAGAIN)
+                                buf = uvc_queue_next_buffer(&video->queue, buf);
+                } while (ret == -EAGAIN);
+
+                if (ret < 0)
+                        continue;
+
+                /* Decode the payload data. */
+                uvc_video_decode_data(video, buf, mem + ret,
+                        urb->iso_frame_desc[i].actual_length - ret);
+
+                /* Process the header again. */
+                uvc_video_decode_end(video, buf, mem, ret);
+
+                if (buf->state == UVC_BUF_STATE_DONE ||
+                    buf->state == UVC_BUF_STATE_ERROR)
+                        buf = uvc_queue_next_buffer(&video->queue, buf);
+        }
+}
+
+static void uvc_video_decode_bulk(struct urb *urb,
+        struct uvc_video_device *video, struct uvc_buffer *buf)
+{
+        u8 *mem;
+        int len, ret;
+
+        mem = urb->transfer_buffer;
+        len = urb->actual_length;
+        video->bulk.payload_size += len;
+
+        /* If the URB is the first of its payload, decode and save the
+         * header.
+         */
+        if (video->bulk.header_size == 0) {
+                do {
+                        ret = uvc_video_decode_start(video, buf, mem, len);
+                        if (ret == -EAGAIN)
+                                buf = uvc_queue_next_buffer(&video->queue, buf);
+                } while (ret == -EAGAIN);
+
+                /* If an error occured skip the rest of the payload. */
+                if (ret < 0 || buf == NULL) {
+                        video->bulk.skip_payload = 1;
+                        return;
+                }
+
+                video->bulk.header_size = ret;
+                memcpy(video->bulk.header, mem, video->bulk.header_size);
+
+                mem += ret;
+                len -= ret;
+        }
+
+        /* The buffer queue might have been cancelled while a bulk transfer
+         * was in progress, so we can reach here with buf equal to NULL. Make
+         * sure buf is never dereferenced if NULL.
+         */
+
+        /* Process video data. */
+        if (!video->bulk.skip_payload && buf != NULL)
+                uvc_video_decode_data(video, buf, mem, len);
+
+        /* Detect the payload end by a URB smaller than the maximum size (or
+         * a payload size equal to the maximum) and process the header again.
+         */
+        if (urb->actual_length < urb->transfer_buffer_length ||
+            video->bulk.payload_size >= video->bulk.max_payload_size) {
+                if (!video->bulk.skip_payload && buf != NULL) {
+                        uvc_video_decode_end(video, buf, video->bulk.header,
+                                video->bulk.header_size);
+                        if (buf->state == UVC_BUF_STATE_DONE ||
+                            buf->state == UVC_BUF_STATE_ERROR)
+                                buf = uvc_queue_next_buffer(&video->queue, buf);
+                }
+
+                video->bulk.header_size = 0;
+                video->bulk.skip_payload = 0;
+                video->bulk.payload_size = 0;
+        }
+}
+
+static void uvc_video_complete(struct urb *urb)
+{
+        struct uvc_video_device *video = urb->context;
+        struct uvc_video_queue *queue = &video->queue;
+        struct uvc_buffer *buf = NULL;
+        unsigned long flags;
+        int ret;
+
+        switch (urb->status) {
+        case 0:
+                break;
+
+        default:
+                uvc_printk(KERN_WARNING, "Non-zero status (%d) in video "
+                        "completion handler.\n", urb->status);
+
+        case -ENOENT:           /* usb_kill_urb() called. */
+                if (video->frozen)
+                        return;
+
+        case -ECONNRESET:       /* usb_unlink_urb() called. */
+        case -ESHUTDOWN:        /* The endpoint is being disabled. */
+                uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
+                return;
+        }
+
+        spin_lock_irqsave(&queue->irqlock, flags);
+        if (!list_empty(&queue->irqqueue))
+                buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
+                                       queue);
+        spin_unlock_irqrestore(&queue->irqlock, flags);
+
+        video->decode(urb, video, buf);
+
+        if ((ret = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
+                uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n",
+                        ret);
+        }
+}
+
+/*
+ * Uninitialize isochronous/bulk URBs and free transfer buffers.
+ */
+static void uvc_uninit_video(struct uvc_video_device *video)
+{
+        struct urb *urb;
+        unsigned int i;
+
+        for (i = 0; i < UVC_URBS; ++i) {
+                if ((urb = video->urb[i]) == NULL)
+                        continue;
+
+                usb_kill_urb(urb);
+                /* urb->transfer_buffer_length is not touched by USB core, so
+                 * we can use it here as the buffer length.
+                 */
+                if (video->urb_buffer[i]) {
+                        usb_buffer_free(video->dev->udev,
+                                urb->transfer_buffer_length,
+                                video->urb_buffer[i], urb->transfer_dma);
+                        video->urb_buffer[i] = NULL;
+                }
+
+                usb_free_urb(urb);
+                video->urb[i] = NULL;
+        }
+}
+
+/*
+ * Initialize isochronous URBs and allocate transfer buffers. The packet size
+ * is given by the endpoint.
+ */
+static int uvc_init_video_isoc(struct uvc_video_device *video,
+        struct usb_host_endpoint *ep)
+{
+        struct urb *urb;
+        unsigned int npackets, i, j;
+        __u16 psize;
+        __u32 size;
+
+        /* Compute the number of isochronous packets to allocate by dividing
+         * the maximum video frame size by the packet size. Limit the result
+         * to UVC_MAX_ISO_PACKETS.
+         */
+        psize = le16_to_cpu(ep->desc.wMaxPacketSize);
+        psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
+
+        size = video->streaming->ctrl.dwMaxVideoFrameSize;
+        if (size > UVC_MAX_FRAME_SIZE)
+                return -EINVAL;
+
+        npackets = (size + psize - 1) / psize;
+        if (npackets > UVC_MAX_ISO_PACKETS)
+                npackets = UVC_MAX_ISO_PACKETS;
+
+        size = npackets * psize;
+
+        for (i = 0; i < UVC_URBS; ++i) {
+                urb = usb_alloc_urb(npackets, GFP_KERNEL);
+                if (urb == NULL) {
+                        uvc_uninit_video(video);
+                        return -ENOMEM;
+                }
+
+                video->urb_buffer[i] = usb_buffer_alloc(video->dev->udev,
+                        size, GFP_KERNEL, &urb->transfer_dma);
+                if (video->urb_buffer[i] == NULL) {
+                        usb_free_urb(urb);
+                        uvc_uninit_video(video);
+                        return -ENOMEM;
+                }
+
+                urb->dev = video->dev->udev;
+                urb->context = video;
+                urb->pipe = usb_rcvisocpipe(video->dev->udev,
+                                ep->desc.bEndpointAddress);
+                urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
+                urb->interval = ep->desc.bInterval;
+                urb->transfer_buffer = video->urb_buffer[i];
+                urb->complete = uvc_video_complete;
+                urb->number_of_packets = npackets;
+                urb->transfer_buffer_length = size;
+
+                for (j = 0; j < npackets; ++j) {
+                        urb->iso_frame_desc[j].offset = j * psize;
+                        urb->iso_frame_desc[j].length = psize;
+                }
+
+                video->urb[i] = urb;
+        }
+
+        return 0;
+}
+
+/*
+ * Initialize bulk URBs and allocate transfer buffers. The packet size is
+ * given by the endpoint.
+ */
+static int uvc_init_video_bulk(struct uvc_video_device *video,
+        struct usb_host_endpoint *ep)
+{
+        struct urb *urb;
+        unsigned int pipe, i;
+        __u16 psize;
+        __u32 size;
+
+        /* Compute the bulk URB size. Some devices set the maximum payload
+         * size to a value too high for memory-constrained devices. We must
+         * then transfer the payload accross multiple URBs. To be consistant
+         * with isochronous mode, allocate maximum UVC_MAX_ISO_PACKETS per bulk
+         * URB.
+         */
+        psize = le16_to_cpu(ep->desc.wMaxPacketSize) & 0x07ff;
+        size = video->streaming->ctrl.dwMaxPayloadTransferSize;
+        video->bulk.max_payload_size = size;
+        if (size > psize * UVC_MAX_ISO_PACKETS)
+                size = psize * UVC_MAX_ISO_PACKETS;
+
+        pipe = usb_rcvbulkpipe(video->dev->udev, ep->desc.bEndpointAddress);
+
+        for (i = 0; i < UVC_URBS; ++i) {
+                urb = usb_alloc_urb(0, GFP_KERNEL);
+                if (urb == NULL) {
+                        uvc_uninit_video(video);
+                        return -ENOMEM;
+                }
+
+                video->urb_buffer[i] = usb_buffer_alloc(video->dev->udev,
+                        size, GFP_KERNEL, &urb->transfer_dma);
+                if (video->urb_buffer[i] == NULL) {
+                        usb_free_urb(urb);
+                        uvc_uninit_video(video);
+                        return -ENOMEM;
+                }
+
+                usb_fill_bulk_urb(urb, video->dev->udev, pipe,
+                        video->urb_buffer[i], size, uvc_video_complete,
+                        video);
+                urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+
+                video->urb[i] = urb;
+        }
+
+        return 0;
+}
+
+/*
+ * Initialize isochronous/bulk URBs and allocate transfer buffers.
+ */
+static int uvc_init_video(struct uvc_video_device *video)
+{
+        struct usb_interface *intf = video->streaming->intf;
+        struct usb_host_interface *alts;
+        struct usb_host_endpoint *ep = NULL;
+        int intfnum = video->streaming->intfnum;
+        unsigned int bandwidth, psize, i;
+        int ret;
+
+        video->last_fid = -1;
+        video->bulk.header_size = 0;
+        video->bulk.skip_payload = 0;
+        video->bulk.payload_size = 0;
+
+        if (intf->num_altsetting > 1) {
+                /* Isochronous endpoint, select the alternate setting. */
+                bandwidth = video->streaming->ctrl.dwMaxPayloadTransferSize;
+
+                if (bandwidth == 0) {
+                        uvc_printk(KERN_WARNING, "device %s requested null "
+                                "bandwidth, defaulting to lowest.\n",
+                                video->vdev->name);
+                        bandwidth = 1;
+                }
+
+                for (i = 0; i < intf->num_altsetting; ++i) {
+                        alts = &intf->altsetting[i];
+                        ep = uvc_find_endpoint(alts,
+                                video->streaming->header.bEndpointAddress);
+                        if (ep == NULL)
+                                continue;
+
+                        /* Check if the bandwidth is high enough. */
+                        psize = le16_to_cpu(ep->desc.wMaxPacketSize);
+                        psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
+                        if (psize >= bandwidth)
+                                break;
+                }
+
+                if (i >= intf->num_altsetting)
+                        return -EIO;
+
+                if ((ret = usb_set_interface(video->dev->udev, intfnum, i)) < 0)
+                        return ret;
+
+                ret = uvc_init_video_isoc(video, ep);
+        } else {
+                /* Bulk endpoint, proceed to URB initialization. */
+                ep = uvc_find_endpoint(&intf->altsetting[0],
+                                video->streaming->header.bEndpointAddress);
+                if (ep == NULL)
+                        return -EIO;
+
+                ret = uvc_init_video_bulk(video, ep);
+        }
+
+        if (ret < 0)
+                return ret;
+
+        /* Submit the URBs. */
+        for (i = 0; i < UVC_URBS; ++i) {
+                if ((ret = usb_submit_urb(video->urb[i], GFP_KERNEL)) < 0) {
+                        uvc_printk(KERN_ERR, "Failed to submit URB %u "
+                                        "(%d).\n", i, ret);
+                        uvc_uninit_video(video);
+                        return ret;
+                }
+        }
+
+        return 0;
+}
+
+/* --------------------------------------------------------------------------
+ * Suspend/resume
+ */
+
+/*
+ * Stop streaming without disabling the video queue.
+ *
+ * To let userspace applications resume without trouble, we must not touch the
+ * video buffers in any way. We mark the device as frozen to make sure the URB
+ * completion handler won't try to cancel the queue when we kill the URBs.
+ */
+int uvc_video_suspend(struct uvc_video_device *video)
+{
+        if (!uvc_queue_streaming(&video->queue))
+                return 0;
+
+        video->frozen = 1;
+        uvc_uninit_video(video);
+        usb_set_interface(video->dev->udev, video->streaming->intfnum, 0);
+        return 0;
+}
+
+/*
+ * Reconfigure the video interface and restart streaming if it was enable
+ * before suspend.
+ *
+ * If an error occurs, disable the video queue. This will wake all pending
+ * buffers, making sure userspace applications are notified of the problem
+ * instead of waiting forever.
+ */
+int uvc_video_resume(struct uvc_video_device *video)
+{
+        int ret;
+
+        video->frozen = 0;
+
+        if ((ret = uvc_set_video_ctrl(video, &video->streaming->ctrl, 0)) < 0) {
+                uvc_queue_enable(&video->queue, 0);
+                return ret;
+        }
+
+        if (!uvc_queue_streaming(&video->queue))
+                return 0;
+
+        if ((ret = uvc_init_video(video)) < 0)
+                uvc_queue_enable(&video->queue, 0);
+
+        return ret;
+}
+
+/* ------------------------------------------------------------------------
+ * Video device
+ */
+
+/*
+ * Initialize the UVC video device by retrieving the default format and
+ * committing it.
+ *
+ * Some cameras (namely the Fuji Finepix) set the format and frame
+ * indexes to zero. The UVC standard doesn't clearly make this a spec
+ * violation, so try to silently fix the values if possible.
+ *
+ * This function is called before registering the device with V4L.
+ */
+int uvc_video_init(struct uvc_video_device *video)
+{
+        struct uvc_streaming_control *probe = &video->streaming->ctrl;
+        struct uvc_format *format = NULL;
+        struct uvc_frame *frame = NULL;
+        unsigned int i;
+        int ret;
+
+        if (video->streaming->nformats == 0) {
+                uvc_printk(KERN_INFO, "No supported video formats found.\n");
+                return -EINVAL;
+        }
+
+        /* Alternate setting 0 should be the default, yet the XBox Live Vision
+         * Cam (and possibly other devices) crash or otherwise misbehave if
+         * they don't receive a SET_INTERFACE request before any other video
+         * control request.
+         */
+        usb_set_interface(video->dev->udev, video->streaming->intfnum, 0);
+
+        /* Some webcams don't suport GET_DEF request on the probe control. We
+         * fall back to GET_CUR if GET_DEF fails.
+         */
+        if ((ret = uvc_get_video_ctrl(video, probe, 1, GET_DEF)) < 0 &&
+            (ret = uvc_get_video_ctrl(video, probe, 1, GET_CUR)) < 0)
+                return ret;
+
+        /* Check if the default format descriptor exists. Use the first
+         * available format otherwise.
+         */
+        for (i = video->streaming->nformats; i > 0; --i) {
+                format = &video->streaming->format[i-1];
+                if (format->index == probe->bFormatIndex)
+                        break;
+        }
+
+        if (format->nframes == 0) {
+                uvc_printk(KERN_INFO, "No frame descriptor found for the "
+                        "default format.\n");
+                return -EINVAL;
+        }
+
+        /* Zero bFrameIndex might be correct. Stream-based formats (including
+         * MPEG-2 TS and DV) do not support frames but have a dummy frame
+         * descriptor with bFrameIndex set to zero. If the default frame
+         * descriptor is not found, use the first avalable frame.
+         */
+        for (i = format->nframes; i > 0; --i) {
+                frame = &format->frame[i-1];
+                if (frame->bFrameIndex == probe->bFrameIndex)
+                        break;
+        }
+
+        /* Commit the default settings. */
+        probe->bFormatIndex = format->index;
+        probe->bFrameIndex = frame->bFrameIndex;
+        if ((ret = uvc_set_video_ctrl(video, probe, 0)) < 0)
+                return ret;
+
+        video->streaming->cur_format = format;
+        video->streaming->cur_frame = frame;
+        atomic_set(&video->active, 0);
+
+        /* Select the video decoding function */
+        if (video->dev->quirks & UVC_QUIRK_BUILTIN_ISIGHT)
+                video->decode = uvc_video_decode_isight;
+        else if (video->streaming->intf->num_altsetting > 1)
+                video->decode = uvc_video_decode_isoc;
+        else
+                video->decode = uvc_video_decode_bulk;
+
+        return 0;
+}
+
+/*
+ * Enable or disable the video stream.
+ */
+int uvc_video_enable(struct uvc_video_device *video, int enable)
+{
+        int ret;
+
+        if (!enable) {
+                uvc_uninit_video(video);
+                usb_set_interface(video->dev->udev,
+                        video->streaming->intfnum, 0);
+                uvc_queue_enable(&video->queue, 0);
+                return 0;
+        }
+
+        if ((ret = uvc_queue_enable(&video->queue, 1)) < 0)
+                return ret;
+
+        return uvc_init_video(video);
+}