drivers/media/video/uvc/uvc_video.c

   1 /*
   2  *      uvc_video.c  --  USB Video Class driver - Video handling
   3  *
   4  *      Copyright (C) 2005-2010
   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.
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/list.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/usb.h>
  19 #include <linux/videodev2.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/wait.h>
  22 #include <linux/atomic.h>
  23 #include <asm/unaligned.h>
  24
  25 #include <media/v4l2-common.h>
  26
  27 #include "uvcvideo.h"
  28
  29 /* ------------------------------------------------------------------------
  30  * UVC Controls
  31  */
  32
  33 static int __uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
  34                         __u8 intfnum, __u8 cs, void *data, __u16 size,
  35                         int timeout)
  36 {
  37         __u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
  38         unsigned int pipe;
  39
  40         pipe = (query & 0x80) ? usb_rcvctrlpipe(dev->udev, 0)
  41                               : usb_sndctrlpipe(dev->udev, 0);
  42         type |= (query & 0x80) ? USB_DIR_IN : USB_DIR_OUT;
  43
  44         return usb_control_msg(dev->udev, pipe, query, type, cs << 8,
  45                         unit << 8 | intfnum, data, size, timeout);
  46 }
  47
  48 static const char *uvc_query_name(__u8 query)
  49 {
  50         switch (query) {
  51         case UVC_SET_CUR:
  52                 return "SET_CUR";
  53         case UVC_GET_CUR:
  54                 return "GET_CUR";
  55         case UVC_GET_MIN:
  56                 return "GET_MIN";
  57         case UVC_GET_MAX:
  58                 return "GET_MAX";
  59         case UVC_GET_RES:
  60                 return "GET_RES";
  61         case UVC_GET_LEN:
  62                 return "GET_LEN";
  63         case UVC_GET_INFO:
  64                 return "GET_INFO";
  65         case UVC_GET_DEF:
  66                 return "GET_DEF";
  67         default:
  68                 return "<invalid>";
  69         }
  70 }
  71
  72 int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
  73                         __u8 intfnum, __u8 cs, void *data, __u16 size)
  74 {
  75         int ret;
  76
  77         ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,
  78                                 UVC_CTRL_CONTROL_TIMEOUT);
  79         if (ret != size) {
  80                 uvc_printk(KERN_ERR, "Failed to query (%s) UVC control %u on "
  81                         "unit %u: %d (exp. %u).\n", uvc_query_name(query), cs,
  82                         unit, ret, size);
  83                 return -EIO;
  84         }
  85
  86         return 0;
  87 }
  88
  89 static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
  90         struct uvc_streaming_control *ctrl)
  91 {
  92         struct uvc_format *format = NULL;
  93         struct uvc_frame *frame = NULL;
  94         unsigned int i;
  95
  96         for (i = 0; i < stream->nformats; ++i) {
  97                 if (stream->format[i].index == ctrl->bFormatIndex) {
  98                         format = &stream->format[i];
  99                         break;
 100                 }
 101         }
 102
 103         if (format == NULL)
 104                 return;
 105
 106         for (i = 0; i < format->nframes; ++i) {
 107                 if (format->frame[i].bFrameIndex == ctrl->bFrameIndex) {
 108                         frame = &format->frame[i];
 109                         break;
 110                 }
 111         }
 112
 113         if (frame == NULL)
 114                 return;
 115
 116         if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) ||
 117              (ctrl->dwMaxVideoFrameSize == 0 &&
 118               stream->dev->uvc_version < 0x0110))
 119                 ctrl->dwMaxVideoFrameSize =
 120                         frame->dwMaxVideoFrameBufferSize;
 121
 122         if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) &&
 123             stream->dev->quirks & UVC_QUIRK_FIX_BANDWIDTH &&
 124             stream->intf->num_altsetting > 1) {
 125                 u32 interval;
 126                 u32 bandwidth;
 127
 128                 interval = (ctrl->dwFrameInterval > 100000)
 129                          ? ctrl->dwFrameInterval
 130                          : frame->dwFrameInterval[0];
 131
 132                 /* Compute a bandwidth estimation by multiplying the frame
 133                  * size by the number of video frames per second, divide the
 134                  * result by the number of USB frames (or micro-frames for
 135                  * high-speed devices) per second and add the UVC header size
 136                  * (assumed to be 12 bytes long).
 137                  */
 138                 bandwidth = frame->wWidth * frame->wHeight / 8 * format->bpp;
 139                 bandwidth *= 10000000 / interval + 1;
 140                 bandwidth /= 1000;
 141                 if (stream->dev->udev->speed == USB_SPEED_HIGH)
 142                         bandwidth /= 8;
 143                 bandwidth += 12;
 144
 145                 /* The bandwidth estimate is too low for many cameras. Don't use
 146                  * maximum packet sizes lower than 1024 bytes to try and work
 147                  * around the problem. According to measurements done on two
 148                  * different camera models, the value is high enough to get most
 149                  * resolutions working while not preventing two simultaneous
 150                  * VGA streams at 15 fps.
 151                  */
 152                 bandwidth = max_t(u32, bandwidth, 1024);
 153
 154                 ctrl->dwMaxPayloadTransferSize = bandwidth;
 155         }
 156 }
 157
 158 static int uvc_get_video_ctrl(struct uvc_streaming *stream,
 159         struct uvc_streaming_control *ctrl, int probe, __u8 query)
 160 {
 161         __u8 *data;
 162         __u16 size;
 163         int ret;
 164
 165         size = stream->dev->uvc_version >= 0x0110 ? 34 : 26;
 166         if ((stream->dev->quirks & UVC_QUIRK_PROBE_DEF) &&
 167                         query == UVC_GET_DEF)
 168                 return -EIO;
 169
 170         data = kmalloc(size, GFP_KERNEL);
 171         if (data == NULL)
 172                 return -ENOMEM;
 173
 174         ret = __uvc_query_ctrl(stream->dev, query, 0, stream->intfnum,
 175                 probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data,
 176                 size, uvc_timeout_param);
 177
 178         if ((query == UVC_GET_MIN || query == UVC_GET_MAX) && ret == 2) {
 179                 /* Some cameras, mostly based on Bison Electronics chipsets,
 180                  * answer a GET_MIN or GET_MAX request with the wCompQuality
 181                  * field only.
 182                  */
 183                 uvc_warn_once(stream->dev, UVC_WARN_MINMAX, "UVC non "
 184                         "compliance - GET_MIN/MAX(PROBE) incorrectly "
 185                         "supported. Enabling workaround.\n");
 186                 memset(ctrl, 0, sizeof *ctrl);
 187                 ctrl->wCompQuality = le16_to_cpup((__le16 *)data);
 188                 ret = 0;
 189                 goto out;
 190         } else if (query == UVC_GET_DEF && probe == 1 && ret != size) {
 191                 /* Many cameras don't support the GET_DEF request on their
 192                  * video probe control. Warn once and return, the caller will
 193                  * fall back to GET_CUR.
 194                  */
 195                 uvc_warn_once(stream->dev, UVC_WARN_PROBE_DEF, "UVC non "
 196                         "compliance - GET_DEF(PROBE) not supported. "
 197                         "Enabling workaround.\n");
 198                 ret = -EIO;
 199                 goto out;
 200         } else if (ret != size) {
 201                 uvc_printk(KERN_ERR, "Failed to query (%u) UVC %s control : "
 202                         "%d (exp. %u).\n", query, probe ? "probe" : "commit",
 203                         ret, size);
 204                 ret = -EIO;
 205                 goto out;
 206         }
 207
 208         ctrl->bmHint = le16_to_cpup((__le16 *)&data[0]);
 209         ctrl->bFormatIndex = data[2];
 210         ctrl->bFrameIndex = data[3];
 211         ctrl->dwFrameInterval = le32_to_cpup((__le32 *)&data[4]);
 212         ctrl->wKeyFrameRate = le16_to_cpup((__le16 *)&data[8]);
 213         ctrl->wPFrameRate = le16_to_cpup((__le16 *)&data[10]);
 214         ctrl->wCompQuality = le16_to_cpup((__le16 *)&data[12]);
 215         ctrl->wCompWindowSize = le16_to_cpup((__le16 *)&data[14]);
 216         ctrl->wDelay = le16_to_cpup((__le16 *)&data[16]);
 217         ctrl->dwMaxVideoFrameSize = get_unaligned_le32(&data[18]);
 218         ctrl->dwMaxPayloadTransferSize = get_unaligned_le32(&data[22]);
 219
 220         if (size == 34) {
 221                 ctrl->dwClockFrequency = get_unaligned_le32(&data[26]);
 222                 ctrl->bmFramingInfo = data[30];
 223                 ctrl->bPreferedVersion = data[31];
 224                 ctrl->bMinVersion = data[32];
 225                 ctrl->bMaxVersion = data[33];
 226         } else {
 227                 ctrl->dwClockFrequency = stream->dev->clock_frequency;
 228                 ctrl->bmFramingInfo = 0;
 229                 ctrl->bPreferedVersion = 0;
 230                 ctrl->bMinVersion = 0;
 231                 ctrl->bMaxVersion = 0;
 232         }
 233
 234         /* Some broken devices return null or wrong dwMaxVideoFrameSize and
 235          * dwMaxPayloadTransferSize fields. Try to get the value from the
 236          * format and frame descriptors.
 237          */
 238         uvc_fixup_video_ctrl(stream, ctrl);
 239         ret = 0;
 240
 241 out:
 242         kfree(data);
 243         return ret;
 244 }
 245
 246 static int uvc_set_video_ctrl(struct uvc_streaming *stream,
 247         struct uvc_streaming_control *ctrl, int probe)
 248 {
 249         __u8 *data;
 250         __u16 size;
 251         int ret;
 252
 253         size = stream->dev->uvc_version >= 0x0110 ? 34 : 26;
 254         data = kzalloc(size, GFP_KERNEL);
 255         if (data == NULL)
 256                 return -ENOMEM;
 257
 258         *(__le16 *)&data[0] = cpu_to_le16(ctrl->bmHint);
 259         data[2] = ctrl->bFormatIndex;
 260         data[3] = ctrl->bFrameIndex;
 261         *(__le32 *)&data[4] = cpu_to_le32(ctrl->dwFrameInterval);
 262         *(__le16 *)&data[8] = cpu_to_le16(ctrl->wKeyFrameRate);
 263         *(__le16 *)&data[10] = cpu_to_le16(ctrl->wPFrameRate);
 264         *(__le16 *)&data[12] = cpu_to_le16(ctrl->wCompQuality);
 265         *(__le16 *)&data[14] = cpu_to_le16(ctrl->wCompWindowSize);
 266         *(__le16 *)&data[16] = cpu_to_le16(ctrl->wDelay);
 267         put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[18]);
 268         put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[22]);
 269
 270         if (size == 34) {
 271                 put_unaligned_le32(ctrl->dwClockFrequency, &data[26]);
 272                 data[30] = ctrl->bmFramingInfo;
 273                 data[31] = ctrl->bPreferedVersion;
 274                 data[32] = ctrl->bMinVersion;
 275                 data[33] = ctrl->bMaxVersion;
 276         }
 277
 278         ret = __uvc_query_ctrl(stream->dev, UVC_SET_CUR, 0, stream->intfnum,
 279                 probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data,
 280                 size, uvc_timeout_param);
 281         if (ret != size) {
 282                 uvc_printk(KERN_ERR, "Failed to set UVC %s control : "
 283                         "%d (exp. %u).\n", probe ? "probe" : "commit",
 284                         ret, size);
 285                 ret = -EIO;
 286         }
 287
 288         kfree(data);
 289         return ret;
 290 }
 291
 292 int uvc_probe_video(struct uvc_streaming *stream,
 293         struct uvc_streaming_control *probe)
 294 {
 295         struct uvc_streaming_control probe_min, probe_max;
 296         __u16 bandwidth;
 297         unsigned int i;
 298         int ret;
 299
 300         /* Perform probing. The device should adjust the requested values
 301          * according to its capabilities. However, some devices, namely the
 302          * first generation UVC Logitech webcams, don't implement the Video
 303          * Probe control properly, and just return the needed bandwidth. For
 304          * that reason, if the needed bandwidth exceeds the maximum available
 305          * bandwidth, try to lower the quality.
 306          */
 307         ret = uvc_set_video_ctrl(stream, probe, 1);
 308         if (ret < 0)
 309                 goto done;
 310
 311         /* Get the minimum and maximum values for compression settings. */
 312         if (!(stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX)) {
 313                 ret = uvc_get_video_ctrl(stream, &probe_min, 1, UVC_GET_MIN);
 314                 if (ret < 0)
 315                         goto done;
 316                 ret = uvc_get_video_ctrl(stream, &probe_max, 1, UVC_GET_MAX);
 317                 if (ret < 0)
 318                         goto done;
 319
 320                 probe->wCompQuality = probe_max.wCompQuality;
 321         }
 322
 323         for (i = 0; i < 2; ++i) {
 324                 ret = uvc_set_video_ctrl(stream, probe, 1);
 325                 if (ret < 0)
 326                         goto done;
 327                 ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
 328                 if (ret < 0)
 329                         goto done;
 330
 331                 if (stream->intf->num_altsetting == 1)
 332                         break;
 333
 334                 bandwidth = probe->dwMaxPayloadTransferSize;
 335                 if (bandwidth <= stream->maxpsize)
 336                         break;
 337
 338                 if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
 339                         ret = -ENOSPC;
 340                         goto done;
 341                 }
 342
 343                 /* TODO: negotiate compression parameters */
 344                 probe->wKeyFrameRate = probe_min.wKeyFrameRate;
 345                 probe->wPFrameRate = probe_min.wPFrameRate;
 346                 probe->wCompQuality = probe_max.wCompQuality;
 347                 probe->wCompWindowSize = probe_min.wCompWindowSize;
 348         }
 349
 350 done:
 351         return ret;
 352 }
 353
 354 static int uvc_commit_video(struct uvc_streaming *stream,
 355                             struct uvc_streaming_control *probe)
 356 {
 357         return uvc_set_video_ctrl(stream, probe, 0);
 358 }
 359
 360 /* ------------------------------------------------------------------------
 361  * Stream statistics
 362  */
 363
 364 static void uvc_video_stats_decode(struct uvc_streaming *stream,
 365                 const __u8 *data, int len)
 366 {
 367         unsigned int header_size;
 368
 369         if (stream->stats.stream.nb_frames == 0 &&
 370             stream->stats.frame.nb_packets == 0)
 371                 ktime_get_ts(&stream->stats.stream.start_ts);
 372
 373         switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
 374         case UVC_STREAM_PTS | UVC_STREAM_SCR:
 375                 header_size = 12;
 376                 break;
 377         case UVC_STREAM_PTS:
 378                 header_size = 6;
 379                 break;
 380         case UVC_STREAM_SCR:
 381                 header_size = 8;
 382                 break;
 383         default:
 384                 header_size = 2;
 385                 break;
 386         }
 387
 388         /* Check for invalid headers. */
 389         if (len < header_size || data[0] < header_size) {
 390                 stream->stats.frame.nb_invalid++;
 391                 return;
 392         }
 393
 394         /* Record the first non-empty packet number. */
 395         if (stream->stats.frame.size == 0 && len > header_size)
 396                 stream->stats.frame.first_data = stream->stats.frame.nb_packets;
 397
 398         /* Update the frame size. */
 399         stream->stats.frame.size += len - header_size;
 400
 401         /* Update the packets counters. */
 402         stream->stats.frame.nb_packets++;
 403         if (len > header_size)
 404                 stream->stats.frame.nb_empty++;
 405
 406         if (data[1] & UVC_STREAM_ERR)
 407                 stream->stats.frame.nb_errors++;
 408 }
 409
 410 static void uvc_video_stats_update(struct uvc_streaming *stream)
 411 {
 412         struct uvc_stats_frame *frame = &stream->stats.frame;
 413
 414         uvc_trace(UVC_TRACE_STATS, "frame %u stats: %u/%u/%u packets\n",
 415                   stream->sequence, frame->first_data,
 416                   frame->nb_packets - frame->nb_empty, frame->nb_packets);
 417
 418         stream->stats.stream.nb_frames++;
 419         stream->stats.stream.nb_packets += stream->stats.frame.nb_packets;
 420         stream->stats.stream.nb_empty += stream->stats.frame.nb_empty;
 421         stream->stats.stream.nb_errors += stream->stats.frame.nb_errors;
 422         stream->stats.stream.nb_invalid += stream->stats.frame.nb_invalid;
 423
 424         memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));
 425 }
 426
 427 size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
 428                             size_t size)
 429 {
 430         size_t count = 0;
 431
 432         count += scnprintf(buf + count, size - count,
 433                            "frames:  %u\npackets: %u\nempty:   %u\n"
 434                            "errors:  %u\ninvalid: %u\n",
 435                            stream->stats.stream.nb_frames,
 436                            stream->stats.stream.nb_packets,
 437                            stream->stats.stream.nb_empty,
 438                            stream->stats.stream.nb_errors,
 439                            stream->stats.stream.nb_invalid);
 440
 441         return count;
 442 }
 443
 444 static void uvc_video_stats_start(struct uvc_streaming *stream)
 445 {
 446         memset(&stream->stats, 0, sizeof(stream->stats));
 447 }
 448
 449 static void uvc_video_stats_stop(struct uvc_streaming *stream)
 450 {
 451         ktime_get_ts(&stream->stats.stream.stop_ts);
 452 }
 453
 454 /* ------------------------------------------------------------------------
 455  * Video codecs
 456  */
 457
 458 /* Video payload decoding is handled by uvc_video_decode_start(),
 459  * uvc_video_decode_data() and uvc_video_decode_end().
 460  *
 461  * uvc_video_decode_start is called with URB data at the start of a bulk or
 462  * isochronous payload. It processes header data and returns the header size
 463  * in bytes if successful. If an error occurs, it returns a negative error
 464  * code. The following error codes have special meanings.
 465  *
 466  * - EAGAIN informs the caller that the current video buffer should be marked
 467  *   as done, and that the function should be called again with the same data
 468  *   and a new video buffer. This is used when end of frame conditions can be
 469  *   reliably detected at the beginning of the next frame only.
 470  *
 471  * If an error other than -EAGAIN is returned, the caller will drop the current
 472  * payload. No call to uvc_video_decode_data and uvc_video_decode_end will be
 473  * made until the next payload. -ENODATA can be used to drop the current
 474  * payload if no other error code is appropriate.
 475  *
 476  * uvc_video_decode_data is called for every URB with URB data. It copies the
 477  * data to the video buffer.
 478  *
 479  * uvc_video_decode_end is called with header data at the end of a bulk or
 480  * isochronous payload. It performs any additional header data processing and
 481  * returns 0 or a negative error code if an error occurred. As header data have
 482  * already been processed by uvc_video_decode_start, this functions isn't
 483  * required to perform sanity checks a second time.
 484  *
 485  * For isochronous transfers where a payload is always transferred in a single
 486  * URB, the three functions will be called in a row.
 487  *
 488  * To let the decoder process header data and update its internal state even
 489  * when no video buffer is available, uvc_video_decode_start must be prepared
 490  * to be called with a NULL buf parameter. uvc_video_decode_data and
 491  * uvc_video_decode_end will never be called with a NULL buffer.
 492  */
 493 static int uvc_video_decode_start(struct uvc_streaming *stream,
 494                 struct uvc_buffer *buf, const __u8 *data, int len)
 495 {
 496         __u8 fid;
 497
 498         /* Sanity checks:
 499          * - packet must be at least 2 bytes long
 500          * - bHeaderLength value must be at least 2 bytes (see above)
 501          * - bHeaderLength value can't be larger than the packet size.
 502          */
 503         if (len < 2 || data[0] < 2 || data[0] > len) {
 504                 stream->stats.frame.nb_invalid++;
 505                 return -EINVAL;
 506         }
 507
 508         fid = data[1] & UVC_STREAM_FID;
 509
 510         /* Increase the sequence number regardless of any buffer states, so
 511          * that discontinuous sequence numbers always indicate lost frames.
 512          */
 513         if (stream->last_fid != fid) {
 514                 stream->sequence++;
 515                 if (stream->sequence)
 516                         uvc_video_stats_update(stream);
 517         }
 518
 519         uvc_video_stats_decode(stream, data, len);
 520
 521         /* Store the payload FID bit and return immediately when the buffer is
 522          * NULL.
 523          */
 524         if (buf == NULL) {
 525                 stream->last_fid = fid;
 526                 return -ENODATA;
 527         }
 528
 529         /* Mark the buffer as bad if the error bit is set. */
 530         if (data[1] & UVC_STREAM_ERR) {
 531                 uvc_trace(UVC_TRACE_FRAME, "Marking buffer as bad (error bit "
 532                           "set).\n");
 533                 buf->error = 1;
 534         }
 535
 536         /* Synchronize to the input stream by waiting for the FID bit to be
 537          * toggled when the the buffer state is not UVC_BUF_STATE_ACTIVE.
 538          * stream->last_fid is initialized to -1, so the first isochronous
 539          * frame will always be in sync.
 540          *
 541          * If the device doesn't toggle the FID bit, invert stream->last_fid
 542          * when the EOF bit is set to force synchronisation on the next packet.
 543          */
 544         if (buf->state != UVC_BUF_STATE_ACTIVE) {
 545                 struct timespec ts;
 546
 547                 if (fid == stream->last_fid) {
 548                         uvc_trace(UVC_TRACE_FRAME, "Dropping payload (out of "
 549                                 "sync).\n");
 550                         if ((stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID) &&
 551                             (data[1] & UVC_STREAM_EOF))
 552                                 stream->last_fid ^= UVC_STREAM_FID;
 553                         return -ENODATA;
 554                 }
 555
 556                 if (uvc_clock_param == CLOCK_MONOTONIC)
 557                         ktime_get_ts(&ts);
 558                 else
 559                         ktime_get_real_ts(&ts);
 560
 561                 buf->buf.v4l2_buf.sequence = stream->sequence;
 562                 buf->buf.v4l2_buf.timestamp.tv_sec = ts.tv_sec;
 563                 buf->buf.v4l2_buf.timestamp.tv_usec =
 564                         ts.tv_nsec / NSEC_PER_USEC;
 565
 566                 /* TODO: Handle PTS and SCR. */
 567                 buf->state = UVC_BUF_STATE_ACTIVE;
 568         }
 569
 570         /* Mark the buffer as done if we're at the beginning of a new frame.
 571          * End of frame detection is better implemented by checking the EOF
 572          * bit (FID bit toggling is delayed by one frame compared to the EOF
 573          * bit), but some devices don't set the bit at end of frame (and the
 574          * last payload can be lost anyway). We thus must check if the FID has
 575          * been toggled.
 576          *
 577          * stream->last_fid is initialized to -1, so the first isochronous
 578          * frame will never trigger an end of frame detection.
 579          *
 580          * Empty buffers (bytesused == 0) don't trigger end of frame detection
 581          * as it doesn't make sense to return an empty buffer. This also
 582          * avoids detecting end of frame conditions at FID toggling if the
 583          * previous payload had the EOF bit set.
 584          */
 585         if (fid != stream->last_fid && buf->bytesused != 0) {
 586                 uvc_trace(UVC_TRACE_FRAME, "Frame complete (FID bit "
 587                                 "toggled).\n");
 588                 buf->state = UVC_BUF_STATE_READY;
 589                 return -EAGAIN;
 590         }
 591
 592         stream->last_fid = fid;
 593
 594         return data[0];
 595 }
 596
 597 static void uvc_video_decode_data(struct uvc_streaming *stream,
 598                 struct uvc_buffer *buf, const __u8 *data, int len)
 599 {
 600         unsigned int maxlen, nbytes;
 601         void *mem;
 602
 603         if (len <= 0)
 604                 return;
 605
 606         /* Copy the video data to the buffer. */
 607         maxlen = buf->length - buf->bytesused;
 608         mem = buf->mem + buf->bytesused;
 609         nbytes = min((unsigned int)len, maxlen);
 610         memcpy(mem, data, nbytes);
 611         buf->bytesused += nbytes;
 612
 613         /* Complete the current frame if the buffer size was exceeded. */
 614         if (len > maxlen) {
 615                 uvc_trace(UVC_TRACE_FRAME, "Frame complete (overflow).\n");
 616                 buf->state = UVC_BUF_STATE_READY;
 617         }
 618 }
 619
 620 static void uvc_video_decode_end(struct uvc_streaming *stream,
 621                 struct uvc_buffer *buf, const __u8 *data, int len)
 622 {
 623         /* Mark the buffer as done if the EOF marker is set. */
 624         if (data[1] & UVC_STREAM_EOF && buf->bytesused != 0) {
 625                 uvc_trace(UVC_TRACE_FRAME, "Frame complete (EOF found).\n");
 626                 if (data[0] == len)
 627                         uvc_trace(UVC_TRACE_FRAME, "EOF in empty payload.\n");
 628                 buf->state = UVC_BUF_STATE_READY;
 629                 if (stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID)
 630                         stream->last_fid ^= UVC_STREAM_FID;
 631         }
 632 }
 633
 634 /* Video payload encoding is handled by uvc_video_encode_header() and
 635  * uvc_video_encode_data(). Only bulk transfers are currently supported.
 636  *
 637  * uvc_video_encode_header is called at the start of a payload. It adds header
 638  * data to the transfer buffer and returns the header size. As the only known
 639  * UVC output device transfers a whole frame in a single payload, the EOF bit
 640  * is always set in the header.
 641  *
 642  * uvc_video_encode_data is called for every URB and copies the data from the
 643  * video buffer to the transfer buffer.
 644  */
 645 static int uvc_video_encode_header(struct uvc_streaming *stream,
 646                 struct uvc_buffer *buf, __u8 *data, int len)
 647 {
 648         data[0] = 2;    /* Header length */
 649         data[1] = UVC_STREAM_EOH | UVC_STREAM_EOF
 650                 | (stream->last_fid & UVC_STREAM_FID);
 651         return 2;
 652 }
 653
 654 static int uvc_video_encode_data(struct uvc_streaming *stream,
 655                 struct uvc_buffer *buf, __u8 *data, int len)
 656 {
 657         struct uvc_video_queue *queue = &stream->queue;
 658         unsigned int nbytes;
 659         void *mem;
 660
 661         /* Copy video data to the URB buffer. */
 662         mem = buf->mem + queue->buf_used;
 663         nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
 664         nbytes = min(stream->bulk.max_payload_size - stream->bulk.payload_size,
 665                         nbytes);
 666         memcpy(data, mem, nbytes);
 667
 668         queue->buf_used += nbytes;
 669
 670         return nbytes;
 671 }
 672
 673 /* ------------------------------------------------------------------------
 674  * URB handling
 675  */
 676
 677 /*
 678  * Completion handler for video URBs.
 679  */
 680 static void uvc_video_decode_isoc(struct urb *urb, struct uvc_streaming *stream,
 681         struct uvc_buffer *buf)
 682 {
 683         u8 *mem;
 684         int ret, i;
 685
 686         for (i = 0; i < urb->number_of_packets; ++i) {
 687                 if (urb->iso_frame_desc[i].status < 0) {
 688                         uvc_trace(UVC_TRACE_FRAME, "USB isochronous frame "
 689                                 "lost (%d).\n", urb->iso_frame_desc[i].status);
 690                         /* Mark the buffer as faulty. */
 691                         if (buf != NULL)
 692                                 buf->error = 1;
 693                         continue;
 694                 }
 695
 696                 /* Decode the payload header. */
 697                 mem = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
 698                 do {
 699                         ret = uvc_video_decode_start(stream, buf, mem,
 700                                 urb->iso_frame_desc[i].actual_length);
 701                         if (ret == -EAGAIN)
 702                                 buf = uvc_queue_next_buffer(&stream->queue,
 703                                                             buf);
 704                 } while (ret == -EAGAIN);
 705
 706                 if (ret < 0)
 707                         continue;
 708
 709                 /* Decode the payload data. */
 710                 uvc_video_decode_data(stream, buf, mem + ret,
 711                         urb->iso_frame_desc[i].actual_length - ret);
 712
 713                 /* Process the header again. */
 714                 uvc_video_decode_end(stream, buf, mem,
 715                         urb->iso_frame_desc[i].actual_length);
 716
 717                 if (buf->state == UVC_BUF_STATE_READY) {
 718                         if (buf->length != buf->bytesused &&
 719                             !(stream->cur_format->flags &
 720                               UVC_FMT_FLAG_COMPRESSED))
 721                                 buf->error = 1;
 722
 723                         buf = uvc_queue_next_buffer(&stream->queue, buf);
 724                 }
 725         }
 726 }
 727
 728 static void uvc_video_decode_bulk(struct urb *urb, struct uvc_streaming *stream,
 729         struct uvc_buffer *buf)
 730 {
 731         u8 *mem;
 732         int len, ret;
 733
 734         if (urb->actual_length == 0)
 735                 return;
 736
 737         mem = urb->transfer_buffer;
 738         len = urb->actual_length;
 739         stream->bulk.payload_size += len;
 740
 741         /* If the URB is the first of its payload, decode and save the
 742          * header.
 743          */
 744         if (stream->bulk.header_size == 0 && !stream->bulk.skip_payload) {
 745                 do {
 746                         ret = uvc_video_decode_start(stream, buf, mem, len);
 747                         if (ret == -EAGAIN)
 748                                 buf = uvc_queue_next_buffer(&stream->queue,
 749                                                             buf);
 750                 } while (ret == -EAGAIN);
 751
 752                 /* If an error occurred skip the rest of the payload. */
 753                 if (ret < 0 || buf == NULL) {
 754                         stream->bulk.skip_payload = 1;
 755                 } else {
 756                         memcpy(stream->bulk.header, mem, ret);
 757                         stream->bulk.header_size = ret;
 758
 759                         mem += ret;
 760                         len -= ret;
 761                 }
 762         }
 763
 764         /* The buffer queue might have been cancelled while a bulk transfer
 765          * was in progress, so we can reach here with buf equal to NULL. Make
 766          * sure buf is never dereferenced if NULL.
 767          */
 768
 769         /* Process video data. */
 770         if (!stream->bulk.skip_payload && buf != NULL)
 771                 uvc_video_decode_data(stream, buf, mem, len);
 772
 773         /* Detect the payload end by a URB smaller than the maximum size (or
 774          * a payload size equal to the maximum) and process the header again.
 775          */
 776         if (urb->actual_length < urb->transfer_buffer_length ||
 777             stream->bulk.payload_size >= stream->bulk.max_payload_size) {
 778                 if (!stream->bulk.skip_payload && buf != NULL) {
 779                         uvc_video_decode_end(stream, buf, stream->bulk.header,
 780                                 stream->bulk.payload_size);
 781                         if (buf->state == UVC_BUF_STATE_READY)
 782                                 buf = uvc_queue_next_buffer(&stream->queue,
 783                                                             buf);
 784                 }
 785
 786                 stream->bulk.header_size = 0;
 787                 stream->bulk.skip_payload = 0;
 788                 stream->bulk.payload_size = 0;
 789         }
 790 }
 791
 792 static void uvc_video_encode_bulk(struct urb *urb, struct uvc_streaming *stream,
 793         struct uvc_buffer *buf)
 794 {
 795         u8 *mem = urb->transfer_buffer;
 796         int len = stream->urb_size, ret;
 797
 798         if (buf == NULL) {
 799                 urb->transfer_buffer_length = 0;
 800                 return;
 801         }
 802
 803         /* If the URB is the first of its payload, add the header. */
 804         if (stream->bulk.header_size == 0) {
 805                 ret = uvc_video_encode_header(stream, buf, mem, len);
 806                 stream->bulk.header_size = ret;
 807                 stream->bulk.payload_size += ret;
 808                 mem += ret;
 809                 len -= ret;
 810         }
 811
 812         /* Process video data. */
 813         ret = uvc_video_encode_data(stream, buf, mem, len);
 814
 815         stream->bulk.payload_size += ret;
 816         len -= ret;
 817
 818         if (buf->bytesused == stream->queue.buf_used ||
 819             stream->bulk.payload_size == stream->bulk.max_payload_size) {
 820                 if (buf->bytesused == stream->queue.buf_used) {
 821                         stream->queue.buf_used = 0;
 822                         buf->state = UVC_BUF_STATE_READY;
 823                         buf->buf.v4l2_buf.sequence = ++stream->sequence;
 824                         uvc_queue_next_buffer(&stream->queue, buf);
 825                         stream->last_fid ^= UVC_STREAM_FID;
 826                 }
 827
 828                 stream->bulk.header_size = 0;
 829                 stream->bulk.payload_size = 0;
 830         }
 831
 832         urb->transfer_buffer_length = stream->urb_size - len;
 833 }
 834
 835 static void uvc_video_complete(struct urb *urb)
 836 {
 837         struct uvc_streaming *stream = urb->context;
 838         struct uvc_video_queue *queue = &stream->queue;
 839         struct uvc_buffer *buf = NULL;
 840         unsigned long flags;
 841         int ret;
 842
 843         switch (urb->status) {
 844         case 0:
 845                 break;
 846
 847         default:
 848                 uvc_printk(KERN_WARNING, "Non-zero status (%d) in video "
 849                         "completion handler.\n", urb->status);
 850
 851         case -ENOENT:           /* usb_kill_urb() called. */
 852                 if (stream->frozen)
 853                         return;
 854
 855         case -ECONNRESET:       /* usb_unlink_urb() called. */
 856         case -ESHUTDOWN:        /* The endpoint is being disabled. */
 857                 uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
 858                 return;
 859         }
 860
 861         spin_lock_irqsave(&queue->irqlock, flags);
 862         if (!list_empty(&queue->irqqueue))
 863                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 864                                        queue);
 865         spin_unlock_irqrestore(&queue->irqlock, flags);
 866
 867         stream->decode(urb, stream, buf);
 868
 869         if ((ret = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
 870                 uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n",
 871                         ret);
 872         }
 873 }
 874
 875 /*
 876  * Free transfer buffers.
 877  */
 878 static void uvc_free_urb_buffers(struct uvc_streaming *stream)
 879 {
 880         unsigned int i;
 881
 882         for (i = 0; i < UVC_URBS; ++i) {
 883                 if (stream->urb_buffer[i]) {
 884 #ifndef CONFIG_DMA_NONCOHERENT
 885                         usb_free_coherent(stream->dev->udev, stream->urb_size,
 886                                 stream->urb_buffer[i], stream->urb_dma[i]);
 887 #else
 888                         kfree(stream->urb_buffer[i]);
 889 #endif
 890                         stream->urb_buffer[i] = NULL;
 891                 }
 892         }
 893
 894         stream->urb_size = 0;
 895 }
 896
 897 /*
 898  * Allocate transfer buffers. This function can be called with buffers
 899  * already allocated when resuming from suspend, in which case it will
 900  * return without touching the buffers.
 901  *
 902  * Limit the buffer size to UVC_MAX_PACKETS bulk/isochronous packets. If the
 903  * system is too low on memory try successively smaller numbers of packets
 904  * until allocation succeeds.
 905  *
 906  * Return the number of allocated packets on success or 0 when out of memory.
 907  */
 908 static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
 909         unsigned int size, unsigned int psize, gfp_t gfp_flags)
 910 {
 911         unsigned int npackets;
 912         unsigned int i;
 913
 914         /* Buffers are already allocated, bail out. */
 915         if (stream->urb_size)
 916                 return stream->urb_size / psize;
 917
 918         /* Compute the number of packets. Bulk endpoints might transfer UVC
 919          * payloads across multiple URBs.
 920          */
 921         npackets = DIV_ROUND_UP(size, psize);
 922         if (npackets > UVC_MAX_PACKETS)
 923                 npackets = UVC_MAX_PACKETS;
 924
 925         /* Retry allocations until one succeed. */
 926         for (; npackets > 1; npackets /= 2) {
 927                 for (i = 0; i < UVC_URBS; ++i) {
 928                         stream->urb_size = psize * npackets;
 929 #ifndef CONFIG_DMA_NONCOHERENT
 930                         stream->urb_buffer[i] = usb_alloc_coherent(
 931                                 stream->dev->udev, stream->urb_size,
 932                                 gfp_flags | __GFP_NOWARN, &stream->urb_dma[i]);
 933 #else
 934                         stream->urb_buffer[i] =
 935                             kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);
 936 #endif
 937                         if (!stream->urb_buffer[i]) {
 938                                 uvc_free_urb_buffers(stream);
 939                                 break;
 940                         }
 941                 }
 942
 943                 if (i == UVC_URBS) {
 944                         uvc_trace(UVC_TRACE_VIDEO, "Allocated %u URB buffers "
 945                                 "of %ux%u bytes each.\n", UVC_URBS, npackets,
 946                                 psize);
 947                         return npackets;
 948                 }
 949         }
 950
 951         uvc_trace(UVC_TRACE_VIDEO, "Failed to allocate URB buffers (%u bytes "
 952                 "per packet).\n", psize);
 953         return 0;
 954 }
 955
 956 /*
 957  * Uninitialize isochronous/bulk URBs and free transfer buffers.
 958  */
 959 static void uvc_uninit_video(struct uvc_streaming *stream, int free_buffers)
 960 {
 961         struct urb *urb;
 962         unsigned int i;
 963
 964         uvc_video_stats_stop(stream);
 965
 966         for (i = 0; i < UVC_URBS; ++i) {
 967                 urb = stream->urb[i];
 968                 if (urb == NULL)
 969                         continue;
 970
 971                 usb_kill_urb(urb);
 972                 usb_free_urb(urb);
 973                 stream->urb[i] = NULL;
 974         }
 975
 976         if (free_buffers)
 977                 uvc_free_urb_buffers(stream);
 978 }
 979
 980 /*
 981  * Initialize isochronous URBs and allocate transfer buffers. The packet size
 982  * is given by the endpoint.
 983  */
 984 static int uvc_init_video_isoc(struct uvc_streaming *stream,
 985         struct usb_host_endpoint *ep, gfp_t gfp_flags)
 986 {
 987         struct urb *urb;
 988         unsigned int npackets, i, j;
 989         u16 psize;
 990         u32 size;
 991
 992         psize = le16_to_cpu(ep->desc.wMaxPacketSize);
 993         psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
 994         size = stream->ctrl.dwMaxVideoFrameSize;
 995
 996         npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
 997         if (npackets == 0)
 998                 return -ENOMEM;
 999
1000         size = npackets * psize;
1001
1002         for (i = 0; i < UVC_URBS; ++i) {
1003                 urb = usb_alloc_urb(npackets, gfp_flags);
1004                 if (urb == NULL) {
1005                         uvc_uninit_video(stream, 1);
1006                         return -ENOMEM;
1007                 }
1008
1009                 urb->dev = stream->dev->udev;
1010                 urb->context = stream;
1011                 urb->pipe = usb_rcvisocpipe(stream->dev->udev,
1012                                 ep->desc.bEndpointAddress);
1013 #ifndef CONFIG_DMA_NONCOHERENT
1014                 urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
1015                 urb->transfer_dma = stream->urb_dma[i];
1016 #else
1017                 urb->transfer_flags = URB_ISO_ASAP;
1018 #endif
1019                 urb->interval = ep->desc.bInterval;
1020                 urb->transfer_buffer = stream->urb_buffer[i];
1021                 urb->complete = uvc_video_complete;
1022                 urb->number_of_packets = npackets;
1023                 urb->transfer_buffer_length = size;
1024
1025                 for (j = 0; j < npackets; ++j) {
1026                         urb->iso_frame_desc[j].offset = j * psize;
1027                         urb->iso_frame_desc[j].length = psize;
1028                 }
1029
1030                 stream->urb[i] = urb;
1031         }
1032
1033         return 0;
1034 }
1035
1036 /*
1037  * Initialize bulk URBs and allocate transfer buffers. The packet size is
1038  * given by the endpoint.
1039  */
1040 static int uvc_init_video_bulk(struct uvc_streaming *stream,
1041         struct usb_host_endpoint *ep, gfp_t gfp_flags)
1042 {
1043         struct urb *urb;
1044         unsigned int npackets, pipe, i;
1045         u16 psize;
1046         u32 size;
1047
1048         psize = le16_to_cpu(ep->desc.wMaxPacketSize) & 0x07ff;
1049         size = stream->ctrl.dwMaxPayloadTransferSize;
1050         stream->bulk.max_payload_size = size;
1051
1052         npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1053         if (npackets == 0)
1054                 return -ENOMEM;
1055
1056         size = npackets * psize;
1057
1058         if (usb_endpoint_dir_in(&ep->desc))
1059                 pipe = usb_rcvbulkpipe(stream->dev->udev,
1060                                        ep->desc.bEndpointAddress);
1061         else
1062                 pipe = usb_sndbulkpipe(stream->dev->udev,
1063                                        ep->desc.bEndpointAddress);
1064
1065         if (stream->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
1066                 size = 0;
1067
1068         for (i = 0; i < UVC_URBS; ++i) {
1069                 urb = usb_alloc_urb(0, gfp_flags);
1070                 if (urb == NULL) {
1071                         uvc_uninit_video(stream, 1);
1072                         return -ENOMEM;
1073                 }
1074
1075                 usb_fill_bulk_urb(urb, stream->dev->udev, pipe,
1076                         stream->urb_buffer[i], size, uvc_video_complete,
1077                         stream);
1078 #ifndef CONFIG_DMA_NONCOHERENT
1079                 urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1080                 urb->transfer_dma = stream->urb_dma[i];
1081 #endif
1082
1083                 stream->urb[i] = urb;
1084         }
1085
1086         return 0;
1087 }
1088
1089 /*
1090  * Initialize isochronous/bulk URBs and allocate transfer buffers.
1091  */
1092 static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
1093 {
1094         struct usb_interface *intf = stream->intf;
1095         struct usb_host_endpoint *ep;
1096         unsigned int i;
1097         int ret;
1098
1099         stream->sequence = -1;
1100         stream->last_fid = -1;
1101         stream->bulk.header_size = 0;
1102         stream->bulk.skip_payload = 0;
1103         stream->bulk.payload_size = 0;
1104
1105         uvc_video_stats_start(stream);
1106
1107         if (intf->num_altsetting > 1) {
1108                 struct usb_host_endpoint *best_ep = NULL;
1109                 unsigned int best_psize = 3 * 1024;
1110                 unsigned int bandwidth;
1111                 unsigned int uninitialized_var(altsetting);
1112                 int intfnum = stream->intfnum;
1113
1114                 /* Isochronous endpoint, select the alternate setting. */
1115                 bandwidth = stream->ctrl.dwMaxPayloadTransferSize;
1116
1117                 if (bandwidth == 0) {
1118                         uvc_trace(UVC_TRACE_VIDEO, "Device requested null "
1119                                 "bandwidth, defaulting to lowest.\n");
1120                         bandwidth = 1;
1121                 } else {
1122                         uvc_trace(UVC_TRACE_VIDEO, "Device requested %u "
1123                                 "B/frame bandwidth.\n", bandwidth);
1124                 }
1125
1126                 for (i = 0; i < intf->num_altsetting; ++i) {
1127                         struct usb_host_interface *alts;
1128                         unsigned int psize;
1129
1130                         alts = &intf->altsetting[i];
1131                         ep = uvc_find_endpoint(alts,
1132                                 stream->header.bEndpointAddress);
1133                         if (ep == NULL)
1134                                 continue;
1135
1136                         /* Check if the bandwidth is high enough. */
1137                         psize = le16_to_cpu(ep->desc.wMaxPacketSize);
1138                         psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
1139                         if (psize >= bandwidth && psize <= best_psize) {
1140                                 altsetting = i;
1141                                 best_psize = psize;
1142                                 best_ep = ep;
1143                         }
1144                 }
1145
1146                 if (best_ep == NULL) {
1147                         uvc_trace(UVC_TRACE_VIDEO, "No fast enough alt setting "
1148                                 "for requested bandwidth.\n");
1149                         return -EIO;
1150                 }
1151
1152                 uvc_trace(UVC_TRACE_VIDEO, "Selecting alternate setting %u "
1153                         "(%u B/frame bandwidth).\n", altsetting, best_psize);
1154
1155                 ret = usb_set_interface(stream->dev->udev, intfnum, altsetting);
1156                 if (ret < 0)
1157                         return ret;
1158
1159                 ret = uvc_init_video_isoc(stream, best_ep, gfp_flags);
1160         } else {
1161                 /* Bulk endpoint, proceed to URB initialization. */
1162                 ep = uvc_find_endpoint(&intf->altsetting[0],
1163                                 stream->header.bEndpointAddress);
1164                 if (ep == NULL)
1165                         return -EIO;
1166
1167                 ret = uvc_init_video_bulk(stream, ep, gfp_flags);
1168         }
1169
1170         if (ret < 0)
1171                 return ret;
1172
1173         /* Submit the URBs. */
1174         for (i = 0; i < UVC_URBS; ++i) {
1175                 ret = usb_submit_urb(stream->urb[i], gfp_flags);
1176                 if (ret < 0) {
1177                         uvc_printk(KERN_ERR, "Failed to submit URB %u "
1178                                         "(%d).\n", i, ret);
1179                         uvc_uninit_video(stream, 1);
1180                         return ret;
1181                 }
1182         }
1183
1184         return 0;
1185 }
1186
1187 /* --------------------------------------------------------------------------
1188  * Suspend/resume
1189  */
1190
1191 /*
1192  * Stop streaming without disabling the video queue.
1193  *
1194  * To let userspace applications resume without trouble, we must not touch the
1195  * video buffers in any way. We mark the device as frozen to make sure the URB
1196  * completion handler won't try to cancel the queue when we kill the URBs.
1197  */
1198 int uvc_video_suspend(struct uvc_streaming *stream)
1199 {
1200         if (!uvc_queue_streaming(&stream->queue))
1201                 return 0;
1202
1203         stream->frozen = 1;
1204         uvc_uninit_video(stream, 0);
1205         usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1206         return 0;
1207 }
1208
1209 /*
1210  * Reconfigure the video interface and restart streaming if it was enabled
1211  * before suspend.
1212  *
1213  * If an error occurs, disable the video queue. This will wake all pending
1214  * buffers, making sure userspace applications are notified of the problem
1215  * instead of waiting forever.
1216  */
1217 int uvc_video_resume(struct uvc_streaming *stream, int reset)
1218 {
1219         int ret;
1220
1221         /* If the bus has been reset on resume, set the alternate setting to 0.
1222          * This should be the default value, but some devices crash or otherwise
1223          * misbehave if they don't receive a SET_INTERFACE request before any
1224          * other video control request.
1225          */
1226         if (reset)
1227                 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1228
1229         stream->frozen = 0;
1230
1231         ret = uvc_commit_video(stream, &stream->ctrl);
1232         if (ret < 0) {
1233                 uvc_queue_enable(&stream->queue, 0);
1234                 return ret;
1235         }
1236
1237         if (!uvc_queue_streaming(&stream->queue))
1238                 return 0;
1239
1240         ret = uvc_init_video(stream, GFP_NOIO);
1241         if (ret < 0)
1242                 uvc_queue_enable(&stream->queue, 0);
1243
1244         return ret;
1245 }
1246
1247 /* ------------------------------------------------------------------------
1248  * Video device
1249  */
1250
1251 /*
1252  * Initialize the UVC video device by switching to alternate setting 0 and
1253  * retrieve the default format.
1254  *
1255  * Some cameras (namely the Fuji Finepix) set the format and frame
1256  * indexes to zero. The UVC standard doesn't clearly make this a spec
1257  * violation, so try to silently fix the values if possible.
1258  *
1259  * This function is called before registering the device with V4L.
1260  */
1261 int uvc_video_init(struct uvc_streaming *stream)
1262 {
1263         struct uvc_streaming_control *probe = &stream->ctrl;
1264         struct uvc_format *format = NULL;
1265         struct uvc_frame *frame = NULL;
1266         unsigned int i;
1267         int ret;
1268
1269         if (stream->nformats == 0) {
1270                 uvc_printk(KERN_INFO, "No supported video formats found.\n");
1271                 return -EINVAL;
1272         }
1273
1274         atomic_set(&stream->active, 0);
1275
1276         /* Initialize the video buffers queue. */
1277         uvc_queue_init(&stream->queue, stream->type, !uvc_no_drop_param);
1278
1279         /* Alternate setting 0 should be the default, yet the XBox Live Vision
1280          * Cam (and possibly other devices) crash or otherwise misbehave if
1281          * they don't receive a SET_INTERFACE request before any other video
1282          * control request.
1283          */
1284         usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1285
1286         /* Set the streaming probe control with default streaming parameters
1287          * retrieved from the device. Webcams that don't suport GET_DEF
1288          * requests on the probe control will just keep their current streaming
1289          * parameters.
1290          */
1291         if (uvc_get_video_ctrl(stream, probe, 1, UVC_GET_DEF) == 0)
1292                 uvc_set_video_ctrl(stream, probe, 1);
1293
1294         /* Initialize the streaming parameters with the probe control current
1295          * value. This makes sure SET_CUR requests on the streaming commit
1296          * control will always use values retrieved from a successful GET_CUR
1297          * request on the probe control, as required by the UVC specification.
1298          */
1299         ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
1300         if (ret < 0)
1301                 return ret;
1302
1303         /* Check if the default format descriptor exists. Use the first
1304          * available format otherwise.
1305          */
1306         for (i = stream->nformats; i > 0; --i) {
1307                 format = &stream->format[i-1];
1308                 if (format->index == probe->bFormatIndex)
1309                         break;
1310         }
1311
1312         if (format->nframes == 0) {
1313                 uvc_printk(KERN_INFO, "No frame descriptor found for the "
1314                         "default format.\n");
1315                 return -EINVAL;
1316         }
1317
1318         /* Zero bFrameIndex might be correct. Stream-based formats (including
1319          * MPEG-2 TS and DV) do not support frames but have a dummy frame
1320          * descriptor with bFrameIndex set to zero. If the default frame
1321          * descriptor is not found, use the first available frame.
1322          */
1323         for (i = format->nframes; i > 0; --i) {
1324                 frame = &format->frame[i-1];
1325                 if (frame->bFrameIndex == probe->bFrameIndex)
1326                         break;
1327         }
1328
1329         probe->bFormatIndex = format->index;
1330         probe->bFrameIndex = frame->bFrameIndex;
1331
1332         stream->cur_format = format;
1333         stream->cur_frame = frame;
1334
1335         /* Select the video decoding function */
1336         if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
1337                 if (stream->dev->quirks & UVC_QUIRK_BUILTIN_ISIGHT)
1338                         stream->decode = uvc_video_decode_isight;
1339                 else if (stream->intf->num_altsetting > 1)
1340                         stream->decode = uvc_video_decode_isoc;
1341                 else
1342                         stream->decode = uvc_video_decode_bulk;
1343         } else {
1344                 if (stream->intf->num_altsetting == 1)
1345                         stream->decode = uvc_video_encode_bulk;
1346                 else {
1347                         uvc_printk(KERN_INFO, "Isochronous endpoints are not "
1348                                 "supported for video output devices.\n");
1349                         return -EINVAL;
1350                 }
1351         }
1352
1353         return 0;
1354 }
1355
1356 /*
1357  * Enable or disable the video stream.
1358  */
1359 int uvc_video_enable(struct uvc_streaming *stream, int enable)
1360 {
1361         int ret;
1362
1363         if (!enable) {
1364                 uvc_uninit_video(stream, 1);
1365                 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1366                 uvc_queue_enable(&stream->queue, 0);
1367                 return 0;
1368         }
1369
1370         ret = uvc_queue_enable(&stream->queue, 1);
1371         if (ret < 0)
1372                 return ret;
1373
1374         /* Commit the streaming parameters. */
1375         ret = uvc_commit_video(stream, &stream->ctrl);
1376         if (ret < 0) {
1377                 uvc_queue_enable(&stream->queue, 0);
1378                 return ret;
1379         }
1380
1381         ret = uvc_init_video(stream, GFP_KERNEL);
1382         if (ret < 0) {
1383                 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1384                 uvc_queue_enable(&stream->queue, 0);
1385         }
1386
1387         return ret;
1388 }