sound/usb/usx2y/usb_stream.c

   1 /*
   2  * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software Foundation,
  16  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 #include <linux/usb.h>
  20 #include <linux/gfp.h>
  21
  22 #include "usb_stream.h"
  23
  24
  25 /*                             setup                                  */
  26
  27 static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
  28 {
  29         struct usb_stream *s = sk->s;
  30         sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
  31         return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
  32 }
  33
  34 static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
  35 {
  36         struct usb_stream *s = sk->s;
  37         int pack, lb = 0;
  38
  39         for (pack = 0; pack < sk->n_o_ps; pack++) {
  40                 int l = usb_stream_next_packet_size(sk);
  41                 if (s->idle_outsize + lb + l > s->period_size)
  42                         goto check;
  43
  44                 sk->out_phase = sk->out_phase_peeked;
  45                 urb->iso_frame_desc[pack].offset = lb;
  46                 urb->iso_frame_desc[pack].length = l;
  47                 lb += l;
  48         }
  49         snd_printdd(KERN_DEBUG "%i\n", lb);
  50
  51 check:
  52         urb->number_of_packets = pack;
  53         urb->transfer_buffer_length = lb;
  54         s->idle_outsize += lb - s->period_size;
  55         snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
  56                     lb, s->period_size);
  57 }
  58
  59 static int init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
  60                            struct urb **urbs, char *transfer,
  61                            struct usb_device *dev, int pipe)
  62 {
  63         int u, p;
  64         int maxpacket = use_packsize ?
  65                 use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
  66         int transfer_length = maxpacket * sk->n_o_ps;
  67
  68         for (u = 0; u < USB_STREAM_NURBS;
  69              ++u, transfer += transfer_length) {
  70                 struct urb *urb = urbs[u];
  71                 struct usb_iso_packet_descriptor *desc;
  72                 urb->transfer_buffer = transfer;
  73                 urb->dev = dev;
  74                 urb->pipe = pipe;
  75                 urb->number_of_packets = sk->n_o_ps;
  76                 urb->context = sk;
  77                 urb->interval = 1;
  78                 if (usb_pipeout(pipe))
  79                         continue;
  80                 if (usb_urb_ep_type_check(urb))
  81                         return -EINVAL;
  82
  83                 urb->transfer_buffer_length = transfer_length;
  84                 desc = urb->iso_frame_desc;
  85                 desc->offset = 0;
  86                 desc->length = maxpacket;
  87                 for (p = 1; p < sk->n_o_ps; ++p) {
  88                         desc[p].offset = desc[p - 1].offset + maxpacket;
  89                         desc[p].length = maxpacket;
  90                 }
  91         }
  92
  93         return 0;
  94 }
  95
  96 static int init_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
  97                       struct usb_device *dev, int in_pipe, int out_pipe)
  98 {
  99         struct usb_stream       *s = sk->s;
 100         char                    *indata = (char *)s + sizeof(*s) +
 101                                         sizeof(struct usb_stream_packet) *
 102                                         s->inpackets;
 103         int                     u;
 104
 105         for (u = 0; u < USB_STREAM_NURBS; ++u) {
 106                 sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
 107                 sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
 108         }
 109
 110         if (init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe) ||
 111             init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
 112                            out_pipe))
 113                 return -EINVAL;
 114
 115         return 0;
 116 }
 117
 118
 119 /*
 120  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 121  * this will overflow at approx 524 kHz
 122  */
 123 static inline unsigned get_usb_full_speed_rate(unsigned rate)
 124 {
 125         return ((rate << 13) + 62) / 125;
 126 }
 127
 128 /*
 129  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 130  * this will overflow at approx 4 MHz
 131  */
 132 static inline unsigned get_usb_high_speed_rate(unsigned rate)
 133 {
 134         return ((rate << 10) + 62) / 125;
 135 }
 136
 137 void usb_stream_free(struct usb_stream_kernel *sk)
 138 {
 139         struct usb_stream *s;
 140         unsigned u;
 141
 142         for (u = 0; u < USB_STREAM_NURBS; ++u) {
 143                 usb_free_urb(sk->inurb[u]);
 144                 sk->inurb[u] = NULL;
 145                 usb_free_urb(sk->outurb[u]);
 146                 sk->outurb[u] = NULL;
 147         }
 148
 149         s = sk->s;
 150         if (!s)
 151                 return;
 152
 153         free_pages((unsigned long)sk->write_page, get_order(s->write_size));
 154         sk->write_page = NULL;
 155         free_pages((unsigned long)s, get_order(s->read_size));
 156         sk->s = NULL;
 157 }
 158
 159 struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
 160                                   struct usb_device *dev,
 161                                   unsigned in_endpoint, unsigned out_endpoint,
 162                                   unsigned sample_rate, unsigned use_packsize,
 163                                   unsigned period_frames, unsigned frame_size)
 164 {
 165         int packets, max_packsize;
 166         int in_pipe, out_pipe;
 167         int read_size = sizeof(struct usb_stream);
 168         int write_size;
 169         int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
 170         int pg;
 171
 172         in_pipe = usb_rcvisocpipe(dev, in_endpoint);
 173         out_pipe = usb_sndisocpipe(dev, out_endpoint);
 174
 175         max_packsize = use_packsize ?
 176                 use_packsize : usb_maxpacket(dev, in_pipe, 0);
 177
 178         /*
 179                 t_period = period_frames / sample_rate
 180                 iso_packs = t_period / t_iso_frame
 181                         = (period_frames / sample_rate) * (1 / t_iso_frame)
 182         */
 183
 184         packets = period_frames * usb_frames / sample_rate + 1;
 185
 186         if (dev->speed == USB_SPEED_HIGH)
 187                 packets = (packets + 7) & ~7;
 188
 189         read_size += packets * USB_STREAM_URBDEPTH *
 190                 (max_packsize + sizeof(struct usb_stream_packet));
 191
 192         max_packsize = usb_maxpacket(dev, out_pipe, 1);
 193         write_size = max_packsize * packets * USB_STREAM_URBDEPTH;
 194
 195         if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
 196                 snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
 197                 goto out;
 198         }
 199
 200         pg = get_order(read_size);
 201         sk->s = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO|
 202                                           __GFP_NOWARN, pg);
 203         if (!sk->s) {
 204                 snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
 205                 goto out;
 206         }
 207         sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;
 208
 209         sk->s->read_size = read_size;
 210
 211         sk->s->cfg.sample_rate = sample_rate;
 212         sk->s->cfg.frame_size = frame_size;
 213         sk->n_o_ps = packets;
 214         sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
 215         sk->s->cfg.period_frames = period_frames;
 216         sk->s->period_size = frame_size * period_frames;
 217
 218         sk->s->write_size = write_size;
 219         pg = get_order(write_size);
 220
 221         sk->write_page =
 222                 (void *)__get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO|
 223                                          __GFP_NOWARN, pg);
 224         if (!sk->write_page) {
 225                 snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
 226                 usb_stream_free(sk);
 227                 return NULL;
 228         }
 229
 230         /* calculate the frequency in 16.16 format */
 231         if (dev->speed == USB_SPEED_FULL)
 232                 sk->freqn = get_usb_full_speed_rate(sample_rate);
 233         else
 234                 sk->freqn = get_usb_high_speed_rate(sample_rate);
 235
 236         if (init_urbs(sk, use_packsize, dev, in_pipe, out_pipe) < 0) {
 237                 usb_stream_free(sk);
 238                 return NULL;
 239         }
 240
 241         sk->s->state = usb_stream_stopped;
 242 out:
 243         return sk->s;
 244 }
 245
 246
 247 /*                             start                                  */
 248
 249 static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
 250 {
 251         bool r;
 252         if (unlikely(urb->status)) {
 253                 if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
 254                         snd_printk(KERN_WARNING "status=%i\n", urb->status);
 255                 sk->iso_frame_balance = 0x7FFFFFFF;
 256                 return false;
 257         }
 258         r = sk->iso_frame_balance == 0;
 259         if (!r)
 260                 sk->i_urb = urb;
 261         return r;
 262 }
 263
 264 static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
 265 {
 266         sk->iso_frame_balance += urb->number_of_packets;
 267         return balance_check(sk, urb);
 268 }
 269
 270 static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
 271 {
 272         sk->iso_frame_balance -= urb->number_of_packets;
 273         return balance_check(sk, urb);
 274 }
 275
 276 static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
 277 {
 278         int u;
 279
 280         for (u = 0; u < USB_STREAM_NURBS; u++) {
 281                 struct urb *urb = urbs[u];
 282                 urb->complete = complete;
 283         }
 284 }
 285
 286 static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
 287                 struct urb *inurb)
 288 {
 289         struct usb_stream *s = sk->s;
 290         struct urb *io;
 291         struct usb_iso_packet_descriptor *id, *od;
 292         int p = 0, lb = 0, l = 0;
 293
 294         io = sk->idle_outurb;
 295         od = io->iso_frame_desc;
 296
 297         for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
 298                 struct urb *ii = sk->completed_inurb;
 299                 id = ii->iso_frame_desc +
 300                         ii->number_of_packets + s->sync_packet;
 301                 l = id->actual_length;
 302
 303                 od[p].length = l;
 304                 od[p].offset = lb;
 305                 lb += l;
 306         }
 307
 308         for (;
 309              s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
 310              ++p, ++s->sync_packet) {
 311                 l = inurb->iso_frame_desc[s->sync_packet].actual_length;
 312
 313                 if (s->idle_outsize + lb + l > s->period_size)
 314                         goto check_ok;
 315
 316                 od[p].length = l;
 317                 od[p].offset = lb;
 318                 lb += l;
 319         }
 320
 321 check_ok:
 322         s->sync_packet -= inurb->number_of_packets;
 323         if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
 324                 snd_printk(KERN_WARNING "invalid sync_packet = %i;"
 325                            " p=%i nop=%i %i %x %x %x > %x\n",
 326                            s->sync_packet, p, inurb->number_of_packets,
 327                            s->idle_outsize + lb + l,
 328                            s->idle_outsize, lb,  l,
 329                            s->period_size);
 330                 return -1;
 331         }
 332         if (unlikely(lb % s->cfg.frame_size)) {
 333                 snd_printk(KERN_WARNING"invalid outsize = %i\n",
 334                            lb);
 335                 return -1;
 336         }
 337         s->idle_outsize += lb - s->period_size;
 338         io->number_of_packets = p;
 339         io->transfer_buffer_length = lb;
 340         if (s->idle_outsize <= 0)
 341                 return 0;
 342
 343         snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
 344         return -1;
 345 }
 346
 347 static void prepare_inurb(int number_of_packets, struct urb *iu)
 348 {
 349         struct usb_iso_packet_descriptor *id;
 350         int p;
 351
 352         iu->number_of_packets = number_of_packets;
 353         id = iu->iso_frame_desc;
 354         id->offset = 0;
 355         for (p = 0; p < iu->number_of_packets - 1; ++p)
 356                 id[p + 1].offset = id[p].offset + id[p].length;
 357
 358         iu->transfer_buffer_length =
 359                 id[0].length * iu->number_of_packets;
 360 }
 361
 362 static int submit_urbs(struct usb_stream_kernel *sk,
 363                        struct urb *inurb, struct urb *outurb)
 364 {
 365         int err;
 366         prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
 367         err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
 368         if (err < 0)
 369                 goto report_failure;
 370
 371         sk->idle_inurb = sk->completed_inurb;
 372         sk->completed_inurb = inurb;
 373         err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
 374         if (err < 0)
 375                 goto report_failure;
 376
 377         sk->idle_outurb = sk->completed_outurb;
 378         sk->completed_outurb = outurb;
 379         return 0;
 380
 381 report_failure:
 382         snd_printk(KERN_ERR "%i\n", err);
 383         return err;
 384 }
 385
 386 #ifdef DEBUG_LOOP_BACK
 387 /*
 388   This loop_back() shows how to read/write the period data.
 389  */
 390 static void loop_back(struct usb_stream *s)
 391 {
 392         char *i, *o;
 393         int il, ol, l, p;
 394         struct urb *iu;
 395         struct usb_iso_packet_descriptor *id;
 396
 397         o = s->playback1st_to;
 398         ol = s->playback1st_size;
 399         l = 0;
 400
 401         if (s->insplit_pack >= 0) {
 402                 iu = sk->idle_inurb;
 403                 id = iu->iso_frame_desc;
 404                 p = s->insplit_pack;
 405         } else
 406                 goto second;
 407 loop:
 408         for (; p < iu->number_of_packets && l < s->period_size; ++p) {
 409                 i = iu->transfer_buffer + id[p].offset;
 410                 il = id[p].actual_length;
 411                 if (l + il > s->period_size)
 412                         il = s->period_size - l;
 413                 if (il <= ol) {
 414                         memcpy(o, i, il);
 415                         o += il;
 416                         ol -= il;
 417                 } else {
 418                         memcpy(o, i, ol);
 419                         singen_6pack(o, ol);
 420                         o = s->playback_to;
 421                         memcpy(o, i + ol, il - ol);
 422                         o += il - ol;
 423                         ol = s->period_size - s->playback1st_size;
 424                 }
 425                 l += il;
 426         }
 427         if (iu == sk->completed_inurb) {
 428                 if (l != s->period_size)
 429                         printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
 430                                l/(int)s->cfg.frame_size);
 431
 432                 return;
 433         }
 434 second:
 435         iu = sk->completed_inurb;
 436         id = iu->iso_frame_desc;
 437         p = 0;
 438         goto loop;
 439
 440 }
 441 #else
 442 static void loop_back(struct usb_stream *s)
 443 {
 444 }
 445 #endif
 446
 447 static void stream_idle(struct usb_stream_kernel *sk,
 448                         struct urb *inurb, struct urb *outurb)
 449 {
 450         struct usb_stream *s = sk->s;
 451         int l, p;
 452         int insize = s->idle_insize;
 453         int urb_size = 0;
 454
 455         s->inpacket_split = s->next_inpacket_split;
 456         s->inpacket_split_at = s->next_inpacket_split_at;
 457         s->next_inpacket_split = -1;
 458         s->next_inpacket_split_at = 0;
 459
 460         for (p = 0; p < inurb->number_of_packets; ++p) {
 461                 struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
 462                 l = id[p].actual_length;
 463                 if (unlikely(l == 0 || id[p].status)) {
 464                         snd_printk(KERN_WARNING "underrun, status=%u\n",
 465                                    id[p].status);
 466                         goto err_out;
 467                 }
 468                 s->inpacket_head++;
 469                 s->inpacket_head %= s->inpackets;
 470                 if (s->inpacket_split == -1)
 471                         s->inpacket_split = s->inpacket_head;
 472
 473                 s->inpacket[s->inpacket_head].offset =
 474                         id[p].offset + (inurb->transfer_buffer - (void *)s);
 475                 s->inpacket[s->inpacket_head].length = l;
 476                 if (insize + l > s->period_size &&
 477                     s->next_inpacket_split == -1) {
 478                         s->next_inpacket_split = s->inpacket_head;
 479                         s->next_inpacket_split_at = s->period_size - insize;
 480                 }
 481                 insize += l;
 482                 urb_size += l;
 483         }
 484         s->idle_insize += urb_size - s->period_size;
 485         if (s->idle_insize < 0) {
 486                 snd_printk(KERN_WARNING "%i\n",
 487                            (s->idle_insize)/(int)s->cfg.frame_size);
 488                 goto err_out;
 489         }
 490         s->insize_done += urb_size;
 491
 492         l = s->idle_outsize;
 493         s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
 494                                   sk->write_page) - l;
 495
 496         if (usb_stream_prepare_playback(sk, inurb) < 0)
 497                 goto err_out;
 498
 499         s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
 500         s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
 501                 sk->write_page;
 502
 503         if (submit_urbs(sk, inurb, outurb) < 0)
 504                 goto err_out;
 505
 506         loop_back(s);
 507         s->periods_done++;
 508         wake_up_all(&sk->sleep);
 509         return;
 510 err_out:
 511         s->state = usb_stream_xrun;
 512         wake_up_all(&sk->sleep);
 513 }
 514
 515 static void i_capture_idle(struct urb *urb)
 516 {
 517         struct usb_stream_kernel *sk = urb->context;
 518         if (balance_capture(sk, urb))
 519                 stream_idle(sk, urb, sk->i_urb);
 520 }
 521
 522 static void i_playback_idle(struct urb *urb)
 523 {
 524         struct usb_stream_kernel *sk = urb->context;
 525         if (balance_playback(sk, urb))
 526                 stream_idle(sk, sk->i_urb, urb);
 527 }
 528
 529 static void stream_start(struct usb_stream_kernel *sk,
 530                          struct urb *inurb, struct urb *outurb)
 531 {
 532         struct usb_stream *s = sk->s;
 533         if (s->state >= usb_stream_sync1) {
 534                 int l, p, max_diff, max_diff_0;
 535                 int urb_size = 0;
 536                 unsigned frames_per_packet, min_frames = 0;
 537                 frames_per_packet = (s->period_size - s->idle_insize);
 538                 frames_per_packet <<= 8;
 539                 frames_per_packet /=
 540                         s->cfg.frame_size * inurb->number_of_packets;
 541                 frames_per_packet++;
 542
 543                 max_diff_0 = s->cfg.frame_size;
 544                 if (s->cfg.period_frames >= 256)
 545                         max_diff_0 <<= 1;
 546                 if (s->cfg.period_frames >= 1024)
 547                         max_diff_0 <<= 1;
 548                 max_diff = max_diff_0;
 549                 for (p = 0; p < inurb->number_of_packets; ++p) {
 550                         int diff;
 551                         l = inurb->iso_frame_desc[p].actual_length;
 552                         urb_size += l;
 553
 554                         min_frames += frames_per_packet;
 555                         diff = urb_size -
 556                                 (min_frames >> 8) * s->cfg.frame_size;
 557                         if (diff < max_diff) {
 558                                 snd_printdd(KERN_DEBUG "%i %i %i %i\n",
 559                                             s->insize_done,
 560                                             urb_size / (int)s->cfg.frame_size,
 561                                             inurb->number_of_packets, diff);
 562                                 max_diff = diff;
 563                         }
 564                 }
 565                 s->idle_insize -= max_diff - max_diff_0;
 566                 s->idle_insize += urb_size - s->period_size;
 567                 if (s->idle_insize < 0) {
 568                         snd_printk(KERN_WARNING "%i %i %i\n",
 569                                    s->idle_insize, urb_size, s->period_size);
 570                         return;
 571                 } else if (s->idle_insize == 0) {
 572                         s->next_inpacket_split =
 573                                 (s->inpacket_head + 1) % s->inpackets;
 574                         s->next_inpacket_split_at = 0;
 575                 } else {
 576                         unsigned split = s->inpacket_head;
 577                         l = s->idle_insize;
 578                         while (l > s->inpacket[split].length) {
 579                                 l -= s->inpacket[split].length;
 580                                 if (split == 0)
 581                                         split = s->inpackets - 1;
 582                                 else
 583                                         split--;
 584                         }
 585                         s->next_inpacket_split = split;
 586                         s->next_inpacket_split_at =
 587                                 s->inpacket[split].length - l;
 588                 }
 589
 590                 s->insize_done += urb_size;
 591
 592                 if (usb_stream_prepare_playback(sk, inurb) < 0)
 593                         return;
 594
 595         } else
 596                 playback_prep_freqn(sk, sk->idle_outurb);
 597
 598         if (submit_urbs(sk, inurb, outurb) < 0)
 599                 return;
 600
 601         if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
 602                 /* just guesswork                            ^^^^^^ */
 603                 s->state = usb_stream_ready;
 604                 subs_set_complete(sk->inurb, i_capture_idle);
 605                 subs_set_complete(sk->outurb, i_playback_idle);
 606         }
 607 }
 608
 609 static void i_capture_start(struct urb *urb)
 610 {
 611         struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
 612         struct usb_stream_kernel *sk = urb->context;
 613         struct usb_stream *s = sk->s;
 614         int p;
 615         int empty = 0;
 616
 617         if (urb->status) {
 618                 snd_printk(KERN_WARNING "status=%i\n", urb->status);
 619                 return;
 620         }
 621
 622         for (p = 0; p < urb->number_of_packets; ++p) {
 623                 int l = id[p].actual_length;
 624                 if (l < s->cfg.frame_size) {
 625                         ++empty;
 626                         if (s->state >= usb_stream_sync0) {
 627                                 snd_printk(KERN_WARNING "%i\n", l);
 628                                 return;
 629                         }
 630                 }
 631                 s->inpacket_head++;
 632                 s->inpacket_head %= s->inpackets;
 633                 s->inpacket[s->inpacket_head].offset =
 634                         id[p].offset + (urb->transfer_buffer - (void *)s);
 635                 s->inpacket[s->inpacket_head].length = l;
 636         }
 637 #ifdef SHOW_EMPTY
 638         if (empty) {
 639                 printk(KERN_DEBUG"%s:%i: %i", __func__, __LINE__,
 640                        urb->iso_frame_desc[0].actual_length);
 641                 for (pack = 1; pack < urb->number_of_packets; ++pack) {
 642                         int l = urb->iso_frame_desc[pack].actual_length;
 643                         printk(KERN_CONT " %i", l);
 644                 }
 645                 printk(KERN_CONT "\n");
 646         }
 647 #endif
 648         if (!empty && s->state < usb_stream_sync1)
 649                 ++s->state;
 650
 651         if (balance_capture(sk, urb))
 652                 stream_start(sk, urb, sk->i_urb);
 653 }
 654
 655 static void i_playback_start(struct urb *urb)
 656 {
 657         struct usb_stream_kernel *sk = urb->context;
 658         if (balance_playback(sk, urb))
 659                 stream_start(sk, sk->i_urb, urb);
 660 }
 661
 662 int usb_stream_start(struct usb_stream_kernel *sk)
 663 {
 664         struct usb_stream *s = sk->s;
 665         int frame = 0, iters = 0;
 666         int u, err;
 667         int try = 0;
 668
 669         if (s->state != usb_stream_stopped)
 670                 return -EAGAIN;
 671
 672         subs_set_complete(sk->inurb, i_capture_start);
 673         subs_set_complete(sk->outurb, i_playback_start);
 674         memset(sk->write_page, 0, s->write_size);
 675 dotry:
 676         s->insize_done = 0;
 677         s->idle_insize = 0;
 678         s->idle_outsize = 0;
 679         s->sync_packet = -1;
 680         s->inpacket_head = -1;
 681         sk->iso_frame_balance = 0;
 682         ++try;
 683         for (u = 0; u < 2; u++) {
 684                 struct urb *inurb = sk->inurb[u];
 685                 struct urb *outurb = sk->outurb[u];
 686                 playback_prep_freqn(sk, outurb);
 687                 inurb->number_of_packets = outurb->number_of_packets;
 688                 inurb->transfer_buffer_length =
 689                         inurb->number_of_packets *
 690                         inurb->iso_frame_desc[0].length;
 691
 692                 if (u == 0) {
 693                         int now;
 694                         struct usb_device *dev = inurb->dev;
 695                         frame = usb_get_current_frame_number(dev);
 696                         do {
 697                                 now = usb_get_current_frame_number(dev);
 698                                 ++iters;
 699                         } while (now > -1 && now == frame);
 700                 }
 701                 err = usb_submit_urb(inurb, GFP_ATOMIC);
 702                 if (err < 0) {
 703                         snd_printk(KERN_ERR"usb_submit_urb(sk->inurb[%i])"
 704                                    " returned %i\n", u, err);
 705                         return err;
 706                 }
 707                 err = usb_submit_urb(outurb, GFP_ATOMIC);
 708                 if (err < 0) {
 709                         snd_printk(KERN_ERR"usb_submit_urb(sk->outurb[%i])"
 710                                    " returned %i\n", u, err);
 711                         return err;
 712                 }
 713
 714                 if (inurb->start_frame != outurb->start_frame) {
 715                         snd_printd(KERN_DEBUG
 716                                    "u[%i] start_frames differ in:%u out:%u\n",
 717                                    u, inurb->start_frame, outurb->start_frame);
 718                         goto check_retry;
 719                 }
 720         }
 721         snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
 722         try = 0;
 723 check_retry:
 724         if (try) {
 725                 usb_stream_stop(sk);
 726                 if (try < 5) {
 727                         msleep(1500);
 728                         snd_printd(KERN_DEBUG "goto dotry;\n");
 729                         goto dotry;
 730                 }
 731                 snd_printk(KERN_WARNING"couldn't start"
 732                            " all urbs on the same start_frame.\n");
 733                 return -EFAULT;
 734         }
 735
 736         sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
 737         sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
 738         sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
 739         sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
 740
 741 /* wait, check */
 742         {
 743                 int wait_ms = 3000;
 744                 while (s->state != usb_stream_ready && wait_ms > 0) {
 745                         snd_printdd(KERN_DEBUG "%i\n", s->state);
 746                         msleep(200);
 747                         wait_ms -= 200;
 748                 }
 749         }
 750
 751         return s->state == usb_stream_ready ? 0 : -EFAULT;
 752 }
 753
 754
 755 /*                             stop                                   */
 756
 757 void usb_stream_stop(struct usb_stream_kernel *sk)
 758 {
 759         int u;
 760         if (!sk->s)
 761                 return;
 762         for (u = 0; u < USB_STREAM_NURBS; ++u) {
 763                 usb_kill_urb(sk->inurb[u]);
 764                 usb_kill_urb(sk->outurb[u]);
 765         }
 766         sk->s->state = usb_stream_stopped;
 767         msleep(400);
 768 }