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