linux/sound/usb/usx2y/usb_stream.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
   4 */
   5
   6#include <linux/usb.h>
   7#include <linux/gfp.h>
   8
   9#include "usb_stream.h"
  10
  11/*                             setup                                  */
  12
  13static unsigned int usb_stream_next_packet_size(struct usb_stream_kernel *sk)
  14{
  15        struct usb_stream *s = sk->s;
  16
  17        sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
  18        return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
  19}
  20
  21static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
  22{
  23        struct usb_stream *s = sk->s;
  24        int pack, lb = 0;
  25
  26        for (pack = 0; pack < sk->n_o_ps; pack++) {
  27                int l = usb_stream_next_packet_size(sk);
  28
  29                if (s->idle_outsize + lb + l > s->period_size)
  30                        goto check;
  31
  32                sk->out_phase = sk->out_phase_peeked;
  33                urb->iso_frame_desc[pack].offset = lb;
  34                urb->iso_frame_desc[pack].length = l;
  35                lb += l;
  36        }
  37        snd_printdd(KERN_DEBUG "%i\n", lb);
  38
  39check:
  40        urb->number_of_packets = pack;
  41        urb->transfer_buffer_length = lb;
  42        s->idle_outsize += lb - s->period_size;
  43        snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
  44                    lb, s->period_size);
  45}
  46
  47static int init_pipe_urbs(struct usb_stream_kernel *sk,
  48                          unsigned int use_packsize,
  49                          struct urb **urbs, char *transfer,
  50                          struct usb_device *dev, int pipe)
  51{
  52        int u, p;
  53        int maxpacket = use_packsize ?
  54                use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
  55        int transfer_length = maxpacket * sk->n_o_ps;
  56
  57        for (u = 0; u < USB_STREAM_NURBS;
  58             ++u, transfer += transfer_length) {
  59                struct urb *urb = urbs[u];
  60                struct usb_iso_packet_descriptor *desc;
  61
  62                urb->transfer_buffer = transfer;
  63                urb->dev = dev;
  64                urb->pipe = pipe;
  65                urb->number_of_packets = sk->n_o_ps;
  66                urb->context = sk;
  67                urb->interval = 1;
  68                if (usb_pipeout(pipe))
  69                        continue;
  70                if (usb_urb_ep_type_check(urb))
  71                        return -EINVAL;
  72
  73                urb->transfer_buffer_length = transfer_length;
  74                desc = urb->iso_frame_desc;
  75                desc->offset = 0;
  76                desc->length = maxpacket;
  77                for (p = 1; p < sk->n_o_ps; ++p) {
  78                        desc[p].offset = desc[p - 1].offset + maxpacket;
  79                        desc[p].length = maxpacket;
  80                }
  81        }
  82
  83        return 0;
  84}
  85
  86static int init_urbs(struct usb_stream_kernel *sk, unsigned int use_packsize,
  87                     struct usb_device *dev, int in_pipe, int out_pipe)
  88{
  89        struct usb_stream       *s = sk->s;
  90        char                    *indata =
  91                (char *)s + sizeof(*s) + sizeof(struct usb_stream_packet) * s->inpackets;
  92        int                     u;
  93
  94        for (u = 0; u < USB_STREAM_NURBS; ++u) {
  95                sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
  96                if (!sk->inurb[u])
  97                        return -ENOMEM;
  98
  99                sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
 100                if (!sk->outurb[u])
 101                        return -ENOMEM;
 102        }
 103
 104        if (init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe) ||
 105            init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
 106                           out_pipe))
 107                return -EINVAL;
 108
 109        return 0;
 110}
 111
 112/*
 113 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 114 * this will overflow at approx 524 kHz
 115 */
 116static inline unsigned int get_usb_full_speed_rate(unsigned int rate)
 117{
 118        return ((rate << 13) + 62) / 125;
 119}
 120
 121/*
 122 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 123 * this will overflow at approx 4 MHz
 124 */
 125static inline unsigned int get_usb_high_speed_rate(unsigned int rate)
 126{
 127        return ((rate << 10) + 62) / 125;
 128}
 129
 130void usb_stream_free(struct usb_stream_kernel *sk)
 131{
 132        struct usb_stream *s;
 133        unsigned int u;
 134
 135        for (u = 0; u < USB_STREAM_NURBS; ++u) {
 136                usb_free_urb(sk->inurb[u]);
 137                sk->inurb[u] = NULL;
 138                usb_free_urb(sk->outurb[u]);
 139                sk->outurb[u] = NULL;
 140        }
 141
 142        s = sk->s;
 143        if (!s)
 144                return;
 145
 146        if (sk->write_page) {
 147                free_pages_exact(sk->write_page, s->write_size);
 148                sk->write_page = NULL;
 149        }
 150
 151        free_pages_exact(s, s->read_size);
 152        sk->s = NULL;
 153}
 154
 155struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
 156                                  struct usb_device *dev,
 157                                  unsigned int in_endpoint,
 158                                  unsigned int out_endpoint,
 159                                  unsigned int sample_rate,
 160                                  unsigned int use_packsize,
 161                                  unsigned int period_frames,
 162                                  unsigned int 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
 170        in_pipe = usb_rcvisocpipe(dev, in_endpoint);
 171        out_pipe = usb_sndisocpipe(dev, out_endpoint);
 172
 173        max_packsize = use_packsize ?
 174                use_packsize : usb_maxpacket(dev, in_pipe, 0);
 175
 176        /*
 177                t_period = period_frames / sample_rate
 178                iso_packs = t_period / t_iso_frame
 179                        = (period_frames / sample_rate) * (1 / t_iso_frame)
 180        */
 181
 182        packets = period_frames * usb_frames / sample_rate + 1;
 183
 184        if (dev->speed == USB_SPEED_HIGH)
 185                packets = (packets + 7) & ~7;
 186
 187        read_size += packets * USB_STREAM_URBDEPTH *
 188                (max_packsize + sizeof(struct usb_stream_packet));
 189
 190        max_packsize = usb_maxpacket(dev, out_pipe, 1);
 191        write_size = max_packsize * packets * USB_STREAM_URBDEPTH;
 192
 193        if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
 194                snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
 195                goto out;
 196        }
 197
 198        sk->s = alloc_pages_exact(read_size,
 199                                  GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
 200        if (!sk->s) {
 201                pr_warn("us122l: couldn't allocate read buffer\n");
 202                goto out;
 203        }
 204        sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;
 205
 206        sk->s->read_size = read_size;
 207
 208        sk->s->cfg.sample_rate = sample_rate;
 209        sk->s->cfg.frame_size = frame_size;
 210        sk->n_o_ps = packets;
 211        sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
 212        sk->s->cfg.period_frames = period_frames;
 213        sk->s->period_size = frame_size * period_frames;
 214
 215        sk->s->write_size = write_size;
 216
 217        sk->write_page = alloc_pages_exact(write_size,
 218                                           GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
 219        if (!sk->write_page) {
 220                pr_warn("us122l: couldn't allocate write buffer\n");
 221                usb_stream_free(sk);
 222                return NULL;
 223        }
 224
 225        /* calculate the frequency in 16.16 format */
 226        if (dev->speed == USB_SPEED_FULL)
 227                sk->freqn = get_usb_full_speed_rate(sample_rate);
 228        else
 229                sk->freqn = get_usb_high_speed_rate(sample_rate);
 230
 231        if (init_urbs(sk, use_packsize, dev, in_pipe, out_pipe) < 0) {
 232                usb_stream_free(sk);
 233                return NULL;
 234        }
 235
 236        sk->s->state = usb_stream_stopped;
 237out:
 238        return sk->s;
 239}
 240
 241/*                             start                                  */
 242
 243static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
 244{
 245        bool r;
 246
 247        if (unlikely(urb->status)) {
 248                if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
 249                        snd_printk(KERN_WARNING "status=%i\n", urb->status);
 250                sk->iso_frame_balance = 0x7FFFFFFF;
 251                return false;
 252        }
 253        r = sk->iso_frame_balance == 0;
 254        if (!r)
 255                sk->i_urb = urb;
 256        return r;
 257}
 258
 259static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
 260{
 261        sk->iso_frame_balance += urb->number_of_packets;
 262        return balance_check(sk, urb);
 263}
 264
 265static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
 266{
 267        sk->iso_frame_balance -= urb->number_of_packets;
 268        return balance_check(sk, urb);
 269}
 270
 271static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
 272{
 273        int u;
 274
 275        for (u = 0; u < USB_STREAM_NURBS; u++) {
 276                struct urb *urb = urbs[u];
 277
 278                urb->complete = complete;
 279        }
 280}
 281
 282static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
 283                struct urb *inurb)
 284{
 285        struct usb_stream *s = sk->s;
 286        struct urb *io;
 287        struct usb_iso_packet_descriptor *id, *od;
 288        int p = 0, lb = 0, l = 0;
 289
 290        io = sk->idle_outurb;
 291        od = io->iso_frame_desc;
 292
 293        for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
 294                struct urb *ii = sk->completed_inurb;
 295
 296                id = ii->iso_frame_desc +
 297                        ii->number_of_packets + s->sync_packet;
 298                l = id->actual_length;
 299
 300                od[p].length = l;
 301                od[p].offset = lb;
 302                lb += l;
 303        }
 304
 305        for (;
 306             s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
 307             ++p, ++s->sync_packet) {
 308                l = inurb->iso_frame_desc[s->sync_packet].actual_length;
 309
 310                if (s->idle_outsize + lb + l > s->period_size)
 311                        goto check_ok;
 312
 313                od[p].length = l;
 314                od[p].offset = lb;
 315                lb += l;
 316        }
 317
 318check_ok:
 319        s->sync_packet -= inurb->number_of_packets;
 320        if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
 321                snd_printk(KERN_WARNING "invalid sync_packet = %i;"
 322                           " p=%i nop=%i %i %x %x %x > %x\n",
 323                           s->sync_packet, p, inurb->number_of_packets,
 324                           s->idle_outsize + lb + l,
 325                           s->idle_outsize, lb,  l,
 326                           s->period_size);
 327                return -1;
 328        }
 329        if (unlikely(lb % s->cfg.frame_size)) {
 330                snd_printk(KERN_WARNING"invalid outsize = %i\n",
 331                           lb);
 332                return -1;
 333        }
 334        s->idle_outsize += lb - s->period_size;
 335        io->number_of_packets = p;
 336        io->transfer_buffer_length = lb;
 337        if (s->idle_outsize <= 0)
 338                return 0;
 339
 340        snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
 341        return -1;
 342}
 343
 344static void prepare_inurb(int number_of_packets, struct urb *iu)
 345{
 346        struct usb_iso_packet_descriptor *id;
 347        int p;
 348
 349        iu->number_of_packets = number_of_packets;
 350        id = iu->iso_frame_desc;
 351        id->offset = 0;
 352        for (p = 0; p < iu->number_of_packets - 1; ++p)
 353                id[p + 1].offset = id[p].offset + id[p].length;
 354
 355        iu->transfer_buffer_length =
 356                id[0].length * iu->number_of_packets;
 357}
 358
 359static int submit_urbs(struct usb_stream_kernel *sk,
 360                       struct urb *inurb, struct urb *outurb)
 361{
 362        int err;
 363
 364        prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
 365        err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
 366        if (err < 0)
 367                goto report_failure;
 368
 369        sk->idle_inurb = sk->completed_inurb;
 370        sk->completed_inurb = inurb;
 371        err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
 372        if (err < 0)
 373                goto report_failure;
 374
 375        sk->idle_outurb = sk->completed_outurb;
 376        sk->completed_outurb = outurb;
 377        return 0;
 378
 379report_failure:
 380        snd_printk(KERN_ERR "%i\n", err);
 381        return err;
 382}
 383
 384#ifdef DEBUG_LOOP_BACK
 385/*
 386  This loop_back() shows how to read/write the period data.
 387 */
 388static void loop_back(struct usb_stream *s)
 389{
 390        char *i, *o;
 391        int il, ol, l, p;
 392        struct urb *iu;
 393        struct usb_iso_packet_descriptor *id;
 394
 395        o = s->playback1st_to;
 396        ol = s->playback1st_size;
 397        l = 0;
 398
 399        if (s->insplit_pack >= 0) {
 400                iu = sk->idle_inurb;
 401                id = iu->iso_frame_desc;
 402                p = s->insplit_pack;
 403        } else
 404                goto second;
 405loop:
 406        for (; p < iu->number_of_packets && l < s->period_size; ++p) {
 407                i = iu->transfer_buffer + id[p].offset;
 408                il = id[p].actual_length;
 409                if (l + il > s->period_size)
 410                        il = s->period_size - l;
 411                if (il <= ol) {
 412                        memcpy(o, i, il);
 413                        o += il;
 414                        ol -= il;
 415                } else {
 416                        memcpy(o, i, ol);
 417                        singen_6pack(o, ol);
 418                        o = s->playback_to;
 419                        memcpy(o, i + ol, il - ol);
 420                        o += il - ol;
 421                        ol = s->period_size - s->playback1st_size;
 422                }
 423                l += il;
 424        }
 425        if (iu == sk->completed_inurb) {
 426                if (l != s->period_size)
 427                        printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
 428                               l/(int)s->cfg.frame_size);
 429
 430                return;
 431        }
 432second:
 433        iu = sk->completed_inurb;
 434        id = iu->iso_frame_desc;
 435        p = 0;
 436        goto loop;
 437
 438}
 439#else
 440static void loop_back(struct usb_stream *s)
 441{
 442}
 443#endif
 444
 445static void stream_idle(struct usb_stream_kernel *sk,
 446                        struct urb *inurb, struct urb *outurb)
 447{
 448        struct usb_stream *s = sk->s;
 449        int l, p;
 450        int insize = s->idle_insize;
 451        int urb_size = 0;
 452
 453        s->inpacket_split = s->next_inpacket_split;
 454        s->inpacket_split_at = s->next_inpacket_split_at;
 455        s->next_inpacket_split = -1;
 456        s->next_inpacket_split_at = 0;
 457
 458        for (p = 0; p < inurb->number_of_packets; ++p) {
 459                struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
 460
 461                l = id[p].actual_length;
 462                if (unlikely(l == 0 || id[p].status)) {
 463                        snd_printk(KERN_WARNING "underrun, status=%u\n",
 464                                   id[p].status);
 465                        goto err_out;
 466                }
 467                s->inpacket_head++;
 468                s->inpacket_head %= s->inpackets;
 469                if (s->inpacket_split == -1)
 470                        s->inpacket_split = s->inpacket_head;
 471
 472                s->inpacket[s->inpacket_head].offset =
 473                        id[p].offset + (inurb->transfer_buffer - (void *)s);
 474                s->inpacket[s->inpacket_head].length = l;
 475                if (insize + l > s->period_size &&
 476                    s->next_inpacket_split == -1) {
 477                        s->next_inpacket_split = s->inpacket_head;
 478                        s->next_inpacket_split_at = s->period_size - insize;
 479                }
 480                insize += l;
 481                urb_size += l;
 482        }
 483        s->idle_insize += urb_size - s->period_size;
 484        if (s->idle_insize < 0) {
 485                snd_printk(KERN_WARNING "%i\n",
 486                           (s->idle_insize)/(int)s->cfg.frame_size);
 487                goto err_out;
 488        }
 489        s->insize_done += urb_size;
 490
 491        l = s->idle_outsize;
 492        s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
 493                                  sk->write_page) - l;
 494
 495        if (usb_stream_prepare_playback(sk, inurb) < 0)
 496                goto err_out;
 497
 498        s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
 499        s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
 500                sk->write_page;
 501
 502        if (submit_urbs(sk, inurb, outurb) < 0)
 503                goto err_out;
 504
 505        loop_back(s);
 506        s->periods_done++;
 507        wake_up_all(&sk->sleep);
 508        return;
 509err_out:
 510        s->state = usb_stream_xrun;
 511        wake_up_all(&sk->sleep);
 512}
 513
 514static void i_capture_idle(struct urb *urb)
 515{
 516        struct usb_stream_kernel *sk = urb->context;
 517
 518        if (balance_capture(sk, urb))
 519                stream_idle(sk, urb, sk->i_urb);
 520}
 521
 522static void i_playback_idle(struct urb *urb)
 523{
 524        struct usb_stream_kernel *sk = urb->context;
 525
 526        if (balance_playback(sk, urb))
 527                stream_idle(sk, sk->i_urb, urb);
 528}
 529
 530static void stream_start(struct usb_stream_kernel *sk,
 531                         struct urb *inurb, struct urb *outurb)
 532{
 533        struct usb_stream *s = sk->s;
 534
 535        if (s->state >= usb_stream_sync1) {
 536                int l, p, max_diff, max_diff_0;
 537                int urb_size = 0;
 538                unsigned int frames_per_packet, min_frames = 0;
 539
 540                frames_per_packet = (s->period_size - s->idle_insize);
 541                frames_per_packet <<= 8;
 542                frames_per_packet /=
 543                        s->cfg.frame_size * inurb->number_of_packets;
 544                frames_per_packet++;
 545
 546                max_diff_0 = s->cfg.frame_size;
 547                if (s->cfg.period_frames >= 256)
 548                        max_diff_0 <<= 1;
 549                if (s->cfg.period_frames >= 1024)
 550                        max_diff_0 <<= 1;
 551                max_diff = max_diff_0;
 552                for (p = 0; p < inurb->number_of_packets; ++p) {
 553                        int diff;
 554
 555                        l = inurb->iso_frame_desc[p].actual_length;
 556                        urb_size += l;
 557
 558                        min_frames += frames_per_packet;
 559                        diff = urb_size -
 560                                (min_frames >> 8) * s->cfg.frame_size;
 561                        if (diff < max_diff) {
 562                                snd_printdd(KERN_DEBUG "%i %i %i %i\n",
 563                                            s->insize_done,
 564                                            urb_size / (int)s->cfg.frame_size,
 565                                            inurb->number_of_packets, diff);
 566                                max_diff = diff;
 567                        }
 568                }
 569                s->idle_insize -= max_diff - max_diff_0;
 570                s->idle_insize += urb_size - s->period_size;
 571                if (s->idle_insize < 0) {
 572                        snd_printk(KERN_WARNING "%i %i %i\n",
 573                                   s->idle_insize, urb_size, s->period_size);
 574                        return;
 575                } else if (s->idle_insize == 0) {
 576                        s->next_inpacket_split =
 577                                (s->inpacket_head + 1) % s->inpackets;
 578                        s->next_inpacket_split_at = 0;
 579                } else {
 580                        unsigned int split = s->inpacket_head;
 581
 582                        l = s->idle_insize;
 583                        while (l > s->inpacket[split].length) {
 584                                l -= s->inpacket[split].length;
 585                                if (split == 0)
 586                                        split = s->inpackets - 1;
 587                                else
 588                                        split--;
 589                        }
 590                        s->next_inpacket_split = split;
 591                        s->next_inpacket_split_at =
 592                                s->inpacket[split].length - l;
 593                }
 594
 595                s->insize_done += urb_size;
 596
 597                if (usb_stream_prepare_playback(sk, inurb) < 0)
 598                        return;
 599
 600        } else
 601                playback_prep_freqn(sk, sk->idle_outurb);
 602
 603        if (submit_urbs(sk, inurb, outurb) < 0)
 604                return;
 605
 606        if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
 607                /* just guesswork                            ^^^^^^ */
 608                s->state = usb_stream_ready;
 609                subs_set_complete(sk->inurb, i_capture_idle);
 610                subs_set_complete(sk->outurb, i_playback_idle);
 611        }
 612}
 613
 614static void i_capture_start(struct urb *urb)
 615{
 616        struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
 617        struct usb_stream_kernel *sk = urb->context;
 618        struct usb_stream *s = sk->s;
 619        int p;
 620        int empty = 0;
 621
 622        if (urb->status) {
 623                snd_printk(KERN_WARNING "status=%i\n", urb->status);
 624                return;
 625        }
 626
 627        for (p = 0; p < urb->number_of_packets; ++p) {
 628                int l = id[p].actual_length;
 629
 630                if (l < s->cfg.frame_size) {
 631                        ++empty;
 632                        if (s->state >= usb_stream_sync0) {
 633                                snd_printk(KERN_WARNING "%i\n", l);
 634                                return;
 635                        }
 636                }
 637                s->inpacket_head++;
 638                s->inpacket_head %= s->inpackets;
 639                s->inpacket[s->inpacket_head].offset =
 640                        id[p].offset + (urb->transfer_buffer - (void *)s);
 641                s->inpacket[s->inpacket_head].length = l;
 642        }
 643#ifdef SHOW_EMPTY
 644        if (empty) {
 645                printk(KERN_DEBUG"%s:%i: %i", __func__, __LINE__,
 646                       urb->iso_frame_desc[0].actual_length);
 647                for (pack = 1; pack < urb->number_of_packets; ++pack) {
 648                        int l = urb->iso_frame_desc[pack].actual_length;
 649
 650                        printk(KERN_CONT " %i", l);
 651                }
 652                printk(KERN_CONT "\n");
 653        }
 654#endif
 655        if (!empty && s->state < usb_stream_sync1)
 656                ++s->state;
 657
 658        if (balance_capture(sk, urb))
 659                stream_start(sk, urb, sk->i_urb);
 660}
 661
 662static void i_playback_start(struct urb *urb)
 663{
 664        struct usb_stream_kernel *sk = urb->context;
 665
 666        if (balance_playback(sk, urb))
 667                stream_start(sk, sk->i_urb, urb);
 668}
 669
 670int usb_stream_start(struct usb_stream_kernel *sk)
 671{
 672        struct usb_stream *s = sk->s;
 673        int frame = 0, iters = 0;
 674        int u, err;
 675        int try = 0;
 676
 677        if (s->state != usb_stream_stopped)
 678                return -EAGAIN;
 679
 680        subs_set_complete(sk->inurb, i_capture_start);
 681        subs_set_complete(sk->outurb, i_playback_start);
 682        memset(sk->write_page, 0, s->write_size);
 683dotry:
 684        s->insize_done = 0;
 685        s->idle_insize = 0;
 686        s->idle_outsize = 0;
 687        s->sync_packet = -1;
 688        s->inpacket_head = -1;
 689        sk->iso_frame_balance = 0;
 690        ++try;
 691        for (u = 0; u < 2; u++) {
 692                struct urb *inurb = sk->inurb[u];
 693                struct urb *outurb = sk->outurb[u];
 694
 695                playback_prep_freqn(sk, outurb);
 696                inurb->number_of_packets = outurb->number_of_packets;
 697                inurb->transfer_buffer_length =
 698                        inurb->number_of_packets *
 699                        inurb->iso_frame_desc[0].length;
 700
 701                if (u == 0) {
 702                        int now;
 703                        struct usb_device *dev = inurb->dev;
 704
 705                        frame = usb_get_current_frame_number(dev);
 706                        do {
 707                                now = usb_get_current_frame_number(dev);
 708                                ++iters;
 709                        } while (now > -1 && now == frame);
 710                }
 711                err = usb_submit_urb(inurb, GFP_ATOMIC);
 712                if (err < 0) {
 713                        snd_printk(KERN_ERR
 714                                   "usb_submit_urb(sk->inurb[%i]) returned %i\n",
 715                                   u, err);
 716                        return err;
 717                }
 718                err = usb_submit_urb(outurb, GFP_ATOMIC);
 719                if (err < 0) {
 720                        snd_printk(KERN_ERR
 721                                   "usb_submit_urb(sk->outurb[%i]) returned %i\n",
 722                                   u, err);
 723                        return err;
 724                }
 725
 726                if (inurb->start_frame != outurb->start_frame) {
 727                        snd_printd(KERN_DEBUG
 728                                   "u[%i] start_frames differ in:%u out:%u\n",
 729                                   u, inurb->start_frame, outurb->start_frame);
 730                        goto check_retry;
 731                }
 732        }
 733        snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
 734        try = 0;
 735check_retry:
 736        if (try) {
 737                usb_stream_stop(sk);
 738                if (try < 5) {
 739                        msleep(1500);
 740                        snd_printd(KERN_DEBUG "goto dotry;\n");
 741                        goto dotry;
 742                }
 743                snd_printk(KERN_WARNING
 744                           "couldn't start all urbs on the same start_frame.\n");
 745                return -EFAULT;
 746        }
 747
 748        sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
 749        sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
 750        sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
 751        sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
 752
 753/* wait, check */
 754        {
 755                int wait_ms = 3000;
 756
 757                while (s->state != usb_stream_ready && wait_ms > 0) {
 758                        snd_printdd(KERN_DEBUG "%i\n", s->state);
 759                        msleep(200);
 760                        wait_ms -= 200;
 761                }
 762        }
 763
 764        return s->state == usb_stream_ready ? 0 : -EFAULT;
 765}
 766
 767
 768/*                             stop                                   */
 769
 770void usb_stream_stop(struct usb_stream_kernel *sk)
 771{
 772        int u;
 773
 774        if (!sk->s)
 775                return;
 776        for (u = 0; u < USB_STREAM_NURBS; ++u) {
 777                usb_kill_urb(sk->inurb[u]);
 778                usb_kill_urb(sk->outurb[u]);
 779        }
 780        sk->s->state = usb_stream_stopped;
 781        msleep(400);
 782}
 783