sound/usb/pcm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  */
   4
   5 #include <linux/init.h>
   6 #include <linux/slab.h>
   7 #include <linux/bitrev.h>
   8 #include <linux/ratelimit.h>
   9 #include <linux/usb.h>
  10 #include <linux/usb/audio.h>
  11 #include <linux/usb/audio-v2.h>
  12
  13 #include <sound/core.h>
  14 #include <sound/pcm.h>
  15 #include <sound/pcm_params.h>
  16
  17 #include "usbaudio.h"
  18 #include "card.h"
  19 #include "quirks.h"
  20 #include "endpoint.h"
  21 #include "helper.h"
  22 #include "pcm.h"
  23 #include "clock.h"
  24 #include "power.h"
  25 #include "media.h"
  26 #include "implicit.h"
  27
  28 #define SUBSTREAM_FLAG_DATA_EP_STARTED  0
  29 #define SUBSTREAM_FLAG_SYNC_EP_STARTED  1
  30
  31 /* return the estimated delay based on USB frame counters */
  32 static snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
  33                                            struct snd_pcm_runtime *runtime)
  34 {
  35         unsigned int current_frame_number;
  36         unsigned int frame_diff;
  37         int est_delay;
  38         int queued;
  39
  40         if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
  41                 queued = bytes_to_frames(runtime, subs->inflight_bytes);
  42                 if (!queued)
  43                         return 0;
  44         } else if (!subs->running) {
  45                 return 0;
  46         }
  47
  48         current_frame_number = usb_get_current_frame_number(subs->dev);
  49         /*
  50          * HCD implementations use different widths, use lower 8 bits.
  51          * The delay will be managed up to 256ms, which is more than
  52          * enough
  53          */
  54         frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
  55
  56         /* Approximation based on number of samples per USB frame (ms),
  57            some truncation for 44.1 but the estimate is good enough */
  58         est_delay = frame_diff * runtime->rate / 1000;
  59
  60         if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
  61                 est_delay = queued - est_delay;
  62                 if (est_delay < 0)
  63                         est_delay = 0;
  64         }
  65
  66         return est_delay;
  67 }
  68
  69 /*
  70  * return the current pcm pointer.  just based on the hwptr_done value.
  71  */
  72 static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
  73 {
  74         struct snd_pcm_runtime *runtime = substream->runtime;
  75         struct snd_usb_substream *subs = runtime->private_data;
  76         unsigned int hwptr_done;
  77
  78         if (atomic_read(&subs->stream->chip->shutdown))
  79                 return SNDRV_PCM_POS_XRUN;
  80         spin_lock(&subs->lock);
  81         hwptr_done = subs->hwptr_done;
  82         runtime->delay = snd_usb_pcm_delay(subs, runtime);
  83         spin_unlock(&subs->lock);
  84         return bytes_to_frames(runtime, hwptr_done);
  85 }
  86
  87 /*
  88  * find a matching audio format
  89  */
  90 static const struct audioformat *
  91 find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
  92             unsigned int rate, unsigned int channels, bool strict_match,
  93             struct snd_usb_substream *subs)
  94 {
  95         const struct audioformat *fp;
  96         const struct audioformat *found = NULL;
  97         int cur_attr = 0, attr;
  98
  99         list_for_each_entry(fp, fmt_list_head, list) {
 100                 if (strict_match) {
 101                         if (!(fp->formats & pcm_format_to_bits(format)))
 102                                 continue;
 103                         if (fp->channels != channels)
 104                                 continue;
 105                 }
 106                 if (rate < fp->rate_min || rate > fp->rate_max)
 107                         continue;
 108                 if (!(fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
 109                         unsigned int i;
 110                         for (i = 0; i < fp->nr_rates; i++)
 111                                 if (fp->rate_table[i] == rate)
 112                                         break;
 113                         if (i >= fp->nr_rates)
 114                                 continue;
 115                 }
 116                 attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
 117                 if (!found) {
 118                         found = fp;
 119                         cur_attr = attr;
 120                         continue;
 121                 }
 122                 /* avoid async out and adaptive in if the other method
 123                  * supports the same format.
 124                  * this is a workaround for the case like
 125                  * M-audio audiophile USB.
 126                  */
 127                 if (subs && attr != cur_attr) {
 128                         if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
 129                              subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
 130                             (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
 131                              subs->direction == SNDRV_PCM_STREAM_CAPTURE))
 132                                 continue;
 133                         if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
 134                              subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
 135                             (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
 136                              subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
 137                                 found = fp;
 138                                 cur_attr = attr;
 139                                 continue;
 140                         }
 141                 }
 142                 /* find the format with the largest max. packet size */
 143                 if (fp->maxpacksize > found->maxpacksize) {
 144                         found = fp;
 145                         cur_attr = attr;
 146                 }
 147         }
 148         return found;
 149 }
 150
 151 static const struct audioformat *
 152 find_substream_format(struct snd_usb_substream *subs,
 153                       const struct snd_pcm_hw_params *params)
 154 {
 155         return find_format(&subs->fmt_list, params_format(params),
 156                            params_rate(params), params_channels(params),
 157                            true, subs);
 158 }
 159
 160 bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs)
 161 {
 162         const struct audioformat *fp;
 163         struct snd_usb_audio *chip;
 164         int rate = -1;
 165
 166         if (!subs)
 167                 return false;
 168         chip = subs->stream->chip;
 169         if (!(chip->quirk_flags & QUIRK_FLAG_FIXED_RATE))
 170                 return false;
 171         list_for_each_entry(fp, &subs->fmt_list, list) {
 172                 if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
 173                         return false;
 174                 if (fp->nr_rates < 1)
 175                         continue;
 176                 if (fp->nr_rates > 1)
 177                         return false;
 178                 if (rate < 0) {
 179                         rate = fp->rate_table[0];
 180                         continue;
 181                 }
 182                 if (rate != fp->rate_table[0])
 183                         return false;
 184         }
 185         return true;
 186 }
 187
 188 static int init_pitch_v1(struct snd_usb_audio *chip, int ep)
 189 {
 190         struct usb_device *dev = chip->dev;
 191         unsigned char data[1];
 192         int err;
 193
 194         data[0] = 1;
 195         err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 196                               USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
 197                               UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
 198                               data, sizeof(data));
 199         return err;
 200 }
 201
 202 static int init_pitch_v2(struct snd_usb_audio *chip, int ep)
 203 {
 204         struct usb_device *dev = chip->dev;
 205         unsigned char data[1];
 206         int err;
 207
 208         data[0] = 1;
 209         err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
 210                               USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 211                               UAC2_EP_CS_PITCH << 8, 0,
 212                               data, sizeof(data));
 213         return err;
 214 }
 215
 216 /*
 217  * initialize the pitch control and sample rate
 218  */
 219 int snd_usb_init_pitch(struct snd_usb_audio *chip,
 220                        const struct audioformat *fmt)
 221 {
 222         int err;
 223
 224         /* if endpoint doesn't have pitch control, bail out */
 225         if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
 226                 return 0;
 227
 228         usb_audio_dbg(chip, "enable PITCH for EP 0x%x\n", fmt->endpoint);
 229
 230         switch (fmt->protocol) {
 231         case UAC_VERSION_1:
 232                 err = init_pitch_v1(chip, fmt->endpoint);
 233                 break;
 234         case UAC_VERSION_2:
 235                 err = init_pitch_v2(chip, fmt->endpoint);
 236                 break;
 237         default:
 238                 return 0;
 239         }
 240
 241         if (err < 0) {
 242                 usb_audio_err(chip, "failed to enable PITCH for EP 0x%x\n",
 243                               fmt->endpoint);
 244                 return err;
 245         }
 246
 247         return 0;
 248 }
 249
 250 static bool stop_endpoints(struct snd_usb_substream *subs, bool keep_pending)
 251 {
 252         bool stopped = 0;
 253
 254         if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
 255                 snd_usb_endpoint_stop(subs->sync_endpoint, keep_pending);
 256                 stopped = true;
 257         }
 258         if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
 259                 snd_usb_endpoint_stop(subs->data_endpoint, keep_pending);
 260                 stopped = true;
 261         }
 262         return stopped;
 263 }
 264
 265 static int start_endpoints(struct snd_usb_substream *subs)
 266 {
 267         int err;
 268
 269         if (!subs->data_endpoint)
 270                 return -EINVAL;
 271
 272         if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
 273                 err = snd_usb_endpoint_start(subs->data_endpoint);
 274                 if (err < 0) {
 275                         clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
 276                         goto error;
 277                 }
 278         }
 279
 280         if (subs->sync_endpoint &&
 281             !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
 282                 err = snd_usb_endpoint_start(subs->sync_endpoint);
 283                 if (err < 0) {
 284                         clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
 285                         goto error;
 286                 }
 287         }
 288
 289         return 0;
 290
 291  error:
 292         stop_endpoints(subs, false);
 293         return err;
 294 }
 295
 296 static void sync_pending_stops(struct snd_usb_substream *subs)
 297 {
 298         snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
 299         snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
 300 }
 301
 302 /* PCM sync_stop callback */
 303 static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream)
 304 {
 305         struct snd_usb_substream *subs = substream->runtime->private_data;
 306
 307         sync_pending_stops(subs);
 308         return 0;
 309 }
 310
 311 /* Set up sync endpoint */
 312 int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip,
 313                                     struct audioformat *fmt)
 314 {
 315         struct usb_device *dev = chip->dev;
 316         struct usb_host_interface *alts;
 317         struct usb_interface_descriptor *altsd;
 318         unsigned int ep, attr, sync_attr;
 319         bool is_playback;
 320         int err;
 321
 322         if (fmt->sync_ep)
 323                 return 0; /* already set up */
 324
 325         alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);
 326         if (!alts)
 327                 return 0;
 328         altsd = get_iface_desc(alts);
 329
 330         err = snd_usb_parse_implicit_fb_quirk(chip, fmt, alts);
 331         if (err > 0)
 332                 return 0; /* matched */
 333
 334         /*
 335          * Generic sync EP handling
 336          */
 337
 338         if (fmt->ep_idx > 0 || altsd->bNumEndpoints < 2)
 339                 return 0;
 340
 341         is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
 342         attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
 343         if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
 344                              attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
 345             (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
 346                 return 0;
 347
 348         sync_attr = get_endpoint(alts, 1)->bmAttributes;
 349
 350         /*
 351          * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
 352          * if we don't find a sync endpoint, as on M-Audio Transit. In case of
 353          * error fall back to SYNC mode and don't create sync endpoint
 354          */
 355
 356         /* check sync-pipe endpoint */
 357         /* ... and check descriptor size before accessing bSynchAddress
 358            because there is a version of the SB Audigy 2 NX firmware lacking
 359            the audio fields in the endpoint descriptors */
 360         if ((sync_attr & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
 361             (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 362              get_endpoint(alts, 1)->bSynchAddress != 0)) {
 363                 dev_err(&dev->dev,
 364                         "%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
 365                            fmt->iface, fmt->altsetting,
 366                            get_endpoint(alts, 1)->bmAttributes,
 367                            get_endpoint(alts, 1)->bLength,
 368                            get_endpoint(alts, 1)->bSynchAddress);
 369                 if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 370                         return 0;
 371                 return -EINVAL;
 372         }
 373         ep = get_endpoint(alts, 1)->bEndpointAddress;
 374         if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 375             get_endpoint(alts, 0)->bSynchAddress != 0 &&
 376             ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
 377              (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
 378                 dev_err(&dev->dev,
 379                         "%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
 380                            fmt->iface, fmt->altsetting,
 381                            is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
 382                 if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 383                         return 0;
 384                 return -EINVAL;
 385         }
 386
 387         fmt->sync_ep = ep;
 388         fmt->sync_iface = altsd->bInterfaceNumber;
 389         fmt->sync_altsetting = altsd->bAlternateSetting;
 390         fmt->sync_ep_idx = 1;
 391         if ((sync_attr & USB_ENDPOINT_USAGE_MASK) == USB_ENDPOINT_USAGE_IMPLICIT_FB)
 392                 fmt->implicit_fb = 1;
 393
 394         dev_dbg(&dev->dev, "%d:%d: found sync_ep=0x%x, iface=%d, alt=%d, implicit_fb=%d\n",
 395                 fmt->iface, fmt->altsetting, fmt->sync_ep, fmt->sync_iface,
 396                 fmt->sync_altsetting, fmt->implicit_fb);
 397
 398         return 0;
 399 }
 400
 401 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
 402 {
 403         int ret;
 404
 405         if (!subs->str_pd)
 406                 return 0;
 407
 408         ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
 409         if (ret < 0) {
 410                 dev_err(&subs->dev->dev,
 411                         "Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
 412                         subs->str_pd->pd_id, state, ret);
 413                 return ret;
 414         }
 415
 416         return 0;
 417 }
 418
 419 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
 420 {
 421         int ret;
 422
 423         ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
 424         if (ret < 0)
 425                 return ret;
 426
 427         ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
 428         if (ret < 0)
 429                 return ret;
 430
 431         return 0;
 432 }
 433
 434 int snd_usb_pcm_resume(struct snd_usb_stream *as)
 435 {
 436         int ret;
 437
 438         ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
 439         if (ret < 0)
 440                 return ret;
 441
 442         ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
 443         if (ret < 0)
 444                 return ret;
 445
 446         return 0;
 447 }
 448
 449 static void close_endpoints(struct snd_usb_audio *chip,
 450                             struct snd_usb_substream *subs)
 451 {
 452         if (subs->data_endpoint) {
 453                 snd_usb_endpoint_set_sync(chip, subs->data_endpoint, NULL);
 454                 snd_usb_endpoint_close(chip, subs->data_endpoint);
 455                 subs->data_endpoint = NULL;
 456         }
 457
 458         if (subs->sync_endpoint) {
 459                 snd_usb_endpoint_close(chip, subs->sync_endpoint);
 460                 subs->sync_endpoint = NULL;
 461         }
 462 }
 463
 464 /*
 465  * hw_params callback
 466  *
 467  * allocate a buffer and set the given audio format.
 468  *
 469  * so far we use a physically linear buffer although packetize transfer
 470  * doesn't need a continuous area.
 471  * if sg buffer is supported on the later version of alsa, we'll follow
 472  * that.
 473  */
 474 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 475                              struct snd_pcm_hw_params *hw_params)
 476 {
 477         struct snd_usb_substream *subs = substream->runtime->private_data;
 478         struct snd_usb_audio *chip = subs->stream->chip;
 479         const struct audioformat *fmt;
 480         const struct audioformat *sync_fmt;
 481         bool fixed_rate, sync_fixed_rate;
 482         int ret;
 483
 484         ret = snd_media_start_pipeline(subs);
 485         if (ret)
 486                 return ret;
 487
 488         fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
 489         fmt = find_substream_format(subs, hw_params);
 490         if (!fmt) {
 491                 usb_audio_dbg(chip,
 492                               "cannot find format: format=%s, rate=%d, channels=%d\n",
 493                               snd_pcm_format_name(params_format(hw_params)),
 494                               params_rate(hw_params), params_channels(hw_params));
 495                 ret = -EINVAL;
 496                 goto stop_pipeline;
 497         }
 498
 499         if (fmt->implicit_fb) {
 500                 sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
 501                                                                 hw_params,
 502                                                                 !substream->stream,
 503                                                                 &sync_fixed_rate);
 504                 if (!sync_fmt) {
 505                         usb_audio_dbg(chip,
 506                                       "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
 507                                       fmt->sync_ep, fmt->sync_iface,
 508                                       fmt->sync_altsetting,
 509                                       snd_pcm_format_name(params_format(hw_params)),
 510                                       params_rate(hw_params), params_channels(hw_params));
 511                         ret = -EINVAL;
 512                         goto stop_pipeline;
 513                 }
 514         } else {
 515                 sync_fmt = fmt;
 516                 sync_fixed_rate = fixed_rate;
 517         }
 518
 519         ret = snd_usb_lock_shutdown(chip);
 520         if (ret < 0)
 521                 goto stop_pipeline;
 522
 523         ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
 524         if (ret < 0)
 525                 goto unlock;
 526
 527         if (subs->data_endpoint) {
 528                 if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
 529                                                 fmt, hw_params))
 530                         goto unlock;
 531                 if (stop_endpoints(subs, false))
 532                         sync_pending_stops(subs);
 533                 close_endpoints(chip, subs);
 534         }
 535
 536         subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false, fixed_rate);
 537         if (!subs->data_endpoint) {
 538                 ret = -EINVAL;
 539                 goto unlock;
 540         }
 541
 542         if (fmt->sync_ep) {
 543                 subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
 544                                                             hw_params,
 545                                                             fmt == sync_fmt,
 546                                                             sync_fixed_rate);
 547                 if (!subs->sync_endpoint) {
 548                         ret = -EINVAL;
 549                         goto unlock;
 550                 }
 551
 552                 snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
 553                                           subs->sync_endpoint);
 554         }
 555
 556         mutex_lock(&chip->mutex);
 557         subs->cur_audiofmt = fmt;
 558         mutex_unlock(&chip->mutex);
 559
 560         if (!subs->data_endpoint->need_setup)
 561                 goto unlock;
 562
 563         if (subs->sync_endpoint) {
 564                 ret = snd_usb_endpoint_set_params(chip, subs->sync_endpoint);
 565                 if (ret < 0)
 566                         goto unlock;
 567         }
 568
 569         ret = snd_usb_endpoint_set_params(chip, subs->data_endpoint);
 570
 571  unlock:
 572         if (ret < 0)
 573                 close_endpoints(chip, subs);
 574
 575         snd_usb_unlock_shutdown(chip);
 576  stop_pipeline:
 577         if (ret < 0)
 578                 snd_media_stop_pipeline(subs);
 579
 580         return ret;
 581 }
 582
 583 /*
 584  * hw_free callback
 585  *
 586  * reset the audio format and release the buffer
 587  */
 588 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
 589 {
 590         struct snd_usb_substream *subs = substream->runtime->private_data;
 591         struct snd_usb_audio *chip = subs->stream->chip;
 592
 593         snd_media_stop_pipeline(subs);
 594         mutex_lock(&chip->mutex);
 595         subs->cur_audiofmt = NULL;
 596         mutex_unlock(&chip->mutex);
 597         if (!snd_usb_lock_shutdown(chip)) {
 598                 if (stop_endpoints(subs, false))
 599                         sync_pending_stops(subs);
 600                 close_endpoints(chip, subs);
 601                 snd_usb_unlock_shutdown(chip);
 602         }
 603
 604         return 0;
 605 }
 606
 607 /* free-wheeling mode? (e.g. dmix) */
 608 static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
 609 {
 610         return runtime->stop_threshold > runtime->buffer_size;
 611 }
 612
 613 /* check whether early start is needed for playback stream */
 614 static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
 615                                          struct snd_usb_substream *subs)
 616 {
 617         struct snd_usb_audio *chip = subs->stream->chip;
 618
 619         if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
 620                 return false;
 621         /* disabled via module option? */
 622         if (!chip->lowlatency)
 623                 return false;
 624         if (in_free_wheeling_mode(runtime))
 625                 return false;
 626         /* implicit feedback mode has own operation mode */
 627         if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
 628                 return false;
 629         return true;
 630 }
 631
 632 /*
 633  * prepare callback
 634  *
 635  * only a few subtle things...
 636  */
 637 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
 638 {
 639         struct snd_pcm_runtime *runtime = substream->runtime;
 640         struct snd_usb_substream *subs = runtime->private_data;
 641         struct snd_usb_audio *chip = subs->stream->chip;
 642         int retry = 0;
 643         int ret;
 644
 645         ret = snd_usb_lock_shutdown(chip);
 646         if (ret < 0)
 647                 return ret;
 648         if (snd_BUG_ON(!subs->data_endpoint)) {
 649                 ret = -EIO;
 650                 goto unlock;
 651         }
 652
 653         ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
 654         if (ret < 0)
 655                 goto unlock;
 656
 657  again:
 658         if (subs->sync_endpoint) {
 659                 ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
 660                 if (ret < 0)
 661                         goto unlock;
 662         }
 663
 664         ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
 665         if (ret < 0)
 666                 goto unlock;
 667         else if (ret > 0)
 668                 snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
 669         ret = 0;
 670
 671         /* reset the pointer */
 672         subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
 673         subs->inflight_bytes = 0;
 674         subs->hwptr_done = 0;
 675         subs->transfer_done = 0;
 676         subs->last_frame_number = 0;
 677         subs->period_elapsed_pending = 0;
 678         runtime->delay = 0;
 679
 680         subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
 681         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 682             !subs->lowlatency_playback) {
 683                 ret = start_endpoints(subs);
 684                 /* if XRUN happens at starting streams (possibly with implicit
 685                  * fb case), restart again, but only try once.
 686                  */
 687                 if (ret == -EPIPE && !retry++) {
 688                         sync_pending_stops(subs);
 689                         goto again;
 690                 }
 691         }
 692  unlock:
 693         snd_usb_unlock_shutdown(chip);
 694         return ret;
 695 }
 696
 697 /*
 698  * h/w constraints
 699  */
 700
 701 #ifdef HW_CONST_DEBUG
 702 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
 703 #else
 704 #define hwc_debug(fmt, args...) do { } while(0)
 705 #endif
 706
 707 static const struct snd_pcm_hardware snd_usb_hardware =
 708 {
 709         .info =                 SNDRV_PCM_INFO_MMAP |
 710                                 SNDRV_PCM_INFO_MMAP_VALID |
 711                                 SNDRV_PCM_INFO_BATCH |
 712                                 SNDRV_PCM_INFO_INTERLEAVED |
 713                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
 714                                 SNDRV_PCM_INFO_PAUSE,
 715         .channels_min =         1,
 716         .channels_max =         256,
 717         .buffer_bytes_max =     INT_MAX, /* limited by BUFFER_TIME later */
 718         .period_bytes_min =     64,
 719         .period_bytes_max =     INT_MAX, /* limited by PERIOD_TIME later */
 720         .periods_min =          2,
 721         .periods_max =          1024,
 722 };
 723
 724 static int hw_check_valid_format(struct snd_usb_substream *subs,
 725                                  struct snd_pcm_hw_params *params,
 726                                  const struct audioformat *fp)
 727 {
 728         struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 729         struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 730         struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
 731         struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
 732         struct snd_mask check_fmts;
 733         unsigned int ptime;
 734
 735         /* check the format */
 736         snd_mask_none(&check_fmts);
 737         check_fmts.bits[0] = (u32)fp->formats;
 738         check_fmts.bits[1] = (u32)(fp->formats >> 32);
 739         snd_mask_intersect(&check_fmts, fmts);
 740         if (snd_mask_empty(&check_fmts)) {
 741                 hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
 742                 return 0;
 743         }
 744         /* check the channels */
 745         if (fp->channels < ct->min || fp->channels > ct->max) {
 746                 hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
 747                 return 0;
 748         }
 749         /* check the rate is within the range */
 750         if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
 751                 hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
 752                 return 0;
 753         }
 754         if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
 755                 hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
 756                 return 0;
 757         }
 758         /* check whether the period time is >= the data packet interval */
 759         if (subs->speed != USB_SPEED_FULL) {
 760                 ptime = 125 * (1 << fp->datainterval);
 761                 if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
 762                         hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
 763                         return 0;
 764                 }
 765         }
 766         return 1;
 767 }
 768
 769 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
 770                                   unsigned int rmax)
 771 {
 772         int changed;
 773
 774         if (rmin > rmax) {
 775                 hwc_debug("  --> get empty\n");
 776                 it->empty = 1;
 777                 return -EINVAL;
 778         }
 779
 780         changed = 0;
 781         if (it->min < rmin) {
 782                 it->min = rmin;
 783                 it->openmin = 0;
 784                 changed = 1;
 785         }
 786         if (it->max > rmax) {
 787                 it->max = rmax;
 788                 it->openmax = 0;
 789                 changed = 1;
 790         }
 791         if (snd_interval_checkempty(it)) {
 792                 it->empty = 1;
 793                 return -EINVAL;
 794         }
 795         hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
 796         return changed;
 797 }
 798
 799 /* get the specified endpoint object that is being used by other streams
 800  * (i.e. the parameter is locked)
 801  */
 802 static const struct snd_usb_endpoint *
 803 get_endpoint_in_use(struct snd_usb_audio *chip, int endpoint,
 804                     const struct snd_usb_endpoint *ref_ep)
 805 {
 806         const struct snd_usb_endpoint *ep;
 807
 808         ep = snd_usb_get_endpoint(chip, endpoint);
 809         if (ep && ep->cur_audiofmt && (ep != ref_ep || ep->opened > 1))
 810                 return ep;
 811         return NULL;
 812 }
 813
 814 static int hw_rule_rate(struct snd_pcm_hw_params *params,
 815                         struct snd_pcm_hw_rule *rule)
 816 {
 817         struct snd_usb_substream *subs = rule->private;
 818         struct snd_usb_audio *chip = subs->stream->chip;
 819         const struct snd_usb_endpoint *ep;
 820         const struct audioformat *fp;
 821         struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 822         unsigned int rmin, rmax, r;
 823         int i;
 824
 825         hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
 826         rmin = UINT_MAX;
 827         rmax = 0;
 828         list_for_each_entry(fp, &subs->fmt_list, list) {
 829                 if (!hw_check_valid_format(subs, params, fp))
 830                         continue;
 831
 832                 ep = get_endpoint_in_use(chip, fp->endpoint,
 833                                          subs->data_endpoint);
 834                 if (ep) {
 835                         hwc_debug("rate limit %d for ep#%x\n",
 836                                   ep->cur_rate, fp->endpoint);
 837                         rmin = min(rmin, ep->cur_rate);
 838                         rmax = max(rmax, ep->cur_rate);
 839                         continue;
 840                 }
 841
 842                 if (fp->implicit_fb) {
 843                         ep = get_endpoint_in_use(chip, fp->sync_ep,
 844                                                  subs->sync_endpoint);
 845                         if (ep) {
 846                                 hwc_debug("rate limit %d for sync_ep#%x\n",
 847                                           ep->cur_rate, fp->sync_ep);
 848                                 rmin = min(rmin, ep->cur_rate);
 849                                 rmax = max(rmax, ep->cur_rate);
 850                                 continue;
 851                         }
 852                 }
 853
 854                 r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
 855                 if (r > 0) {
 856                         if (!snd_interval_test(it, r))
 857                                 continue;
 858                         rmin = min(rmin, r);
 859                         rmax = max(rmax, r);
 860                         continue;
 861                 }
 862                 if (fp->rate_table && fp->nr_rates) {
 863                         for (i = 0; i < fp->nr_rates; i++) {
 864                                 r = fp->rate_table[i];
 865                                 if (!snd_interval_test(it, r))
 866                                         continue;
 867                                 rmin = min(rmin, r);
 868                                 rmax = max(rmax, r);
 869                         }
 870                 } else {
 871                         rmin = min(rmin, fp->rate_min);
 872                         rmax = max(rmax, fp->rate_max);
 873                 }
 874         }
 875
 876         return apply_hw_params_minmax(it, rmin, rmax);
 877 }
 878
 879
 880 static int hw_rule_channels(struct snd_pcm_hw_params *params,
 881                             struct snd_pcm_hw_rule *rule)
 882 {
 883         struct snd_usb_substream *subs = rule->private;
 884         const struct audioformat *fp;
 885         struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 886         unsigned int rmin, rmax;
 887
 888         hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
 889         rmin = UINT_MAX;
 890         rmax = 0;
 891         list_for_each_entry(fp, &subs->fmt_list, list) {
 892                 if (!hw_check_valid_format(subs, params, fp))
 893                         continue;
 894                 rmin = min(rmin, fp->channels);
 895                 rmax = max(rmax, fp->channels);
 896         }
 897
 898         return apply_hw_params_minmax(it, rmin, rmax);
 899 }
 900
 901 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
 902 {
 903         u32 oldbits[2];
 904         int changed;
 905
 906         oldbits[0] = fmt->bits[0];
 907         oldbits[1] = fmt->bits[1];
 908         fmt->bits[0] &= (u32)fbits;
 909         fmt->bits[1] &= (u32)(fbits >> 32);
 910         if (!fmt->bits[0] && !fmt->bits[1]) {
 911                 hwc_debug("  --> get empty\n");
 912                 return -EINVAL;
 913         }
 914         changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
 915         hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
 916         return changed;
 917 }
 918
 919 static int hw_rule_format(struct snd_pcm_hw_params *params,
 920                           struct snd_pcm_hw_rule *rule)
 921 {
 922         struct snd_usb_substream *subs = rule->private;
 923         struct snd_usb_audio *chip = subs->stream->chip;
 924         const struct snd_usb_endpoint *ep;
 925         const struct audioformat *fp;
 926         struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
 927         u64 fbits;
 928
 929         hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
 930         fbits = 0;
 931         list_for_each_entry(fp, &subs->fmt_list, list) {
 932                 if (!hw_check_valid_format(subs, params, fp))
 933                         continue;
 934
 935                 ep = get_endpoint_in_use(chip, fp->endpoint,
 936                                          subs->data_endpoint);
 937                 if (ep) {
 938                         hwc_debug("format limit %d for ep#%x\n",
 939                                   ep->cur_format, fp->endpoint);
 940                         fbits |= pcm_format_to_bits(ep->cur_format);
 941                         continue;
 942                 }
 943
 944                 if (fp->implicit_fb) {
 945                         ep = get_endpoint_in_use(chip, fp->sync_ep,
 946                                                  subs->sync_endpoint);
 947                         if (ep) {
 948                                 hwc_debug("format limit %d for sync_ep#%x\n",
 949                                           ep->cur_format, fp->sync_ep);
 950                                 fbits |= pcm_format_to_bits(ep->cur_format);
 951                                 continue;
 952                         }
 953                 }
 954
 955                 fbits |= fp->formats;
 956         }
 957         return apply_hw_params_format_bits(fmt, fbits);
 958 }
 959
 960 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
 961                                struct snd_pcm_hw_rule *rule)
 962 {
 963         struct snd_usb_substream *subs = rule->private;
 964         const struct audioformat *fp;
 965         struct snd_interval *it;
 966         unsigned char min_datainterval;
 967         unsigned int pmin;
 968
 969         it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
 970         hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
 971         min_datainterval = 0xff;
 972         list_for_each_entry(fp, &subs->fmt_list, list) {
 973                 if (!hw_check_valid_format(subs, params, fp))
 974                         continue;
 975                 min_datainterval = min(min_datainterval, fp->datainterval);
 976         }
 977         if (min_datainterval == 0xff) {
 978                 hwc_debug("  --> get empty\n");
 979                 it->empty = 1;
 980                 return -EINVAL;
 981         }
 982         pmin = 125 * (1 << min_datainterval);
 983
 984         return apply_hw_params_minmax(it, pmin, UINT_MAX);
 985 }
 986
 987 /* additional hw constraints for implicit feedback mode */
 988 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
 989                                            struct snd_pcm_hw_rule *rule)
 990 {
 991         struct snd_usb_substream *subs = rule->private;
 992         struct snd_usb_audio *chip = subs->stream->chip;
 993         const struct audioformat *fp;
 994         const struct snd_usb_endpoint *ep;
 995         struct snd_interval *it;
 996         unsigned int rmin, rmax;
 997
 998         it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
 999         hwc_debug("hw_rule_period_size: (%u,%u)\n", it->min, it->max);
1000         rmin = UINT_MAX;
1001         rmax = 0;
1002         list_for_each_entry(fp, &subs->fmt_list, list) {
1003                 if (!hw_check_valid_format(subs, params, fp))
1004                         continue;
1005                 ep = get_endpoint_in_use(chip, fp->endpoint,
1006                                          subs->data_endpoint);
1007                 if (ep) {
1008                         hwc_debug("period size limit %d for ep#%x\n",
1009                                   ep->cur_period_frames, fp->endpoint);
1010                         rmin = min(rmin, ep->cur_period_frames);
1011                         rmax = max(rmax, ep->cur_period_frames);
1012                         continue;
1013                 }
1014
1015                 if (fp->implicit_fb) {
1016                         ep = get_endpoint_in_use(chip, fp->sync_ep,
1017                                                  subs->sync_endpoint);
1018                         if (ep) {
1019                                 hwc_debug("period size limit %d for sync_ep#%x\n",
1020                                           ep->cur_period_frames, fp->sync_ep);
1021                                 rmin = min(rmin, ep->cur_period_frames);
1022                                 rmax = max(rmax, ep->cur_period_frames);
1023                                 continue;
1024                         }
1025                 }
1026         }
1027
1028         if (!rmax)
1029                 return 0; /* no limit by implicit fb */
1030         return apply_hw_params_minmax(it, rmin, rmax);
1031 }
1032
1033 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
1034                                        struct snd_pcm_hw_rule *rule)
1035 {
1036         struct snd_usb_substream *subs = rule->private;
1037         struct snd_usb_audio *chip = subs->stream->chip;
1038         const struct audioformat *fp;
1039         const struct snd_usb_endpoint *ep;
1040         struct snd_interval *it;
1041         unsigned int rmin, rmax;
1042
1043         it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
1044         hwc_debug("hw_rule_periods: (%u,%u)\n", it->min, it->max);
1045         rmin = UINT_MAX;
1046         rmax = 0;
1047         list_for_each_entry(fp, &subs->fmt_list, list) {
1048                 if (!hw_check_valid_format(subs, params, fp))
1049                         continue;
1050                 ep = get_endpoint_in_use(chip, fp->endpoint,
1051                                          subs->data_endpoint);
1052                 if (ep) {
1053                         hwc_debug("periods limit %d for ep#%x\n",
1054                                   ep->cur_buffer_periods, fp->endpoint);
1055                         rmin = min(rmin, ep->cur_buffer_periods);
1056                         rmax = max(rmax, ep->cur_buffer_periods);
1057                         continue;
1058                 }
1059
1060                 if (fp->implicit_fb) {
1061                         ep = get_endpoint_in_use(chip, fp->sync_ep,
1062                                                  subs->sync_endpoint);
1063                         if (ep) {
1064                                 hwc_debug("periods limit %d for sync_ep#%x\n",
1065                                           ep->cur_buffer_periods, fp->sync_ep);
1066                                 rmin = min(rmin, ep->cur_buffer_periods);
1067                                 rmax = max(rmax, ep->cur_buffer_periods);
1068                                 continue;
1069                         }
1070                 }
1071         }
1072
1073         if (!rmax)
1074                 return 0; /* no limit by implicit fb */
1075         return apply_hw_params_minmax(it, rmin, rmax);
1076 }
1077
1078 /*
1079  * set up the runtime hardware information.
1080  */
1081
1082 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1083 {
1084         const struct audioformat *fp;
1085         unsigned int pt, ptmin;
1086         int param_period_time_if_needed = -1;
1087         int err;
1088
1089         runtime->hw.formats = subs->formats;
1090
1091         runtime->hw.rate_min = 0x7fffffff;
1092         runtime->hw.rate_max = 0;
1093         runtime->hw.channels_min = 256;
1094         runtime->hw.channels_max = 0;
1095         runtime->hw.rates = 0;
1096         ptmin = UINT_MAX;
1097         /* check min/max rates and channels */
1098         list_for_each_entry(fp, &subs->fmt_list, list) {
1099                 runtime->hw.rates |= fp->rates;
1100                 if (runtime->hw.rate_min > fp->rate_min)
1101                         runtime->hw.rate_min = fp->rate_min;
1102                 if (runtime->hw.rate_max < fp->rate_max)
1103                         runtime->hw.rate_max = fp->rate_max;
1104                 if (runtime->hw.channels_min > fp->channels)
1105                         runtime->hw.channels_min = fp->channels;
1106                 if (runtime->hw.channels_max < fp->channels)
1107                         runtime->hw.channels_max = fp->channels;
1108                 if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1109                         /* FIXME: there might be more than one audio formats... */
1110                         runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1111                                 fp->frame_size;
1112                 }
1113                 pt = 125 * (1 << fp->datainterval);
1114                 ptmin = min(ptmin, pt);
1115         }
1116
1117         param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1118         if (subs->speed == USB_SPEED_FULL)
1119                 /* full speed devices have fixed data packet interval */
1120                 ptmin = 1000;
1121         if (ptmin == 1000)
1122                 /* if period time doesn't go below 1 ms, no rules needed */
1123                 param_period_time_if_needed = -1;
1124
1125         err = snd_pcm_hw_constraint_minmax(runtime,
1126                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1127                                            ptmin, UINT_MAX);
1128         if (err < 0)
1129                 return err;
1130
1131         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1132                                   hw_rule_rate, subs,
1133                                   SNDRV_PCM_HW_PARAM_RATE,
1134                                   SNDRV_PCM_HW_PARAM_FORMAT,
1135                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1136                                   param_period_time_if_needed,
1137                                   -1);
1138         if (err < 0)
1139                 return err;
1140
1141         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1142                                   hw_rule_channels, subs,
1143                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1144                                   SNDRV_PCM_HW_PARAM_FORMAT,
1145                                   SNDRV_PCM_HW_PARAM_RATE,
1146                                   param_period_time_if_needed,
1147                                   -1);
1148         if (err < 0)
1149                 return err;
1150         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1151                                   hw_rule_format, subs,
1152                                   SNDRV_PCM_HW_PARAM_FORMAT,
1153                                   SNDRV_PCM_HW_PARAM_RATE,
1154                                   SNDRV_PCM_HW_PARAM_CHANNELS,
1155                                   param_period_time_if_needed,
1156                                   -1);
1157         if (err < 0)
1158                 return err;
1159         if (param_period_time_if_needed >= 0) {
1160                 err = snd_pcm_hw_rule_add(runtime, 0,
1161                                           SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1162                                           hw_rule_period_time, subs,
1163                                           SNDRV_PCM_HW_PARAM_FORMAT,
1164                                           SNDRV_PCM_HW_PARAM_CHANNELS,
1165                                           SNDRV_PCM_HW_PARAM_RATE,
1166                                           -1);
1167                 if (err < 0)
1168                         return err;
1169         }
1170
1171         /* set max period and buffer sizes for 1 and 2 seconds, respectively */
1172         err = snd_pcm_hw_constraint_minmax(runtime,
1173                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1174                                            0, 1000000);
1175         if (err < 0)
1176                 return err;
1177         err = snd_pcm_hw_constraint_minmax(runtime,
1178                                            SNDRV_PCM_HW_PARAM_BUFFER_TIME,
1179                                            0, 2000000);
1180         if (err < 0)
1181                 return err;
1182
1183         /* additional hw constraints for implicit fb */
1184         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1185                                   hw_rule_period_size_implicit_fb, subs,
1186                                   SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1187         if (err < 0)
1188                 return err;
1189         err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1190                                   hw_rule_periods_implicit_fb, subs,
1191                                   SNDRV_PCM_HW_PARAM_PERIODS, -1);
1192         if (err < 0)
1193                 return err;
1194
1195         list_for_each_entry(fp, &subs->fmt_list, list) {
1196                 if (fp->implicit_fb) {
1197                         runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1198                         break;
1199                 }
1200         }
1201
1202         return 0;
1203 }
1204
1205 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1206 {
1207         int direction = substream->stream;
1208         struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1209         struct snd_pcm_runtime *runtime = substream->runtime;
1210         struct snd_usb_substream *subs = &as->substream[direction];
1211         int ret;
1212
1213         runtime->hw = snd_usb_hardware;
1214         /* need an explicit sync to catch applptr update in low-latency mode */
1215         if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1216             as->chip->lowlatency)
1217                 runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1218         runtime->private_data = subs;
1219         subs->pcm_substream = substream;
1220         /* runtime PM is also done there */
1221
1222         /* initialize DSD/DOP context */
1223         subs->dsd_dop.byte_idx = 0;
1224         subs->dsd_dop.channel = 0;
1225         subs->dsd_dop.marker = 1;
1226
1227         ret = setup_hw_info(runtime, subs);
1228         if (ret < 0)
1229                 return ret;
1230         ret = snd_usb_autoresume(subs->stream->chip);
1231         if (ret < 0)
1232                 return ret;
1233         ret = snd_media_stream_init(subs, as->pcm, direction);
1234         if (ret < 0)
1235                 snd_usb_autosuspend(subs->stream->chip);
1236         return ret;
1237 }
1238
1239 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1240 {
1241         int direction = substream->stream;
1242         struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1243         struct snd_usb_substream *subs = &as->substream[direction];
1244         int ret;
1245
1246         snd_media_stop_pipeline(subs);
1247
1248         if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1249                 ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1250                 snd_usb_unlock_shutdown(subs->stream->chip);
1251                 if (ret < 0)
1252                         return ret;
1253         }
1254
1255         subs->pcm_substream = NULL;
1256         snd_usb_autosuspend(subs->stream->chip);
1257
1258         return 0;
1259 }
1260
1261 /* Since a URB can handle only a single linear buffer, we must use double
1262  * buffering when the data to be transferred overflows the buffer boundary.
1263  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1264  * for all URBs.
1265  */
1266 static void retire_capture_urb(struct snd_usb_substream *subs,
1267                                struct urb *urb)
1268 {
1269         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1270         unsigned int stride, frames, bytes, oldptr;
1271         int i, period_elapsed = 0;
1272         unsigned long flags;
1273         unsigned char *cp;
1274         int current_frame_number;
1275
1276         /* read frame number here, update pointer in critical section */
1277         current_frame_number = usb_get_current_frame_number(subs->dev);
1278
1279         stride = runtime->frame_bits >> 3;
1280
1281         for (i = 0; i < urb->number_of_packets; i++) {
1282                 cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1283                 if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1284                         dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1285                                 i, urb->iso_frame_desc[i].status);
1286                         // continue;
1287                 }
1288                 bytes = urb->iso_frame_desc[i].actual_length;
1289                 if (subs->stream_offset_adj > 0) {
1290                         unsigned int adj = min(subs->stream_offset_adj, bytes);
1291                         cp += adj;
1292                         bytes -= adj;
1293                         subs->stream_offset_adj -= adj;
1294                 }
1295                 frames = bytes / stride;
1296                 if (!subs->txfr_quirk)
1297                         bytes = frames * stride;
1298                 if (bytes % (runtime->sample_bits >> 3) != 0) {
1299                         int oldbytes = bytes;
1300                         bytes = frames * stride;
1301                         dev_warn_ratelimited(&subs->dev->dev,
1302                                  "Corrected urb data len. %d->%d\n",
1303                                                         oldbytes, bytes);
1304                 }
1305                 /* update the current pointer */
1306                 spin_lock_irqsave(&subs->lock, flags);
1307                 oldptr = subs->hwptr_done;
1308                 subs->hwptr_done += bytes;
1309                 if (subs->hwptr_done >= subs->buffer_bytes)
1310                         subs->hwptr_done -= subs->buffer_bytes;
1311                 frames = (bytes + (oldptr % stride)) / stride;
1312                 subs->transfer_done += frames;
1313                 if (subs->transfer_done >= runtime->period_size) {
1314                         subs->transfer_done -= runtime->period_size;
1315                         period_elapsed = 1;
1316                 }
1317
1318                 /* realign last_frame_number */
1319                 subs->last_frame_number = current_frame_number;
1320
1321                 spin_unlock_irqrestore(&subs->lock, flags);
1322                 /* copy a data chunk */
1323                 if (oldptr + bytes > subs->buffer_bytes) {
1324                         unsigned int bytes1 = subs->buffer_bytes - oldptr;
1325
1326                         memcpy(runtime->dma_area + oldptr, cp, bytes1);
1327                         memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1328                 } else {
1329                         memcpy(runtime->dma_area + oldptr, cp, bytes);
1330                 }
1331         }
1332
1333         if (period_elapsed)
1334                 snd_pcm_period_elapsed(subs->pcm_substream);
1335 }
1336
1337 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1338                                   struct urb *urb, unsigned int bytes)
1339 {
1340         struct snd_urb_ctx *ctx = urb->context;
1341
1342         ctx->queued += bytes;
1343         subs->inflight_bytes += bytes;
1344         subs->hwptr_done += bytes;
1345         if (subs->hwptr_done >= subs->buffer_bytes)
1346                 subs->hwptr_done -= subs->buffer_bytes;
1347 }
1348
1349 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1350                                              struct urb *urb, unsigned int bytes)
1351 {
1352         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1353         unsigned int dst_idx = 0;
1354         unsigned int src_idx = subs->hwptr_done;
1355         unsigned int wrap = subs->buffer_bytes;
1356         u8 *dst = urb->transfer_buffer;
1357         u8 *src = runtime->dma_area;
1358         static const u8 marker[] = { 0x05, 0xfa };
1359         unsigned int queued = 0;
1360
1361         /*
1362          * The DSP DOP format defines a way to transport DSD samples over
1363          * normal PCM data endpoints. It requires stuffing of marker bytes
1364          * (0x05 and 0xfa, alternating per sample frame), and then expects
1365          * 2 additional bytes of actual payload. The whole frame is stored
1366          * LSB.
1367          *
1368          * Hence, for a stereo transport, the buffer layout looks like this,
1369          * where L refers to left channel samples and R to right.
1370          *
1371          *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1372          *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1373          *   .....
1374          *
1375          */
1376
1377         while (bytes--) {
1378                 if (++subs->dsd_dop.byte_idx == 3) {
1379                         /* frame boundary? */
1380                         dst[dst_idx++] = marker[subs->dsd_dop.marker];
1381                         src_idx += 2;
1382                         subs->dsd_dop.byte_idx = 0;
1383
1384                         if (++subs->dsd_dop.channel % runtime->channels == 0) {
1385                                 /* alternate the marker */
1386                                 subs->dsd_dop.marker++;
1387                                 subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1388                                 subs->dsd_dop.channel = 0;
1389                         }
1390                 } else {
1391                         /* stuff the DSD payload */
1392                         int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1393
1394                         if (subs->cur_audiofmt->dsd_bitrev)
1395                                 dst[dst_idx++] = bitrev8(src[idx]);
1396                         else
1397                                 dst[dst_idx++] = src[idx];
1398                         queued++;
1399                 }
1400         }
1401
1402         urb_ctx_queue_advance(subs, urb, queued);
1403 }
1404
1405 /* copy bit-reversed bytes onto transfer buffer */
1406 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1407                                          struct urb *urb, unsigned int bytes)
1408 {
1409         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1410         const u8 *src = runtime->dma_area;
1411         u8 *buf = urb->transfer_buffer;
1412         int i, ofs = subs->hwptr_done;
1413
1414         for (i = 0; i < bytes; i++) {
1415                 *buf++ = bitrev8(src[ofs]);
1416                 if (++ofs >= subs->buffer_bytes)
1417                         ofs = 0;
1418         }
1419
1420         urb_ctx_queue_advance(subs, urb, bytes);
1421 }
1422
1423 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1424                         int offset, int stride, unsigned int bytes)
1425 {
1426         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1427
1428         if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1429                 /* err, the transferred area goes over buffer boundary. */
1430                 unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1431
1432                 memcpy(urb->transfer_buffer + offset,
1433                        runtime->dma_area + subs->hwptr_done, bytes1);
1434                 memcpy(urb->transfer_buffer + offset + bytes1,
1435                        runtime->dma_area, bytes - bytes1);
1436         } else {
1437                 memcpy(urb->transfer_buffer + offset,
1438                        runtime->dma_area + subs->hwptr_done, bytes);
1439         }
1440
1441         urb_ctx_queue_advance(subs, urb, bytes);
1442 }
1443
1444 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1445                                       struct urb *urb, int stride,
1446                                       unsigned int bytes)
1447 {
1448         __le32 packet_length;
1449         int i;
1450
1451         /* Put __le32 length descriptor at start of each packet. */
1452         for (i = 0; i < urb->number_of_packets; i++) {
1453                 unsigned int length = urb->iso_frame_desc[i].length;
1454                 unsigned int offset = urb->iso_frame_desc[i].offset;
1455
1456                 packet_length = cpu_to_le32(length);
1457                 offset += i * sizeof(packet_length);
1458                 urb->iso_frame_desc[i].offset = offset;
1459                 urb->iso_frame_desc[i].length += sizeof(packet_length);
1460                 memcpy(urb->transfer_buffer + offset,
1461                        &packet_length, sizeof(packet_length));
1462                 copy_to_urb(subs, urb, offset + sizeof(packet_length),
1463                             stride, length);
1464         }
1465         /* Adjust transfer size accordingly. */
1466         bytes += urb->number_of_packets * sizeof(packet_length);
1467         return bytes;
1468 }
1469
1470 static int prepare_playback_urb(struct snd_usb_substream *subs,
1471                                 struct urb *urb,
1472                                 bool in_stream_lock)
1473 {
1474         struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1475         struct snd_usb_endpoint *ep = subs->data_endpoint;
1476         struct snd_urb_ctx *ctx = urb->context;
1477         unsigned int frames, bytes;
1478         int counts;
1479         unsigned int transfer_done, frame_limit, avail = 0;
1480         int i, stride, period_elapsed = 0;
1481         unsigned long flags;
1482         int err = 0;
1483
1484         stride = ep->stride;
1485
1486         frames = 0;
1487         ctx->queued = 0;
1488         urb->number_of_packets = 0;
1489
1490         spin_lock_irqsave(&subs->lock, flags);
1491         frame_limit = subs->frame_limit + ep->max_urb_frames;
1492         transfer_done = subs->transfer_done;
1493
1494         if (subs->lowlatency_playback &&
1495             runtime->state != SNDRV_PCM_STATE_DRAINING) {
1496                 unsigned int hwptr = subs->hwptr_done / stride;
1497
1498                 /* calculate the byte offset-in-buffer of the appl_ptr */
1499                 avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1500                         % runtime->buffer_size;
1501                 if (avail <= hwptr)
1502                         avail += runtime->buffer_size;
1503                 avail -= hwptr;
1504         }
1505
1506         for (i = 0; i < ctx->packets; i++) {
1507                 counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1508                 if (counts < 0)
1509                         break;
1510                 /* set up descriptor */
1511                 urb->iso_frame_desc[i].offset = frames * stride;
1512                 urb->iso_frame_desc[i].length = counts * stride;
1513                 frames += counts;
1514                 avail -= counts;
1515                 urb->number_of_packets++;
1516                 transfer_done += counts;
1517                 if (transfer_done >= runtime->period_size) {
1518                         transfer_done -= runtime->period_size;
1519                         frame_limit = 0;
1520                         period_elapsed = 1;
1521                         if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1522                                 if (transfer_done > 0) {
1523                                         /* FIXME: fill-max mode is not
1524                                          * supported yet */
1525                                         frames -= transfer_done;
1526                                         counts -= transfer_done;
1527                                         urb->iso_frame_desc[i].length =
1528                                                 counts * stride;
1529                                         transfer_done = 0;
1530                                 }
1531                                 i++;
1532                                 if (i < ctx->packets) {
1533                                         /* add a transfer delimiter */
1534                                         urb->iso_frame_desc[i].offset =
1535                                                 frames * stride;
1536                                         urb->iso_frame_desc[i].length = 0;
1537                                         urb->number_of_packets++;
1538                                 }
1539                                 break;
1540                         }
1541                 }
1542                 /* finish at the period boundary or after enough frames */
1543                 if ((period_elapsed || transfer_done >= frame_limit) &&
1544                     !snd_usb_endpoint_implicit_feedback_sink(ep))
1545                         break;
1546         }
1547
1548         if (!frames) {
1549                 err = -EAGAIN;
1550                 goto unlock;
1551         }
1552
1553         bytes = frames * stride;
1554         subs->transfer_done = transfer_done;
1555         subs->frame_limit = frame_limit;
1556         if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1557                      subs->cur_audiofmt->dsd_dop)) {
1558                 fill_playback_urb_dsd_dop(subs, urb, bytes);
1559         } else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1560                            subs->cur_audiofmt->dsd_bitrev)) {
1561                 fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1562         } else {
1563                 /* usual PCM */
1564                 if (!subs->tx_length_quirk)
1565                         copy_to_urb(subs, urb, 0, stride, bytes);
1566                 else
1567                         bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1568                         /* bytes is now amount of outgoing data */
1569         }
1570
1571         subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1572
1573         if (subs->trigger_tstamp_pending_update) {
1574                 /* this is the first actual URB submitted,
1575                  * update trigger timestamp to reflect actual start time
1576                  */
1577                 snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1578                 subs->trigger_tstamp_pending_update = false;
1579         }
1580
1581         if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1582                 subs->period_elapsed_pending = 1;
1583                 period_elapsed = 0;
1584         }
1585
1586  unlock:
1587         spin_unlock_irqrestore(&subs->lock, flags);
1588         if (err < 0)
1589                 return err;
1590         urb->transfer_buffer_length = bytes;
1591         if (period_elapsed) {
1592                 if (in_stream_lock)
1593                         snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1594                 else
1595                         snd_pcm_period_elapsed(subs->pcm_substream);
1596         }
1597         return 0;
1598 }
1599
1600 /*
1601  * process after playback data complete
1602  * - decrease the delay count again
1603  */
1604 static void retire_playback_urb(struct snd_usb_substream *subs,
1605                                struct urb *urb)
1606 {
1607         unsigned long flags;
1608         struct snd_urb_ctx *ctx = urb->context;
1609         bool period_elapsed = false;
1610
1611         spin_lock_irqsave(&subs->lock, flags);
1612         if (ctx->queued) {
1613                 if (subs->inflight_bytes >= ctx->queued)
1614                         subs->inflight_bytes -= ctx->queued;
1615                 else
1616                         subs->inflight_bytes = 0;
1617         }
1618
1619         subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1620         if (subs->running) {
1621                 period_elapsed = subs->period_elapsed_pending;
1622                 subs->period_elapsed_pending = 0;
1623         }
1624         spin_unlock_irqrestore(&subs->lock, flags);
1625         if (period_elapsed)
1626                 snd_pcm_period_elapsed(subs->pcm_substream);
1627 }
1628
1629 /* PCM ack callback for the playback stream;
1630  * this plays a role only when the stream is running in low-latency mode.
1631  */
1632 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1633 {
1634         struct snd_usb_substream *subs = substream->runtime->private_data;
1635         struct snd_usb_endpoint *ep;
1636
1637         if (!subs->lowlatency_playback || !subs->running)
1638                 return 0;
1639         ep = subs->data_endpoint;
1640         if (!ep)
1641                 return 0;
1642         /* When no more in-flight URBs available, try to process the pending
1643          * outputs here
1644          */
1645         if (!ep->active_mask)
1646                 return snd_usb_queue_pending_output_urbs(ep, true);
1647         return 0;
1648 }
1649
1650 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1651                                               int cmd)
1652 {
1653         struct snd_usb_substream *subs = substream->runtime->private_data;
1654         int err;
1655
1656         switch (cmd) {
1657         case SNDRV_PCM_TRIGGER_START:
1658                 subs->trigger_tstamp_pending_update = true;
1659                 fallthrough;
1660         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1661                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1662                                               prepare_playback_urb,
1663                                               retire_playback_urb,
1664                                               subs);
1665                 if (subs->lowlatency_playback &&
1666                     cmd == SNDRV_PCM_TRIGGER_START) {
1667                         if (in_free_wheeling_mode(substream->runtime))
1668                                 subs->lowlatency_playback = false;
1669                         err = start_endpoints(subs);
1670                         if (err < 0) {
1671                                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1672                                                               NULL, NULL, NULL);
1673                                 return err;
1674                         }
1675                 }
1676                 subs->running = 1;
1677                 dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1678                         subs->cur_audiofmt->iface,
1679                         subs->cur_audiofmt->altsetting);
1680                 return 0;
1681         case SNDRV_PCM_TRIGGER_SUSPEND:
1682         case SNDRV_PCM_TRIGGER_STOP:
1683                 stop_endpoints(subs, substream->runtime->state == SNDRV_PCM_STATE_DRAINING);
1684                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1685                                               NULL, NULL, NULL);
1686                 subs->running = 0;
1687                 dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1688                         subs->cur_audiofmt->iface,
1689                         subs->cur_audiofmt->altsetting);
1690                 return 0;
1691         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1692                 /* keep retire_data_urb for delay calculation */
1693                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1694                                               NULL,
1695                                               retire_playback_urb,
1696                                               subs);
1697                 subs->running = 0;
1698                 dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1699                         subs->cur_audiofmt->iface,
1700                         subs->cur_audiofmt->altsetting);
1701                 return 0;
1702         }
1703
1704         return -EINVAL;
1705 }
1706
1707 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1708                                              int cmd)
1709 {
1710         int err;
1711         struct snd_usb_substream *subs = substream->runtime->private_data;
1712
1713         switch (cmd) {
1714         case SNDRV_PCM_TRIGGER_START:
1715                 err = start_endpoints(subs);
1716                 if (err < 0)
1717                         return err;
1718                 fallthrough;
1719         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1720                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1721                                               NULL, retire_capture_urb,
1722                                               subs);
1723                 subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1724                 subs->running = 1;
1725                 dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1726                         subs->cur_audiofmt->iface,
1727                         subs->cur_audiofmt->altsetting);
1728                 return 0;
1729         case SNDRV_PCM_TRIGGER_SUSPEND:
1730         case SNDRV_PCM_TRIGGER_STOP:
1731                 stop_endpoints(subs, false);
1732                 fallthrough;
1733         case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1734                 snd_usb_endpoint_set_callback(subs->data_endpoint,
1735                                               NULL, NULL, NULL);
1736                 subs->running = 0;
1737                 dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1738                         subs->cur_audiofmt->iface,
1739                         subs->cur_audiofmt->altsetting);
1740                 return 0;
1741         }
1742
1743         return -EINVAL;
1744 }
1745
1746 static const struct snd_pcm_ops snd_usb_playback_ops = {
1747         .open =         snd_usb_pcm_open,
1748         .close =        snd_usb_pcm_close,
1749         .hw_params =    snd_usb_hw_params,
1750         .hw_free =      snd_usb_hw_free,
1751         .prepare =      snd_usb_pcm_prepare,
1752         .trigger =      snd_usb_substream_playback_trigger,
1753         .sync_stop =    snd_usb_pcm_sync_stop,
1754         .pointer =      snd_usb_pcm_pointer,
1755         .ack =          snd_usb_pcm_playback_ack,
1756 };
1757
1758 static const struct snd_pcm_ops snd_usb_capture_ops = {
1759         .open =         snd_usb_pcm_open,
1760         .close =        snd_usb_pcm_close,
1761         .hw_params =    snd_usb_hw_params,
1762         .hw_free =      snd_usb_hw_free,
1763         .prepare =      snd_usb_pcm_prepare,
1764         .trigger =      snd_usb_substream_capture_trigger,
1765         .sync_stop =    snd_usb_pcm_sync_stop,
1766         .pointer =      snd_usb_pcm_pointer,
1767 };
1768
1769 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1770 {
1771         const struct snd_pcm_ops *ops;
1772
1773         ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1774                         &snd_usb_playback_ops : &snd_usb_capture_ops;
1775         snd_pcm_set_ops(pcm, stream, ops);
1776 }
1777
1778 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1779 {
1780         struct snd_pcm *pcm = subs->stream->pcm;
1781         struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1782         struct device *dev = subs->dev->bus->sysdev;
1783
1784         if (snd_usb_use_vmalloc)
1785                 snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1786                                            NULL, 0, 0);
1787         else
1788                 snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1789                                            dev, 64*1024, 512*1024);
1790 }