sound/usb/stream.c

   1 /*
   2  *   This program is free software; you can redistribute it and/or modify
   3  *   it under the terms of the GNU General Public License as published by
   4  *   the Free Software Foundation; either version 2 of the License, or
   5  *   (at your option) any later version.
   6  *
   7  *   This program is distributed in the hope that it will be useful,
   8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  *   GNU General Public License for more details.
  11  *
  12  *   You should have received a copy of the GNU General Public License
  13  *   along with this program; if not, write to the Free Software
  14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  15  */
  16
  17
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/usb.h>
  21 #include <linux/usb/audio.h>
  22 #include <linux/usb/audio-v2.h>
  23
  24 #include <sound/core.h>
  25 #include <sound/pcm.h>
  26 #include <sound/control.h>
  27 #include <sound/tlv.h>
  28
  29 #include "usbaudio.h"
  30 #include "card.h"
  31 #include "proc.h"
  32 #include "quirks.h"
  33 #include "endpoint.h"
  34 #include "pcm.h"
  35 #include "helper.h"
  36 #include "format.h"
  37 #include "clock.h"
  38 #include "stream.h"
  39
  40 /*
  41  * free a substream
  42  */
  43 static void free_substream(struct snd_usb_substream *subs)
  44 {
  45         struct audioformat *fp, *n;
  46
  47         if (!subs->num_formats)
  48                 return; /* not initialized */
  49         list_for_each_entry_safe(fp, n, &subs->fmt_list, list) {
  50                 kfree(fp->rate_table);
  51                 kfree(fp->chmap);
  52                 kfree(fp);
  53         }
  54         kfree(subs->rate_list.list);
  55 }
  56
  57
  58 /*
  59  * free a usb stream instance
  60  */
  61 static void snd_usb_audio_stream_free(struct snd_usb_stream *stream)
  62 {
  63         free_substream(&stream->substream[0]);
  64         free_substream(&stream->substream[1]);
  65         list_del(&stream->list);
  66         kfree(stream);
  67 }
  68
  69 static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
  70 {
  71         struct snd_usb_stream *stream = pcm->private_data;
  72         if (stream) {
  73                 stream->pcm = NULL;
  74                 snd_usb_audio_stream_free(stream);
  75         }
  76 }
  77
  78 /*
  79  * initialize the substream instance.
  80  */
  81
  82 static void snd_usb_init_substream(struct snd_usb_stream *as,
  83                                    int stream,
  84                                    struct audioformat *fp)
  85 {
  86         struct snd_usb_substream *subs = &as->substream[stream];
  87
  88         INIT_LIST_HEAD(&subs->fmt_list);
  89         spin_lock_init(&subs->lock);
  90
  91         subs->stream = as;
  92         subs->direction = stream;
  93         subs->dev = as->chip->dev;
  94         subs->txfr_quirk = as->chip->txfr_quirk;
  95         subs->tx_length_quirk = as->chip->tx_length_quirk;
  96         subs->speed = snd_usb_get_speed(subs->dev);
  97         subs->pkt_offset_adj = 0;
  98         subs->stream_offset_adj = 0;
  99
 100         snd_usb_set_pcm_ops(as->pcm, stream);
 101
 102         list_add_tail(&fp->list, &subs->fmt_list);
 103         subs->formats |= fp->formats;
 104         subs->num_formats++;
 105         subs->fmt_type = fp->fmt_type;
 106         subs->ep_num = fp->endpoint;
 107         if (fp->channels > subs->channels_max)
 108                 subs->channels_max = fp->channels;
 109 }
 110
 111 /* kctl callbacks for usb-audio channel maps */
 112 static int usb_chmap_ctl_info(struct snd_kcontrol *kcontrol,
 113                               struct snd_ctl_elem_info *uinfo)
 114 {
 115         struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
 116         struct snd_usb_substream *subs = info->private_data;
 117
 118         uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 119         uinfo->count = subs->channels_max;
 120         uinfo->value.integer.min = 0;
 121         uinfo->value.integer.max = SNDRV_CHMAP_LAST;
 122         return 0;
 123 }
 124
 125 /* check whether a duplicated entry exists in the audiofmt list */
 126 static bool have_dup_chmap(struct snd_usb_substream *subs,
 127                            struct audioformat *fp)
 128 {
 129         struct audioformat *prev = fp;
 130
 131         list_for_each_entry_continue_reverse(prev, &subs->fmt_list, list) {
 132                 if (prev->chmap &&
 133                     !memcmp(prev->chmap, fp->chmap, sizeof(*fp->chmap)))
 134                         return true;
 135         }
 136         return false;
 137 }
 138
 139 static int usb_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
 140                              unsigned int size, unsigned int __user *tlv)
 141 {
 142         struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
 143         struct snd_usb_substream *subs = info->private_data;
 144         struct audioformat *fp;
 145         unsigned int __user *dst;
 146         int count = 0;
 147
 148         if (size < 8)
 149                 return -ENOMEM;
 150         if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
 151                 return -EFAULT;
 152         size -= 8;
 153         dst = tlv + 2;
 154         list_for_each_entry(fp, &subs->fmt_list, list) {
 155                 int i, ch_bytes;
 156
 157                 if (!fp->chmap)
 158                         continue;
 159                 if (have_dup_chmap(subs, fp))
 160                         continue;
 161                 /* copy the entry */
 162                 ch_bytes = fp->chmap->channels * 4;
 163                 if (size < 8 + ch_bytes)
 164                         return -ENOMEM;
 165                 if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
 166                     put_user(ch_bytes, dst + 1))
 167                         return -EFAULT;
 168                 dst += 2;
 169                 for (i = 0; i < fp->chmap->channels; i++, dst++) {
 170                         if (put_user(fp->chmap->map[i], dst))
 171                                 return -EFAULT;
 172                 }
 173
 174                 count += 8 + ch_bytes;
 175                 size -= 8 + ch_bytes;
 176         }
 177         if (put_user(count, tlv + 1))
 178                 return -EFAULT;
 179         return 0;
 180 }
 181
 182 static int usb_chmap_ctl_get(struct snd_kcontrol *kcontrol,
 183                              struct snd_ctl_elem_value *ucontrol)
 184 {
 185         struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
 186         struct snd_usb_substream *subs = info->private_data;
 187         struct snd_pcm_chmap_elem *chmap = NULL;
 188         int i = 0;
 189
 190         if (subs->cur_audiofmt)
 191                 chmap = subs->cur_audiofmt->chmap;
 192         if (chmap) {
 193                 for (i = 0; i < chmap->channels; i++)
 194                         ucontrol->value.integer.value[i] = chmap->map[i];
 195         }
 196         for (; i < subs->channels_max; i++)
 197                 ucontrol->value.integer.value[i] = 0;
 198         return 0;
 199 }
 200
 201 /* create a chmap kctl assigned to the given USB substream */
 202 static int add_chmap(struct snd_pcm *pcm, int stream,
 203                      struct snd_usb_substream *subs)
 204 {
 205         struct audioformat *fp;
 206         struct snd_pcm_chmap *chmap;
 207         struct snd_kcontrol *kctl;
 208         int err;
 209
 210         list_for_each_entry(fp, &subs->fmt_list, list)
 211                 if (fp->chmap)
 212                         goto ok;
 213         /* no chmap is found */
 214         return 0;
 215
 216  ok:
 217         err = snd_pcm_add_chmap_ctls(pcm, stream, NULL, 0, 0, &chmap);
 218         if (err < 0)
 219                 return err;
 220
 221         /* override handlers */
 222         chmap->private_data = subs;
 223         kctl = chmap->kctl;
 224         kctl->info = usb_chmap_ctl_info;
 225         kctl->get = usb_chmap_ctl_get;
 226         kctl->tlv.c = usb_chmap_ctl_tlv;
 227
 228         return 0;
 229 }
 230
 231 /* convert from USB ChannelConfig bits to ALSA chmap element */
 232 static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
 233                                                 int protocol)
 234 {
 235         static unsigned int uac1_maps[] = {
 236                 SNDRV_CHMAP_FL,         /* left front */
 237                 SNDRV_CHMAP_FR,         /* right front */
 238                 SNDRV_CHMAP_FC,         /* center front */
 239                 SNDRV_CHMAP_LFE,        /* LFE */
 240                 SNDRV_CHMAP_SL,         /* left surround */
 241                 SNDRV_CHMAP_SR,         /* right surround */
 242                 SNDRV_CHMAP_FLC,        /* left of center */
 243                 SNDRV_CHMAP_FRC,        /* right of center */
 244                 SNDRV_CHMAP_RC,         /* surround */
 245                 SNDRV_CHMAP_SL,         /* side left */
 246                 SNDRV_CHMAP_SR,         /* side right */
 247                 SNDRV_CHMAP_TC,         /* top */
 248                 0 /* terminator */
 249         };
 250         static unsigned int uac2_maps[] = {
 251                 SNDRV_CHMAP_FL,         /* front left */
 252                 SNDRV_CHMAP_FR,         /* front right */
 253                 SNDRV_CHMAP_FC,         /* front center */
 254                 SNDRV_CHMAP_LFE,        /* LFE */
 255                 SNDRV_CHMAP_RL,         /* back left */
 256                 SNDRV_CHMAP_RR,         /* back right */
 257                 SNDRV_CHMAP_FLC,        /* front left of center */
 258                 SNDRV_CHMAP_FRC,        /* front right of center */
 259                 SNDRV_CHMAP_RC,         /* back center */
 260                 SNDRV_CHMAP_SL,         /* side left */
 261                 SNDRV_CHMAP_SR,         /* side right */
 262                 SNDRV_CHMAP_TC,         /* top center */
 263                 SNDRV_CHMAP_TFL,        /* top front left */
 264                 SNDRV_CHMAP_TFC,        /* top front center */
 265                 SNDRV_CHMAP_TFR,        /* top front right */
 266                 SNDRV_CHMAP_TRL,        /* top back left */
 267                 SNDRV_CHMAP_TRC,        /* top back center */
 268                 SNDRV_CHMAP_TRR,        /* top back right */
 269                 SNDRV_CHMAP_TFLC,       /* top front left of center */
 270                 SNDRV_CHMAP_TFRC,       /* top front right of center */
 271                 SNDRV_CHMAP_LLFE,       /* left LFE */
 272                 SNDRV_CHMAP_RLFE,       /* right LFE */
 273                 SNDRV_CHMAP_TSL,        /* top side left */
 274                 SNDRV_CHMAP_TSR,        /* top side right */
 275                 SNDRV_CHMAP_BC,         /* bottom center */
 276                 SNDRV_CHMAP_RLC,        /* back left of center */
 277                 SNDRV_CHMAP_RRC,        /* back right of center */
 278                 0 /* terminator */
 279         };
 280         struct snd_pcm_chmap_elem *chmap;
 281         const unsigned int *maps;
 282         int c;
 283
 284         if (channels > ARRAY_SIZE(chmap->map))
 285                 return NULL;
 286
 287         chmap = kzalloc(sizeof(*chmap), GFP_KERNEL);
 288         if (!chmap)
 289                 return NULL;
 290
 291         maps = protocol == UAC_VERSION_2 ? uac2_maps : uac1_maps;
 292         chmap->channels = channels;
 293         c = 0;
 294
 295         if (bits) {
 296                 for (; bits && *maps; maps++, bits >>= 1)
 297                         if (bits & 1)
 298                                 chmap->map[c++] = *maps;
 299         } else {
 300                 /* If we're missing wChannelConfig, then guess something
 301                     to make sure the channel map is not skipped entirely */
 302                 if (channels == 1)
 303                         chmap->map[c++] = SNDRV_CHMAP_MONO;
 304                 else
 305                         for (; c < channels && *maps; maps++)
 306                                 chmap->map[c++] = *maps;
 307         }
 308
 309         for (; c < channels; c++)
 310                 chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
 311
 312         return chmap;
 313 }
 314
 315 /*
 316  * add this endpoint to the chip instance.
 317  * if a stream with the same endpoint already exists, append to it.
 318  * if not, create a new pcm stream. note, fp is added to the substream
 319  * fmt_list and will be freed on the chip instance release. do not free
 320  * fp or do remove it from the substream fmt_list to avoid double-free.
 321  */
 322 int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
 323                              int stream,
 324                              struct audioformat *fp)
 325 {
 326         struct snd_usb_stream *as;
 327         struct snd_usb_substream *subs;
 328         struct snd_pcm *pcm;
 329         int err;
 330
 331         list_for_each_entry(as, &chip->pcm_list, list) {
 332                 if (as->fmt_type != fp->fmt_type)
 333                         continue;
 334                 subs = &as->substream[stream];
 335                 if (subs->ep_num == fp->endpoint) {
 336                         list_add_tail(&fp->list, &subs->fmt_list);
 337                         subs->num_formats++;
 338                         subs->formats |= fp->formats;
 339                         return 0;
 340                 }
 341         }
 342         /* look for an empty stream */
 343         list_for_each_entry(as, &chip->pcm_list, list) {
 344                 if (as->fmt_type != fp->fmt_type)
 345                         continue;
 346                 subs = &as->substream[stream];
 347                 if (subs->ep_num)
 348                         continue;
 349                 err = snd_pcm_new_stream(as->pcm, stream, 1);
 350                 if (err < 0)
 351                         return err;
 352                 snd_usb_init_substream(as, stream, fp);
 353                 return add_chmap(as->pcm, stream, subs);
 354         }
 355
 356         /* create a new pcm */
 357         as = kzalloc(sizeof(*as), GFP_KERNEL);
 358         if (!as)
 359                 return -ENOMEM;
 360         as->pcm_index = chip->pcm_devs;
 361         as->chip = chip;
 362         as->fmt_type = fp->fmt_type;
 363         err = snd_pcm_new(chip->card, "USB Audio", chip->pcm_devs,
 364                           stream == SNDRV_PCM_STREAM_PLAYBACK ? 1 : 0,
 365                           stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1,
 366                           &pcm);
 367         if (err < 0) {
 368                 kfree(as);
 369                 return err;
 370         }
 371         as->pcm = pcm;
 372         pcm->private_data = as;
 373         pcm->private_free = snd_usb_audio_pcm_free;
 374         pcm->info_flags = 0;
 375         if (chip->pcm_devs > 0)
 376                 sprintf(pcm->name, "USB Audio #%d", chip->pcm_devs);
 377         else
 378                 strcpy(pcm->name, "USB Audio");
 379
 380         snd_usb_init_substream(as, stream, fp);
 381
 382         /*
 383          * Keep using head insertion for M-Audio Audiophile USB (tm) which has a
 384          * fix to swap capture stream order in conf/cards/USB-audio.conf
 385          */
 386         if (chip->usb_id == USB_ID(0x0763, 0x2003))
 387                 list_add(&as->list, &chip->pcm_list);
 388         else
 389                 list_add_tail(&as->list, &chip->pcm_list);
 390
 391         chip->pcm_devs++;
 392
 393         snd_usb_proc_pcm_format_add(as);
 394
 395         return add_chmap(pcm, stream, &as->substream[stream]);
 396 }
 397
 398 static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
 399                                          struct usb_host_interface *alts,
 400                                          int protocol, int iface_no)
 401 {
 402         /* parsed with a v1 header here. that's ok as we only look at the
 403          * header first which is the same for both versions */
 404         struct uac_iso_endpoint_descriptor *csep;
 405         struct usb_interface_descriptor *altsd = get_iface_desc(alts);
 406         int attributes = 0;
 407
 408         csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
 409
 410         /* Creamware Noah has this descriptor after the 2nd endpoint */
 411         if (!csep && altsd->bNumEndpoints >= 2)
 412                 csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
 413
 414         /*
 415          * If we can't locate the USB_DT_CS_ENDPOINT descriptor in the extra
 416          * bytes after the first endpoint, go search the entire interface.
 417          * Some devices have it directly *before* the standard endpoint.
 418          */
 419         if (!csep)
 420                 csep = snd_usb_find_desc(alts->extra, alts->extralen, NULL, USB_DT_CS_ENDPOINT);
 421
 422         if (!csep || csep->bLength < 7 ||
 423             csep->bDescriptorSubtype != UAC_EP_GENERAL) {
 424                 usb_audio_warn(chip,
 425                                "%u:%d : no or invalid class specific endpoint descriptor\n",
 426                                iface_no, altsd->bAlternateSetting);
 427                 return 0;
 428         }
 429
 430         if (protocol == UAC_VERSION_1) {
 431                 attributes = csep->bmAttributes;
 432         } else {
 433                 struct uac2_iso_endpoint_descriptor *csep2 =
 434                         (struct uac2_iso_endpoint_descriptor *) csep;
 435
 436                 attributes = csep->bmAttributes & UAC_EP_CS_ATTR_FILL_MAX;
 437
 438                 /* emulate the endpoint attributes of a v1 device */
 439                 if (csep2->bmControls & UAC2_CONTROL_PITCH)
 440                         attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
 441         }
 442
 443         return attributes;
 444 }
 445
 446 /* find an input terminal descriptor (either UAC1 or UAC2) with the given
 447  * terminal id
 448  */
 449 static void *
 450 snd_usb_find_input_terminal_descriptor(struct usb_host_interface *ctrl_iface,
 451                                                int terminal_id)
 452 {
 453         struct uac2_input_terminal_descriptor *term = NULL;
 454
 455         while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
 456                                                ctrl_iface->extralen,
 457                                                term, UAC_INPUT_TERMINAL))) {
 458                 if (term->bTerminalID == terminal_id)
 459                         return term;
 460         }
 461
 462         return NULL;
 463 }
 464
 465 static struct uac2_output_terminal_descriptor *
 466         snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
 467                                                 int terminal_id)
 468 {
 469         struct uac2_output_terminal_descriptor *term = NULL;
 470
 471         while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
 472                                                ctrl_iface->extralen,
 473                                                term, UAC_OUTPUT_TERMINAL))) {
 474                 if (term->bTerminalID == terminal_id)
 475                         return term;
 476         }
 477
 478         return NULL;
 479 }
 480
 481 int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
 482 {
 483         struct usb_device *dev;
 484         struct usb_interface *iface;
 485         struct usb_host_interface *alts;
 486         struct usb_interface_descriptor *altsd;
 487         int i, altno, err, stream;
 488         unsigned int format = 0, num_channels = 0;
 489         struct audioformat *fp = NULL;
 490         int num, protocol, clock = 0;
 491         struct uac_format_type_i_continuous_descriptor *fmt;
 492         unsigned int chconfig;
 493
 494         dev = chip->dev;
 495
 496         /* parse the interface's altsettings */
 497         iface = usb_ifnum_to_if(dev, iface_no);
 498
 499         num = iface->num_altsetting;
 500
 501         /*
 502          * Dallas DS4201 workaround: It presents 5 altsettings, but the last
 503          * one misses syncpipe, and does not produce any sound.
 504          */
 505         if (chip->usb_id == USB_ID(0x04fa, 0x4201))
 506                 num = 4;
 507
 508         for (i = 0; i < num; i++) {
 509                 alts = &iface->altsetting[i];
 510                 altsd = get_iface_desc(alts);
 511                 protocol = altsd->bInterfaceProtocol;
 512                 /* skip invalid one */
 513                 if (((altsd->bInterfaceClass != USB_CLASS_AUDIO ||
 514                       (altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING &&
 515                        altsd->bInterfaceSubClass != USB_SUBCLASS_VENDOR_SPEC)) &&
 516                      altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
 517                     altsd->bNumEndpoints < 1 ||
 518                     le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == 0)
 519                         continue;
 520                 /* must be isochronous */
 521                 if ((get_endpoint(alts, 0)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
 522                     USB_ENDPOINT_XFER_ISOC)
 523                         continue;
 524                 /* check direction */
 525                 stream = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN) ?
 526                         SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
 527                 altno = altsd->bAlternateSetting;
 528
 529                 if (snd_usb_apply_interface_quirk(chip, iface_no, altno))
 530                         continue;
 531
 532                 /*
 533                  * Roland audio streaming interfaces are marked with protocols
 534                  * 0/1/2, but are UAC 1 compatible.
 535                  */
 536                 if (USB_ID_VENDOR(chip->usb_id) == 0x0582 &&
 537                     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
 538                     protocol <= 2)
 539                         protocol = UAC_VERSION_1;
 540
 541                 chconfig = 0;
 542                 /* get audio formats */
 543                 switch (protocol) {
 544                 default:
 545                         dev_dbg(&dev->dev, "%u:%d: unknown interface protocol %#02x, assuming v1\n",
 546                                 iface_no, altno, protocol);
 547                         protocol = UAC_VERSION_1;
 548                         /* fall through */
 549
 550                 case UAC_VERSION_1: {
 551                         struct uac1_as_header_descriptor *as =
 552                                 snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
 553                         struct uac_input_terminal_descriptor *iterm;
 554
 555                         if (!as) {
 556                                 dev_err(&dev->dev,
 557                                         "%u:%d : UAC_AS_GENERAL descriptor not found\n",
 558                                         iface_no, altno);
 559                                 continue;
 560                         }
 561
 562                         if (as->bLength < sizeof(*as)) {
 563                                 dev_err(&dev->dev,
 564                                         "%u:%d : invalid UAC_AS_GENERAL desc\n",
 565                                         iface_no, altno);
 566                                 continue;
 567                         }
 568
 569                         format = le16_to_cpu(as->wFormatTag); /* remember the format value */
 570
 571                         iterm = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
 572                                                                        as->bTerminalLink);
 573                         if (iterm) {
 574                                 num_channels = iterm->bNrChannels;
 575                                 chconfig = le16_to_cpu(iterm->wChannelConfig);
 576                         }
 577
 578                         break;
 579                 }
 580
 581                 case UAC_VERSION_2: {
 582                         struct uac2_input_terminal_descriptor *input_term;
 583                         struct uac2_output_terminal_descriptor *output_term;
 584                         struct uac2_as_header_descriptor *as =
 585                                 snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
 586
 587                         if (!as) {
 588                                 dev_err(&dev->dev,
 589                                         "%u:%d : UAC_AS_GENERAL descriptor not found\n",
 590                                         iface_no, altno);
 591                                 continue;
 592                         }
 593
 594                         if (as->bLength < sizeof(*as)) {
 595                                 dev_err(&dev->dev,
 596                                         "%u:%d : invalid UAC_AS_GENERAL desc\n",
 597                                         iface_no, altno);
 598                                 continue;
 599                         }
 600
 601                         num_channels = as->bNrChannels;
 602                         format = le32_to_cpu(as->bmFormats);
 603                         chconfig = le32_to_cpu(as->bmChannelConfig);
 604
 605                         /* lookup the terminal associated to this interface
 606                          * to extract the clock */
 607                         input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
 608                                                                             as->bTerminalLink);
 609                         if (input_term) {
 610                                 clock = input_term->bCSourceID;
 611                                 if (!chconfig && (num_channels == input_term->bNrChannels))
 612                                         chconfig = le32_to_cpu(input_term->bmChannelConfig);
 613                                 break;
 614                         }
 615
 616                         output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
 617                                                                               as->bTerminalLink);
 618                         if (output_term) {
 619                                 clock = output_term->bCSourceID;
 620                                 break;
 621                         }
 622
 623                         dev_err(&dev->dev,
 624                                 "%u:%d : bogus bTerminalLink %d\n",
 625                                 iface_no, altno, as->bTerminalLink);
 626                         continue;
 627                 }
 628                 }
 629
 630                 /* get format type */
 631                 fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_FORMAT_TYPE);
 632                 if (!fmt) {
 633                         dev_err(&dev->dev,
 634                                 "%u:%d : no UAC_FORMAT_TYPE desc\n",
 635                                 iface_no, altno);
 636                         continue;
 637                 }
 638                 if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8)) ||
 639                     ((protocol == UAC_VERSION_2) && (fmt->bLength < 6))) {
 640                         dev_err(&dev->dev,
 641                                 "%u:%d : invalid UAC_FORMAT_TYPE desc\n",
 642                                 iface_no, altno);
 643                         continue;
 644                 }
 645
 646                 /*
 647                  * Blue Microphones workaround: The last altsetting is identical
 648                  * with the previous one, except for a larger packet size, but
 649                  * is actually a mislabeled two-channel setting; ignore it.
 650                  */
 651                 if (fmt->bNrChannels == 1 &&
 652                     fmt->bSubframeSize == 2 &&
 653                     altno == 2 && num == 3 &&
 654                     fp && fp->altsetting == 1 && fp->channels == 1 &&
 655                     fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
 656                     protocol == UAC_VERSION_1 &&
 657                     le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
 658                                                         fp->maxpacksize * 2)
 659                         continue;
 660
 661                 fp = kzalloc(sizeof(*fp), GFP_KERNEL);
 662                 if (!fp)
 663                         return -ENOMEM;
 664
 665                 fp->iface = iface_no;
 666                 fp->altsetting = altno;
 667                 fp->altset_idx = i;
 668                 fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
 669                 fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
 670                 fp->datainterval = snd_usb_parse_datainterval(chip, alts);
 671                 fp->protocol = protocol;
 672                 fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
 673                 fp->channels = num_channels;
 674                 if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
 675                         fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
 676                                         * (fp->maxpacksize & 0x7ff);
 677                 fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
 678                 fp->clock = clock;
 679                 INIT_LIST_HEAD(&fp->list);
 680
 681                 /* some quirks for attributes here */
 682
 683                 switch (chip->usb_id) {
 684                 case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
 685                         /* Optoplay sets the sample rate attribute although
 686                          * it seems not supporting it in fact.
 687                          */
 688                         fp->attributes &= ~UAC_EP_CS_ATTR_SAMPLE_RATE;
 689                         break;
 690                 case USB_ID(0x041e, 0x3020): /* Creative SB Audigy 2 NX */
 691                 case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
 692                         /* doesn't set the sample rate attribute, but supports it */
 693                         fp->attributes |= UAC_EP_CS_ATTR_SAMPLE_RATE;
 694                         break;
 695                 case USB_ID(0x0763, 0x2001):  /* M-Audio Quattro USB */
 696                 case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
 697                 case USB_ID(0x047f, 0x0ca1): /* plantronics headset */
 698                 case USB_ID(0x077d, 0x07af): /* Griffin iMic (note that there is
 699                                                 an older model 77d:223) */
 700                 /*
 701                  * plantronics headset and Griffin iMic have set adaptive-in
 702                  * although it's really not...
 703                  */
 704                         fp->ep_attr &= ~USB_ENDPOINT_SYNCTYPE;
 705                         if (stream == SNDRV_PCM_STREAM_PLAYBACK)
 706                                 fp->ep_attr |= USB_ENDPOINT_SYNC_ADAPTIVE;
 707                         else
 708                                 fp->ep_attr |= USB_ENDPOINT_SYNC_SYNC;
 709                         break;
 710                 }
 711
 712                 /* ok, let's parse further... */
 713                 if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream) < 0) {
 714                         kfree(fp->rate_table);
 715                         kfree(fp);
 716                         fp = NULL;
 717                         continue;
 718                 }
 719
 720                 /* Create chmap */
 721                 if (fp->channels != num_channels)
 722                         chconfig = 0;
 723                 fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
 724
 725                 dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
 726                 err = snd_usb_add_audio_stream(chip, stream, fp);
 727                 if (err < 0) {
 728                         list_del(&fp->list); /* unlink for avoiding double-free */
 729                         kfree(fp->rate_table);
 730                         kfree(fp->chmap);
 731                         kfree(fp);
 732                         return err;
 733                 }
 734                 /* try to set the interface... */
 735                 usb_set_interface(chip->dev, iface_no, altno);
 736                 snd_usb_init_pitch(chip, iface_no, alts, fp);
 737                 snd_usb_init_sample_rate(chip, iface_no, alts, fp, fp->rate_max);
 738         }
 739         return 0;
 740 }
 741