sound/usb/card.c

   1 /*
   2  *   (Tentative) USB Audio Driver for ALSA
   3  *
   4  *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
   5  *
   6  *   Many codes borrowed from audio.c by
   7  *          Alan Cox (alan@lxorguk.ukuu.org.uk)
   8  *          Thomas Sailer (sailer@ife.ee.ethz.ch)
   9  *
  10  *
  11  *   This program is free software; you can redistribute it and/or modify
  12  *   it under the terms of the GNU General Public License as published by
  13  *   the Free Software Foundation; either version 2 of the License, or
  14  *   (at your option) any later version.
  15  *
  16  *   This program is distributed in the hope that it will be useful,
  17  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *   GNU General Public License for more details.
  20  *
  21  *   You should have received a copy of the GNU General Public License
  22  *   along with this program; if not, write to the Free Software
  23  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  24  *
  25  *
  26  *  NOTES:
  27  *
  28  *   - async unlink should be used for avoiding the sleep inside lock.
  29  *     2.4.22 usb-uhci seems buggy for async unlinking and results in
  30  *     oops.  in such a cse, pass async_unlink=0 option.
  31  *   - the linked URBs would be preferred but not used so far because of
  32  *     the instability of unlinking.
  33  *   - type II is not supported properly.  there is no device which supports
  34  *     this type *correctly*.  SB extigy looks as if it supports, but it's
  35  *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
  36  */
  37
  38
  39 #include <linux/bitops.h>
  40 #include <linux/init.h>
  41 #include <linux/list.h>
  42 #include <linux/slab.h>
  43 #include <linux/string.h>
  44 #include <linux/usb.h>
  45 #include <linux/moduleparam.h>
  46 #include <linux/mutex.h>
  47 #include <linux/usb/audio.h>
  48 #include <linux/usb/audio-v2.h>
  49
  50 #include <sound/core.h>
  51 #include <sound/info.h>
  52 #include <sound/pcm.h>
  53 #include <sound/pcm_params.h>
  54 #include <sound/initval.h>
  55
  56 #include "usbaudio.h"
  57 #include "card.h"
  58 #include "midi.h"
  59 #include "mixer.h"
  60 #include "proc.h"
  61 #include "quirks.h"
  62 #include "endpoint.h"
  63 #include "helper.h"
  64 #include "debug.h"
  65 #include "pcm.h"
  66 #include "urb.h"
  67 #include "format.h"
  68
  69 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  70 MODULE_DESCRIPTION("USB Audio");
  71 MODULE_LICENSE("GPL");
  72 MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
  73
  74
  75 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  76 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  77 static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
  78 /* Vendor/product IDs for this card */
  79 static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
  80 static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
  81 static int nrpacks = 8;         /* max. number of packets per urb */
  82 static int async_unlink = 1;
  83 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
  84 static int ignore_ctl_error;
  85
  86 module_param_array(index, int, NULL, 0444);
  87 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
  88 module_param_array(id, charp, NULL, 0444);
  89 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
  90 module_param_array(enable, bool, NULL, 0444);
  91 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
  92 module_param_array(vid, int, NULL, 0444);
  93 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
  94 module_param_array(pid, int, NULL, 0444);
  95 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
  96 module_param(nrpacks, int, 0644);
  97 MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
  98 module_param(async_unlink, bool, 0444);
  99 MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
 100 module_param_array(device_setup, int, NULL, 0444);
 101 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
 102 module_param(ignore_ctl_error, bool, 0444);
 103 MODULE_PARM_DESC(ignore_ctl_error,
 104                  "Ignore errors from USB controller for mixer interfaces.");
 105
 106 /*
 107  * we keep the snd_usb_audio_t instances by ourselves for merging
 108  * the all interfaces on the same card as one sound device.
 109  */
 110
 111 static DEFINE_MUTEX(register_mutex);
 112 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
 113 static struct usb_driver usb_audio_driver;
 114
 115 /*
 116  * disconnect streams
 117  * called from snd_usb_audio_disconnect()
 118  */
 119 static void snd_usb_stream_disconnect(struct list_head *head)
 120 {
 121         int idx;
 122         struct snd_usb_stream *as;
 123         struct snd_usb_substream *subs;
 124
 125         as = list_entry(head, struct snd_usb_stream, list);
 126         for (idx = 0; idx < 2; idx++) {
 127                 subs = &as->substream[idx];
 128                 if (!subs->num_formats)
 129                         continue;
 130                 snd_usb_release_substream_urbs(subs, 1);
 131                 subs->interface = -1;
 132         }
 133 }
 134
 135 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
 136 {
 137         struct usb_device *dev = chip->dev;
 138         struct usb_host_interface *alts;
 139         struct usb_interface_descriptor *altsd;
 140         struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
 141
 142         if (!iface) {
 143                 snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
 144                            dev->devnum, ctrlif, interface);
 145                 return -EINVAL;
 146         }
 147
 148         if (usb_interface_claimed(iface)) {
 149                 snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
 150                                                 dev->devnum, ctrlif, interface);
 151                 return -EINVAL;
 152         }
 153
 154         alts = &iface->altsetting[0];
 155         altsd = get_iface_desc(alts);
 156         if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
 157              altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
 158             altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
 159                 int err = snd_usbmidi_create(chip->card, iface,
 160                                              &chip->midi_list, NULL);
 161                 if (err < 0) {
 162                         snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
 163                                                 dev->devnum, ctrlif, interface);
 164                         return -EINVAL;
 165                 }
 166                 usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
 167
 168                 return 0;
 169         }
 170
 171         if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
 172              altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
 173             altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
 174                 snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
 175                                         dev->devnum, ctrlif, interface, altsd->bInterfaceClass);
 176                 /* skip non-supported classes */
 177                 return -EINVAL;
 178         }
 179
 180         if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
 181                 snd_printk(KERN_ERR "low speed audio streaming not supported\n");
 182                 return -EINVAL;
 183         }
 184
 185         if (! snd_usb_parse_audio_endpoints(chip, interface)) {
 186                 usb_set_interface(dev, interface, 0); /* reset the current interface */
 187                 usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
 188                 return -EINVAL;
 189         }
 190
 191         return 0;
 192 }
 193
 194 /*
 195  * parse audio control descriptor and create pcm/midi streams
 196  */
 197 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
 198 {
 199         struct usb_device *dev = chip->dev;
 200         struct usb_host_interface *host_iface;
 201         struct usb_interface_descriptor *altsd;
 202         void *control_header;
 203         int i, protocol;
 204
 205         /* find audiocontrol interface */
 206         host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
 207         control_header = snd_usb_find_csint_desc(host_iface->extra,
 208                                                  host_iface->extralen,
 209                                                  NULL, UAC_HEADER);
 210         altsd = get_iface_desc(host_iface);
 211         protocol = altsd->bInterfaceProtocol;
 212
 213         if (!control_header) {
 214                 snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
 215                 return -EINVAL;
 216         }
 217
 218         switch (protocol) {
 219         default:
 220                 snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
 221                             protocol);
 222                 /* fall through */
 223
 224         case UAC_VERSION_1: {
 225                 struct uac1_ac_header_descriptor *h1 = control_header;
 226
 227                 if (!h1->bInCollection) {
 228                         snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
 229                         return -EINVAL;
 230                 }
 231
 232                 if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
 233                         snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
 234                         return -EINVAL;
 235                 }
 236
 237                 for (i = 0; i < h1->bInCollection; i++)
 238                         snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
 239
 240                 break;
 241         }
 242
 243         case UAC_VERSION_2: {
 244                 struct usb_interface_assoc_descriptor *assoc =
 245                         usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
 246
 247                 if (!assoc) {
 248                         snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
 249                         return -EINVAL;
 250                 }
 251
 252                 for (i = 0; i < assoc->bInterfaceCount; i++) {
 253                         int intf = assoc->bFirstInterface + i;
 254
 255                         if (intf != ctrlif)
 256                                 snd_usb_create_stream(chip, ctrlif, intf);
 257                 }
 258
 259                 break;
 260         }
 261         }
 262
 263         return 0;
 264 }
 265
 266 /*
 267  * free the chip instance
 268  *
 269  * here we have to do not much, since pcm and controls are already freed
 270  *
 271  */
 272
 273 static int snd_usb_audio_free(struct snd_usb_audio *chip)
 274 {
 275         kfree(chip);
 276         return 0;
 277 }
 278
 279 static int snd_usb_audio_dev_free(struct snd_device *device)
 280 {
 281         struct snd_usb_audio *chip = device->device_data;
 282         return snd_usb_audio_free(chip);
 283 }
 284
 285
 286 /*
 287  * create a chip instance and set its names.
 288  */
 289 static int snd_usb_audio_create(struct usb_device *dev, int idx,
 290                                 const struct snd_usb_audio_quirk *quirk,
 291                                 struct snd_usb_audio **rchip)
 292 {
 293         struct snd_card *card;
 294         struct snd_usb_audio *chip;
 295         int err, len;
 296         char component[14];
 297         static struct snd_device_ops ops = {
 298                 .dev_free =     snd_usb_audio_dev_free,
 299         };
 300
 301         *rchip = NULL;
 302
 303         switch (snd_usb_get_speed(dev)) {
 304         case USB_SPEED_LOW:
 305         case USB_SPEED_FULL:
 306         case USB_SPEED_HIGH:
 307         case USB_SPEED_SUPER:
 308                 break;
 309         default:
 310                 snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
 311                 return -ENXIO;
 312         }
 313
 314         err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
 315         if (err < 0) {
 316                 snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
 317                 return err;
 318         }
 319
 320         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 321         if (! chip) {
 322                 snd_card_free(card);
 323                 return -ENOMEM;
 324         }
 325
 326         chip->index = idx;
 327         chip->dev = dev;
 328         chip->card = card;
 329         chip->setup = device_setup[idx];
 330         chip->nrpacks = nrpacks;
 331         chip->async_unlink = async_unlink;
 332
 333         chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
 334                               le16_to_cpu(dev->descriptor.idProduct));
 335         INIT_LIST_HEAD(&chip->pcm_list);
 336         INIT_LIST_HEAD(&chip->midi_list);
 337         INIT_LIST_HEAD(&chip->mixer_list);
 338
 339         if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
 340                 snd_usb_audio_free(chip);
 341                 snd_card_free(card);
 342                 return err;
 343         }
 344
 345         strcpy(card->driver, "USB-Audio");
 346         sprintf(component, "USB%04x:%04x",
 347                 USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
 348         snd_component_add(card, component);
 349
 350         /* retrieve the device string as shortname */
 351         if (quirk && quirk->product_name) {
 352                 strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
 353         } else {
 354                 if (!dev->descriptor.iProduct ||
 355                     usb_string(dev, dev->descriptor.iProduct,
 356                     card->shortname, sizeof(card->shortname)) <= 0) {
 357                         /* no name available from anywhere, so use ID */
 358                         sprintf(card->shortname, "USB Device %#04x:%#04x",
 359                                 USB_ID_VENDOR(chip->usb_id),
 360                                 USB_ID_PRODUCT(chip->usb_id));
 361                 }
 362         }
 363
 364         /* retrieve the vendor and device strings as longname */
 365         if (quirk && quirk->vendor_name) {
 366                 len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
 367         } else {
 368                 if (dev->descriptor.iManufacturer)
 369                         len = usb_string(dev, dev->descriptor.iManufacturer,
 370                                          card->longname, sizeof(card->longname));
 371                 else
 372                         len = 0;
 373                 /* we don't really care if there isn't any vendor string */
 374         }
 375         if (len > 0)
 376                 strlcat(card->longname, " ", sizeof(card->longname));
 377
 378         strlcat(card->longname, card->shortname, sizeof(card->longname));
 379
 380         len = strlcat(card->longname, " at ", sizeof(card->longname));
 381
 382         if (len < sizeof(card->longname))
 383                 usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
 384
 385         switch (snd_usb_get_speed(dev)) {
 386         case USB_SPEED_LOW:
 387                 strlcat(card->longname, ", low speed", sizeof(card->longname));
 388                 break;
 389         case USB_SPEED_FULL:
 390                 strlcat(card->longname, ", full speed", sizeof(card->longname));
 391                 break;
 392         case USB_SPEED_HIGH:
 393                 strlcat(card->longname, ", high speed", sizeof(card->longname));
 394                 break;
 395         case USB_SPEED_SUPER:
 396                 strlcat(card->longname, ", super speed", sizeof(card->longname));
 397                 break;
 398         default:
 399                 break;
 400         }
 401
 402         snd_usb_audio_create_proc(chip);
 403
 404         *rchip = chip;
 405         return 0;
 406 }
 407
 408 /*
 409  * probe the active usb device
 410  *
 411  * note that this can be called multiple times per a device, when it
 412  * includes multiple audio control interfaces.
 413  *
 414  * thus we check the usb device pointer and creates the card instance
 415  * only at the first time.  the successive calls of this function will
 416  * append the pcm interface to the corresponding card.
 417  */
 418 static void *snd_usb_audio_probe(struct usb_device *dev,
 419                                  struct usb_interface *intf,
 420                                  const struct usb_device_id *usb_id)
 421 {
 422         const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
 423         int i, err;
 424         struct snd_usb_audio *chip;
 425         struct usb_host_interface *alts;
 426         int ifnum;
 427         u32 id;
 428
 429         alts = &intf->altsetting[0];
 430         ifnum = get_iface_desc(alts)->bInterfaceNumber;
 431         id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
 432                     le16_to_cpu(dev->descriptor.idProduct));
 433         if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
 434                 goto __err_val;
 435
 436         if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
 437                 goto __err_val;
 438
 439         /*
 440          * found a config.  now register to ALSA
 441          */
 442
 443         /* check whether it's already registered */
 444         chip = NULL;
 445         mutex_lock(&register_mutex);
 446         for (i = 0; i < SNDRV_CARDS; i++) {
 447                 if (usb_chip[i] && usb_chip[i]->dev == dev) {
 448                         if (usb_chip[i]->shutdown) {
 449                                 snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
 450                                 goto __error;
 451                         }
 452                         chip = usb_chip[i];
 453                         break;
 454                 }
 455         }
 456         if (! chip) {
 457                 /* it's a fresh one.
 458                  * now look for an empty slot and create a new card instance
 459                  */
 460                 for (i = 0; i < SNDRV_CARDS; i++)
 461                         if (enable[i] && ! usb_chip[i] &&
 462                             (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
 463                             (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
 464                                 if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
 465                                         goto __error;
 466                                 }
 467                                 snd_card_set_dev(chip->card, &intf->dev);
 468                                 break;
 469                         }
 470                 if (!chip) {
 471                         printk(KERN_ERR "no available usb audio device\n");
 472                         goto __error;
 473                 }
 474         }
 475
 476         chip->txfr_quirk = 0;
 477         err = 1; /* continue */
 478         if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
 479                 /* need some special handlings */
 480                 if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
 481                         goto __error;
 482         }
 483
 484         /*
 485          * For devices with more than one control interface, we assume the
 486          * first contains the audio controls. We might need a more specific
 487          * check here in the future.
 488          */
 489         if (!chip->ctrl_intf)
 490                 chip->ctrl_intf = alts;
 491
 492         if (err > 0) {
 493                 /* create normal USB audio interfaces */
 494                 if (snd_usb_create_streams(chip, ifnum) < 0 ||
 495                     snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
 496                         goto __error;
 497                 }
 498         }
 499
 500         /* we are allowed to call snd_card_register() many times */
 501         if (snd_card_register(chip->card) < 0) {
 502                 goto __error;
 503         }
 504
 505         usb_chip[chip->index] = chip;
 506         chip->num_interfaces++;
 507         mutex_unlock(&register_mutex);
 508         return chip;
 509
 510  __error:
 511         if (chip && !chip->num_interfaces)
 512                 snd_card_free(chip->card);
 513         mutex_unlock(&register_mutex);
 514  __err_val:
 515         return NULL;
 516 }
 517
 518 /*
 519  * we need to take care of counter, since disconnection can be called also
 520  * many times as well as usb_audio_probe().
 521  */
 522 static void snd_usb_audio_disconnect(struct usb_device *dev, void *ptr)
 523 {
 524         struct snd_usb_audio *chip;
 525         struct snd_card *card;
 526         struct list_head *p;
 527
 528         if (ptr == (void *)-1L)
 529                 return;
 530
 531         chip = ptr;
 532         card = chip->card;
 533         mutex_lock(&register_mutex);
 534         chip->shutdown = 1;
 535         chip->num_interfaces--;
 536         if (chip->num_interfaces <= 0) {
 537                 snd_card_disconnect(card);
 538                 /* release the pcm resources */
 539                 list_for_each(p, &chip->pcm_list) {
 540                         snd_usb_stream_disconnect(p);
 541                 }
 542                 /* release the midi resources */
 543                 list_for_each(p, &chip->midi_list) {
 544                         snd_usbmidi_disconnect(p);
 545                 }
 546                 /* release mixer resources */
 547                 list_for_each(p, &chip->mixer_list) {
 548                         snd_usb_mixer_disconnect(p);
 549                 }
 550                 usb_chip[chip->index] = NULL;
 551                 mutex_unlock(&register_mutex);
 552                 snd_card_free_when_closed(card);
 553         } else {
 554                 mutex_unlock(&register_mutex);
 555         }
 556 }
 557
 558 /*
 559  * new 2.5 USB kernel API
 560  */
 561 static int usb_audio_probe(struct usb_interface *intf,
 562                            const struct usb_device_id *id)
 563 {
 564         void *chip;
 565         chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
 566         if (chip) {
 567                 usb_set_intfdata(intf, chip);
 568                 return 0;
 569         } else
 570                 return -EIO;
 571 }
 572
 573 static void usb_audio_disconnect(struct usb_interface *intf)
 574 {
 575         snd_usb_audio_disconnect(interface_to_usbdev(intf),
 576                                  usb_get_intfdata(intf));
 577 }
 578
 579 #ifdef CONFIG_PM
 580 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
 581 {
 582         struct snd_usb_audio *chip = usb_get_intfdata(intf);
 583         struct list_head *p;
 584         struct snd_usb_stream *as;
 585
 586         if (chip == (void *)-1L)
 587                 return 0;
 588
 589         snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
 590         if (!chip->num_suspended_intf++) {
 591                 list_for_each(p, &chip->pcm_list) {
 592                         as = list_entry(p, struct snd_usb_stream, list);
 593                         snd_pcm_suspend_all(as->pcm);
 594                 }
 595         }
 596
 597         return 0;
 598 }
 599
 600 static int usb_audio_resume(struct usb_interface *intf)
 601 {
 602         struct snd_usb_audio *chip = usb_get_intfdata(intf);
 603
 604         if (chip == (void *)-1L)
 605                 return 0;
 606         if (--chip->num_suspended_intf)
 607                 return 0;
 608         /*
 609          * ALSA leaves material resumption to user space
 610          * we just notify
 611          */
 612
 613         snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
 614
 615         return 0;
 616 }
 617 #else
 618 #define usb_audio_suspend       NULL
 619 #define usb_audio_resume        NULL
 620 #endif          /* CONFIG_PM */
 621
 622 static struct usb_device_id usb_audio_ids [] = {
 623 #include "quirks-table.h"
 624     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
 625       .bInterfaceClass = USB_CLASS_AUDIO,
 626       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
 627     { }                                         /* Terminating entry */
 628 };
 629
 630 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
 631
 632 /*
 633  * entry point for linux usb interface
 634  */
 635
 636 static struct usb_driver usb_audio_driver = {
 637         .name =         "snd-usb-audio",
 638         .probe =        usb_audio_probe,
 639         .disconnect =   usb_audio_disconnect,
 640         .suspend =      usb_audio_suspend,
 641         .resume =       usb_audio_resume,
 642         .id_table =     usb_audio_ids,
 643 };
 644
 645 static int __init snd_usb_audio_init(void)
 646 {
 647         if (nrpacks < 1 || nrpacks > MAX_PACKS) {
 648                 printk(KERN_WARNING "invalid nrpacks value.\n");
 649                 return -EINVAL;
 650         }
 651         return usb_register(&usb_audio_driver);
 652 }
 653
 654 static void __exit snd_usb_audio_cleanup(void)
 655 {
 656         usb_deregister(&usb_audio_driver);
 657 }
 658
 659 module_init(snd_usb_audio_init);
 660 module_exit(snd_usb_audio_cleanup);