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
  49 #include <sound/core.h>
  50 #include <sound/info.h>
  51 #include <sound/pcm.h>
  52 #include <sound/pcm_params.h>
  53 #include <sound/initval.h>
  54
  55 #include "usbaudio.h"
  56 #include "card.h"
  57 #include "midi.h"
  58 #include "usbmixer.h"
  59 #include "proc.h"
  60 #include "quirks.h"
  61 #include "endpoint.h"
  62 #include "helper.h"
  63 #include "debug.h"
  64 #include "pcm.h"
  65 #include "urb.h"
  66 #include "format.h"
  67
  68 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  69 MODULE_DESCRIPTION("USB Audio");
  70 MODULE_LICENSE("GPL");
  71 MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
  72
  73
  74 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;      /* Index 0-MAX */
  75 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
  76 static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
  77 /* Vendor/product IDs for this card */
  78 static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
  79 static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
  80 static int nrpacks = 8;         /* max. number of packets per urb */
  81 static int async_unlink = 1;
  82 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
  83 static int ignore_ctl_error;
  84
  85 module_param_array(index, int, NULL, 0444);
  86 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
  87 module_param_array(id, charp, NULL, 0444);
  88 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
  89 module_param_array(enable, bool, NULL, 0444);
  90 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
  91 module_param_array(vid, int, NULL, 0444);
  92 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
  93 module_param_array(pid, int, NULL, 0444);
  94 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
  95 module_param(nrpacks, int, 0644);
  96 MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
  97 module_param(async_unlink, bool, 0444);
  98 MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
  99 module_param_array(device_setup, int, NULL, 0444);
 100 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
 101 module_param(ignore_ctl_error, bool, 0444);
 102 MODULE_PARM_DESC(ignore_ctl_error,
 103                  "Ignore errors from USB controller for mixer interfaces.");
 104
 105 /*
 106  * we keep the snd_usb_audio_t instances by ourselves for merging
 107  * the all interfaces on the same card as one sound device.
 108  */
 109
 110 static DEFINE_MUTEX(register_mutex);
 111 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
 112 static struct usb_driver usb_audio_driver;
 113
 114 /*
 115  * disconnect streams
 116  * called from snd_usb_audio_disconnect()
 117  */
 118 static void snd_usb_stream_disconnect(struct list_head *head)
 119 {
 120         int idx;
 121         struct snd_usb_stream *as;
 122         struct snd_usb_substream *subs;
 123
 124         as = list_entry(head, struct snd_usb_stream, list);
 125         for (idx = 0; idx < 2; idx++) {
 126                 subs = &as->substream[idx];
 127                 if (!subs->num_formats)
 128                         return;
 129                 snd_usb_release_substream_urbs(subs, 1);
 130                 subs->interface = -1;
 131         }
 132 }
 133
 134 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
 135 {
 136         struct usb_device *dev = chip->dev;
 137         struct usb_host_interface *alts;
 138         struct usb_interface_descriptor *altsd;
 139         struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
 140
 141         if (!iface) {
 142                 snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
 143                            dev->devnum, ctrlif, interface);
 144                 return -EINVAL;
 145         }
 146
 147         if (usb_interface_claimed(iface)) {
 148                 snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
 149                                                 dev->devnum, ctrlif, interface);
 150                 return -EINVAL;
 151         }
 152
 153         alts = &iface->altsetting[0];
 154         altsd = get_iface_desc(alts);
 155         if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
 156              altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
 157             altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
 158                 int err = snd_usbmidi_create(chip->card, iface,
 159                                              &chip->midi_list, NULL);
 160                 if (err < 0) {
 161                         snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
 162                                                 dev->devnum, ctrlif, interface);
 163                         return -EINVAL;
 164                 }
 165                 usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
 166
 167                 return 0;
 168         }
 169
 170         if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
 171              altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
 172             altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
 173                 snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
 174                                         dev->devnum, ctrlif, interface, altsd->bInterfaceClass);
 175                 /* skip non-supported classes */
 176                 return -EINVAL;
 177         }
 178
 179         if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
 180                 snd_printk(KERN_ERR "low speed audio streaming not supported\n");
 181                 return -EINVAL;
 182         }
 183
 184         if (! snd_usb_parse_audio_endpoints(chip, interface)) {
 185                 usb_set_interface(dev, interface, 0); /* reset the current interface */
 186                 usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
 187                 return -EINVAL;
 188         }
 189
 190         return 0;
 191 }
 192
 193 /*
 194  * parse audio control descriptor and create pcm/midi streams
 195  */
 196 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
 197 {
 198         struct usb_device *dev = chip->dev;
 199         struct usb_host_interface *host_iface;
 200         struct usb_interface_descriptor *altsd;
 201         void *control_header;
 202         int i, protocol;
 203
 204         /* find audiocontrol interface */
 205         host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
 206         control_header = snd_usb_find_csint_desc(host_iface->extra,
 207                                                  host_iface->extralen,
 208                                                  NULL, UAC_HEADER);
 209         altsd = get_iface_desc(host_iface);
 210         protocol = altsd->bInterfaceProtocol;
 211
 212         if (!control_header) {
 213                 snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
 214                 return -EINVAL;
 215         }
 216
 217         switch (protocol) {
 218         case UAC_VERSION_1: {
 219                 struct uac_ac_header_descriptor_v1 *h1 = control_header;
 220
 221                 if (!h1->bInCollection) {
 222                         snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
 223                         return -EINVAL;
 224                 }
 225
 226                 if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
 227                         snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
 228                         return -EINVAL;
 229                 }
 230
 231                 for (i = 0; i < h1->bInCollection; i++)
 232                         snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
 233
 234                 break;
 235         }
 236
 237         case UAC_VERSION_2: {
 238                 struct uac_clock_source_descriptor *cs;
 239                 struct usb_interface_assoc_descriptor *assoc =
 240                         usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
 241
 242                 if (!assoc) {
 243                         snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
 244                         return -EINVAL;
 245                 }
 246
 247                 /* FIXME: for now, we expect there is at least one clock source
 248                  * descriptor and we always take the first one.
 249                  * We should properly support devices with multiple clock sources,
 250                  * clock selectors and sample rate conversion units. */
 251
 252                 cs = snd_usb_find_csint_desc(host_iface->extra, host_iface->extralen,
 253                                                 NULL, UAC_CLOCK_SOURCE);
 254
 255                 if (!cs) {
 256                         snd_printk(KERN_ERR "CLOCK_SOURCE descriptor not found\n");
 257                         return -EINVAL;
 258                 }
 259
 260                 chip->clock_id = cs->bClockID;
 261
 262                 for (i = 0; i < assoc->bInterfaceCount; i++) {
 263                         int intf = assoc->bFirstInterface + i;
 264
 265                         if (intf != ctrlif)
 266                                 snd_usb_create_stream(chip, ctrlif, intf);
 267                 }
 268
 269                 break;
 270         }
 271
 272         default:
 273                 snd_printk(KERN_ERR "unknown protocol version 0x%02x\n", protocol);
 274                 return -EINVAL;
 275         }
 276
 277         return 0;
 278 }
 279
 280 /*
 281  * free the chip instance
 282  *
 283  * here we have to do not much, since pcm and controls are already freed
 284  *
 285  */
 286
 287 static int snd_usb_audio_free(struct snd_usb_audio *chip)
 288 {
 289         kfree(chip);
 290         return 0;
 291 }
 292
 293 static int snd_usb_audio_dev_free(struct snd_device *device)
 294 {
 295         struct snd_usb_audio *chip = device->device_data;
 296         return snd_usb_audio_free(chip);
 297 }
 298
 299
 300 /*
 301  * create a chip instance and set its names.
 302  */
 303 static int snd_usb_audio_create(struct usb_device *dev, int idx,
 304                                 const struct snd_usb_audio_quirk *quirk,
 305                                 struct snd_usb_audio **rchip)
 306 {
 307         struct snd_card *card;
 308         struct snd_usb_audio *chip;
 309         int err, len;
 310         char component[14];
 311         static struct snd_device_ops ops = {
 312                 .dev_free =     snd_usb_audio_dev_free,
 313         };
 314
 315         *rchip = NULL;
 316
 317         if (snd_usb_get_speed(dev) != USB_SPEED_LOW &&
 318             snd_usb_get_speed(dev) != USB_SPEED_FULL &&
 319             snd_usb_get_speed(dev) != USB_SPEED_HIGH) {
 320                 snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
 321                 return -ENXIO;
 322         }
 323
 324         err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
 325         if (err < 0) {
 326                 snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
 327                 return err;
 328         }
 329
 330         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 331         if (! chip) {
 332                 snd_card_free(card);
 333                 return -ENOMEM;
 334         }
 335
 336         chip->index = idx;
 337         chip->dev = dev;
 338         chip->card = card;
 339         chip->setup = device_setup[idx];
 340         chip->nrpacks = nrpacks;
 341         chip->async_unlink = async_unlink;
 342
 343         chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
 344                               le16_to_cpu(dev->descriptor.idProduct));
 345         INIT_LIST_HEAD(&chip->pcm_list);
 346         INIT_LIST_HEAD(&chip->midi_list);
 347         INIT_LIST_HEAD(&chip->mixer_list);
 348
 349         if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
 350                 snd_usb_audio_free(chip);
 351                 snd_card_free(card);
 352                 return err;
 353         }
 354
 355         strcpy(card->driver, "USB-Audio");
 356         sprintf(component, "USB%04x:%04x",
 357                 USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
 358         snd_component_add(card, component);
 359
 360         /* retrieve the device string as shortname */
 361         if (quirk && quirk->product_name) {
 362                 strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
 363         } else {
 364                 if (!dev->descriptor.iProduct ||
 365                     usb_string(dev, dev->descriptor.iProduct,
 366                     card->shortname, sizeof(card->shortname)) <= 0) {
 367                         /* no name available from anywhere, so use ID */
 368                         sprintf(card->shortname, "USB Device %#04x:%#04x",
 369                                 USB_ID_VENDOR(chip->usb_id),
 370                                 USB_ID_PRODUCT(chip->usb_id));
 371                 }
 372         }
 373
 374         /* retrieve the vendor and device strings as longname */
 375         if (quirk && quirk->vendor_name) {
 376                 len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
 377         } else {
 378                 if (dev->descriptor.iManufacturer)
 379                         len = usb_string(dev, dev->descriptor.iManufacturer,
 380                                          card->longname, sizeof(card->longname));
 381                 else
 382                         len = 0;
 383                 /* we don't really care if there isn't any vendor string */
 384         }
 385         if (len > 0)
 386                 strlcat(card->longname, " ", sizeof(card->longname));
 387
 388         strlcat(card->longname, card->shortname, sizeof(card->longname));
 389
 390         len = strlcat(card->longname, " at ", sizeof(card->longname));
 391
 392         if (len < sizeof(card->longname))
 393                 usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
 394
 395         strlcat(card->longname,
 396                 snd_usb_get_speed(dev) == USB_SPEED_LOW ? ", low speed" :
 397                 snd_usb_get_speed(dev) == USB_SPEED_FULL ? ", full speed" :
 398                 ", high speed",
 399                 sizeof(card->longname));
 400
 401         snd_usb_audio_create_proc(chip);
 402
 403         *rchip = chip;
 404         return 0;
 405 }
 406
 407 /*
 408  * probe the active usb device
 409  *
 410  * note that this can be called multiple times per a device, when it
 411  * includes multiple audio control interfaces.
 412  *
 413  * thus we check the usb device pointer and creates the card instance
 414  * only at the first time.  the successive calls of this function will
 415  * append the pcm interface to the corresponding card.
 416  */
 417 static void *snd_usb_audio_probe(struct usb_device *dev,
 418                                  struct usb_interface *intf,
 419                                  const struct usb_device_id *usb_id)
 420 {
 421         const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
 422         int i, err;
 423         struct snd_usb_audio *chip;
 424         struct usb_host_interface *alts;
 425         int ifnum;
 426         u32 id;
 427
 428         alts = &intf->altsetting[0];
 429         ifnum = get_iface_desc(alts)->bInterfaceNumber;
 430         id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
 431                     le16_to_cpu(dev->descriptor.idProduct));
 432         if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
 433                 goto __err_val;
 434
 435         if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
 436                 goto __err_val;
 437
 438         /*
 439          * found a config.  now register to ALSA
 440          */
 441
 442         /* check whether it's already registered */
 443         chip = NULL;
 444         mutex_lock(&register_mutex);
 445         for (i = 0; i < SNDRV_CARDS; i++) {
 446                 if (usb_chip[i] && usb_chip[i]->dev == dev) {
 447                         if (usb_chip[i]->shutdown) {
 448                                 snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
 449                                 goto __error;
 450                         }
 451                         chip = usb_chip[i];
 452                         break;
 453                 }
 454         }
 455         if (! chip) {
 456                 /* it's a fresh one.
 457                  * now look for an empty slot and create a new card instance
 458                  */
 459                 for (i = 0; i < SNDRV_CARDS; i++)
 460                         if (enable[i] && ! usb_chip[i] &&
 461                             (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
 462                             (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
 463                                 if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
 464                                         goto __error;
 465                                 }
 466                                 snd_card_set_dev(chip->card, &intf->dev);
 467                                 break;
 468                         }
 469                 if (!chip) {
 470                         printk(KERN_ERR "no available usb audio device\n");
 471                         goto __error;
 472                 }
 473         }
 474
 475         chip->txfr_quirk = 0;
 476         err = 1; /* continue */
 477         if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
 478                 /* need some special handlings */
 479                 if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
 480                         goto __error;
 481         }
 482
 483         if (err > 0) {
 484                 /* create normal USB audio interfaces */
 485                 if (snd_usb_create_streams(chip, ifnum) < 0 ||
 486                     snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
 487                         goto __error;
 488                 }
 489         }
 490
 491         /* we are allowed to call snd_card_register() many times */
 492         if (snd_card_register(chip->card) < 0) {
 493                 goto __error;
 494         }
 495
 496         usb_chip[chip->index] = chip;
 497         chip->num_interfaces++;
 498         mutex_unlock(&register_mutex);
 499         return chip;
 500
 501  __error:
 502         if (chip && !chip->num_interfaces)
 503                 snd_card_free(chip->card);
 504         mutex_unlock(&register_mutex);
 505  __err_val:
 506         return NULL;
 507 }
 508
 509 /*
 510  * we need to take care of counter, since disconnection can be called also
 511  * many times as well as usb_audio_probe().
 512  */
 513 static void snd_usb_audio_disconnect(struct usb_device *dev, void *ptr)
 514 {
 515         struct snd_usb_audio *chip;
 516         struct snd_card *card;
 517         struct list_head *p;
 518
 519         if (ptr == (void *)-1L)
 520                 return;
 521
 522         chip = ptr;
 523         card = chip->card;
 524         mutex_lock(&register_mutex);
 525         chip->shutdown = 1;
 526         chip->num_interfaces--;
 527         if (chip->num_interfaces <= 0) {
 528                 snd_card_disconnect(card);
 529                 /* release the pcm resources */
 530                 list_for_each(p, &chip->pcm_list) {
 531                         snd_usb_stream_disconnect(p);
 532                 }
 533                 /* release the midi resources */
 534                 list_for_each(p, &chip->midi_list) {
 535                         snd_usbmidi_disconnect(p);
 536                 }
 537                 /* release mixer resources */
 538                 list_for_each(p, &chip->mixer_list) {
 539                         snd_usb_mixer_disconnect(p);
 540                 }
 541                 usb_chip[chip->index] = NULL;
 542                 mutex_unlock(&register_mutex);
 543                 snd_card_free_when_closed(card);
 544         } else {
 545                 mutex_unlock(&register_mutex);
 546         }
 547 }
 548
 549 /*
 550  * new 2.5 USB kernel API
 551  */
 552 static int usb_audio_probe(struct usb_interface *intf,
 553                            const struct usb_device_id *id)
 554 {
 555         void *chip;
 556         chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
 557         if (chip) {
 558                 usb_set_intfdata(intf, chip);
 559                 return 0;
 560         } else
 561                 return -EIO;
 562 }
 563
 564 static void usb_audio_disconnect(struct usb_interface *intf)
 565 {
 566         snd_usb_audio_disconnect(interface_to_usbdev(intf),
 567                                  usb_get_intfdata(intf));
 568 }
 569
 570 #ifdef CONFIG_PM
 571 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
 572 {
 573         struct snd_usb_audio *chip = usb_get_intfdata(intf);
 574         struct list_head *p;
 575         struct snd_usb_stream *as;
 576
 577         if (chip == (void *)-1L)
 578                 return 0;
 579
 580         snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
 581         if (!chip->num_suspended_intf++) {
 582                 list_for_each(p, &chip->pcm_list) {
 583                         as = list_entry(p, struct snd_usb_stream, list);
 584                         snd_pcm_suspend_all(as->pcm);
 585                 }
 586         }
 587
 588         return 0;
 589 }
 590
 591 static int usb_audio_resume(struct usb_interface *intf)
 592 {
 593         struct snd_usb_audio *chip = usb_get_intfdata(intf);
 594
 595         if (chip == (void *)-1L)
 596                 return 0;
 597         if (--chip->num_suspended_intf)
 598                 return 0;
 599         /*
 600          * ALSA leaves material resumption to user space
 601          * we just notify
 602          */
 603
 604         snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
 605
 606         return 0;
 607 }
 608 #endif          /* CONFIG_PM */
 609
 610 static struct usb_device_id usb_audio_ids [] = {
 611 #include "quirks-table.h"
 612     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
 613       .bInterfaceClass = USB_CLASS_AUDIO,
 614       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
 615     { }                                         /* Terminating entry */
 616 };
 617
 618 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
 619
 620 /*
 621  * entry point for linux usb interface
 622  */
 623
 624 static struct usb_driver usb_audio_driver = {
 625         .name =         "snd-usb-audio",
 626         .probe =        usb_audio_probe,
 627         .disconnect =   usb_audio_disconnect,
 628         .suspend =      usb_audio_suspend,
 629         .resume =       usb_audio_resume,
 630         .id_table =     usb_audio_ids,
 631 };
 632
 633 static int __init snd_usb_audio_init(void)
 634 {
 635         if (nrpacks < 1 || nrpacks > MAX_PACKS) {
 636                 printk(KERN_WARNING "invalid nrpacks value.\n");
 637                 return -EINVAL;
 638         }
 639         return usb_register(&usb_audio_driver);
 640 }
 641
 642 static void __exit snd_usb_audio_cleanup(void)
 643 {
 644         usb_deregister(&usb_audio_driver);
 645 }
 646
 647 module_init(snd_usb_audio_init);
 648 module_exit(snd_usb_audio_cleanup);