2 * (Tentative) USB Audio Driver for ALSA
4 * Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
6 * Many codes borrowed from audio.c by
7 * Alan Cox (alan@lxorguk.ukuu.org.uk)
8 * Thomas Sailer (sailer@ife.ee.ethz.ch)
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.
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.
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
28 * - the linked URBs would be preferred but not used so far because of
29 * the instability of unlinking.
30 * - type II is not supported properly. there is no device which supports
31 * this type *correctly*. SB extigy looks as if it supports, but it's
32 * indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
36 #include <linux/bitops.h>
37 #include <linux/init.h>
38 #include <linux/list.h>
39 #include <linux/slab.h>
40 #include <linux/string.h>
41 #include <linux/ctype.h>
42 #include <linux/usb.h>
43 #include <linux/moduleparam.h>
44 #include <linux/mutex.h>
45 #include <linux/usb/audio.h>
46 #include <linux/usb/audio-v2.h>
47 #include <linux/module.h>
49 #include <sound/control.h>
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>
70 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
71 MODULE_DESCRIPTION("USB Audio");
72 MODULE_LICENSE("GPL");
73 MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
76 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
77 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
78 static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
79 /* Vendor/product IDs for this card */
80 static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
81 static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
82 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
83 static bool ignore_ctl_error;
84 static bool autoclock = true;
85 static char *quirk_alias[SNDRV_CARDS];
87 module_param_array(index, int, NULL, 0444);
88 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
89 module_param_array(id, charp, NULL, 0444);
90 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
91 module_param_array(enable, bool, NULL, 0444);
92 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
93 module_param_array(vid, int, NULL, 0444);
94 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
95 module_param_array(pid, int, NULL, 0444);
96 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
97 module_param_array(device_setup, int, NULL, 0444);
98 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
99 module_param(ignore_ctl_error, bool, 0444);
100 MODULE_PARM_DESC(ignore_ctl_error,
101 "Ignore errors from USB controller for mixer interfaces.");
102 module_param(autoclock, bool, 0444);
103 MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
104 module_param_array(quirk_alias, charp, NULL, 0444);
105 MODULE_PARM_DESC(quirk_alias, "Quirk aliases, e.g. 0123abcd:5678beef.");
108 * we keep the snd_usb_audio_t instances by ourselves for merging
109 * the all interfaces on the same card as one sound device.
112 static DEFINE_MUTEX(register_mutex);
113 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
114 static struct usb_driver usb_audio_driver;
118 * called from usb_audio_disconnect()
120 static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
123 struct snd_usb_substream *subs;
125 for (idx = 0; idx < 2; idx++) {
126 subs = &as->substream[idx];
127 if (!subs->num_formats)
129 subs->interface = -1;
130 subs->data_endpoint = NULL;
131 subs->sync_endpoint = NULL;
135 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
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);
143 dev_err(&dev->dev, "%u:%d : does not exist\n",
148 alts = &iface->altsetting[0];
149 altsd = get_iface_desc(alts);
152 * Android with both accessory and audio interfaces enabled gets the
153 * interface numbers wrong.
155 if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
156 chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
158 altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
159 altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
161 iface = usb_ifnum_to_if(dev, interface);
164 alts = &iface->altsetting[0];
165 altsd = get_iface_desc(alts);
168 if (usb_interface_claimed(iface)) {
169 dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
174 if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
175 altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
176 altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
177 int err = __snd_usbmidi_create(chip->card, iface,
178 &chip->midi_list, NULL,
182 "%u:%d: cannot create sequencer device\n",
186 usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
191 if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
192 altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
193 altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
195 "%u:%d: skipping non-supported interface %d\n",
196 ctrlif, interface, altsd->bInterfaceClass);
197 /* skip non-supported classes */
201 if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
202 dev_err(&dev->dev, "low speed audio streaming not supported\n");
206 if (! snd_usb_parse_audio_interface(chip, interface)) {
207 usb_set_interface(dev, interface, 0); /* reset the current interface */
208 usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
216 * parse audio control descriptor and create pcm/midi streams
218 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
220 struct usb_device *dev = chip->dev;
221 struct usb_host_interface *host_iface;
222 struct usb_interface_descriptor *altsd;
223 void *control_header;
226 /* find audiocontrol interface */
227 host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
228 control_header = snd_usb_find_csint_desc(host_iface->extra,
229 host_iface->extralen,
231 altsd = get_iface_desc(host_iface);
232 protocol = altsd->bInterfaceProtocol;
234 if (!control_header) {
235 dev_err(&dev->dev, "cannot find UAC_HEADER\n");
242 "unknown interface protocol %#02x, assuming v1\n",
246 case UAC_VERSION_1: {
247 struct uac1_ac_header_descriptor *h1 = control_header;
249 if (!h1->bInCollection) {
250 dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
254 if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
255 dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
259 for (i = 0; i < h1->bInCollection; i++)
260 snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
265 case UAC_VERSION_2: {
266 struct usb_interface_assoc_descriptor *assoc =
267 usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
271 * Firmware writers cannot count to three. So to find
272 * the IAD on the NuForce UDH-100, also check the next
275 struct usb_interface *iface =
276 usb_ifnum_to_if(dev, ctrlif + 1);
279 iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
280 iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
281 assoc = iface->intf_assoc;
285 dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
289 for (i = 0; i < assoc->bInterfaceCount; i++) {
290 int intf = assoc->bFirstInterface + i;
293 snd_usb_create_stream(chip, ctrlif, intf);
304 * free the chip instance
306 * here we have to do not much, since pcm and controls are already freed
310 static int snd_usb_audio_free(struct snd_usb_audio *chip)
312 struct snd_usb_endpoint *ep, *n;
314 list_for_each_entry_safe(ep, n, &chip->ep_list, list)
315 snd_usb_endpoint_free(ep);
317 mutex_destroy(&chip->mutex);
318 if (!atomic_read(&chip->shutdown))
319 dev_set_drvdata(&chip->dev->dev, NULL);
324 static int snd_usb_audio_dev_free(struct snd_device *device)
326 struct snd_usb_audio *chip = device->device_data;
327 return snd_usb_audio_free(chip);
331 * create a chip instance and set its names.
333 static int snd_usb_audio_create(struct usb_interface *intf,
334 struct usb_device *dev, int idx,
335 const struct snd_usb_audio_quirk *quirk,
336 struct snd_usb_audio **rchip)
338 struct snd_card *card;
339 struct snd_usb_audio *chip;
342 static struct snd_device_ops ops = {
343 .dev_free = snd_usb_audio_dev_free,
348 switch (snd_usb_get_speed(dev)) {
352 case USB_SPEED_WIRELESS:
353 case USB_SPEED_SUPER:
354 case USB_SPEED_SUPER_PLUS:
357 dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
361 err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
364 dev_err(&dev->dev, "cannot create card instance %d\n", idx);
368 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
374 mutex_init(&chip->mutex);
375 init_waitqueue_head(&chip->shutdown_wait);
379 chip->setup = device_setup[idx];
380 chip->autoclock = autoclock;
381 atomic_set(&chip->active, 1); /* avoid autopm during probing */
382 atomic_set(&chip->usage_count, 0);
383 atomic_set(&chip->shutdown, 0);
385 chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
386 le16_to_cpu(dev->descriptor.idProduct));
387 INIT_LIST_HEAD(&chip->pcm_list);
388 INIT_LIST_HEAD(&chip->ep_list);
389 INIT_LIST_HEAD(&chip->midi_list);
390 INIT_LIST_HEAD(&chip->mixer_list);
392 if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
393 snd_usb_audio_free(chip);
398 strcpy(card->driver, "USB-Audio");
399 sprintf(component, "USB%04x:%04x",
400 USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
401 snd_component_add(card, component);
403 /* retrieve the device string as shortname */
404 if (quirk && quirk->product_name && *quirk->product_name) {
405 strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
407 if (!dev->descriptor.iProduct ||
408 usb_string(dev, dev->descriptor.iProduct,
409 card->shortname, sizeof(card->shortname)) <= 0) {
410 /* no name available from anywhere, so use ID */
411 sprintf(card->shortname, "USB Device %#04x:%#04x",
412 USB_ID_VENDOR(chip->usb_id),
413 USB_ID_PRODUCT(chip->usb_id));
416 strim(card->shortname);
418 /* retrieve the vendor and device strings as longname */
419 if (quirk && quirk->vendor_name && *quirk->vendor_name) {
420 len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
422 if (dev->descriptor.iManufacturer)
423 len = usb_string(dev, dev->descriptor.iManufacturer,
424 card->longname, sizeof(card->longname));
427 /* we don't really care if there isn't any vendor string */
430 strim(card->longname);
432 strlcat(card->longname, " ", sizeof(card->longname));
435 strlcat(card->longname, card->shortname, sizeof(card->longname));
437 len = strlcat(card->longname, " at ", sizeof(card->longname));
439 if (len < sizeof(card->longname))
440 usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
442 switch (snd_usb_get_speed(dev)) {
444 strlcat(card->longname, ", low speed", sizeof(card->longname));
447 strlcat(card->longname, ", full speed", sizeof(card->longname));
450 strlcat(card->longname, ", high speed", sizeof(card->longname));
452 case USB_SPEED_SUPER:
453 strlcat(card->longname, ", super speed", sizeof(card->longname));
455 case USB_SPEED_SUPER_PLUS:
456 strlcat(card->longname, ", super speed plus", sizeof(card->longname));
462 snd_usb_audio_create_proc(chip);
468 /* look for a matching quirk alias id */
469 static bool get_alias_id(struct usb_device *dev, unsigned int *id)
472 unsigned int src, dst;
474 for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
475 if (!quirk_alias[i] ||
476 sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
480 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
481 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
482 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
490 static struct usb_device_id usb_audio_ids[]; /* defined below */
492 /* look for the corresponding quirk */
493 static const struct snd_usb_audio_quirk *
494 get_alias_quirk(struct usb_device *dev, unsigned int id)
496 const struct usb_device_id *p;
498 for (p = usb_audio_ids; p->match_flags; p++) {
499 /* FIXME: this checks only vendor:product pair in the list */
500 if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==
501 USB_DEVICE_ID_MATCH_DEVICE &&
502 p->idVendor == USB_ID_VENDOR(id) &&
503 p->idProduct == USB_ID_PRODUCT(id))
504 return (const struct snd_usb_audio_quirk *)p->driver_info;
511 * probe the active usb device
513 * note that this can be called multiple times per a device, when it
514 * includes multiple audio control interfaces.
516 * thus we check the usb device pointer and creates the card instance
517 * only at the first time. the successive calls of this function will
518 * append the pcm interface to the corresponding card.
520 static int usb_audio_probe(struct usb_interface *intf,
521 const struct usb_device_id *usb_id)
523 struct usb_device *dev = interface_to_usbdev(intf);
524 const struct snd_usb_audio_quirk *quirk =
525 (const struct snd_usb_audio_quirk *)usb_id->driver_info;
526 struct snd_usb_audio *chip;
528 struct usb_host_interface *alts;
532 alts = &intf->altsetting[0];
533 ifnum = get_iface_desc(alts)->bInterfaceNumber;
534 id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
535 le16_to_cpu(dev->descriptor.idProduct));
536 if (get_alias_id(dev, &id))
537 quirk = get_alias_quirk(dev, id);
538 if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
541 err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
546 * found a config. now register to ALSA
549 /* check whether it's already registered */
551 mutex_lock(®ister_mutex);
552 for (i = 0; i < SNDRV_CARDS; i++) {
553 if (usb_chip[i] && usb_chip[i]->dev == dev) {
554 if (atomic_read(&usb_chip[i]->shutdown)) {
555 dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
560 atomic_inc(&chip->active); /* avoid autopm */
566 * now look for an empty slot and create a new card instance
568 for (i = 0; i < SNDRV_CARDS; i++)
569 if (enable[i] && ! usb_chip[i] &&
570 (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
571 (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
572 err = snd_usb_audio_create(intf, dev, i, quirk,
576 chip->pm_intf = intf;
580 dev_err(&dev->dev, "no available usb audio device\n");
585 dev_set_drvdata(&dev->dev, chip);
588 * For devices with more than one control interface, we assume the
589 * first contains the audio controls. We might need a more specific
590 * check here in the future.
592 if (!chip->ctrl_intf)
593 chip->ctrl_intf = alts;
595 chip->txfr_quirk = 0;
596 err = 1; /* continue */
597 if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
598 /* need some special handlings */
599 err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
605 /* create normal USB audio interfaces */
606 err = snd_usb_create_streams(chip, ifnum);
609 err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
614 /* we are allowed to call snd_card_register() many times */
615 err = snd_card_register(chip->card);
619 usb_chip[chip->index] = chip;
620 chip->num_interfaces++;
621 usb_set_intfdata(intf, chip);
622 atomic_dec(&chip->active);
623 mutex_unlock(®ister_mutex);
628 if (!chip->num_interfaces)
629 snd_card_free(chip->card);
630 atomic_dec(&chip->active);
632 mutex_unlock(®ister_mutex);
637 * we need to take care of counter, since disconnection can be called also
638 * many times as well as usb_audio_probe().
640 static void usb_audio_disconnect(struct usb_interface *intf)
642 struct snd_usb_audio *chip = usb_get_intfdata(intf);
643 struct snd_card *card;
646 if (chip == (void *)-1L)
651 mutex_lock(®ister_mutex);
652 if (atomic_inc_return(&chip->shutdown) == 1) {
653 struct snd_usb_stream *as;
654 struct snd_usb_endpoint *ep;
655 struct usb_mixer_interface *mixer;
657 /* wait until all pending tasks done;
658 * they are protected by snd_usb_lock_shutdown()
660 wait_event(chip->shutdown_wait,
661 !atomic_read(&chip->usage_count));
662 snd_card_disconnect(card);
663 /* release the pcm resources */
664 list_for_each_entry(as, &chip->pcm_list, list) {
665 snd_usb_stream_disconnect(as);
667 /* release the endpoint resources */
668 list_for_each_entry(ep, &chip->ep_list, list) {
669 snd_usb_endpoint_release(ep);
671 /* release the midi resources */
672 list_for_each(p, &chip->midi_list) {
673 snd_usbmidi_disconnect(p);
675 /* release mixer resources */
676 list_for_each_entry(mixer, &chip->mixer_list, list) {
677 snd_usb_mixer_disconnect(mixer);
681 chip->num_interfaces--;
682 if (chip->num_interfaces <= 0) {
683 usb_chip[chip->index] = NULL;
684 mutex_unlock(®ister_mutex);
685 snd_card_free_when_closed(card);
687 mutex_unlock(®ister_mutex);
691 /* lock the shutdown (disconnect) task and autoresume */
692 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
696 atomic_inc(&chip->usage_count);
697 if (atomic_read(&chip->shutdown)) {
701 err = snd_usb_autoresume(chip);
707 if (atomic_dec_and_test(&chip->usage_count))
708 wake_up(&chip->shutdown_wait);
712 /* autosuspend and unlock the shutdown */
713 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
715 snd_usb_autosuspend(chip);
716 if (atomic_dec_and_test(&chip->usage_count))
717 wake_up(&chip->shutdown_wait);
722 int snd_usb_autoresume(struct snd_usb_audio *chip)
724 if (atomic_read(&chip->shutdown))
726 if (atomic_inc_return(&chip->active) == 1)
727 return usb_autopm_get_interface(chip->pm_intf);
731 void snd_usb_autosuspend(struct snd_usb_audio *chip)
733 if (atomic_read(&chip->shutdown))
735 if (atomic_dec_and_test(&chip->active))
736 usb_autopm_put_interface(chip->pm_intf);
739 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
741 struct snd_usb_audio *chip = usb_get_intfdata(intf);
742 struct snd_usb_stream *as;
743 struct usb_mixer_interface *mixer;
746 if (chip == (void *)-1L)
749 chip->autosuspended = !!PMSG_IS_AUTO(message);
750 if (!chip->autosuspended)
751 snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
752 if (!chip->num_suspended_intf++) {
753 list_for_each_entry(as, &chip->pcm_list, list) {
754 snd_pcm_suspend_all(as->pcm);
755 as->substream[0].need_setup_ep =
756 as->substream[1].need_setup_ep = true;
758 list_for_each(p, &chip->midi_list)
759 snd_usbmidi_suspend(p);
760 list_for_each_entry(mixer, &chip->mixer_list, list)
761 snd_usb_mixer_suspend(mixer);
767 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
769 struct snd_usb_audio *chip = usb_get_intfdata(intf);
770 struct usb_mixer_interface *mixer;
774 if (chip == (void *)-1L)
776 if (--chip->num_suspended_intf)
779 atomic_inc(&chip->active); /* avoid autopm */
781 * ALSA leaves material resumption to user space
782 * we just notify and restart the mixers
784 list_for_each_entry(mixer, &chip->mixer_list, list) {
785 err = snd_usb_mixer_resume(mixer, reset_resume);
790 list_for_each(p, &chip->midi_list) {
791 snd_usbmidi_resume(p);
794 if (!chip->autosuspended)
795 snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
796 chip->autosuspended = 0;
799 atomic_dec(&chip->active); /* allow autopm after this point */
803 static int usb_audio_resume(struct usb_interface *intf)
805 return __usb_audio_resume(intf, false);
808 static int usb_audio_reset_resume(struct usb_interface *intf)
810 return __usb_audio_resume(intf, true);
813 #define usb_audio_suspend NULL
814 #define usb_audio_resume NULL
815 #define usb_audio_reset_resume NULL
816 #endif /* CONFIG_PM */
818 static struct usb_device_id usb_audio_ids [] = {
819 #include "quirks-table.h"
820 { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
821 .bInterfaceClass = USB_CLASS_AUDIO,
822 .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
823 { } /* Terminating entry */
825 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
828 * entry point for linux usb interface
831 static struct usb_driver usb_audio_driver = {
832 .name = "snd-usb-audio",
833 .probe = usb_audio_probe,
834 .disconnect = usb_audio_disconnect,
835 .suspend = usb_audio_suspend,
836 .resume = usb_audio_resume,
837 .reset_resume = usb_audio_reset_resume,
838 .id_table = usb_audio_ids,
839 .supports_autosuspend = 1,
842 module_usb_driver(usb_audio_driver);