ALSA: usb-audio: Fix missing autopm for MIDI input
[pandora-kernel.git] / 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  *   - 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).
33  */
34
35
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>
48
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>
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 "format.h"
67 #include "power.h"
68 #include "stream.h"
69
70 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
71 MODULE_DESCRIPTION("USB Audio");
72 MODULE_LICENSE("GPL");
73 MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
74
75
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 nrpacks = 8;         /* max. number of packets per urb */
83 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
84 static bool 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_array(device_setup, int, NULL, 0444);
99 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
100 module_param(ignore_ctl_error, bool, 0444);
101 MODULE_PARM_DESC(ignore_ctl_error,
102                  "Ignore errors from USB controller for mixer interfaces.");
103
104 /*
105  * we keep the snd_usb_audio_t instances by ourselves for merging
106  * the all interfaces on the same card as one sound device.
107  */
108
109 static DEFINE_MUTEX(register_mutex);
110 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
111 static struct usb_driver usb_audio_driver;
112
113 /*
114  * disconnect streams
115  * called from snd_usb_audio_disconnect()
116  */
117 static void snd_usb_stream_disconnect(struct list_head *head)
118 {
119         int idx;
120         struct snd_usb_stream *as;
121         struct snd_usb_substream *subs;
122
123         as = list_entry(head, struct snd_usb_stream, list);
124         for (idx = 0; idx < 2; idx++) {
125                 subs = &as->substream[idx];
126                 if (!subs->num_formats)
127                         continue;
128                 subs->interface = -1;
129                 subs->data_endpoint = NULL;
130                 subs->sync_endpoint = NULL;
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_interface(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         default:
219                 snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
220                             protocol);
221                 /* fall through */
222
223         case UAC_VERSION_1: {
224                 struct uac1_ac_header_descriptor *h1 = control_header;
225
226                 if (!h1->bInCollection) {
227                         snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
228                         return -EINVAL;
229                 }
230
231                 if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
232                         snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
233                         return -EINVAL;
234                 }
235
236                 for (i = 0; i < h1->bInCollection; i++)
237                         snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
238
239                 break;
240         }
241
242         case UAC_VERSION_2: {
243                 struct usb_interface_assoc_descriptor *assoc =
244                         usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
245
246                 if (!assoc) {
247                         snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
248                         return -EINVAL;
249                 }
250
251                 for (i = 0; i < assoc->bInterfaceCount; i++) {
252                         int intf = assoc->bFirstInterface + i;
253
254                         if (intf != ctrlif)
255                                 snd_usb_create_stream(chip, ctrlif, intf);
256                 }
257
258                 break;
259         }
260         }
261
262         return 0;
263 }
264
265 /*
266  * free the chip instance
267  *
268  * here we have to do not much, since pcm and controls are already freed
269  *
270  */
271
272 static int snd_usb_audio_free(struct snd_usb_audio *chip)
273 {
274         mutex_destroy(&chip->mutex);
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 static void remove_trailing_spaces(char *str)
286 {
287         char *p;
288
289         if (!*str)
290                 return;
291         for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
292                 *p = 0;
293 }
294
295 /*
296  * create a chip instance and set its names.
297  */
298 static int snd_usb_audio_create(struct usb_device *dev, int idx,
299                                 const struct snd_usb_audio_quirk *quirk,
300                                 struct snd_usb_audio **rchip)
301 {
302         struct snd_card *card;
303         struct snd_usb_audio *chip;
304         int err, len;
305         char component[14];
306         static struct snd_device_ops ops = {
307                 .dev_free =     snd_usb_audio_dev_free,
308         };
309
310         *rchip = NULL;
311
312         switch (snd_usb_get_speed(dev)) {
313         case USB_SPEED_LOW:
314         case USB_SPEED_FULL:
315         case USB_SPEED_HIGH:
316         case USB_SPEED_SUPER:
317                 break;
318         default:
319                 snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
320                 return -ENXIO;
321         }
322
323         err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
324         if (err < 0) {
325                 snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
326                 return err;
327         }
328
329         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
330         if (! chip) {
331                 snd_card_free(card);
332                 return -ENOMEM;
333         }
334
335         mutex_init(&chip->mutex);
336         init_rwsem(&chip->shutdown_rwsem);
337         chip->index = idx;
338         chip->dev = dev;
339         chip->card = card;
340         chip->setup = device_setup[idx];
341         chip->nrpacks = nrpacks;
342         chip->probing = 1;
343
344         chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
345                               le16_to_cpu(dev->descriptor.idProduct));
346         INIT_LIST_HEAD(&chip->pcm_list);
347         INIT_LIST_HEAD(&chip->ep_list);
348         INIT_LIST_HEAD(&chip->midi_list);
349         INIT_LIST_HEAD(&chip->mixer_list);
350
351         if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
352                 snd_usb_audio_free(chip);
353                 snd_card_free(card);
354                 return err;
355         }
356
357         strcpy(card->driver, "USB-Audio");
358         sprintf(component, "USB%04x:%04x",
359                 USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
360         snd_component_add(card, component);
361
362         /* retrieve the device string as shortname */
363         if (quirk && quirk->product_name && *quirk->product_name) {
364                 strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
365         } else {
366                 if (!dev->descriptor.iProduct ||
367                     usb_string(dev, dev->descriptor.iProduct,
368                     card->shortname, sizeof(card->shortname)) <= 0) {
369                         /* no name available from anywhere, so use ID */
370                         sprintf(card->shortname, "USB Device %#04x:%#04x",
371                                 USB_ID_VENDOR(chip->usb_id),
372                                 USB_ID_PRODUCT(chip->usb_id));
373                 }
374         }
375         remove_trailing_spaces(card->shortname);
376
377         /* retrieve the vendor and device strings as longname */
378         if (quirk && quirk->vendor_name && *quirk->vendor_name) {
379                 len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
380         } else {
381                 if (dev->descriptor.iManufacturer)
382                         len = usb_string(dev, dev->descriptor.iManufacturer,
383                                          card->longname, sizeof(card->longname));
384                 else
385                         len = 0;
386                 /* we don't really care if there isn't any vendor string */
387         }
388         if (len > 0) {
389                 remove_trailing_spaces(card->longname);
390                 if (*card->longname)
391                         strlcat(card->longname, " ", sizeof(card->longname));
392         }
393
394         strlcat(card->longname, card->shortname, sizeof(card->longname));
395
396         len = strlcat(card->longname, " at ", sizeof(card->longname));
397
398         if (len < sizeof(card->longname))
399                 usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
400
401         switch (snd_usb_get_speed(dev)) {
402         case USB_SPEED_LOW:
403                 strlcat(card->longname, ", low speed", sizeof(card->longname));
404                 break;
405         case USB_SPEED_FULL:
406                 strlcat(card->longname, ", full speed", sizeof(card->longname));
407                 break;
408         case USB_SPEED_HIGH:
409                 strlcat(card->longname, ", high speed", sizeof(card->longname));
410                 break;
411         case USB_SPEED_SUPER:
412                 strlcat(card->longname, ", super speed", sizeof(card->longname));
413                 break;
414         default:
415                 break;
416         }
417
418         snd_usb_audio_create_proc(chip);
419
420         *rchip = chip;
421         return 0;
422 }
423
424 /*
425  * probe the active usb device
426  *
427  * note that this can be called multiple times per a device, when it
428  * includes multiple audio control interfaces.
429  *
430  * thus we check the usb device pointer and creates the card instance
431  * only at the first time.  the successive calls of this function will
432  * append the pcm interface to the corresponding card.
433  */
434 static struct snd_usb_audio *
435 snd_usb_audio_probe(struct usb_device *dev,
436                     struct usb_interface *intf,
437                     const struct usb_device_id *usb_id)
438 {
439         const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
440         int i, err;
441         struct snd_usb_audio *chip;
442         struct usb_host_interface *alts;
443         int ifnum;
444         u32 id;
445
446         alts = &intf->altsetting[0];
447         ifnum = get_iface_desc(alts)->bInterfaceNumber;
448         id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
449                     le16_to_cpu(dev->descriptor.idProduct));
450         if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
451                 goto __err_val;
452
453         if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
454                 goto __err_val;
455
456         /*
457          * found a config.  now register to ALSA
458          */
459
460         /* check whether it's already registered */
461         chip = NULL;
462         mutex_lock(&register_mutex);
463         for (i = 0; i < SNDRV_CARDS; i++) {
464                 if (usb_chip[i] && usb_chip[i]->dev == dev) {
465                         if (usb_chip[i]->shutdown) {
466                                 snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
467                                 goto __error;
468                         }
469                         chip = usb_chip[i];
470                         chip->probing = 1;
471                         break;
472                 }
473         }
474         if (! chip) {
475                 /* it's a fresh one.
476                  * now look for an empty slot and create a new card instance
477                  */
478                 for (i = 0; i < SNDRV_CARDS; i++)
479                         if (enable[i] && ! usb_chip[i] &&
480                             (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
481                             (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
482                                 if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
483                                         goto __error;
484                                 }
485                                 snd_card_set_dev(chip->card, &intf->dev);
486                                 chip->pm_intf = intf;
487                                 break;
488                         }
489                 if (!chip) {
490                         printk(KERN_ERR "no available usb audio device\n");
491                         goto __error;
492                 }
493         }
494
495         /*
496          * For devices with more than one control interface, we assume the
497          * first contains the audio controls. We might need a more specific
498          * check here in the future.
499          */
500         if (!chip->ctrl_intf)
501                 chip->ctrl_intf = alts;
502
503         chip->txfr_quirk = 0;
504         err = 1; /* continue */
505         if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
506                 /* need some special handlings */
507                 if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
508                         goto __error;
509         }
510
511         if (err > 0) {
512                 /* create normal USB audio interfaces */
513                 if (snd_usb_create_streams(chip, ifnum) < 0 ||
514                     snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
515                         goto __error;
516                 }
517         }
518
519         /* we are allowed to call snd_card_register() many times */
520         if (snd_card_register(chip->card) < 0) {
521                 goto __error;
522         }
523
524         usb_chip[chip->index] = chip;
525         chip->num_interfaces++;
526         chip->probing = 0;
527         mutex_unlock(&register_mutex);
528         return chip;
529
530  __error:
531         if (chip) {
532                 if (!chip->num_interfaces)
533                         snd_card_free(chip->card);
534                 chip->probing = 0;
535         }
536         mutex_unlock(&register_mutex);
537  __err_val:
538         return NULL;
539 }
540
541 /*
542  * we need to take care of counter, since disconnection can be called also
543  * many times as well as usb_audio_probe().
544  */
545 static void snd_usb_audio_disconnect(struct usb_device *dev,
546                                      struct snd_usb_audio *chip)
547 {
548         struct snd_card *card;
549         struct list_head *p, *n;
550
551         if (chip == (void *)-1L)
552                 return;
553
554         card = chip->card;
555         down_write(&chip->shutdown_rwsem);
556         chip->shutdown = 1;
557         up_write(&chip->shutdown_rwsem);
558
559         mutex_lock(&register_mutex);
560         chip->num_interfaces--;
561         if (chip->num_interfaces <= 0) {
562                 snd_card_disconnect(card);
563                 /* release the pcm resources */
564                 list_for_each(p, &chip->pcm_list) {
565                         snd_usb_stream_disconnect(p);
566                 }
567                 /* release the endpoint resources */
568                 list_for_each_safe(p, n, &chip->ep_list) {
569                         snd_usb_endpoint_free(p);
570                 }
571                 /* release the midi resources */
572                 list_for_each(p, &chip->midi_list) {
573                         snd_usbmidi_disconnect(p);
574                 }
575                 /* release mixer resources */
576                 list_for_each(p, &chip->mixer_list) {
577                         snd_usb_mixer_disconnect(p);
578                 }
579                 usb_chip[chip->index] = NULL;
580                 mutex_unlock(&register_mutex);
581                 snd_card_free_when_closed(card);
582         } else {
583                 mutex_unlock(&register_mutex);
584         }
585 }
586
587 /*
588  * new 2.5 USB kernel API
589  */
590 static int usb_audio_probe(struct usb_interface *intf,
591                            const struct usb_device_id *id)
592 {
593         struct snd_usb_audio *chip;
594         chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
595         if (chip) {
596                 usb_set_intfdata(intf, chip);
597                 return 0;
598         } else
599                 return -EIO;
600 }
601
602 static void usb_audio_disconnect(struct usb_interface *intf)
603 {
604         snd_usb_audio_disconnect(interface_to_usbdev(intf),
605                                  usb_get_intfdata(intf));
606 }
607
608 #ifdef CONFIG_PM
609
610 int snd_usb_autoresume(struct snd_usb_audio *chip)
611 {
612         int err = -ENODEV;
613
614         down_read(&chip->shutdown_rwsem);
615         if (!chip->shutdown && !chip->probing)
616                 err = usb_autopm_get_interface(chip->pm_intf);
617         up_read(&chip->shutdown_rwsem);
618
619         return err;
620 }
621
622 void snd_usb_autosuspend(struct snd_usb_audio *chip)
623 {
624         down_read(&chip->shutdown_rwsem);
625         if (!chip->shutdown && !chip->probing)
626                 usb_autopm_put_interface(chip->pm_intf);
627         up_read(&chip->shutdown_rwsem);
628 }
629
630 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
631 {
632         struct snd_usb_audio *chip = usb_get_intfdata(intf);
633         struct list_head *p;
634         struct snd_usb_stream *as;
635         struct usb_mixer_interface *mixer;
636
637         if (chip == (void *)-1L)
638                 return 0;
639
640         if (!PMSG_IS_AUTO(message)) {
641                 snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
642                 if (!chip->num_suspended_intf++) {
643                         list_for_each(p, &chip->pcm_list) {
644                                 as = list_entry(p, struct snd_usb_stream, list);
645                                 snd_pcm_suspend_all(as->pcm);
646                                 as->substream[0].need_setup_ep =
647                                         as->substream[1].need_setup_ep = true;
648                         }
649                 }
650         } else {
651                 /*
652                  * otherwise we keep the rest of the system in the dark
653                  * to keep this transparent
654                  */
655                 if (!chip->num_suspended_intf++)
656                         chip->autosuspended = 1;
657         }
658
659         list_for_each_entry(mixer, &chip->mixer_list, list)
660                 snd_usb_mixer_inactivate(mixer);
661
662         return 0;
663 }
664
665 static int usb_audio_resume(struct usb_interface *intf)
666 {
667         struct snd_usb_audio *chip = usb_get_intfdata(intf);
668         struct usb_mixer_interface *mixer;
669         int err = 0;
670
671         if (chip == (void *)-1L)
672                 return 0;
673         if (--chip->num_suspended_intf)
674                 return 0;
675         /*
676          * ALSA leaves material resumption to user space
677          * we just notify and restart the mixers
678          */
679         list_for_each_entry(mixer, &chip->mixer_list, list) {
680                 err = snd_usb_mixer_activate(mixer);
681                 if (err < 0)
682                         goto err_out;
683         }
684
685         if (!chip->autosuspended)
686                 snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
687         chip->autosuspended = 0;
688
689 err_out:
690         return err;
691 }
692 #else
693 #define usb_audio_suspend       NULL
694 #define usb_audio_resume        NULL
695 #endif          /* CONFIG_PM */
696
697 static struct usb_device_id usb_audio_ids [] = {
698 #include "quirks-table.h"
699     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
700       .bInterfaceClass = USB_CLASS_AUDIO,
701       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
702     { }                                         /* Terminating entry */
703 };
704
705 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
706
707 /*
708  * entry point for linux usb interface
709  */
710
711 static struct usb_driver usb_audio_driver = {
712         .name =         "snd-usb-audio",
713         .probe =        usb_audio_probe,
714         .disconnect =   usb_audio_disconnect,
715         .suspend =      usb_audio_suspend,
716         .resume =       usb_audio_resume,
717         .id_table =     usb_audio_ids,
718         .supports_autosuspend = 1,
719 };
720
721 static int __init snd_usb_audio_init(void)
722 {
723         if (nrpacks < 1 || nrpacks > MAX_PACKS) {
724                 printk(KERN_WARNING "invalid nrpacks value.\n");
725                 return -EINVAL;
726         }
727         return usb_register(&usb_audio_driver);
728 }
729
730 static void __exit snd_usb_audio_cleanup(void)
731 {
732         usb_deregister(&usb_audio_driver);
733 }
734
735 module_init(snd_usb_audio_init);
736 module_exit(snd_usb_audio_cleanup);