xref: /openbmc/linux/sound/usb/card.c (revision 3ffc1222)
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/ctype.h>
45 #include <linux/usb.h>
46 #include <linux/moduleparam.h>
47 #include <linux/mutex.h>
48 #include <linux/usb/audio.h>
49 #include <linux/usb/audio-v2.h>
50 
51 #include <sound/core.h>
52 #include <sound/info.h>
53 #include <sound/pcm.h>
54 #include <sound/pcm_params.h>
55 #include <sound/initval.h>
56 
57 #include "usbaudio.h"
58 #include "card.h"
59 #include "midi.h"
60 #include "mixer.h"
61 #include "proc.h"
62 #include "quirks.h"
63 #include "endpoint.h"
64 #include "helper.h"
65 #include "debug.h"
66 #include "pcm.h"
67 #include "urb.h"
68 #include "format.h"
69 #include "power.h"
70 
71 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
72 MODULE_DESCRIPTION("USB Audio");
73 MODULE_LICENSE("GPL");
74 MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
75 
76 
77 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
78 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
79 static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
80 /* Vendor/product IDs for this card */
81 static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
82 static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
83 static int nrpacks = 8;		/* max. number of packets per urb */
84 static int async_unlink = 1;
85 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
86 static int ignore_ctl_error;
87 
88 module_param_array(index, int, NULL, 0444);
89 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
90 module_param_array(id, charp, NULL, 0444);
91 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
92 module_param_array(enable, bool, NULL, 0444);
93 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
94 module_param_array(vid, int, NULL, 0444);
95 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
96 module_param_array(pid, int, NULL, 0444);
97 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
98 module_param(nrpacks, int, 0644);
99 MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
100 module_param(async_unlink, bool, 0444);
101 MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
102 module_param_array(device_setup, int, NULL, 0444);
103 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
104 module_param(ignore_ctl_error, bool, 0444);
105 MODULE_PARM_DESC(ignore_ctl_error,
106 		 "Ignore errors from USB controller for mixer interfaces.");
107 
108 /*
109  * we keep the snd_usb_audio_t instances by ourselves for merging
110  * the all interfaces on the same card as one sound device.
111  */
112 
113 static DEFINE_MUTEX(register_mutex);
114 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
115 static struct usb_driver usb_audio_driver;
116 
117 /*
118  * disconnect streams
119  * called from snd_usb_audio_disconnect()
120  */
121 static void snd_usb_stream_disconnect(struct list_head *head)
122 {
123 	int idx;
124 	struct snd_usb_stream *as;
125 	struct snd_usb_substream *subs;
126 
127 	as = list_entry(head, struct snd_usb_stream, list);
128 	for (idx = 0; idx < 2; idx++) {
129 		subs = &as->substream[idx];
130 		if (!subs->num_formats)
131 			continue;
132 		snd_usb_release_substream_urbs(subs, 1);
133 		subs->interface = -1;
134 	}
135 }
136 
137 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
138 {
139 	struct usb_device *dev = chip->dev;
140 	struct usb_host_interface *alts;
141 	struct usb_interface_descriptor *altsd;
142 	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
143 
144 	if (!iface) {
145 		snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
146 			   dev->devnum, ctrlif, interface);
147 		return -EINVAL;
148 	}
149 
150 	if (usb_interface_claimed(iface)) {
151 		snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
152 						dev->devnum, ctrlif, interface);
153 		return -EINVAL;
154 	}
155 
156 	alts = &iface->altsetting[0];
157 	altsd = get_iface_desc(alts);
158 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
159 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
160 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
161 		int err = snd_usbmidi_create(chip->card, iface,
162 					     &chip->midi_list, NULL);
163 		if (err < 0) {
164 			snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
165 						dev->devnum, ctrlif, interface);
166 			return -EINVAL;
167 		}
168 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
169 
170 		return 0;
171 	}
172 
173 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
174 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
175 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
176 		snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
177 					dev->devnum, ctrlif, interface, altsd->bInterfaceClass);
178 		/* skip non-supported classes */
179 		return -EINVAL;
180 	}
181 
182 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
183 		snd_printk(KERN_ERR "low speed audio streaming not supported\n");
184 		return -EINVAL;
185 	}
186 
187 	if (! snd_usb_parse_audio_endpoints(chip, interface)) {
188 		usb_set_interface(dev, interface, 0); /* reset the current interface */
189 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
190 		return -EINVAL;
191 	}
192 
193 	return 0;
194 }
195 
196 /*
197  * parse audio control descriptor and create pcm/midi streams
198  */
199 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
200 {
201 	struct usb_device *dev = chip->dev;
202 	struct usb_host_interface *host_iface;
203 	struct usb_interface_descriptor *altsd;
204 	void *control_header;
205 	int i, protocol;
206 
207 	/* find audiocontrol interface */
208 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
209 	control_header = snd_usb_find_csint_desc(host_iface->extra,
210 						 host_iface->extralen,
211 						 NULL, UAC_HEADER);
212 	altsd = get_iface_desc(host_iface);
213 	protocol = altsd->bInterfaceProtocol;
214 
215 	if (!control_header) {
216 		snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
217 		return -EINVAL;
218 	}
219 
220 	switch (protocol) {
221 	default:
222 		snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
223 			    protocol);
224 		/* fall through */
225 
226 	case UAC_VERSION_1: {
227 		struct uac1_ac_header_descriptor *h1 = control_header;
228 
229 		if (!h1->bInCollection) {
230 			snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
231 			return -EINVAL;
232 		}
233 
234 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
235 			snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
236 			return -EINVAL;
237 		}
238 
239 		for (i = 0; i < h1->bInCollection; i++)
240 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
241 
242 		break;
243 	}
244 
245 	case UAC_VERSION_2: {
246 		struct usb_interface_assoc_descriptor *assoc =
247 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
248 
249 		if (!assoc) {
250 			snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
251 			return -EINVAL;
252 		}
253 
254 		for (i = 0; i < assoc->bInterfaceCount; i++) {
255 			int intf = assoc->bFirstInterface + i;
256 
257 			if (intf != ctrlif)
258 				snd_usb_create_stream(chip, ctrlif, intf);
259 		}
260 
261 		break;
262 	}
263 	}
264 
265 	return 0;
266 }
267 
268 /*
269  * free the chip instance
270  *
271  * here we have to do not much, since pcm and controls are already freed
272  *
273  */
274 
275 static int snd_usb_audio_free(struct snd_usb_audio *chip)
276 {
277 	kfree(chip);
278 	return 0;
279 }
280 
281 static int snd_usb_audio_dev_free(struct snd_device *device)
282 {
283 	struct snd_usb_audio *chip = device->device_data;
284 	return snd_usb_audio_free(chip);
285 }
286 
287 static void remove_trailing_spaces(char *str)
288 {
289 	char *p;
290 
291 	if (!*str)
292 		return;
293 	for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
294 		*p = 0;
295 }
296 
297 /*
298  * create a chip instance and set its names.
299  */
300 static int snd_usb_audio_create(struct usb_device *dev, int idx,
301 				const struct snd_usb_audio_quirk *quirk,
302 				struct snd_usb_audio **rchip)
303 {
304 	struct snd_card *card;
305 	struct snd_usb_audio *chip;
306 	int err, len;
307 	char component[14];
308 	static struct snd_device_ops ops = {
309 		.dev_free =	snd_usb_audio_dev_free,
310 	};
311 
312 	*rchip = NULL;
313 
314 	switch (snd_usb_get_speed(dev)) {
315 	case USB_SPEED_LOW:
316 	case USB_SPEED_FULL:
317 	case USB_SPEED_HIGH:
318 	case USB_SPEED_SUPER:
319 		break;
320 	default:
321 		snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
322 		return -ENXIO;
323 	}
324 
325 	err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
326 	if (err < 0) {
327 		snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
328 		return err;
329 	}
330 
331 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
332 	if (! chip) {
333 		snd_card_free(card);
334 		return -ENOMEM;
335 	}
336 
337 	mutex_init(&chip->shutdown_mutex);
338 	chip->index = idx;
339 	chip->dev = dev;
340 	chip->card = card;
341 	chip->setup = device_setup[idx];
342 	chip->nrpacks = nrpacks;
343 	chip->async_unlink = async_unlink;
344 	chip->probing = 1;
345 
346 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
347 			      le16_to_cpu(dev->descriptor.idProduct));
348 	INIT_LIST_HEAD(&chip->pcm_list);
349 	INIT_LIST_HEAD(&chip->midi_list);
350 	INIT_LIST_HEAD(&chip->mixer_list);
351 
352 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
353 		snd_usb_audio_free(chip);
354 		snd_card_free(card);
355 		return err;
356 	}
357 
358 	strcpy(card->driver, "USB-Audio");
359 	sprintf(component, "USB%04x:%04x",
360 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
361 	snd_component_add(card, component);
362 
363 	/* retrieve the device string as shortname */
364 	if (quirk && quirk->product_name && *quirk->product_name) {
365 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
366 	} else {
367 		if (!dev->descriptor.iProduct ||
368 		    usb_string(dev, dev->descriptor.iProduct,
369 		    card->shortname, sizeof(card->shortname)) <= 0) {
370 			/* no name available from anywhere, so use ID */
371 			sprintf(card->shortname, "USB Device %#04x:%#04x",
372 				USB_ID_VENDOR(chip->usb_id),
373 				USB_ID_PRODUCT(chip->usb_id));
374 		}
375 	}
376 	remove_trailing_spaces(card->shortname);
377 
378 	/* retrieve the vendor and device strings as longname */
379 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
380 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
381 	} else {
382 		if (dev->descriptor.iManufacturer)
383 			len = usb_string(dev, dev->descriptor.iManufacturer,
384 					 card->longname, sizeof(card->longname));
385 		else
386 			len = 0;
387 		/* we don't really care if there isn't any vendor string */
388 	}
389 	if (len > 0) {
390 		remove_trailing_spaces(card->longname);
391 		if (*card->longname)
392 			strlcat(card->longname, " ", sizeof(card->longname));
393 	}
394 
395 	strlcat(card->longname, card->shortname, sizeof(card->longname));
396 
397 	len = strlcat(card->longname, " at ", sizeof(card->longname));
398 
399 	if (len < sizeof(card->longname))
400 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
401 
402 	switch (snd_usb_get_speed(dev)) {
403 	case USB_SPEED_LOW:
404 		strlcat(card->longname, ", low speed", sizeof(card->longname));
405 		break;
406 	case USB_SPEED_FULL:
407 		strlcat(card->longname, ", full speed", sizeof(card->longname));
408 		break;
409 	case USB_SPEED_HIGH:
410 		strlcat(card->longname, ", high speed", sizeof(card->longname));
411 		break;
412 	case USB_SPEED_SUPER:
413 		strlcat(card->longname, ", super speed", sizeof(card->longname));
414 		break;
415 	default:
416 		break;
417 	}
418 
419 	snd_usb_audio_create_proc(chip);
420 
421 	*rchip = chip;
422 	return 0;
423 }
424 
425 /*
426  * probe the active usb device
427  *
428  * note that this can be called multiple times per a device, when it
429  * includes multiple audio control interfaces.
430  *
431  * thus we check the usb device pointer and creates the card instance
432  * only at the first time.  the successive calls of this function will
433  * append the pcm interface to the corresponding card.
434  */
435 static void *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 	chip->txfr_quirk = 0;
496 	err = 1; /* continue */
497 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
498 		/* need some special handlings */
499 		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
500 			goto __error;
501 	}
502 
503 	/*
504 	 * For devices with more than one control interface, we assume the
505 	 * first contains the audio controls. We might need a more specific
506 	 * check here in the future.
507 	 */
508 	if (!chip->ctrl_intf)
509 		chip->ctrl_intf = alts;
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 && !chip->num_interfaces)
532 		snd_card_free(chip->card);
533 	mutex_unlock(&register_mutex);
534  __err_val:
535 	return NULL;
536 }
537 
538 /*
539  * we need to take care of counter, since disconnection can be called also
540  * many times as well as usb_audio_probe().
541  */
542 static void snd_usb_audio_disconnect(struct usb_device *dev, void *ptr)
543 {
544 	struct snd_usb_audio *chip;
545 	struct snd_card *card;
546 	struct list_head *p;
547 
548 	if (ptr == (void *)-1L)
549 		return;
550 
551 	chip = ptr;
552 	card = chip->card;
553 	mutex_lock(&register_mutex);
554 	mutex_lock(&chip->shutdown_mutex);
555 	chip->shutdown = 1;
556 	chip->num_interfaces--;
557 	if (chip->num_interfaces <= 0) {
558 		snd_card_disconnect(card);
559 		/* release the pcm resources */
560 		list_for_each(p, &chip->pcm_list) {
561 			snd_usb_stream_disconnect(p);
562 		}
563 		/* release the midi resources */
564 		list_for_each(p, &chip->midi_list) {
565 			snd_usbmidi_disconnect(p);
566 		}
567 		/* release mixer resources */
568 		list_for_each(p, &chip->mixer_list) {
569 			snd_usb_mixer_disconnect(p);
570 		}
571 		usb_chip[chip->index] = NULL;
572 		mutex_unlock(&chip->shutdown_mutex);
573 		mutex_unlock(&register_mutex);
574 		snd_card_free_when_closed(card);
575 	} else {
576 		mutex_unlock(&chip->shutdown_mutex);
577 		mutex_unlock(&register_mutex);
578 	}
579 }
580 
581 /*
582  * new 2.5 USB kernel API
583  */
584 static int usb_audio_probe(struct usb_interface *intf,
585 			   const struct usb_device_id *id)
586 {
587 	void *chip;
588 	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
589 	if (chip) {
590 		usb_set_intfdata(intf, chip);
591 		return 0;
592 	} else
593 		return -EIO;
594 }
595 
596 static void usb_audio_disconnect(struct usb_interface *intf)
597 {
598 	snd_usb_audio_disconnect(interface_to_usbdev(intf),
599 				 usb_get_intfdata(intf));
600 }
601 
602 #ifdef CONFIG_PM
603 
604 int snd_usb_autoresume(struct snd_usb_audio *chip)
605 {
606 	int err = -ENODEV;
607 
608 	if (!chip->shutdown && !chip->probing)
609 		err = usb_autopm_get_interface(chip->pm_intf);
610 
611 	return err;
612 }
613 
614 void snd_usb_autosuspend(struct snd_usb_audio *chip)
615 {
616 	if (!chip->shutdown && !chip->probing)
617 		usb_autopm_put_interface(chip->pm_intf);
618 }
619 
620 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
621 {
622 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
623 	struct list_head *p;
624 	struct snd_usb_stream *as;
625 	struct usb_mixer_interface *mixer;
626 
627 	if (chip == (void *)-1L)
628 		return 0;
629 
630 	if (!(message.event & PM_EVENT_AUTO)) {
631 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
632 		if (!chip->num_suspended_intf++) {
633 			list_for_each(p, &chip->pcm_list) {
634 				as = list_entry(p, struct snd_usb_stream, list);
635 				snd_pcm_suspend_all(as->pcm);
636 			}
637  		}
638 	} else {
639 		/*
640 		 * otherwise we keep the rest of the system in the dark
641 		 * to keep this transparent
642 		 */
643 		if (!chip->num_suspended_intf++)
644 			chip->autosuspended = 1;
645 	}
646 
647 	list_for_each_entry(mixer, &chip->mixer_list, list)
648 		snd_usb_mixer_inactivate(mixer);
649 
650 	return 0;
651 }
652 
653 static int usb_audio_resume(struct usb_interface *intf)
654 {
655 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
656 	struct usb_mixer_interface *mixer;
657 	int err = 0;
658 
659 	if (chip == (void *)-1L)
660 		return 0;
661 	if (--chip->num_suspended_intf)
662 		return 0;
663 	/*
664 	 * ALSA leaves material resumption to user space
665 	 * we just notify and restart the mixers
666 	 */
667 	list_for_each_entry(mixer, &chip->mixer_list, list) {
668 		err = snd_usb_mixer_activate(mixer);
669 		if (err < 0)
670 			goto err_out;
671 	}
672 
673 	if (!chip->autosuspended)
674 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
675 	chip->autosuspended = 0;
676 
677 err_out:
678 	return err;
679 }
680 #else
681 #define usb_audio_suspend	NULL
682 #define usb_audio_resume	NULL
683 #endif		/* CONFIG_PM */
684 
685 static struct usb_device_id usb_audio_ids [] = {
686 #include "quirks-table.h"
687     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
688       .bInterfaceClass = USB_CLASS_AUDIO,
689       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
690     { }						/* Terminating entry */
691 };
692 
693 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
694 
695 /*
696  * entry point for linux usb interface
697  */
698 
699 static struct usb_driver usb_audio_driver = {
700 	.name =		"snd-usb-audio",
701 	.probe =	usb_audio_probe,
702 	.disconnect =	usb_audio_disconnect,
703 	.suspend =	usb_audio_suspend,
704 	.resume =	usb_audio_resume,
705 	.id_table =	usb_audio_ids,
706 	.supports_autosuspend = 1,
707 };
708 
709 static int __init snd_usb_audio_init(void)
710 {
711 	if (nrpacks < 1 || nrpacks > MAX_PACKS) {
712 		printk(KERN_WARNING "invalid nrpacks value.\n");
713 		return -EINVAL;
714 	}
715 	return usb_register(&usb_audio_driver);
716 }
717 
718 static void __exit snd_usb_audio_cleanup(void)
719 {
720 	usb_deregister(&usb_audio_driver);
721 }
722 
723 module_init(snd_usb_audio_init);
724 module_exit(snd_usb_audio_cleanup);
725