xref: /openbmc/linux/sound/usb/card.c (revision 6ecc07b9)
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/control.h>
52 #include <sound/core.h>
53 #include <sound/info.h>
54 #include <sound/pcm.h>
55 #include <sound/pcm_params.h>
56 #include <sound/initval.h>
57 
58 #include "usbaudio.h"
59 #include "card.h"
60 #include "midi.h"
61 #include "mixer.h"
62 #include "proc.h"
63 #include "quirks.h"
64 #include "endpoint.h"
65 #include "helper.h"
66 #include "debug.h"
67 #include "pcm.h"
68 #include "urb.h"
69 #include "format.h"
70 #include "power.h"
71 
72 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
73 MODULE_DESCRIPTION("USB Audio");
74 MODULE_LICENSE("GPL");
75 MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
76 
77 
78 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
79 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
80 static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
81 /* Vendor/product IDs for this card */
82 static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
83 static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
84 static int nrpacks = 8;		/* max. number of packets per urb */
85 static int async_unlink = 1;
86 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
87 static int ignore_ctl_error;
88 
89 module_param_array(index, int, NULL, 0444);
90 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
91 module_param_array(id, charp, NULL, 0444);
92 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
93 module_param_array(enable, bool, NULL, 0444);
94 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
95 module_param_array(vid, int, NULL, 0444);
96 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
97 module_param_array(pid, int, NULL, 0444);
98 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
99 module_param(nrpacks, int, 0644);
100 MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
101 module_param(async_unlink, bool, 0444);
102 MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
103 module_param_array(device_setup, int, NULL, 0444);
104 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
105 module_param(ignore_ctl_error, bool, 0444);
106 MODULE_PARM_DESC(ignore_ctl_error,
107 		 "Ignore errors from USB controller for mixer interfaces.");
108 
109 /*
110  * we keep the snd_usb_audio_t instances by ourselves for merging
111  * the all interfaces on the same card as one sound device.
112  */
113 
114 static DEFINE_MUTEX(register_mutex);
115 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
116 static struct usb_driver usb_audio_driver;
117 
118 /*
119  * disconnect streams
120  * called from snd_usb_audio_disconnect()
121  */
122 static void snd_usb_stream_disconnect(struct list_head *head)
123 {
124 	int idx;
125 	struct snd_usb_stream *as;
126 	struct snd_usb_substream *subs;
127 
128 	as = list_entry(head, struct snd_usb_stream, list);
129 	for (idx = 0; idx < 2; idx++) {
130 		subs = &as->substream[idx];
131 		if (!subs->num_formats)
132 			continue;
133 		snd_usb_release_substream_urbs(subs, 1);
134 		subs->interface = -1;
135 	}
136 }
137 
138 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
139 {
140 	struct usb_device *dev = chip->dev;
141 	struct usb_host_interface *alts;
142 	struct usb_interface_descriptor *altsd;
143 	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
144 
145 	if (!iface) {
146 		snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
147 			   dev->devnum, ctrlif, interface);
148 		return -EINVAL;
149 	}
150 
151 	if (usb_interface_claimed(iface)) {
152 		snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
153 						dev->devnum, ctrlif, interface);
154 		return -EINVAL;
155 	}
156 
157 	alts = &iface->altsetting[0];
158 	altsd = get_iface_desc(alts);
159 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
160 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
161 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
162 		int err = snd_usbmidi_create(chip->card, iface,
163 					     &chip->midi_list, NULL);
164 		if (err < 0) {
165 			snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
166 						dev->devnum, ctrlif, interface);
167 			return -EINVAL;
168 		}
169 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
170 
171 		return 0;
172 	}
173 
174 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
175 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
176 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
177 		snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
178 					dev->devnum, ctrlif, interface, altsd->bInterfaceClass);
179 		/* skip non-supported classes */
180 		return -EINVAL;
181 	}
182 
183 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
184 		snd_printk(KERN_ERR "low speed audio streaming not supported\n");
185 		return -EINVAL;
186 	}
187 
188 	if (! snd_usb_parse_audio_endpoints(chip, interface)) {
189 		usb_set_interface(dev, interface, 0); /* reset the current interface */
190 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
191 		return -EINVAL;
192 	}
193 
194 	return 0;
195 }
196 
197 /*
198  * parse audio control descriptor and create pcm/midi streams
199  */
200 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
201 {
202 	struct usb_device *dev = chip->dev;
203 	struct usb_host_interface *host_iface;
204 	struct usb_interface_descriptor *altsd;
205 	void *control_header;
206 	int i, protocol;
207 
208 	/* find audiocontrol interface */
209 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
210 	control_header = snd_usb_find_csint_desc(host_iface->extra,
211 						 host_iface->extralen,
212 						 NULL, UAC_HEADER);
213 	altsd = get_iface_desc(host_iface);
214 	protocol = altsd->bInterfaceProtocol;
215 
216 	if (!control_header) {
217 		snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
218 		return -EINVAL;
219 	}
220 
221 	switch (protocol) {
222 	default:
223 		snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
224 			    protocol);
225 		/* fall through */
226 
227 	case UAC_VERSION_1: {
228 		struct uac1_ac_header_descriptor *h1 = control_header;
229 
230 		if (!h1->bInCollection) {
231 			snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
232 			return -EINVAL;
233 		}
234 
235 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
236 			snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
237 			return -EINVAL;
238 		}
239 
240 		for (i = 0; i < h1->bInCollection; i++)
241 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
242 
243 		break;
244 	}
245 
246 	case UAC_VERSION_2: {
247 		struct usb_interface_assoc_descriptor *assoc =
248 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
249 
250 		if (!assoc) {
251 			snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
252 			return -EINVAL;
253 		}
254 
255 		for (i = 0; i < assoc->bInterfaceCount; i++) {
256 			int intf = assoc->bFirstInterface + i;
257 
258 			if (intf != ctrlif)
259 				snd_usb_create_stream(chip, ctrlif, intf);
260 		}
261 
262 		break;
263 	}
264 	}
265 
266 	return 0;
267 }
268 
269 /*
270  * free the chip instance
271  *
272  * here we have to do not much, since pcm and controls are already freed
273  *
274  */
275 
276 static int snd_usb_audio_free(struct snd_usb_audio *chip)
277 {
278 	kfree(chip);
279 	return 0;
280 }
281 
282 static int snd_usb_audio_dev_free(struct snd_device *device)
283 {
284 	struct snd_usb_audio *chip = device->device_data;
285 	return snd_usb_audio_free(chip);
286 }
287 
288 static void remove_trailing_spaces(char *str)
289 {
290 	char *p;
291 
292 	if (!*str)
293 		return;
294 	for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
295 		*p = 0;
296 }
297 
298 /*
299  * create a chip instance and set its names.
300  */
301 static int snd_usb_audio_create(struct usb_device *dev, int idx,
302 				const struct snd_usb_audio_quirk *quirk,
303 				struct snd_usb_audio **rchip)
304 {
305 	struct snd_card *card;
306 	struct snd_usb_audio *chip;
307 	int err, len;
308 	char component[14];
309 	static struct snd_device_ops ops = {
310 		.dev_free =	snd_usb_audio_dev_free,
311 	};
312 
313 	*rchip = NULL;
314 
315 	switch (snd_usb_get_speed(dev)) {
316 	case USB_SPEED_LOW:
317 	case USB_SPEED_FULL:
318 	case USB_SPEED_HIGH:
319 	case USB_SPEED_SUPER:
320 		break;
321 	default:
322 		snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
323 		return -ENXIO;
324 	}
325 
326 	err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
327 	if (err < 0) {
328 		snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
329 		return err;
330 	}
331 
332 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
333 	if (! chip) {
334 		snd_card_free(card);
335 		return -ENOMEM;
336 	}
337 
338 	mutex_init(&chip->shutdown_mutex);
339 	chip->index = idx;
340 	chip->dev = dev;
341 	chip->card = card;
342 	chip->setup = device_setup[idx];
343 	chip->nrpacks = nrpacks;
344 	chip->async_unlink = async_unlink;
345 	chip->probing = 1;
346 
347 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
348 			      le16_to_cpu(dev->descriptor.idProduct));
349 	INIT_LIST_HEAD(&chip->pcm_list);
350 	INIT_LIST_HEAD(&chip->midi_list);
351 	INIT_LIST_HEAD(&chip->mixer_list);
352 
353 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
354 		snd_usb_audio_free(chip);
355 		snd_card_free(card);
356 		return err;
357 	}
358 
359 	strcpy(card->driver, "USB-Audio");
360 	sprintf(component, "USB%04x:%04x",
361 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
362 	snd_component_add(card, component);
363 
364 	/* retrieve the device string as shortname */
365 	if (quirk && quirk->product_name && *quirk->product_name) {
366 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
367 	} else {
368 		if (!dev->descriptor.iProduct ||
369 		    usb_string(dev, dev->descriptor.iProduct,
370 		    card->shortname, sizeof(card->shortname)) <= 0) {
371 			/* no name available from anywhere, so use ID */
372 			sprintf(card->shortname, "USB Device %#04x:%#04x",
373 				USB_ID_VENDOR(chip->usb_id),
374 				USB_ID_PRODUCT(chip->usb_id));
375 		}
376 	}
377 	remove_trailing_spaces(card->shortname);
378 
379 	/* retrieve the vendor and device strings as longname */
380 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
381 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
382 	} else {
383 		if (dev->descriptor.iManufacturer)
384 			len = usb_string(dev, dev->descriptor.iManufacturer,
385 					 card->longname, sizeof(card->longname));
386 		else
387 			len = 0;
388 		/* we don't really care if there isn't any vendor string */
389 	}
390 	if (len > 0) {
391 		remove_trailing_spaces(card->longname);
392 		if (*card->longname)
393 			strlcat(card->longname, " ", sizeof(card->longname));
394 	}
395 
396 	strlcat(card->longname, card->shortname, sizeof(card->longname));
397 
398 	len = strlcat(card->longname, " at ", sizeof(card->longname));
399 
400 	if (len < sizeof(card->longname))
401 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
402 
403 	switch (snd_usb_get_speed(dev)) {
404 	case USB_SPEED_LOW:
405 		strlcat(card->longname, ", low speed", sizeof(card->longname));
406 		break;
407 	case USB_SPEED_FULL:
408 		strlcat(card->longname, ", full speed", sizeof(card->longname));
409 		break;
410 	case USB_SPEED_HIGH:
411 		strlcat(card->longname, ", high speed", sizeof(card->longname));
412 		break;
413 	case USB_SPEED_SUPER:
414 		strlcat(card->longname, ", super speed", sizeof(card->longname));
415 		break;
416 	default:
417 		break;
418 	}
419 
420 	snd_usb_audio_create_proc(chip);
421 
422 	*rchip = chip;
423 	return 0;
424 }
425 
426 /*
427  * probe the active usb device
428  *
429  * note that this can be called multiple times per a device, when it
430  * includes multiple audio control interfaces.
431  *
432  * thus we check the usb device pointer and creates the card instance
433  * only at the first time.  the successive calls of this function will
434  * append the pcm interface to the corresponding card.
435  */
436 static struct snd_usb_audio *
437 snd_usb_audio_probe(struct usb_device *dev,
438 		    struct usb_interface *intf,
439 		    const struct usb_device_id *usb_id)
440 {
441 	const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
442 	int i, err;
443 	struct snd_usb_audio *chip;
444 	struct usb_host_interface *alts;
445 	int ifnum;
446 	u32 id;
447 
448 	alts = &intf->altsetting[0];
449 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
450 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
451 		    le16_to_cpu(dev->descriptor.idProduct));
452 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
453 		goto __err_val;
454 
455 	if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
456 		goto __err_val;
457 
458 	/*
459 	 * found a config.  now register to ALSA
460 	 */
461 
462 	/* check whether it's already registered */
463 	chip = NULL;
464 	mutex_lock(&register_mutex);
465 	for (i = 0; i < SNDRV_CARDS; i++) {
466 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
467 			if (usb_chip[i]->shutdown) {
468 				snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
469 				goto __error;
470 			}
471 			chip = usb_chip[i];
472 			chip->probing = 1;
473 			break;
474 		}
475 	}
476 	if (! chip) {
477 		/* it's a fresh one.
478 		 * now look for an empty slot and create a new card instance
479 		 */
480 		for (i = 0; i < SNDRV_CARDS; i++)
481 			if (enable[i] && ! usb_chip[i] &&
482 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
483 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
484 				if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
485 					goto __error;
486 				}
487 				snd_card_set_dev(chip->card, &intf->dev);
488 				chip->pm_intf = intf;
489 				break;
490 			}
491 		if (!chip) {
492 			printk(KERN_ERR "no available usb audio device\n");
493 			goto __error;
494 		}
495 	}
496 
497 	/*
498 	 * For devices with more than one control interface, we assume the
499 	 * first contains the audio controls. We might need a more specific
500 	 * check here in the future.
501 	 */
502 	if (!chip->ctrl_intf)
503 		chip->ctrl_intf = alts;
504 
505 	chip->txfr_quirk = 0;
506 	err = 1; /* continue */
507 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
508 		/* need some special handlings */
509 		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
510 			goto __error;
511 	}
512 
513 	if (err > 0) {
514 		/* create normal USB audio interfaces */
515 		if (snd_usb_create_streams(chip, ifnum) < 0 ||
516 		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
517 			goto __error;
518 		}
519 	}
520 
521 	/* we are allowed to call snd_card_register() many times */
522 	if (snd_card_register(chip->card) < 0) {
523 		goto __error;
524 	}
525 
526 	usb_chip[chip->index] = chip;
527 	chip->num_interfaces++;
528 	chip->probing = 0;
529 	mutex_unlock(&register_mutex);
530 	return chip;
531 
532  __error:
533 	if (chip && !chip->num_interfaces)
534 		snd_card_free(chip->card);
535 	mutex_unlock(&register_mutex);
536  __err_val:
537 	return NULL;
538 }
539 
540 /*
541  * we need to take care of counter, since disconnection can be called also
542  * many times as well as usb_audio_probe().
543  */
544 static void snd_usb_audio_disconnect(struct usb_device *dev,
545 				     struct snd_usb_audio *chip)
546 {
547 	struct snd_card *card;
548 	struct list_head *p;
549 
550 	if (chip == (void *)-1L)
551 		return;
552 
553 	card = chip->card;
554 	mutex_lock(&register_mutex);
555 	mutex_lock(&chip->shutdown_mutex);
556 	chip->shutdown = 1;
557 	chip->num_interfaces--;
558 	if (chip->num_interfaces <= 0) {
559 		snd_card_disconnect(card);
560 		/* release the pcm resources */
561 		list_for_each(p, &chip->pcm_list) {
562 			snd_usb_stream_disconnect(p);
563 		}
564 		/* release the midi resources */
565 		list_for_each(p, &chip->midi_list) {
566 			snd_usbmidi_disconnect(p);
567 		}
568 		/* release mixer resources */
569 		list_for_each(p, &chip->mixer_list) {
570 			snd_usb_mixer_disconnect(p);
571 		}
572 		usb_chip[chip->index] = NULL;
573 		mutex_unlock(&chip->shutdown_mutex);
574 		mutex_unlock(&register_mutex);
575 		snd_card_free_when_closed(card);
576 	} else {
577 		mutex_unlock(&chip->shutdown_mutex);
578 		mutex_unlock(&register_mutex);
579 	}
580 }
581 
582 /*
583  * new 2.5 USB kernel API
584  */
585 static int usb_audio_probe(struct usb_interface *intf,
586 			   const struct usb_device_id *id)
587 {
588 	struct snd_usb_audio *chip;
589 	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
590 	if (chip) {
591 		usb_set_intfdata(intf, chip);
592 		return 0;
593 	} else
594 		return -EIO;
595 }
596 
597 static void usb_audio_disconnect(struct usb_interface *intf)
598 {
599 	snd_usb_audio_disconnect(interface_to_usbdev(intf),
600 				 usb_get_intfdata(intf));
601 }
602 
603 #ifdef CONFIG_PM
604 
605 int snd_usb_autoresume(struct snd_usb_audio *chip)
606 {
607 	int err = -ENODEV;
608 
609 	if (!chip->shutdown && !chip->probing)
610 		err = usb_autopm_get_interface(chip->pm_intf);
611 
612 	return err;
613 }
614 
615 void snd_usb_autosuspend(struct snd_usb_audio *chip)
616 {
617 	if (!chip->shutdown && !chip->probing)
618 		usb_autopm_put_interface(chip->pm_intf);
619 }
620 
621 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
622 {
623 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
624 	struct list_head *p;
625 	struct snd_usb_stream *as;
626 	struct usb_mixer_interface *mixer;
627 
628 	if (chip == (void *)-1L)
629 		return 0;
630 
631 	if (!(message.event & PM_EVENT_AUTO)) {
632 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
633 		if (!chip->num_suspended_intf++) {
634 			list_for_each(p, &chip->pcm_list) {
635 				as = list_entry(p, struct snd_usb_stream, list);
636 				snd_pcm_suspend_all(as->pcm);
637 			}
638  		}
639 	} else {
640 		/*
641 		 * otherwise we keep the rest of the system in the dark
642 		 * to keep this transparent
643 		 */
644 		if (!chip->num_suspended_intf++)
645 			chip->autosuspended = 1;
646 	}
647 
648 	list_for_each_entry(mixer, &chip->mixer_list, list)
649 		snd_usb_mixer_inactivate(mixer);
650 
651 	return 0;
652 }
653 
654 static int usb_audio_resume(struct usb_interface *intf)
655 {
656 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
657 	struct usb_mixer_interface *mixer;
658 	int err = 0;
659 
660 	if (chip == (void *)-1L)
661 		return 0;
662 	if (--chip->num_suspended_intf)
663 		return 0;
664 	/*
665 	 * ALSA leaves material resumption to user space
666 	 * we just notify and restart the mixers
667 	 */
668 	list_for_each_entry(mixer, &chip->mixer_list, list) {
669 		err = snd_usb_mixer_activate(mixer);
670 		if (err < 0)
671 			goto err_out;
672 	}
673 
674 	if (!chip->autosuspended)
675 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
676 	chip->autosuspended = 0;
677 
678 err_out:
679 	return err;
680 }
681 #else
682 #define usb_audio_suspend	NULL
683 #define usb_audio_resume	NULL
684 #endif		/* CONFIG_PM */
685 
686 static struct usb_device_id usb_audio_ids [] = {
687 #include "quirks-table.h"
688     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
689       .bInterfaceClass = USB_CLASS_AUDIO,
690       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
691     { }						/* Terminating entry */
692 };
693 
694 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
695 
696 /*
697  * entry point for linux usb interface
698  */
699 
700 static struct usb_driver usb_audio_driver = {
701 	.name =		"snd-usb-audio",
702 	.probe =	usb_audio_probe,
703 	.disconnect =	usb_audio_disconnect,
704 	.suspend =	usb_audio_suspend,
705 	.resume =	usb_audio_resume,
706 	.id_table =	usb_audio_ids,
707 	.supports_autosuspend = 1,
708 };
709 
710 static int __init snd_usb_audio_init(void)
711 {
712 	if (nrpacks < 1 || nrpacks > MAX_PACKS) {
713 		printk(KERN_WARNING "invalid nrpacks value.\n");
714 		return -EINVAL;
715 	}
716 	return usb_register(&usb_audio_driver);
717 }
718 
719 static void __exit snd_usb_audio_cleanup(void)
720 {
721 	usb_deregister(&usb_audio_driver);
722 }
723 
724 module_init(snd_usb_audio_init);
725 module_exit(snd_usb_audio_cleanup);
726