xref: /linux/sound/usb/card.c (revision fd639726bf15fca8ee1a00dce8e0096d0ad9bd18)
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 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];
86 
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.");
106 
107 /*
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.
110  */
111 
112 static DEFINE_MUTEX(register_mutex);
113 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
114 static struct usb_driver usb_audio_driver;
115 
116 /*
117  * disconnect streams
118  * called from usb_audio_disconnect()
119  */
120 static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
121 {
122 	int idx;
123 	struct snd_usb_substream *subs;
124 
125 	for (idx = 0; idx < 2; idx++) {
126 		subs = &as->substream[idx];
127 		if (!subs->num_formats)
128 			continue;
129 		subs->interface = -1;
130 		subs->data_endpoint = NULL;
131 		subs->sync_endpoint = NULL;
132 	}
133 }
134 
135 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
136 {
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);
141 
142 	if (!iface) {
143 		dev_err(&dev->dev, "%u:%d : does not exist\n",
144 			ctrlif, interface);
145 		return -EINVAL;
146 	}
147 
148 	alts = &iface->altsetting[0];
149 	altsd = get_iface_desc(alts);
150 
151 	/*
152 	 * Android with both accessory and audio interfaces enabled gets the
153 	 * interface numbers wrong.
154 	 */
155 	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
156 	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
157 	    interface == 0 &&
158 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
159 	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
160 		interface = 2;
161 		iface = usb_ifnum_to_if(dev, interface);
162 		if (!iface)
163 			return -EINVAL;
164 		alts = &iface->altsetting[0];
165 		altsd = get_iface_desc(alts);
166 	}
167 
168 	if (usb_interface_claimed(iface)) {
169 		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
170 			ctrlif, interface);
171 		return -EINVAL;
172 	}
173 
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,
179 					     chip->usb_id);
180 		if (err < 0) {
181 			dev_err(&dev->dev,
182 				"%u:%d: cannot create sequencer device\n",
183 				ctrlif, interface);
184 			return -EINVAL;
185 		}
186 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
187 
188 		return 0;
189 	}
190 
191 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
192 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
193 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
194 		dev_dbg(&dev->dev,
195 			"%u:%d: skipping non-supported interface %d\n",
196 			ctrlif, interface, altsd->bInterfaceClass);
197 		/* skip non-supported classes */
198 		return -EINVAL;
199 	}
200 
201 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
202 		dev_err(&dev->dev, "low speed audio streaming not supported\n");
203 		return -EINVAL;
204 	}
205 
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);
209 	}
210 
211 	return 0;
212 }
213 
214 /*
215  * parse audio control descriptor and create pcm/midi streams
216  */
217 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
218 {
219 	struct usb_device *dev = chip->dev;
220 	struct usb_host_interface *host_iface;
221 	struct usb_interface_descriptor *altsd;
222 	void *control_header;
223 	int i, protocol;
224 	int rest_bytes;
225 
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,
230 						 NULL, UAC_HEADER);
231 	altsd = get_iface_desc(host_iface);
232 	protocol = altsd->bInterfaceProtocol;
233 
234 	if (!control_header) {
235 		dev_err(&dev->dev, "cannot find UAC_HEADER\n");
236 		return -EINVAL;
237 	}
238 
239 	rest_bytes = (void *)(host_iface->extra + host_iface->extralen) -
240 		control_header;
241 
242 	/* just to be sure -- this shouldn't hit at all */
243 	if (rest_bytes <= 0) {
244 		dev_err(&dev->dev, "invalid control header\n");
245 		return -EINVAL;
246 	}
247 
248 	switch (protocol) {
249 	default:
250 		dev_warn(&dev->dev,
251 			 "unknown interface protocol %#02x, assuming v1\n",
252 			 protocol);
253 		/* fall through */
254 
255 	case UAC_VERSION_1: {
256 		struct uac1_ac_header_descriptor *h1 = control_header;
257 
258 		if (rest_bytes < sizeof(*h1)) {
259 			dev_err(&dev->dev, "too short v1 buffer descriptor\n");
260 			return -EINVAL;
261 		}
262 
263 		if (!h1->bInCollection) {
264 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
265 			return -EINVAL;
266 		}
267 
268 		if (rest_bytes < h1->bLength) {
269 			dev_err(&dev->dev, "invalid buffer length (v1)\n");
270 			return -EINVAL;
271 		}
272 
273 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
274 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
275 			return -EINVAL;
276 		}
277 
278 		for (i = 0; i < h1->bInCollection; i++)
279 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
280 
281 		break;
282 	}
283 
284 	case UAC_VERSION_2: {
285 		struct usb_interface_assoc_descriptor *assoc =
286 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
287 
288 		if (!assoc) {
289 			/*
290 			 * Firmware writers cannot count to three.  So to find
291 			 * the IAD on the NuForce UDH-100, also check the next
292 			 * interface.
293 			 */
294 			struct usb_interface *iface =
295 				usb_ifnum_to_if(dev, ctrlif + 1);
296 			if (iface &&
297 			    iface->intf_assoc &&
298 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
299 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
300 				assoc = iface->intf_assoc;
301 		}
302 
303 		if (!assoc) {
304 			dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
305 			return -EINVAL;
306 		}
307 
308 		for (i = 0; i < assoc->bInterfaceCount; i++) {
309 			int intf = assoc->bFirstInterface + i;
310 
311 			if (intf != ctrlif)
312 				snd_usb_create_stream(chip, ctrlif, intf);
313 		}
314 
315 		break;
316 	}
317 	}
318 
319 	return 0;
320 }
321 
322 /*
323  * free the chip instance
324  *
325  * here we have to do not much, since pcm and controls are already freed
326  *
327  */
328 
329 static int snd_usb_audio_free(struct snd_usb_audio *chip)
330 {
331 	struct snd_usb_endpoint *ep, *n;
332 
333 	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
334 		snd_usb_endpoint_free(ep);
335 
336 	mutex_destroy(&chip->mutex);
337 	if (!atomic_read(&chip->shutdown))
338 		dev_set_drvdata(&chip->dev->dev, NULL);
339 	kfree(chip);
340 	return 0;
341 }
342 
343 static int snd_usb_audio_dev_free(struct snd_device *device)
344 {
345 	struct snd_usb_audio *chip = device->device_data;
346 	return snd_usb_audio_free(chip);
347 }
348 
349 /*
350  * create a chip instance and set its names.
351  */
352 static int snd_usb_audio_create(struct usb_interface *intf,
353 				struct usb_device *dev, int idx,
354 				const struct snd_usb_audio_quirk *quirk,
355 				unsigned int usb_id,
356 				struct snd_usb_audio **rchip)
357 {
358 	struct snd_card *card;
359 	struct snd_usb_audio *chip;
360 	int err, len;
361 	char component[14];
362 	static struct snd_device_ops ops = {
363 		.dev_free =	snd_usb_audio_dev_free,
364 	};
365 
366 	*rchip = NULL;
367 
368 	switch (snd_usb_get_speed(dev)) {
369 	case USB_SPEED_LOW:
370 	case USB_SPEED_FULL:
371 	case USB_SPEED_HIGH:
372 	case USB_SPEED_WIRELESS:
373 	case USB_SPEED_SUPER:
374 	case USB_SPEED_SUPER_PLUS:
375 		break;
376 	default:
377 		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
378 		return -ENXIO;
379 	}
380 
381 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
382 			   0, &card);
383 	if (err < 0) {
384 		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
385 		return err;
386 	}
387 
388 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
389 	if (! chip) {
390 		snd_card_free(card);
391 		return -ENOMEM;
392 	}
393 
394 	mutex_init(&chip->mutex);
395 	init_waitqueue_head(&chip->shutdown_wait);
396 	chip->index = idx;
397 	chip->dev = dev;
398 	chip->card = card;
399 	chip->setup = device_setup[idx];
400 	chip->autoclock = autoclock;
401 	atomic_set(&chip->active, 1); /* avoid autopm during probing */
402 	atomic_set(&chip->usage_count, 0);
403 	atomic_set(&chip->shutdown, 0);
404 
405 	chip->usb_id = usb_id;
406 	INIT_LIST_HEAD(&chip->pcm_list);
407 	INIT_LIST_HEAD(&chip->ep_list);
408 	INIT_LIST_HEAD(&chip->midi_list);
409 	INIT_LIST_HEAD(&chip->mixer_list);
410 
411 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
412 		snd_usb_audio_free(chip);
413 		snd_card_free(card);
414 		return err;
415 	}
416 
417 	strcpy(card->driver, "USB-Audio");
418 	sprintf(component, "USB%04x:%04x",
419 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
420 	snd_component_add(card, component);
421 
422 	/* retrieve the device string as shortname */
423 	if (quirk && quirk->product_name && *quirk->product_name) {
424 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
425 	} else {
426 		if (!dev->descriptor.iProduct ||
427 		    usb_string(dev, dev->descriptor.iProduct,
428 		    card->shortname, sizeof(card->shortname)) <= 0) {
429 			/* no name available from anywhere, so use ID */
430 			sprintf(card->shortname, "USB Device %#04x:%#04x",
431 				USB_ID_VENDOR(chip->usb_id),
432 				USB_ID_PRODUCT(chip->usb_id));
433 		}
434 	}
435 	strim(card->shortname);
436 
437 	/* retrieve the vendor and device strings as longname */
438 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
439 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
440 	} else {
441 		if (dev->descriptor.iManufacturer)
442 			len = usb_string(dev, dev->descriptor.iManufacturer,
443 					 card->longname, sizeof(card->longname));
444 		else
445 			len = 0;
446 		/* we don't really care if there isn't any vendor string */
447 	}
448 	if (len > 0) {
449 		strim(card->longname);
450 		if (*card->longname)
451 			strlcat(card->longname, " ", sizeof(card->longname));
452 	}
453 
454 	strlcat(card->longname, card->shortname, sizeof(card->longname));
455 
456 	len = strlcat(card->longname, " at ", sizeof(card->longname));
457 
458 	if (len < sizeof(card->longname))
459 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
460 
461 	switch (snd_usb_get_speed(dev)) {
462 	case USB_SPEED_LOW:
463 		strlcat(card->longname, ", low speed", sizeof(card->longname));
464 		break;
465 	case USB_SPEED_FULL:
466 		strlcat(card->longname, ", full speed", sizeof(card->longname));
467 		break;
468 	case USB_SPEED_HIGH:
469 		strlcat(card->longname, ", high speed", sizeof(card->longname));
470 		break;
471 	case USB_SPEED_SUPER:
472 		strlcat(card->longname, ", super speed", sizeof(card->longname));
473 		break;
474 	case USB_SPEED_SUPER_PLUS:
475 		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
476 		break;
477 	default:
478 		break;
479 	}
480 
481 	snd_usb_audio_create_proc(chip);
482 
483 	*rchip = chip;
484 	return 0;
485 }
486 
487 /* look for a matching quirk alias id */
488 static bool get_alias_id(struct usb_device *dev, unsigned int *id)
489 {
490 	int i;
491 	unsigned int src, dst;
492 
493 	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
494 		if (!quirk_alias[i] ||
495 		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
496 		    src != *id)
497 			continue;
498 		dev_info(&dev->dev,
499 			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
500 			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
501 			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
502 		*id = dst;
503 		return true;
504 	}
505 
506 	return false;
507 }
508 
509 static const struct usb_device_id usb_audio_ids[]; /* defined below */
510 
511 /* look for the corresponding quirk */
512 static const struct snd_usb_audio_quirk *
513 get_alias_quirk(struct usb_device *dev, unsigned int id)
514 {
515 	const struct usb_device_id *p;
516 
517 	for (p = usb_audio_ids; p->match_flags; p++) {
518 		/* FIXME: this checks only vendor:product pair in the list */
519 		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==
520 		    USB_DEVICE_ID_MATCH_DEVICE &&
521 		    p->idVendor == USB_ID_VENDOR(id) &&
522 		    p->idProduct == USB_ID_PRODUCT(id))
523 			return (const struct snd_usb_audio_quirk *)p->driver_info;
524 	}
525 
526 	return NULL;
527 }
528 
529 /*
530  * probe the active usb device
531  *
532  * note that this can be called multiple times per a device, when it
533  * includes multiple audio control interfaces.
534  *
535  * thus we check the usb device pointer and creates the card instance
536  * only at the first time.  the successive calls of this function will
537  * append the pcm interface to the corresponding card.
538  */
539 static int usb_audio_probe(struct usb_interface *intf,
540 			   const struct usb_device_id *usb_id)
541 {
542 	struct usb_device *dev = interface_to_usbdev(intf);
543 	const struct snd_usb_audio_quirk *quirk =
544 		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
545 	struct snd_usb_audio *chip;
546 	int i, err;
547 	struct usb_host_interface *alts;
548 	int ifnum;
549 	u32 id;
550 
551 	alts = &intf->altsetting[0];
552 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
553 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
554 		    le16_to_cpu(dev->descriptor.idProduct));
555 	if (get_alias_id(dev, &id))
556 		quirk = get_alias_quirk(dev, id);
557 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
558 		return -ENXIO;
559 
560 	err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
561 	if (err < 0)
562 		return err;
563 
564 	/*
565 	 * found a config.  now register to ALSA
566 	 */
567 
568 	/* check whether it's already registered */
569 	chip = NULL;
570 	mutex_lock(&register_mutex);
571 	for (i = 0; i < SNDRV_CARDS; i++) {
572 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
573 			if (atomic_read(&usb_chip[i]->shutdown)) {
574 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
575 				err = -EIO;
576 				goto __error;
577 			}
578 			chip = usb_chip[i];
579 			atomic_inc(&chip->active); /* avoid autopm */
580 			break;
581 		}
582 	}
583 	if (! chip) {
584 		/* it's a fresh one.
585 		 * now look for an empty slot and create a new card instance
586 		 */
587 		for (i = 0; i < SNDRV_CARDS; i++)
588 			if (enable[i] && ! usb_chip[i] &&
589 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
590 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
591 				err = snd_usb_audio_create(intf, dev, i, quirk,
592 							   id, &chip);
593 				if (err < 0)
594 					goto __error;
595 				chip->pm_intf = intf;
596 				break;
597 			}
598 		if (!chip) {
599 			dev_err(&dev->dev, "no available usb audio device\n");
600 			err = -ENODEV;
601 			goto __error;
602 		}
603 	}
604 	dev_set_drvdata(&dev->dev, chip);
605 
606 	/*
607 	 * For devices with more than one control interface, we assume the
608 	 * first contains the audio controls. We might need a more specific
609 	 * check here in the future.
610 	 */
611 	if (!chip->ctrl_intf)
612 		chip->ctrl_intf = alts;
613 
614 	chip->txfr_quirk = 0;
615 	err = 1; /* continue */
616 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
617 		/* need some special handlings */
618 		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
619 		if (err < 0)
620 			goto __error;
621 	}
622 
623 	if (err > 0) {
624 		/* create normal USB audio interfaces */
625 		err = snd_usb_create_streams(chip, ifnum);
626 		if (err < 0)
627 			goto __error;
628 		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
629 		if (err < 0)
630 			goto __error;
631 	}
632 
633 	/* we are allowed to call snd_card_register() many times */
634 	err = snd_card_register(chip->card);
635 	if (err < 0)
636 		goto __error;
637 
638 	usb_chip[chip->index] = chip;
639 	chip->num_interfaces++;
640 	usb_set_intfdata(intf, chip);
641 	atomic_dec(&chip->active);
642 	mutex_unlock(&register_mutex);
643 	return 0;
644 
645  __error:
646 	if (chip) {
647 		if (!chip->num_interfaces)
648 			snd_card_free(chip->card);
649 		atomic_dec(&chip->active);
650 	}
651 	mutex_unlock(&register_mutex);
652 	return err;
653 }
654 
655 /*
656  * we need to take care of counter, since disconnection can be called also
657  * many times as well as usb_audio_probe().
658  */
659 static void usb_audio_disconnect(struct usb_interface *intf)
660 {
661 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
662 	struct snd_card *card;
663 	struct list_head *p;
664 
665 	if (chip == (void *)-1L)
666 		return;
667 
668 	card = chip->card;
669 
670 	mutex_lock(&register_mutex);
671 	if (atomic_inc_return(&chip->shutdown) == 1) {
672 		struct snd_usb_stream *as;
673 		struct snd_usb_endpoint *ep;
674 		struct usb_mixer_interface *mixer;
675 
676 		/* wait until all pending tasks done;
677 		 * they are protected by snd_usb_lock_shutdown()
678 		 */
679 		wait_event(chip->shutdown_wait,
680 			   !atomic_read(&chip->usage_count));
681 		snd_card_disconnect(card);
682 		/* release the pcm resources */
683 		list_for_each_entry(as, &chip->pcm_list, list) {
684 			snd_usb_stream_disconnect(as);
685 		}
686 		/* release the endpoint resources */
687 		list_for_each_entry(ep, &chip->ep_list, list) {
688 			snd_usb_endpoint_release(ep);
689 		}
690 		/* release the midi resources */
691 		list_for_each(p, &chip->midi_list) {
692 			snd_usbmidi_disconnect(p);
693 		}
694 		/* release mixer resources */
695 		list_for_each_entry(mixer, &chip->mixer_list, list) {
696 			snd_usb_mixer_disconnect(mixer);
697 		}
698 	}
699 
700 	chip->num_interfaces--;
701 	if (chip->num_interfaces <= 0) {
702 		usb_chip[chip->index] = NULL;
703 		mutex_unlock(&register_mutex);
704 		snd_card_free_when_closed(card);
705 	} else {
706 		mutex_unlock(&register_mutex);
707 	}
708 }
709 
710 /* lock the shutdown (disconnect) task and autoresume */
711 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
712 {
713 	int err;
714 
715 	atomic_inc(&chip->usage_count);
716 	if (atomic_read(&chip->shutdown)) {
717 		err = -EIO;
718 		goto error;
719 	}
720 	err = snd_usb_autoresume(chip);
721 	if (err < 0)
722 		goto error;
723 	return 0;
724 
725  error:
726 	if (atomic_dec_and_test(&chip->usage_count))
727 		wake_up(&chip->shutdown_wait);
728 	return err;
729 }
730 
731 /* autosuspend and unlock the shutdown */
732 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
733 {
734 	snd_usb_autosuspend(chip);
735 	if (atomic_dec_and_test(&chip->usage_count))
736 		wake_up(&chip->shutdown_wait);
737 }
738 
739 #ifdef CONFIG_PM
740 
741 int snd_usb_autoresume(struct snd_usb_audio *chip)
742 {
743 	if (atomic_read(&chip->shutdown))
744 		return -EIO;
745 	if (atomic_inc_return(&chip->active) == 1)
746 		return usb_autopm_get_interface(chip->pm_intf);
747 	return 0;
748 }
749 
750 void snd_usb_autosuspend(struct snd_usb_audio *chip)
751 {
752 	if (atomic_read(&chip->shutdown))
753 		return;
754 	if (atomic_dec_and_test(&chip->active))
755 		usb_autopm_put_interface(chip->pm_intf);
756 }
757 
758 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
759 {
760 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
761 	struct snd_usb_stream *as;
762 	struct usb_mixer_interface *mixer;
763 	struct list_head *p;
764 
765 	if (chip == (void *)-1L)
766 		return 0;
767 
768 	chip->autosuspended = !!PMSG_IS_AUTO(message);
769 	if (!chip->autosuspended)
770 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
771 	if (!chip->num_suspended_intf++) {
772 		list_for_each_entry(as, &chip->pcm_list, list) {
773 			snd_pcm_suspend_all(as->pcm);
774 			as->substream[0].need_setup_ep =
775 				as->substream[1].need_setup_ep = true;
776 		}
777 		list_for_each(p, &chip->midi_list)
778 			snd_usbmidi_suspend(p);
779 		list_for_each_entry(mixer, &chip->mixer_list, list)
780 			snd_usb_mixer_suspend(mixer);
781 	}
782 
783 	return 0;
784 }
785 
786 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
787 {
788 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
789 	struct usb_mixer_interface *mixer;
790 	struct list_head *p;
791 	int err = 0;
792 
793 	if (chip == (void *)-1L)
794 		return 0;
795 	if (--chip->num_suspended_intf)
796 		return 0;
797 
798 	atomic_inc(&chip->active); /* avoid autopm */
799 	/*
800 	 * ALSA leaves material resumption to user space
801 	 * we just notify and restart the mixers
802 	 */
803 	list_for_each_entry(mixer, &chip->mixer_list, list) {
804 		err = snd_usb_mixer_resume(mixer, reset_resume);
805 		if (err < 0)
806 			goto err_out;
807 	}
808 
809 	list_for_each(p, &chip->midi_list) {
810 		snd_usbmidi_resume(p);
811 	}
812 
813 	if (!chip->autosuspended)
814 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
815 	chip->autosuspended = 0;
816 
817 err_out:
818 	atomic_dec(&chip->active); /* allow autopm after this point */
819 	return err;
820 }
821 
822 static int usb_audio_resume(struct usb_interface *intf)
823 {
824 	return __usb_audio_resume(intf, false);
825 }
826 
827 static int usb_audio_reset_resume(struct usb_interface *intf)
828 {
829 	return __usb_audio_resume(intf, true);
830 }
831 #else
832 #define usb_audio_suspend	NULL
833 #define usb_audio_resume	NULL
834 #define usb_audio_reset_resume	NULL
835 #endif		/* CONFIG_PM */
836 
837 static const struct usb_device_id usb_audio_ids [] = {
838 #include "quirks-table.h"
839     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
840       .bInterfaceClass = USB_CLASS_AUDIO,
841       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
842     { }						/* Terminating entry */
843 };
844 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
845 
846 /*
847  * entry point for linux usb interface
848  */
849 
850 static struct usb_driver usb_audio_driver = {
851 	.name =		"snd-usb-audio",
852 	.probe =	usb_audio_probe,
853 	.disconnect =	usb_audio_disconnect,
854 	.suspend =	usb_audio_suspend,
855 	.resume =	usb_audio_resume,
856 	.reset_resume =	usb_audio_reset_resume,
857 	.id_table =	usb_audio_ids,
858 	.supports_autosuspend = 1,
859 };
860 
861 module_usb_driver(usb_audio_driver);
862