xref: /linux/sound/usb/card.c (revision a8b70ccf10e38775785d9cb12ead916474549f99)
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  *   Audio Class 3.0 support by Ruslan Bilovol <ruslan.bilovol@gmail.com>
11  *
12  *   This program is free software; you can redistribute it and/or modify
13  *   it under the terms of the GNU General Public License as published by
14  *   the Free Software Foundation; either version 2 of the License, or
15  *   (at your option) any later version.
16  *
17  *   This program is distributed in the hope that it will be useful,
18  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
19  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  *   GNU General Public License for more details.
21  *
22  *   You should have received a copy of the GNU General Public License
23  *   along with this program; if not, write to the Free Software
24  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
25  *
26  *
27  *  NOTES:
28  *
29  *   - the linked URBs would be preferred but not used so far because of
30  *     the instability of unlinking.
31  *   - type II is not supported properly.  there is no device which supports
32  *     this type *correctly*.  SB extigy looks as if it supports, but it's
33  *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
34  */
35 
36 
37 #include <linux/bitops.h>
38 #include <linux/init.h>
39 #include <linux/list.h>
40 #include <linux/slab.h>
41 #include <linux/string.h>
42 #include <linux/ctype.h>
43 #include <linux/usb.h>
44 #include <linux/moduleparam.h>
45 #include <linux/mutex.h>
46 #include <linux/usb/audio.h>
47 #include <linux/usb/audio-v2.h>
48 #include <linux/usb/audio-v3.h>
49 #include <linux/module.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 "format.h"
69 #include "power.h"
70 #include "stream.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 bool 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 device_setup[SNDRV_CARDS]; /* device parameter for this card */
85 static bool ignore_ctl_error;
86 static bool autoclock = true;
87 static char *quirk_alias[SNDRV_CARDS];
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_array(device_setup, int, NULL, 0444);
100 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
101 module_param(ignore_ctl_error, bool, 0444);
102 MODULE_PARM_DESC(ignore_ctl_error,
103 		 "Ignore errors from USB controller for mixer interfaces.");
104 module_param(autoclock, bool, 0444);
105 MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
106 module_param_array(quirk_alias, charp, NULL, 0444);
107 MODULE_PARM_DESC(quirk_alias, "Quirk aliases, e.g. 0123abcd:5678beef.");
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 usb_audio_disconnect()
121  */
122 static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
123 {
124 	int idx;
125 	struct snd_usb_substream *subs;
126 
127 	for (idx = 0; idx < 2; idx++) {
128 		subs = &as->substream[idx];
129 		if (!subs->num_formats)
130 			continue;
131 		subs->interface = -1;
132 		subs->data_endpoint = NULL;
133 		subs->sync_endpoint = NULL;
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 		dev_err(&dev->dev, "%u:%d : does not exist\n",
146 			ctrlif, interface);
147 		return -EINVAL;
148 	}
149 
150 	alts = &iface->altsetting[0];
151 	altsd = get_iface_desc(alts);
152 
153 	/*
154 	 * Android with both accessory and audio interfaces enabled gets the
155 	 * interface numbers wrong.
156 	 */
157 	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
158 	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
159 	    interface == 0 &&
160 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
161 	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
162 		interface = 2;
163 		iface = usb_ifnum_to_if(dev, interface);
164 		if (!iface)
165 			return -EINVAL;
166 		alts = &iface->altsetting[0];
167 		altsd = get_iface_desc(alts);
168 	}
169 
170 	if (usb_interface_claimed(iface)) {
171 		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
172 			ctrlif, interface);
173 		return -EINVAL;
174 	}
175 
176 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
177 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
178 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
179 		int err = __snd_usbmidi_create(chip->card, iface,
180 					     &chip->midi_list, NULL,
181 					     chip->usb_id);
182 		if (err < 0) {
183 			dev_err(&dev->dev,
184 				"%u:%d: cannot create sequencer device\n",
185 				ctrlif, interface);
186 			return -EINVAL;
187 		}
188 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
189 
190 		return 0;
191 	}
192 
193 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
194 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
195 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
196 		dev_dbg(&dev->dev,
197 			"%u:%d: skipping non-supported interface %d\n",
198 			ctrlif, interface, altsd->bInterfaceClass);
199 		/* skip non-supported classes */
200 		return -EINVAL;
201 	}
202 
203 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
204 		dev_err(&dev->dev, "low speed audio streaming not supported\n");
205 		return -EINVAL;
206 	}
207 
208 	if (! snd_usb_parse_audio_interface(chip, interface)) {
209 		usb_set_interface(dev, interface, 0); /* reset the current interface */
210 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
211 	}
212 
213 	return 0;
214 }
215 
216 /*
217  * parse audio control descriptor and create pcm/midi streams
218  */
219 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
220 {
221 	struct usb_device *dev = chip->dev;
222 	struct usb_host_interface *host_iface;
223 	struct usb_interface_descriptor *altsd;
224 	void *control_header;
225 	int i, protocol;
226 	int rest_bytes;
227 
228 	/* find audiocontrol interface */
229 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
230 	control_header = snd_usb_find_csint_desc(host_iface->extra,
231 						 host_iface->extralen,
232 						 NULL, UAC_HEADER);
233 	altsd = get_iface_desc(host_iface);
234 	protocol = altsd->bInterfaceProtocol;
235 
236 	if (!control_header) {
237 		dev_err(&dev->dev, "cannot find UAC_HEADER\n");
238 		return -EINVAL;
239 	}
240 
241 	rest_bytes = (void *)(host_iface->extra + host_iface->extralen) -
242 		control_header;
243 
244 	/* just to be sure -- this shouldn't hit at all */
245 	if (rest_bytes <= 0) {
246 		dev_err(&dev->dev, "invalid control header\n");
247 		return -EINVAL;
248 	}
249 
250 	switch (protocol) {
251 	default:
252 		dev_warn(&dev->dev,
253 			 "unknown interface protocol %#02x, assuming v1\n",
254 			 protocol);
255 		/* fall through */
256 
257 	case UAC_VERSION_1: {
258 		struct uac1_ac_header_descriptor *h1 = control_header;
259 
260 		if (rest_bytes < sizeof(*h1)) {
261 			dev_err(&dev->dev, "too short v1 buffer descriptor\n");
262 			return -EINVAL;
263 		}
264 
265 		if (!h1->bInCollection) {
266 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
267 			return -EINVAL;
268 		}
269 
270 		if (rest_bytes < h1->bLength) {
271 			dev_err(&dev->dev, "invalid buffer length (v1)\n");
272 			return -EINVAL;
273 		}
274 
275 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
276 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
277 			return -EINVAL;
278 		}
279 
280 		for (i = 0; i < h1->bInCollection; i++)
281 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
282 
283 		break;
284 	}
285 
286 	case UAC_VERSION_2:
287 	case UAC_VERSION_3: {
288 		struct usb_interface_assoc_descriptor *assoc =
289 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
290 
291 		if (!assoc) {
292 			/*
293 			 * Firmware writers cannot count to three.  So to find
294 			 * the IAD on the NuForce UDH-100, also check the next
295 			 * interface.
296 			 */
297 			struct usb_interface *iface =
298 				usb_ifnum_to_if(dev, ctrlif + 1);
299 			if (iface &&
300 			    iface->intf_assoc &&
301 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
302 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
303 				assoc = iface->intf_assoc;
304 		}
305 
306 		if (!assoc) {
307 			dev_err(&dev->dev, "Audio class v2/v3 interfaces need an interface association\n");
308 			return -EINVAL;
309 		}
310 
311 		for (i = 0; i < assoc->bInterfaceCount; i++) {
312 			int intf = assoc->bFirstInterface + i;
313 
314 			if (intf != ctrlif)
315 				snd_usb_create_stream(chip, ctrlif, intf);
316 		}
317 
318 		break;
319 	}
320 	}
321 
322 	return 0;
323 }
324 
325 /*
326  * free the chip instance
327  *
328  * here we have to do not much, since pcm and controls are already freed
329  *
330  */
331 
332 static int snd_usb_audio_free(struct snd_usb_audio *chip)
333 {
334 	struct snd_usb_endpoint *ep, *n;
335 
336 	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
337 		snd_usb_endpoint_free(ep);
338 
339 	mutex_destroy(&chip->mutex);
340 	if (!atomic_read(&chip->shutdown))
341 		dev_set_drvdata(&chip->dev->dev, NULL);
342 	kfree(chip);
343 	return 0;
344 }
345 
346 static int snd_usb_audio_dev_free(struct snd_device *device)
347 {
348 	struct snd_usb_audio *chip = device->device_data;
349 	return snd_usb_audio_free(chip);
350 }
351 
352 /*
353  * create a chip instance and set its names.
354  */
355 static int snd_usb_audio_create(struct usb_interface *intf,
356 				struct usb_device *dev, int idx,
357 				const struct snd_usb_audio_quirk *quirk,
358 				unsigned int usb_id,
359 				struct snd_usb_audio **rchip)
360 {
361 	struct snd_card *card;
362 	struct snd_usb_audio *chip;
363 	int err, len;
364 	char component[14];
365 	static struct snd_device_ops ops = {
366 		.dev_free =	snd_usb_audio_dev_free,
367 	};
368 
369 	*rchip = NULL;
370 
371 	switch (snd_usb_get_speed(dev)) {
372 	case USB_SPEED_LOW:
373 	case USB_SPEED_FULL:
374 	case USB_SPEED_HIGH:
375 	case USB_SPEED_WIRELESS:
376 	case USB_SPEED_SUPER:
377 	case USB_SPEED_SUPER_PLUS:
378 		break;
379 	default:
380 		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
381 		return -ENXIO;
382 	}
383 
384 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
385 			   0, &card);
386 	if (err < 0) {
387 		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
388 		return err;
389 	}
390 
391 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
392 	if (! chip) {
393 		snd_card_free(card);
394 		return -ENOMEM;
395 	}
396 
397 	mutex_init(&chip->mutex);
398 	init_waitqueue_head(&chip->shutdown_wait);
399 	chip->index = idx;
400 	chip->dev = dev;
401 	chip->card = card;
402 	chip->setup = device_setup[idx];
403 	chip->autoclock = autoclock;
404 	atomic_set(&chip->active, 1); /* avoid autopm during probing */
405 	atomic_set(&chip->usage_count, 0);
406 	atomic_set(&chip->shutdown, 0);
407 
408 	chip->usb_id = usb_id;
409 	INIT_LIST_HEAD(&chip->pcm_list);
410 	INIT_LIST_HEAD(&chip->ep_list);
411 	INIT_LIST_HEAD(&chip->midi_list);
412 	INIT_LIST_HEAD(&chip->mixer_list);
413 
414 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
415 		snd_usb_audio_free(chip);
416 		snd_card_free(card);
417 		return err;
418 	}
419 
420 	strcpy(card->driver, "USB-Audio");
421 	sprintf(component, "USB%04x:%04x",
422 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
423 	snd_component_add(card, component);
424 
425 	/* retrieve the device string as shortname */
426 	if (quirk && quirk->product_name && *quirk->product_name) {
427 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
428 	} else {
429 		if (!dev->descriptor.iProduct ||
430 		    usb_string(dev, dev->descriptor.iProduct,
431 		    card->shortname, sizeof(card->shortname)) <= 0) {
432 			/* no name available from anywhere, so use ID */
433 			sprintf(card->shortname, "USB Device %#04x:%#04x",
434 				USB_ID_VENDOR(chip->usb_id),
435 				USB_ID_PRODUCT(chip->usb_id));
436 		}
437 	}
438 	strim(card->shortname);
439 
440 	/* retrieve the vendor and device strings as longname */
441 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
442 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
443 	} else {
444 		if (dev->descriptor.iManufacturer)
445 			len = usb_string(dev, dev->descriptor.iManufacturer,
446 					 card->longname, sizeof(card->longname));
447 		else
448 			len = 0;
449 		/* we don't really care if there isn't any vendor string */
450 	}
451 	if (len > 0) {
452 		strim(card->longname);
453 		if (*card->longname)
454 			strlcat(card->longname, " ", sizeof(card->longname));
455 	}
456 
457 	strlcat(card->longname, card->shortname, sizeof(card->longname));
458 
459 	len = strlcat(card->longname, " at ", sizeof(card->longname));
460 
461 	if (len < sizeof(card->longname))
462 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
463 
464 	switch (snd_usb_get_speed(dev)) {
465 	case USB_SPEED_LOW:
466 		strlcat(card->longname, ", low speed", sizeof(card->longname));
467 		break;
468 	case USB_SPEED_FULL:
469 		strlcat(card->longname, ", full speed", sizeof(card->longname));
470 		break;
471 	case USB_SPEED_HIGH:
472 		strlcat(card->longname, ", high speed", sizeof(card->longname));
473 		break;
474 	case USB_SPEED_SUPER:
475 		strlcat(card->longname, ", super speed", sizeof(card->longname));
476 		break;
477 	case USB_SPEED_SUPER_PLUS:
478 		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
479 		break;
480 	default:
481 		break;
482 	}
483 
484 	snd_usb_audio_create_proc(chip);
485 
486 	*rchip = chip;
487 	return 0;
488 }
489 
490 /* look for a matching quirk alias id */
491 static bool get_alias_id(struct usb_device *dev, unsigned int *id)
492 {
493 	int i;
494 	unsigned int src, dst;
495 
496 	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
497 		if (!quirk_alias[i] ||
498 		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
499 		    src != *id)
500 			continue;
501 		dev_info(&dev->dev,
502 			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
503 			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
504 			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
505 		*id = dst;
506 		return true;
507 	}
508 
509 	return false;
510 }
511 
512 static const struct usb_device_id usb_audio_ids[]; /* defined below */
513 
514 /* look for the corresponding quirk */
515 static const struct snd_usb_audio_quirk *
516 get_alias_quirk(struct usb_device *dev, unsigned int id)
517 {
518 	const struct usb_device_id *p;
519 
520 	for (p = usb_audio_ids; p->match_flags; p++) {
521 		/* FIXME: this checks only vendor:product pair in the list */
522 		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==
523 		    USB_DEVICE_ID_MATCH_DEVICE &&
524 		    p->idVendor == USB_ID_VENDOR(id) &&
525 		    p->idProduct == USB_ID_PRODUCT(id))
526 			return (const struct snd_usb_audio_quirk *)p->driver_info;
527 	}
528 
529 	return NULL;
530 }
531 
532 /*
533  * probe the active usb device
534  *
535  * note that this can be called multiple times per a device, when it
536  * includes multiple audio control interfaces.
537  *
538  * thus we check the usb device pointer and creates the card instance
539  * only at the first time.  the successive calls of this function will
540  * append the pcm interface to the corresponding card.
541  */
542 static int usb_audio_probe(struct usb_interface *intf,
543 			   const struct usb_device_id *usb_id)
544 {
545 	struct usb_device *dev = interface_to_usbdev(intf);
546 	const struct snd_usb_audio_quirk *quirk =
547 		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
548 	struct snd_usb_audio *chip;
549 	int i, err;
550 	struct usb_host_interface *alts;
551 	int ifnum;
552 	u32 id;
553 
554 	alts = &intf->altsetting[0];
555 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
556 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
557 		    le16_to_cpu(dev->descriptor.idProduct));
558 	if (get_alias_id(dev, &id))
559 		quirk = get_alias_quirk(dev, id);
560 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
561 		return -ENXIO;
562 
563 	err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
564 	if (err < 0)
565 		return err;
566 
567 	/*
568 	 * found a config.  now register to ALSA
569 	 */
570 
571 	/* check whether it's already registered */
572 	chip = NULL;
573 	mutex_lock(&register_mutex);
574 	for (i = 0; i < SNDRV_CARDS; i++) {
575 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
576 			if (atomic_read(&usb_chip[i]->shutdown)) {
577 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
578 				err = -EIO;
579 				goto __error;
580 			}
581 			chip = usb_chip[i];
582 			atomic_inc(&chip->active); /* avoid autopm */
583 			break;
584 		}
585 	}
586 	if (! chip) {
587 		/* it's a fresh one.
588 		 * now look for an empty slot and create a new card instance
589 		 */
590 		for (i = 0; i < SNDRV_CARDS; i++)
591 			if (!usb_chip[i] &&
592 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
593 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
594 				if (enable[i]) {
595 					err = snd_usb_audio_create(intf, dev, i, quirk,
596 								   id, &chip);
597 					if (err < 0)
598 						goto __error;
599 					chip->pm_intf = intf;
600 					break;
601 				} else if (vid[i] != -1 || pid[i] != -1) {
602 					dev_info(&dev->dev,
603 						 "device (%04x:%04x) is disabled\n",
604 						 USB_ID_VENDOR(id),
605 						 USB_ID_PRODUCT(id));
606 					err = -ENOENT;
607 					goto __error;
608 				}
609 			}
610 		if (!chip) {
611 			dev_err(&dev->dev, "no available usb audio device\n");
612 			err = -ENODEV;
613 			goto __error;
614 		}
615 	}
616 	dev_set_drvdata(&dev->dev, chip);
617 
618 	/*
619 	 * For devices with more than one control interface, we assume the
620 	 * first contains the audio controls. We might need a more specific
621 	 * check here in the future.
622 	 */
623 	if (!chip->ctrl_intf)
624 		chip->ctrl_intf = alts;
625 
626 	chip->txfr_quirk = 0;
627 	err = 1; /* continue */
628 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
629 		/* need some special handlings */
630 		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
631 		if (err < 0)
632 			goto __error;
633 	}
634 
635 	if (err > 0) {
636 		/* create normal USB audio interfaces */
637 		err = snd_usb_create_streams(chip, ifnum);
638 		if (err < 0)
639 			goto __error;
640 		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
641 		if (err < 0)
642 			goto __error;
643 	}
644 
645 	/* we are allowed to call snd_card_register() many times */
646 	err = snd_card_register(chip->card);
647 	if (err < 0)
648 		goto __error;
649 
650 	usb_chip[chip->index] = chip;
651 	chip->num_interfaces++;
652 	usb_set_intfdata(intf, chip);
653 	atomic_dec(&chip->active);
654 	mutex_unlock(&register_mutex);
655 	return 0;
656 
657  __error:
658 	if (chip) {
659 		if (!chip->num_interfaces)
660 			snd_card_free(chip->card);
661 		atomic_dec(&chip->active);
662 	}
663 	mutex_unlock(&register_mutex);
664 	return err;
665 }
666 
667 /*
668  * we need to take care of counter, since disconnection can be called also
669  * many times as well as usb_audio_probe().
670  */
671 static void usb_audio_disconnect(struct usb_interface *intf)
672 {
673 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
674 	struct snd_card *card;
675 	struct list_head *p;
676 
677 	if (chip == (void *)-1L)
678 		return;
679 
680 	card = chip->card;
681 
682 	mutex_lock(&register_mutex);
683 	if (atomic_inc_return(&chip->shutdown) == 1) {
684 		struct snd_usb_stream *as;
685 		struct snd_usb_endpoint *ep;
686 		struct usb_mixer_interface *mixer;
687 
688 		/* wait until all pending tasks done;
689 		 * they are protected by snd_usb_lock_shutdown()
690 		 */
691 		wait_event(chip->shutdown_wait,
692 			   !atomic_read(&chip->usage_count));
693 		snd_card_disconnect(card);
694 		/* release the pcm resources */
695 		list_for_each_entry(as, &chip->pcm_list, list) {
696 			snd_usb_stream_disconnect(as);
697 		}
698 		/* release the endpoint resources */
699 		list_for_each_entry(ep, &chip->ep_list, list) {
700 			snd_usb_endpoint_release(ep);
701 		}
702 		/* release the midi resources */
703 		list_for_each(p, &chip->midi_list) {
704 			snd_usbmidi_disconnect(p);
705 		}
706 		/* release mixer resources */
707 		list_for_each_entry(mixer, &chip->mixer_list, list) {
708 			snd_usb_mixer_disconnect(mixer);
709 		}
710 	}
711 
712 	chip->num_interfaces--;
713 	if (chip->num_interfaces <= 0) {
714 		usb_chip[chip->index] = NULL;
715 		mutex_unlock(&register_mutex);
716 		snd_card_free_when_closed(card);
717 	} else {
718 		mutex_unlock(&register_mutex);
719 	}
720 }
721 
722 /* lock the shutdown (disconnect) task and autoresume */
723 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
724 {
725 	int err;
726 
727 	atomic_inc(&chip->usage_count);
728 	if (atomic_read(&chip->shutdown)) {
729 		err = -EIO;
730 		goto error;
731 	}
732 	err = snd_usb_autoresume(chip);
733 	if (err < 0)
734 		goto error;
735 	return 0;
736 
737  error:
738 	if (atomic_dec_and_test(&chip->usage_count))
739 		wake_up(&chip->shutdown_wait);
740 	return err;
741 }
742 
743 /* autosuspend and unlock the shutdown */
744 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
745 {
746 	snd_usb_autosuspend(chip);
747 	if (atomic_dec_and_test(&chip->usage_count))
748 		wake_up(&chip->shutdown_wait);
749 }
750 
751 #ifdef CONFIG_PM
752 
753 int snd_usb_autoresume(struct snd_usb_audio *chip)
754 {
755 	if (atomic_read(&chip->shutdown))
756 		return -EIO;
757 	if (atomic_inc_return(&chip->active) == 1)
758 		return usb_autopm_get_interface(chip->pm_intf);
759 	return 0;
760 }
761 
762 void snd_usb_autosuspend(struct snd_usb_audio *chip)
763 {
764 	if (atomic_read(&chip->shutdown))
765 		return;
766 	if (atomic_dec_and_test(&chip->active))
767 		usb_autopm_put_interface(chip->pm_intf);
768 }
769 
770 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
771 {
772 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
773 	struct snd_usb_stream *as;
774 	struct usb_mixer_interface *mixer;
775 	struct list_head *p;
776 
777 	if (chip == (void *)-1L)
778 		return 0;
779 
780 	chip->autosuspended = !!PMSG_IS_AUTO(message);
781 	if (!chip->autosuspended)
782 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
783 	if (!chip->num_suspended_intf++) {
784 		list_for_each_entry(as, &chip->pcm_list, list) {
785 			snd_pcm_suspend_all(as->pcm);
786 			as->substream[0].need_setup_ep =
787 				as->substream[1].need_setup_ep = true;
788 		}
789 		list_for_each(p, &chip->midi_list)
790 			snd_usbmidi_suspend(p);
791 		list_for_each_entry(mixer, &chip->mixer_list, list)
792 			snd_usb_mixer_suspend(mixer);
793 	}
794 
795 	return 0;
796 }
797 
798 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
799 {
800 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
801 	struct usb_mixer_interface *mixer;
802 	struct list_head *p;
803 	int err = 0;
804 
805 	if (chip == (void *)-1L)
806 		return 0;
807 	if (--chip->num_suspended_intf)
808 		return 0;
809 
810 	atomic_inc(&chip->active); /* avoid autopm */
811 	/*
812 	 * ALSA leaves material resumption to user space
813 	 * we just notify and restart the mixers
814 	 */
815 	list_for_each_entry(mixer, &chip->mixer_list, list) {
816 		err = snd_usb_mixer_resume(mixer, reset_resume);
817 		if (err < 0)
818 			goto err_out;
819 	}
820 
821 	list_for_each(p, &chip->midi_list) {
822 		snd_usbmidi_resume(p);
823 	}
824 
825 	if (!chip->autosuspended)
826 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
827 	chip->autosuspended = 0;
828 
829 err_out:
830 	atomic_dec(&chip->active); /* allow autopm after this point */
831 	return err;
832 }
833 
834 static int usb_audio_resume(struct usb_interface *intf)
835 {
836 	return __usb_audio_resume(intf, false);
837 }
838 
839 static int usb_audio_reset_resume(struct usb_interface *intf)
840 {
841 	return __usb_audio_resume(intf, true);
842 }
843 #else
844 #define usb_audio_suspend	NULL
845 #define usb_audio_resume	NULL
846 #define usb_audio_reset_resume	NULL
847 #endif		/* CONFIG_PM */
848 
849 static const struct usb_device_id usb_audio_ids [] = {
850 #include "quirks-table.h"
851     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
852       .bInterfaceClass = USB_CLASS_AUDIO,
853       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
854     { }						/* Terminating entry */
855 };
856 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
857 
858 /*
859  * entry point for linux usb interface
860  */
861 
862 static struct usb_driver usb_audio_driver = {
863 	.name =		"snd-usb-audio",
864 	.probe =	usb_audio_probe,
865 	.disconnect =	usb_audio_disconnect,
866 	.suspend =	usb_audio_suspend,
867 	.resume =	usb_audio_resume,
868 	.reset_resume =	usb_audio_reset_resume,
869 	.id_table =	usb_audio_ids,
870 	.supports_autosuspend = 1,
871 };
872 
873 module_usb_driver(usb_audio_driver);
874