xref: /openbmc/linux/sound/usb/card.c (revision 3d624617)
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 	int i, protocol;
225 
226 	/* find audiocontrol interface */
227 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
228 	altsd = get_iface_desc(host_iface);
229 	protocol = altsd->bInterfaceProtocol;
230 
231 	switch (protocol) {
232 	default:
233 		dev_warn(&dev->dev,
234 			 "unknown interface protocol %#02x, assuming v1\n",
235 			 protocol);
236 		/* fall through */
237 
238 	case UAC_VERSION_1: {
239 		struct uac1_ac_header_descriptor *h1;
240 		int rest_bytes;
241 
242 		h1 = snd_usb_find_csint_desc(host_iface->extra,
243 							 host_iface->extralen,
244 							 NULL, UAC_HEADER);
245 		if (!h1) {
246 			dev_err(&dev->dev, "cannot find UAC_HEADER\n");
247 			return -EINVAL;
248 		}
249 
250 		rest_bytes = (void *)(host_iface->extra +
251 				host_iface->extralen) - (void *)h1;
252 
253 		/* just to be sure -- this shouldn't hit at all */
254 		if (rest_bytes <= 0) {
255 			dev_err(&dev->dev, "invalid control header\n");
256 			return -EINVAL;
257 		}
258 
259 		if (rest_bytes < sizeof(*h1)) {
260 			dev_err(&dev->dev, "too short v1 buffer descriptor\n");
261 			return -EINVAL;
262 		}
263 
264 		if (!h1->bInCollection) {
265 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
266 			return -EINVAL;
267 		}
268 
269 		if (rest_bytes < h1->bLength) {
270 			dev_err(&dev->dev, "invalid buffer length (v1)\n");
271 			return -EINVAL;
272 		}
273 
274 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
275 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
276 			return -EINVAL;
277 		}
278 
279 		for (i = 0; i < h1->bInCollection; i++)
280 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
281 
282 		break;
283 	}
284 
285 	case UAC_VERSION_2:
286 	case UAC_VERSION_3: {
287 		struct usb_interface_assoc_descriptor *assoc =
288 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
289 
290 		if (!assoc) {
291 			/*
292 			 * Firmware writers cannot count to three.  So to find
293 			 * the IAD on the NuForce UDH-100, also check the next
294 			 * interface.
295 			 */
296 			struct usb_interface *iface =
297 				usb_ifnum_to_if(dev, ctrlif + 1);
298 			if (iface &&
299 			    iface->intf_assoc &&
300 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
301 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
302 				assoc = iface->intf_assoc;
303 		}
304 
305 		if (!assoc) {
306 			dev_err(&dev->dev, "Audio class v2/v3 interfaces need an interface association\n");
307 			return -EINVAL;
308 		}
309 
310 		if (protocol == UAC_VERSION_3) {
311 			int badd = assoc->bFunctionSubClass;
312 
313 			if (badd != UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0 &&
314 			    (badd < UAC3_FUNCTION_SUBCLASS_GENERIC_IO ||
315 			     badd > UAC3_FUNCTION_SUBCLASS_SPEAKERPHONE)) {
316 				dev_err(&dev->dev,
317 					"Unsupported UAC3 BADD profile\n");
318 				return -EINVAL;
319 			}
320 
321 			chip->badd_profile = badd;
322 		}
323 
324 		for (i = 0; i < assoc->bInterfaceCount; i++) {
325 			int intf = assoc->bFirstInterface + i;
326 
327 			if (intf != ctrlif)
328 				snd_usb_create_stream(chip, ctrlif, intf);
329 		}
330 
331 		break;
332 	}
333 	}
334 
335 	return 0;
336 }
337 
338 /*
339  * free the chip instance
340  *
341  * here we have to do not much, since pcm and controls are already freed
342  *
343  */
344 
345 static int snd_usb_audio_free(struct snd_usb_audio *chip)
346 {
347 	struct snd_usb_endpoint *ep, *n;
348 
349 	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
350 		snd_usb_endpoint_free(ep);
351 
352 	mutex_destroy(&chip->mutex);
353 	if (!atomic_read(&chip->shutdown))
354 		dev_set_drvdata(&chip->dev->dev, NULL);
355 	kfree(chip);
356 	return 0;
357 }
358 
359 static int snd_usb_audio_dev_free(struct snd_device *device)
360 {
361 	struct snd_usb_audio *chip = device->device_data;
362 	return snd_usb_audio_free(chip);
363 }
364 
365 static void usb_audio_make_shortname(struct usb_device *dev,
366 				     struct snd_usb_audio *chip,
367 				     const struct snd_usb_audio_quirk *quirk)
368 {
369 	struct snd_card *card = chip->card;
370 
371 	if (quirk && quirk->product_name && *quirk->product_name) {
372 		strlcpy(card->shortname, quirk->product_name,
373 			sizeof(card->shortname));
374 		return;
375 	}
376 
377 	/* retrieve the device string as shortname */
378 	if (!dev->descriptor.iProduct ||
379 	    usb_string(dev, dev->descriptor.iProduct,
380 		       card->shortname, sizeof(card->shortname)) <= 0) {
381 		/* no name available from anywhere, so use ID */
382 		sprintf(card->shortname, "USB Device %#04x:%#04x",
383 			USB_ID_VENDOR(chip->usb_id),
384 			USB_ID_PRODUCT(chip->usb_id));
385 	}
386 
387 	strim(card->shortname);
388 }
389 
390 static void usb_audio_make_longname(struct usb_device *dev,
391 				    struct snd_usb_audio *chip,
392 				    const struct snd_usb_audio_quirk *quirk)
393 {
394 	struct snd_card *card = chip->card;
395 	int len;
396 
397 	/* shortcut - if any pre-defined string is given, use it */
398 	if (quirk && quirk->profile_name && *quirk->profile_name) {
399 		strlcpy(card->longname, quirk->profile_name,
400 			sizeof(card->longname));
401 		return;
402 	}
403 
404 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
405 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
406 	} else {
407 		/* retrieve the vendor and device strings as longname */
408 		if (dev->descriptor.iManufacturer)
409 			len = usb_string(dev, dev->descriptor.iManufacturer,
410 					 card->longname, sizeof(card->longname));
411 		else
412 			len = 0;
413 		/* we don't really care if there isn't any vendor string */
414 	}
415 	if (len > 0) {
416 		strim(card->longname);
417 		if (*card->longname)
418 			strlcat(card->longname, " ", sizeof(card->longname));
419 	}
420 
421 	strlcat(card->longname, card->shortname, sizeof(card->longname));
422 
423 	len = strlcat(card->longname, " at ", sizeof(card->longname));
424 
425 	if (len < sizeof(card->longname))
426 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
427 
428 	switch (snd_usb_get_speed(dev)) {
429 	case USB_SPEED_LOW:
430 		strlcat(card->longname, ", low speed", sizeof(card->longname));
431 		break;
432 	case USB_SPEED_FULL:
433 		strlcat(card->longname, ", full speed", sizeof(card->longname));
434 		break;
435 	case USB_SPEED_HIGH:
436 		strlcat(card->longname, ", high speed", sizeof(card->longname));
437 		break;
438 	case USB_SPEED_SUPER:
439 		strlcat(card->longname, ", super speed", sizeof(card->longname));
440 		break;
441 	case USB_SPEED_SUPER_PLUS:
442 		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
443 		break;
444 	default:
445 		break;
446 	}
447 }
448 
449 /*
450  * create a chip instance and set its names.
451  */
452 static int snd_usb_audio_create(struct usb_interface *intf,
453 				struct usb_device *dev, int idx,
454 				const struct snd_usb_audio_quirk *quirk,
455 				unsigned int usb_id,
456 				struct snd_usb_audio **rchip)
457 {
458 	struct snd_card *card;
459 	struct snd_usb_audio *chip;
460 	int err;
461 	char component[14];
462 	static struct snd_device_ops ops = {
463 		.dev_free =	snd_usb_audio_dev_free,
464 	};
465 
466 	*rchip = NULL;
467 
468 	switch (snd_usb_get_speed(dev)) {
469 	case USB_SPEED_LOW:
470 	case USB_SPEED_FULL:
471 	case USB_SPEED_HIGH:
472 	case USB_SPEED_WIRELESS:
473 	case USB_SPEED_SUPER:
474 	case USB_SPEED_SUPER_PLUS:
475 		break;
476 	default:
477 		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
478 		return -ENXIO;
479 	}
480 
481 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
482 			   0, &card);
483 	if (err < 0) {
484 		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
485 		return err;
486 	}
487 
488 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
489 	if (! chip) {
490 		snd_card_free(card);
491 		return -ENOMEM;
492 	}
493 
494 	mutex_init(&chip->mutex);
495 	init_waitqueue_head(&chip->shutdown_wait);
496 	chip->index = idx;
497 	chip->dev = dev;
498 	chip->card = card;
499 	chip->setup = device_setup[idx];
500 	chip->autoclock = autoclock;
501 	atomic_set(&chip->active, 1); /* avoid autopm during probing */
502 	atomic_set(&chip->usage_count, 0);
503 	atomic_set(&chip->shutdown, 0);
504 
505 	chip->usb_id = usb_id;
506 	INIT_LIST_HEAD(&chip->pcm_list);
507 	INIT_LIST_HEAD(&chip->ep_list);
508 	INIT_LIST_HEAD(&chip->midi_list);
509 	INIT_LIST_HEAD(&chip->mixer_list);
510 
511 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
512 		snd_usb_audio_free(chip);
513 		snd_card_free(card);
514 		return err;
515 	}
516 
517 	strcpy(card->driver, "USB-Audio");
518 	sprintf(component, "USB%04x:%04x",
519 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
520 	snd_component_add(card, component);
521 
522 	usb_audio_make_shortname(dev, chip, quirk);
523 	usb_audio_make_longname(dev, chip, quirk);
524 
525 	snd_usb_audio_create_proc(chip);
526 
527 	*rchip = chip;
528 	return 0;
529 }
530 
531 /* look for a matching quirk alias id */
532 static bool get_alias_id(struct usb_device *dev, unsigned int *id)
533 {
534 	int i;
535 	unsigned int src, dst;
536 
537 	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
538 		if (!quirk_alias[i] ||
539 		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
540 		    src != *id)
541 			continue;
542 		dev_info(&dev->dev,
543 			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
544 			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
545 			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
546 		*id = dst;
547 		return true;
548 	}
549 
550 	return false;
551 }
552 
553 static const struct usb_device_id usb_audio_ids[]; /* defined below */
554 
555 /* look for the corresponding quirk */
556 static const struct snd_usb_audio_quirk *
557 get_alias_quirk(struct usb_device *dev, unsigned int id)
558 {
559 	const struct usb_device_id *p;
560 
561 	for (p = usb_audio_ids; p->match_flags; p++) {
562 		/* FIXME: this checks only vendor:product pair in the list */
563 		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==
564 		    USB_DEVICE_ID_MATCH_DEVICE &&
565 		    p->idVendor == USB_ID_VENDOR(id) &&
566 		    p->idProduct == USB_ID_PRODUCT(id))
567 			return (const struct snd_usb_audio_quirk *)p->driver_info;
568 	}
569 
570 	return NULL;
571 }
572 
573 /*
574  * probe the active usb device
575  *
576  * note that this can be called multiple times per a device, when it
577  * includes multiple audio control interfaces.
578  *
579  * thus we check the usb device pointer and creates the card instance
580  * only at the first time.  the successive calls of this function will
581  * append the pcm interface to the corresponding card.
582  */
583 static int usb_audio_probe(struct usb_interface *intf,
584 			   const struct usb_device_id *usb_id)
585 {
586 	struct usb_device *dev = interface_to_usbdev(intf);
587 	const struct snd_usb_audio_quirk *quirk =
588 		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
589 	struct snd_usb_audio *chip;
590 	int i, err;
591 	struct usb_host_interface *alts;
592 	int ifnum;
593 	u32 id;
594 
595 	alts = &intf->altsetting[0];
596 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
597 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
598 		    le16_to_cpu(dev->descriptor.idProduct));
599 	if (get_alias_id(dev, &id))
600 		quirk = get_alias_quirk(dev, id);
601 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
602 		return -ENXIO;
603 
604 	err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
605 	if (err < 0)
606 		return err;
607 
608 	/*
609 	 * found a config.  now register to ALSA
610 	 */
611 
612 	/* check whether it's already registered */
613 	chip = NULL;
614 	mutex_lock(&register_mutex);
615 	for (i = 0; i < SNDRV_CARDS; i++) {
616 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
617 			if (atomic_read(&usb_chip[i]->shutdown)) {
618 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
619 				err = -EIO;
620 				goto __error;
621 			}
622 			chip = usb_chip[i];
623 			atomic_inc(&chip->active); /* avoid autopm */
624 			break;
625 		}
626 	}
627 	if (! chip) {
628 		/* it's a fresh one.
629 		 * now look for an empty slot and create a new card instance
630 		 */
631 		for (i = 0; i < SNDRV_CARDS; i++)
632 			if (!usb_chip[i] &&
633 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
634 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
635 				if (enable[i]) {
636 					err = snd_usb_audio_create(intf, dev, i, quirk,
637 								   id, &chip);
638 					if (err < 0)
639 						goto __error;
640 					chip->pm_intf = intf;
641 					break;
642 				} else if (vid[i] != -1 || pid[i] != -1) {
643 					dev_info(&dev->dev,
644 						 "device (%04x:%04x) is disabled\n",
645 						 USB_ID_VENDOR(id),
646 						 USB_ID_PRODUCT(id));
647 					err = -ENOENT;
648 					goto __error;
649 				}
650 			}
651 		if (!chip) {
652 			dev_err(&dev->dev, "no available usb audio device\n");
653 			err = -ENODEV;
654 			goto __error;
655 		}
656 	}
657 	dev_set_drvdata(&dev->dev, chip);
658 
659 	/*
660 	 * For devices with more than one control interface, we assume the
661 	 * first contains the audio controls. We might need a more specific
662 	 * check here in the future.
663 	 */
664 	if (!chip->ctrl_intf)
665 		chip->ctrl_intf = alts;
666 
667 	chip->txfr_quirk = 0;
668 	err = 1; /* continue */
669 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
670 		/* need some special handlings */
671 		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
672 		if (err < 0)
673 			goto __error;
674 	}
675 
676 	if (err > 0) {
677 		/* create normal USB audio interfaces */
678 		err = snd_usb_create_streams(chip, ifnum);
679 		if (err < 0)
680 			goto __error;
681 		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
682 		if (err < 0)
683 			goto __error;
684 	}
685 
686 	/* we are allowed to call snd_card_register() many times */
687 	err = snd_card_register(chip->card);
688 	if (err < 0)
689 		goto __error;
690 
691 	usb_chip[chip->index] = chip;
692 	chip->num_interfaces++;
693 	usb_set_intfdata(intf, chip);
694 	atomic_dec(&chip->active);
695 	mutex_unlock(&register_mutex);
696 	return 0;
697 
698  __error:
699 	if (chip) {
700 		if (!chip->num_interfaces)
701 			snd_card_free(chip->card);
702 		atomic_dec(&chip->active);
703 	}
704 	mutex_unlock(&register_mutex);
705 	return err;
706 }
707 
708 /*
709  * we need to take care of counter, since disconnection can be called also
710  * many times as well as usb_audio_probe().
711  */
712 static void usb_audio_disconnect(struct usb_interface *intf)
713 {
714 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
715 	struct snd_card *card;
716 	struct list_head *p;
717 
718 	if (chip == (void *)-1L)
719 		return;
720 
721 	card = chip->card;
722 
723 	mutex_lock(&register_mutex);
724 	if (atomic_inc_return(&chip->shutdown) == 1) {
725 		struct snd_usb_stream *as;
726 		struct snd_usb_endpoint *ep;
727 		struct usb_mixer_interface *mixer;
728 
729 		/* wait until all pending tasks done;
730 		 * they are protected by snd_usb_lock_shutdown()
731 		 */
732 		wait_event(chip->shutdown_wait,
733 			   !atomic_read(&chip->usage_count));
734 		snd_card_disconnect(card);
735 		/* release the pcm resources */
736 		list_for_each_entry(as, &chip->pcm_list, list) {
737 			snd_usb_stream_disconnect(as);
738 		}
739 		/* release the endpoint resources */
740 		list_for_each_entry(ep, &chip->ep_list, list) {
741 			snd_usb_endpoint_release(ep);
742 		}
743 		/* release the midi resources */
744 		list_for_each(p, &chip->midi_list) {
745 			snd_usbmidi_disconnect(p);
746 		}
747 		/* release mixer resources */
748 		list_for_each_entry(mixer, &chip->mixer_list, list) {
749 			snd_usb_mixer_disconnect(mixer);
750 		}
751 	}
752 
753 	chip->num_interfaces--;
754 	if (chip->num_interfaces <= 0) {
755 		usb_chip[chip->index] = NULL;
756 		mutex_unlock(&register_mutex);
757 		snd_card_free_when_closed(card);
758 	} else {
759 		mutex_unlock(&register_mutex);
760 	}
761 }
762 
763 /* lock the shutdown (disconnect) task and autoresume */
764 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
765 {
766 	int err;
767 
768 	atomic_inc(&chip->usage_count);
769 	if (atomic_read(&chip->shutdown)) {
770 		err = -EIO;
771 		goto error;
772 	}
773 	err = snd_usb_autoresume(chip);
774 	if (err < 0)
775 		goto error;
776 	return 0;
777 
778  error:
779 	if (atomic_dec_and_test(&chip->usage_count))
780 		wake_up(&chip->shutdown_wait);
781 	return err;
782 }
783 
784 /* autosuspend and unlock the shutdown */
785 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
786 {
787 	snd_usb_autosuspend(chip);
788 	if (atomic_dec_and_test(&chip->usage_count))
789 		wake_up(&chip->shutdown_wait);
790 }
791 
792 #ifdef CONFIG_PM
793 
794 int snd_usb_autoresume(struct snd_usb_audio *chip)
795 {
796 	if (atomic_read(&chip->shutdown))
797 		return -EIO;
798 	if (atomic_inc_return(&chip->active) == 1)
799 		return usb_autopm_get_interface(chip->pm_intf);
800 	return 0;
801 }
802 
803 void snd_usb_autosuspend(struct snd_usb_audio *chip)
804 {
805 	if (atomic_read(&chip->shutdown))
806 		return;
807 	if (atomic_dec_and_test(&chip->active))
808 		usb_autopm_put_interface(chip->pm_intf);
809 }
810 
811 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
812 {
813 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
814 	struct snd_usb_stream *as;
815 	struct usb_mixer_interface *mixer;
816 	struct list_head *p;
817 
818 	if (chip == (void *)-1L)
819 		return 0;
820 
821 	chip->autosuspended = !!PMSG_IS_AUTO(message);
822 	if (!chip->autosuspended)
823 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
824 	if (!chip->num_suspended_intf++) {
825 		list_for_each_entry(as, &chip->pcm_list, list) {
826 			snd_pcm_suspend_all(as->pcm);
827 			as->substream[0].need_setup_ep =
828 				as->substream[1].need_setup_ep = true;
829 		}
830 		list_for_each(p, &chip->midi_list)
831 			snd_usbmidi_suspend(p);
832 		list_for_each_entry(mixer, &chip->mixer_list, list)
833 			snd_usb_mixer_suspend(mixer);
834 	}
835 
836 	return 0;
837 }
838 
839 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
840 {
841 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
842 	struct usb_mixer_interface *mixer;
843 	struct list_head *p;
844 	int err = 0;
845 
846 	if (chip == (void *)-1L)
847 		return 0;
848 	if (--chip->num_suspended_intf)
849 		return 0;
850 
851 	atomic_inc(&chip->active); /* avoid autopm */
852 	/*
853 	 * ALSA leaves material resumption to user space
854 	 * we just notify and restart the mixers
855 	 */
856 	list_for_each_entry(mixer, &chip->mixer_list, list) {
857 		err = snd_usb_mixer_resume(mixer, reset_resume);
858 		if (err < 0)
859 			goto err_out;
860 	}
861 
862 	list_for_each(p, &chip->midi_list) {
863 		snd_usbmidi_resume(p);
864 	}
865 
866 	if (!chip->autosuspended)
867 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
868 	chip->autosuspended = 0;
869 
870 err_out:
871 	atomic_dec(&chip->active); /* allow autopm after this point */
872 	return err;
873 }
874 
875 static int usb_audio_resume(struct usb_interface *intf)
876 {
877 	return __usb_audio_resume(intf, false);
878 }
879 
880 static int usb_audio_reset_resume(struct usb_interface *intf)
881 {
882 	return __usb_audio_resume(intf, true);
883 }
884 #else
885 #define usb_audio_suspend	NULL
886 #define usb_audio_resume	NULL
887 #define usb_audio_reset_resume	NULL
888 #endif		/* CONFIG_PM */
889 
890 static const struct usb_device_id usb_audio_ids [] = {
891 #include "quirks-table.h"
892     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
893       .bInterfaceClass = USB_CLASS_AUDIO,
894       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
895     { }						/* Terminating entry */
896 };
897 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
898 
899 /*
900  * entry point for linux usb interface
901  */
902 
903 static struct usb_driver usb_audio_driver = {
904 	.name =		"snd-usb-audio",
905 	.probe =	usb_audio_probe,
906 	.disconnect =	usb_audio_disconnect,
907 	.suspend =	usb_audio_suspend,
908 	.resume =	usb_audio_resume,
909 	.reset_resume =	usb_audio_reset_resume,
910 	.id_table =	usb_audio_ids,
911 	.supports_autosuspend = 1,
912 };
913 
914 module_usb_driver(usb_audio_driver);
915