xref: /linux/sound/usb/card.c (revision fcc8487d477a3452a1d0ccbdd4c5e0e1e3cb8bed)
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 
225 	/* find audiocontrol interface */
226 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
227 	control_header = snd_usb_find_csint_desc(host_iface->extra,
228 						 host_iface->extralen,
229 						 NULL, UAC_HEADER);
230 	altsd = get_iface_desc(host_iface);
231 	protocol = altsd->bInterfaceProtocol;
232 
233 	if (!control_header) {
234 		dev_err(&dev->dev, "cannot find UAC_HEADER\n");
235 		return -EINVAL;
236 	}
237 
238 	switch (protocol) {
239 	default:
240 		dev_warn(&dev->dev,
241 			 "unknown interface protocol %#02x, assuming v1\n",
242 			 protocol);
243 		/* fall through */
244 
245 	case UAC_VERSION_1: {
246 		struct uac1_ac_header_descriptor *h1 = control_header;
247 
248 		if (!h1->bInCollection) {
249 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
250 			return -EINVAL;
251 		}
252 
253 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
254 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
255 			return -EINVAL;
256 		}
257 
258 		for (i = 0; i < h1->bInCollection; i++)
259 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
260 
261 		break;
262 	}
263 
264 	case UAC_VERSION_2: {
265 		struct usb_interface_assoc_descriptor *assoc =
266 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
267 
268 		if (!assoc) {
269 			/*
270 			 * Firmware writers cannot count to three.  So to find
271 			 * the IAD on the NuForce UDH-100, also check the next
272 			 * interface.
273 			 */
274 			struct usb_interface *iface =
275 				usb_ifnum_to_if(dev, ctrlif + 1);
276 			if (iface &&
277 			    iface->intf_assoc &&
278 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
279 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
280 				assoc = iface->intf_assoc;
281 		}
282 
283 		if (!assoc) {
284 			dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
285 			return -EINVAL;
286 		}
287 
288 		for (i = 0; i < assoc->bInterfaceCount; i++) {
289 			int intf = assoc->bFirstInterface + i;
290 
291 			if (intf != ctrlif)
292 				snd_usb_create_stream(chip, ctrlif, intf);
293 		}
294 
295 		break;
296 	}
297 	}
298 
299 	return 0;
300 }
301 
302 /*
303  * free the chip instance
304  *
305  * here we have to do not much, since pcm and controls are already freed
306  *
307  */
308 
309 static int snd_usb_audio_free(struct snd_usb_audio *chip)
310 {
311 	struct snd_usb_endpoint *ep, *n;
312 
313 	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
314 		snd_usb_endpoint_free(ep);
315 
316 	mutex_destroy(&chip->mutex);
317 	if (!atomic_read(&chip->shutdown))
318 		dev_set_drvdata(&chip->dev->dev, NULL);
319 	kfree(chip);
320 	return 0;
321 }
322 
323 static int snd_usb_audio_dev_free(struct snd_device *device)
324 {
325 	struct snd_usb_audio *chip = device->device_data;
326 	return snd_usb_audio_free(chip);
327 }
328 
329 /*
330  * create a chip instance and set its names.
331  */
332 static int snd_usb_audio_create(struct usb_interface *intf,
333 				struct usb_device *dev, int idx,
334 				const struct snd_usb_audio_quirk *quirk,
335 				unsigned int usb_id,
336 				struct snd_usb_audio **rchip)
337 {
338 	struct snd_card *card;
339 	struct snd_usb_audio *chip;
340 	int err, len;
341 	char component[14];
342 	static struct snd_device_ops ops = {
343 		.dev_free =	snd_usb_audio_dev_free,
344 	};
345 
346 	*rchip = NULL;
347 
348 	switch (snd_usb_get_speed(dev)) {
349 	case USB_SPEED_LOW:
350 	case USB_SPEED_FULL:
351 	case USB_SPEED_HIGH:
352 	case USB_SPEED_WIRELESS:
353 	case USB_SPEED_SUPER:
354 	case USB_SPEED_SUPER_PLUS:
355 		break;
356 	default:
357 		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
358 		return -ENXIO;
359 	}
360 
361 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
362 			   0, &card);
363 	if (err < 0) {
364 		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
365 		return err;
366 	}
367 
368 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
369 	if (! chip) {
370 		snd_card_free(card);
371 		return -ENOMEM;
372 	}
373 
374 	mutex_init(&chip->mutex);
375 	init_waitqueue_head(&chip->shutdown_wait);
376 	chip->index = idx;
377 	chip->dev = dev;
378 	chip->card = card;
379 	chip->setup = device_setup[idx];
380 	chip->autoclock = autoclock;
381 	atomic_set(&chip->active, 1); /* avoid autopm during probing */
382 	atomic_set(&chip->usage_count, 0);
383 	atomic_set(&chip->shutdown, 0);
384 
385 	chip->usb_id = usb_id;
386 	INIT_LIST_HEAD(&chip->pcm_list);
387 	INIT_LIST_HEAD(&chip->ep_list);
388 	INIT_LIST_HEAD(&chip->midi_list);
389 	INIT_LIST_HEAD(&chip->mixer_list);
390 
391 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
392 		snd_usb_audio_free(chip);
393 		snd_card_free(card);
394 		return err;
395 	}
396 
397 	strcpy(card->driver, "USB-Audio");
398 	sprintf(component, "USB%04x:%04x",
399 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
400 	snd_component_add(card, component);
401 
402 	/* retrieve the device string as shortname */
403 	if (quirk && quirk->product_name && *quirk->product_name) {
404 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
405 	} else {
406 		if (!dev->descriptor.iProduct ||
407 		    usb_string(dev, dev->descriptor.iProduct,
408 		    card->shortname, sizeof(card->shortname)) <= 0) {
409 			/* no name available from anywhere, so use ID */
410 			sprintf(card->shortname, "USB Device %#04x:%#04x",
411 				USB_ID_VENDOR(chip->usb_id),
412 				USB_ID_PRODUCT(chip->usb_id));
413 		}
414 	}
415 	strim(card->shortname);
416 
417 	/* retrieve the vendor and device strings as longname */
418 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
419 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
420 	} else {
421 		if (dev->descriptor.iManufacturer)
422 			len = usb_string(dev, dev->descriptor.iManufacturer,
423 					 card->longname, sizeof(card->longname));
424 		else
425 			len = 0;
426 		/* we don't really care if there isn't any vendor string */
427 	}
428 	if (len > 0) {
429 		strim(card->longname);
430 		if (*card->longname)
431 			strlcat(card->longname, " ", sizeof(card->longname));
432 	}
433 
434 	strlcat(card->longname, card->shortname, sizeof(card->longname));
435 
436 	len = strlcat(card->longname, " at ", sizeof(card->longname));
437 
438 	if (len < sizeof(card->longname))
439 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
440 
441 	switch (snd_usb_get_speed(dev)) {
442 	case USB_SPEED_LOW:
443 		strlcat(card->longname, ", low speed", sizeof(card->longname));
444 		break;
445 	case USB_SPEED_FULL:
446 		strlcat(card->longname, ", full speed", sizeof(card->longname));
447 		break;
448 	case USB_SPEED_HIGH:
449 		strlcat(card->longname, ", high speed", sizeof(card->longname));
450 		break;
451 	case USB_SPEED_SUPER:
452 		strlcat(card->longname, ", super speed", sizeof(card->longname));
453 		break;
454 	case USB_SPEED_SUPER_PLUS:
455 		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
456 		break;
457 	default:
458 		break;
459 	}
460 
461 	snd_usb_audio_create_proc(chip);
462 
463 	*rchip = chip;
464 	return 0;
465 }
466 
467 /* look for a matching quirk alias id */
468 static bool get_alias_id(struct usb_device *dev, unsigned int *id)
469 {
470 	int i;
471 	unsigned int src, dst;
472 
473 	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
474 		if (!quirk_alias[i] ||
475 		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
476 		    src != *id)
477 			continue;
478 		dev_info(&dev->dev,
479 			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
480 			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
481 			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
482 		*id = dst;
483 		return true;
484 	}
485 
486 	return false;
487 }
488 
489 static struct usb_device_id usb_audio_ids[]; /* defined below */
490 
491 /* look for the corresponding quirk */
492 static const struct snd_usb_audio_quirk *
493 get_alias_quirk(struct usb_device *dev, unsigned int id)
494 {
495 	const struct usb_device_id *p;
496 
497 	for (p = usb_audio_ids; p->match_flags; p++) {
498 		/* FIXME: this checks only vendor:product pair in the list */
499 		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==
500 		    USB_DEVICE_ID_MATCH_DEVICE &&
501 		    p->idVendor == USB_ID_VENDOR(id) &&
502 		    p->idProduct == USB_ID_PRODUCT(id))
503 			return (const struct snd_usb_audio_quirk *)p->driver_info;
504 	}
505 
506 	return NULL;
507 }
508 
509 /*
510  * probe the active usb device
511  *
512  * note that this can be called multiple times per a device, when it
513  * includes multiple audio control interfaces.
514  *
515  * thus we check the usb device pointer and creates the card instance
516  * only at the first time.  the successive calls of this function will
517  * append the pcm interface to the corresponding card.
518  */
519 static int usb_audio_probe(struct usb_interface *intf,
520 			   const struct usb_device_id *usb_id)
521 {
522 	struct usb_device *dev = interface_to_usbdev(intf);
523 	const struct snd_usb_audio_quirk *quirk =
524 		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
525 	struct snd_usb_audio *chip;
526 	int i, err;
527 	struct usb_host_interface *alts;
528 	int ifnum;
529 	u32 id;
530 
531 	alts = &intf->altsetting[0];
532 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
533 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
534 		    le16_to_cpu(dev->descriptor.idProduct));
535 	if (get_alias_id(dev, &id))
536 		quirk = get_alias_quirk(dev, id);
537 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
538 		return -ENXIO;
539 
540 	err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
541 	if (err < 0)
542 		return err;
543 
544 	/*
545 	 * found a config.  now register to ALSA
546 	 */
547 
548 	/* check whether it's already registered */
549 	chip = NULL;
550 	mutex_lock(&register_mutex);
551 	for (i = 0; i < SNDRV_CARDS; i++) {
552 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
553 			if (atomic_read(&usb_chip[i]->shutdown)) {
554 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
555 				err = -EIO;
556 				goto __error;
557 			}
558 			chip = usb_chip[i];
559 			atomic_inc(&chip->active); /* avoid autopm */
560 			break;
561 		}
562 	}
563 	if (! chip) {
564 		/* it's a fresh one.
565 		 * now look for an empty slot and create a new card instance
566 		 */
567 		for (i = 0; i < SNDRV_CARDS; i++)
568 			if (enable[i] && ! usb_chip[i] &&
569 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
570 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
571 				err = snd_usb_audio_create(intf, dev, i, quirk,
572 							   id, &chip);
573 				if (err < 0)
574 					goto __error;
575 				chip->pm_intf = intf;
576 				break;
577 			}
578 		if (!chip) {
579 			dev_err(&dev->dev, "no available usb audio device\n");
580 			err = -ENODEV;
581 			goto __error;
582 		}
583 	}
584 	dev_set_drvdata(&dev->dev, chip);
585 
586 	/*
587 	 * For devices with more than one control interface, we assume the
588 	 * first contains the audio controls. We might need a more specific
589 	 * check here in the future.
590 	 */
591 	if (!chip->ctrl_intf)
592 		chip->ctrl_intf = alts;
593 
594 	chip->txfr_quirk = 0;
595 	err = 1; /* continue */
596 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
597 		/* need some special handlings */
598 		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
599 		if (err < 0)
600 			goto __error;
601 	}
602 
603 	if (err > 0) {
604 		/* create normal USB audio interfaces */
605 		err = snd_usb_create_streams(chip, ifnum);
606 		if (err < 0)
607 			goto __error;
608 		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
609 		if (err < 0)
610 			goto __error;
611 	}
612 
613 	/* we are allowed to call snd_card_register() many times */
614 	err = snd_card_register(chip->card);
615 	if (err < 0)
616 		goto __error;
617 
618 	usb_chip[chip->index] = chip;
619 	chip->num_interfaces++;
620 	usb_set_intfdata(intf, chip);
621 	atomic_dec(&chip->active);
622 	mutex_unlock(&register_mutex);
623 	return 0;
624 
625  __error:
626 	if (chip) {
627 		if (!chip->num_interfaces)
628 			snd_card_free(chip->card);
629 		atomic_dec(&chip->active);
630 	}
631 	mutex_unlock(&register_mutex);
632 	return err;
633 }
634 
635 /*
636  * we need to take care of counter, since disconnection can be called also
637  * many times as well as usb_audio_probe().
638  */
639 static void usb_audio_disconnect(struct usb_interface *intf)
640 {
641 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
642 	struct snd_card *card;
643 	struct list_head *p;
644 
645 	if (chip == (void *)-1L)
646 		return;
647 
648 	card = chip->card;
649 
650 	mutex_lock(&register_mutex);
651 	if (atomic_inc_return(&chip->shutdown) == 1) {
652 		struct snd_usb_stream *as;
653 		struct snd_usb_endpoint *ep;
654 		struct usb_mixer_interface *mixer;
655 
656 		/* wait until all pending tasks done;
657 		 * they are protected by snd_usb_lock_shutdown()
658 		 */
659 		wait_event(chip->shutdown_wait,
660 			   !atomic_read(&chip->usage_count));
661 		snd_card_disconnect(card);
662 		/* release the pcm resources */
663 		list_for_each_entry(as, &chip->pcm_list, list) {
664 			snd_usb_stream_disconnect(as);
665 		}
666 		/* release the endpoint resources */
667 		list_for_each_entry(ep, &chip->ep_list, list) {
668 			snd_usb_endpoint_release(ep);
669 		}
670 		/* release the midi resources */
671 		list_for_each(p, &chip->midi_list) {
672 			snd_usbmidi_disconnect(p);
673 		}
674 		/* release mixer resources */
675 		list_for_each_entry(mixer, &chip->mixer_list, list) {
676 			snd_usb_mixer_disconnect(mixer);
677 		}
678 	}
679 
680 	chip->num_interfaces--;
681 	if (chip->num_interfaces <= 0) {
682 		usb_chip[chip->index] = NULL;
683 		mutex_unlock(&register_mutex);
684 		snd_card_free_when_closed(card);
685 	} else {
686 		mutex_unlock(&register_mutex);
687 	}
688 }
689 
690 /* lock the shutdown (disconnect) task and autoresume */
691 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
692 {
693 	int err;
694 
695 	atomic_inc(&chip->usage_count);
696 	if (atomic_read(&chip->shutdown)) {
697 		err = -EIO;
698 		goto error;
699 	}
700 	err = snd_usb_autoresume(chip);
701 	if (err < 0)
702 		goto error;
703 	return 0;
704 
705  error:
706 	if (atomic_dec_and_test(&chip->usage_count))
707 		wake_up(&chip->shutdown_wait);
708 	return err;
709 }
710 
711 /* autosuspend and unlock the shutdown */
712 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
713 {
714 	snd_usb_autosuspend(chip);
715 	if (atomic_dec_and_test(&chip->usage_count))
716 		wake_up(&chip->shutdown_wait);
717 }
718 
719 #ifdef CONFIG_PM
720 
721 int snd_usb_autoresume(struct snd_usb_audio *chip)
722 {
723 	if (atomic_read(&chip->shutdown))
724 		return -EIO;
725 	if (atomic_inc_return(&chip->active) == 1)
726 		return usb_autopm_get_interface(chip->pm_intf);
727 	return 0;
728 }
729 
730 void snd_usb_autosuspend(struct snd_usb_audio *chip)
731 {
732 	if (atomic_read(&chip->shutdown))
733 		return;
734 	if (atomic_dec_and_test(&chip->active))
735 		usb_autopm_put_interface(chip->pm_intf);
736 }
737 
738 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
739 {
740 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
741 	struct snd_usb_stream *as;
742 	struct usb_mixer_interface *mixer;
743 	struct list_head *p;
744 
745 	if (chip == (void *)-1L)
746 		return 0;
747 
748 	chip->autosuspended = !!PMSG_IS_AUTO(message);
749 	if (!chip->autosuspended)
750 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
751 	if (!chip->num_suspended_intf++) {
752 		list_for_each_entry(as, &chip->pcm_list, list) {
753 			snd_pcm_suspend_all(as->pcm);
754 			as->substream[0].need_setup_ep =
755 				as->substream[1].need_setup_ep = true;
756 		}
757 		list_for_each(p, &chip->midi_list)
758 			snd_usbmidi_suspend(p);
759 		list_for_each_entry(mixer, &chip->mixer_list, list)
760 			snd_usb_mixer_suspend(mixer);
761 	}
762 
763 	return 0;
764 }
765 
766 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
767 {
768 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
769 	struct usb_mixer_interface *mixer;
770 	struct list_head *p;
771 	int err = 0;
772 
773 	if (chip == (void *)-1L)
774 		return 0;
775 	if (--chip->num_suspended_intf)
776 		return 0;
777 
778 	atomic_inc(&chip->active); /* avoid autopm */
779 	/*
780 	 * ALSA leaves material resumption to user space
781 	 * we just notify and restart the mixers
782 	 */
783 	list_for_each_entry(mixer, &chip->mixer_list, list) {
784 		err = snd_usb_mixer_resume(mixer, reset_resume);
785 		if (err < 0)
786 			goto err_out;
787 	}
788 
789 	list_for_each(p, &chip->midi_list) {
790 		snd_usbmidi_resume(p);
791 	}
792 
793 	if (!chip->autosuspended)
794 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
795 	chip->autosuspended = 0;
796 
797 err_out:
798 	atomic_dec(&chip->active); /* allow autopm after this point */
799 	return err;
800 }
801 
802 static int usb_audio_resume(struct usb_interface *intf)
803 {
804 	return __usb_audio_resume(intf, false);
805 }
806 
807 static int usb_audio_reset_resume(struct usb_interface *intf)
808 {
809 	return __usb_audio_resume(intf, true);
810 }
811 #else
812 #define usb_audio_suspend	NULL
813 #define usb_audio_resume	NULL
814 #define usb_audio_reset_resume	NULL
815 #endif		/* CONFIG_PM */
816 
817 static struct usb_device_id usb_audio_ids [] = {
818 #include "quirks-table.h"
819     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
820       .bInterfaceClass = USB_CLASS_AUDIO,
821       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
822     { }						/* Terminating entry */
823 };
824 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
825 
826 /*
827  * entry point for linux usb interface
828  */
829 
830 static struct usb_driver usb_audio_driver = {
831 	.name =		"snd-usb-audio",
832 	.probe =	usb_audio_probe,
833 	.disconnect =	usb_audio_disconnect,
834 	.suspend =	usb_audio_suspend,
835 	.resume =	usb_audio_resume,
836 	.reset_resume =	usb_audio_reset_resume,
837 	.id_table =	usb_audio_ids,
838 	.supports_autosuspend = 1,
839 };
840 
841 module_usb_driver(usb_audio_driver);
842