xref: /linux/sound/usb/card.c (revision b14132797d8041a42e03f4ffa1e722da1425adfb)
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 
86 module_param_array(index, int, NULL, 0444);
87 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
88 module_param_array(id, charp, NULL, 0444);
89 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
90 module_param_array(enable, bool, NULL, 0444);
91 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
92 module_param_array(vid, int, NULL, 0444);
93 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
94 module_param_array(pid, int, NULL, 0444);
95 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
96 module_param_array(device_setup, int, NULL, 0444);
97 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
98 module_param(ignore_ctl_error, bool, 0444);
99 MODULE_PARM_DESC(ignore_ctl_error,
100 		 "Ignore errors from USB controller for mixer interfaces.");
101 module_param(autoclock, bool, 0444);
102 MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
103 
104 /*
105  * we keep the snd_usb_audio_t instances by ourselves for merging
106  * the all interfaces on the same card as one sound device.
107  */
108 
109 static DEFINE_MUTEX(register_mutex);
110 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
111 static struct usb_driver usb_audio_driver;
112 
113 /*
114  * disconnect streams
115  * called from usb_audio_disconnect()
116  */
117 static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
118 {
119 	int idx;
120 	struct snd_usb_substream *subs;
121 
122 	for (idx = 0; idx < 2; idx++) {
123 		subs = &as->substream[idx];
124 		if (!subs->num_formats)
125 			continue;
126 		subs->interface = -1;
127 		subs->data_endpoint = NULL;
128 		subs->sync_endpoint = NULL;
129 	}
130 }
131 
132 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
133 {
134 	struct usb_device *dev = chip->dev;
135 	struct usb_host_interface *alts;
136 	struct usb_interface_descriptor *altsd;
137 	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
138 
139 	if (!iface) {
140 		dev_err(&dev->dev, "%u:%d : does not exist\n",
141 			ctrlif, interface);
142 		return -EINVAL;
143 	}
144 
145 	alts = &iface->altsetting[0];
146 	altsd = get_iface_desc(alts);
147 
148 	/*
149 	 * Android with both accessory and audio interfaces enabled gets the
150 	 * interface numbers wrong.
151 	 */
152 	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
153 	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
154 	    interface == 0 &&
155 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
156 	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
157 		interface = 2;
158 		iface = usb_ifnum_to_if(dev, interface);
159 		if (!iface)
160 			return -EINVAL;
161 		alts = &iface->altsetting[0];
162 		altsd = get_iface_desc(alts);
163 	}
164 
165 	if (usb_interface_claimed(iface)) {
166 		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
167 			ctrlif, interface);
168 		return -EINVAL;
169 	}
170 
171 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
172 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
173 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
174 		int err = snd_usbmidi_create(chip->card, iface,
175 					     &chip->midi_list, NULL);
176 		if (err < 0) {
177 			dev_err(&dev->dev,
178 				"%u:%d: cannot create sequencer device\n",
179 				ctrlif, interface);
180 			return -EINVAL;
181 		}
182 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
183 
184 		return 0;
185 	}
186 
187 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
188 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
189 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
190 		dev_dbg(&dev->dev,
191 			"%u:%d: skipping non-supported interface %d\n",
192 			ctrlif, interface, altsd->bInterfaceClass);
193 		/* skip non-supported classes */
194 		return -EINVAL;
195 	}
196 
197 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
198 		dev_err(&dev->dev, "low speed audio streaming not supported\n");
199 		return -EINVAL;
200 	}
201 
202 	if (! snd_usb_parse_audio_interface(chip, interface)) {
203 		usb_set_interface(dev, interface, 0); /* reset the current interface */
204 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
205 		return -EINVAL;
206 	}
207 
208 	return 0;
209 }
210 
211 /*
212  * parse audio control descriptor and create pcm/midi streams
213  */
214 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
215 {
216 	struct usb_device *dev = chip->dev;
217 	struct usb_host_interface *host_iface;
218 	struct usb_interface_descriptor *altsd;
219 	void *control_header;
220 	int i, protocol;
221 
222 	/* find audiocontrol interface */
223 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
224 	control_header = snd_usb_find_csint_desc(host_iface->extra,
225 						 host_iface->extralen,
226 						 NULL, UAC_HEADER);
227 	altsd = get_iface_desc(host_iface);
228 	protocol = altsd->bInterfaceProtocol;
229 
230 	if (!control_header) {
231 		dev_err(&dev->dev, "cannot find UAC_HEADER\n");
232 		return -EINVAL;
233 	}
234 
235 	switch (protocol) {
236 	default:
237 		dev_warn(&dev->dev,
238 			 "unknown interface protocol %#02x, assuming v1\n",
239 			 protocol);
240 		/* fall through */
241 
242 	case UAC_VERSION_1: {
243 		struct uac1_ac_header_descriptor *h1 = control_header;
244 
245 		if (!h1->bInCollection) {
246 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
247 			return -EINVAL;
248 		}
249 
250 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
251 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
252 			return -EINVAL;
253 		}
254 
255 		for (i = 0; i < h1->bInCollection; i++)
256 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
257 
258 		break;
259 	}
260 
261 	case UAC_VERSION_2: {
262 		struct usb_interface_assoc_descriptor *assoc =
263 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
264 
265 		if (!assoc) {
266 			/*
267 			 * Firmware writers cannot count to three.  So to find
268 			 * the IAD on the NuForce UDH-100, also check the next
269 			 * interface.
270 			 */
271 			struct usb_interface *iface =
272 				usb_ifnum_to_if(dev, ctrlif + 1);
273 			if (iface &&
274 			    iface->intf_assoc &&
275 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
276 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
277 				assoc = iface->intf_assoc;
278 		}
279 
280 		if (!assoc) {
281 			dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
282 			return -EINVAL;
283 		}
284 
285 		for (i = 0; i < assoc->bInterfaceCount; i++) {
286 			int intf = assoc->bFirstInterface + i;
287 
288 			if (intf != ctrlif)
289 				snd_usb_create_stream(chip, ctrlif, intf);
290 		}
291 
292 		break;
293 	}
294 	}
295 
296 	return 0;
297 }
298 
299 /*
300  * free the chip instance
301  *
302  * here we have to do not much, since pcm and controls are already freed
303  *
304  */
305 
306 static int snd_usb_audio_free(struct snd_usb_audio *chip)
307 {
308 	struct snd_usb_endpoint *ep, *n;
309 
310 	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
311 		snd_usb_endpoint_free(ep);
312 
313 	mutex_destroy(&chip->mutex);
314 	kfree(chip);
315 	return 0;
316 }
317 
318 static int snd_usb_audio_dev_free(struct snd_device *device)
319 {
320 	struct snd_usb_audio *chip = device->device_data;
321 	return snd_usb_audio_free(chip);
322 }
323 
324 /*
325  * create a chip instance and set its names.
326  */
327 static int snd_usb_audio_create(struct usb_interface *intf,
328 				struct usb_device *dev, int idx,
329 				const struct snd_usb_audio_quirk *quirk,
330 				struct snd_usb_audio **rchip)
331 {
332 	struct snd_card *card;
333 	struct snd_usb_audio *chip;
334 	int err, len;
335 	char component[14];
336 	static struct snd_device_ops ops = {
337 		.dev_free =	snd_usb_audio_dev_free,
338 	};
339 
340 	*rchip = NULL;
341 
342 	switch (snd_usb_get_speed(dev)) {
343 	case USB_SPEED_LOW:
344 	case USB_SPEED_FULL:
345 	case USB_SPEED_HIGH:
346 	case USB_SPEED_WIRELESS:
347 	case USB_SPEED_SUPER:
348 		break;
349 	default:
350 		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
351 		return -ENXIO;
352 	}
353 
354 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
355 			   0, &card);
356 	if (err < 0) {
357 		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
358 		return err;
359 	}
360 
361 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
362 	if (! chip) {
363 		snd_card_free(card);
364 		return -ENOMEM;
365 	}
366 
367 	mutex_init(&chip->mutex);
368 	init_waitqueue_head(&chip->shutdown_wait);
369 	chip->index = idx;
370 	chip->dev = dev;
371 	chip->card = card;
372 	chip->setup = device_setup[idx];
373 	chip->autoclock = autoclock;
374 	atomic_set(&chip->active, 1); /* avoid autopm during probing */
375 	atomic_set(&chip->usage_count, 0);
376 	atomic_set(&chip->shutdown, 0);
377 
378 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
379 			      le16_to_cpu(dev->descriptor.idProduct));
380 	INIT_LIST_HEAD(&chip->pcm_list);
381 	INIT_LIST_HEAD(&chip->ep_list);
382 	INIT_LIST_HEAD(&chip->midi_list);
383 	INIT_LIST_HEAD(&chip->mixer_list);
384 
385 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
386 		snd_usb_audio_free(chip);
387 		snd_card_free(card);
388 		return err;
389 	}
390 
391 	strcpy(card->driver, "USB-Audio");
392 	sprintf(component, "USB%04x:%04x",
393 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
394 	snd_component_add(card, component);
395 
396 	/* retrieve the device string as shortname */
397 	if (quirk && quirk->product_name && *quirk->product_name) {
398 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
399 	} else {
400 		if (!dev->descriptor.iProduct ||
401 		    usb_string(dev, dev->descriptor.iProduct,
402 		    card->shortname, sizeof(card->shortname)) <= 0) {
403 			/* no name available from anywhere, so use ID */
404 			sprintf(card->shortname, "USB Device %#04x:%#04x",
405 				USB_ID_VENDOR(chip->usb_id),
406 				USB_ID_PRODUCT(chip->usb_id));
407 		}
408 	}
409 	strim(card->shortname);
410 
411 	/* retrieve the vendor and device strings as longname */
412 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
413 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
414 	} else {
415 		if (dev->descriptor.iManufacturer)
416 			len = usb_string(dev, dev->descriptor.iManufacturer,
417 					 card->longname, sizeof(card->longname));
418 		else
419 			len = 0;
420 		/* we don't really care if there isn't any vendor string */
421 	}
422 	if (len > 0) {
423 		strim(card->longname);
424 		if (*card->longname)
425 			strlcat(card->longname, " ", sizeof(card->longname));
426 	}
427 
428 	strlcat(card->longname, card->shortname, sizeof(card->longname));
429 
430 	len = strlcat(card->longname, " at ", sizeof(card->longname));
431 
432 	if (len < sizeof(card->longname))
433 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
434 
435 	switch (snd_usb_get_speed(dev)) {
436 	case USB_SPEED_LOW:
437 		strlcat(card->longname, ", low speed", sizeof(card->longname));
438 		break;
439 	case USB_SPEED_FULL:
440 		strlcat(card->longname, ", full speed", sizeof(card->longname));
441 		break;
442 	case USB_SPEED_HIGH:
443 		strlcat(card->longname, ", high speed", sizeof(card->longname));
444 		break;
445 	case USB_SPEED_SUPER:
446 		strlcat(card->longname, ", super speed", sizeof(card->longname));
447 		break;
448 	default:
449 		break;
450 	}
451 
452 	snd_usb_audio_create_proc(chip);
453 
454 	*rchip = chip;
455 	return 0;
456 }
457 
458 /*
459  * probe the active usb device
460  *
461  * note that this can be called multiple times per a device, when it
462  * includes multiple audio control interfaces.
463  *
464  * thus we check the usb device pointer and creates the card instance
465  * only at the first time.  the successive calls of this function will
466  * append the pcm interface to the corresponding card.
467  */
468 static int usb_audio_probe(struct usb_interface *intf,
469 			   const struct usb_device_id *usb_id)
470 {
471 	struct usb_device *dev = interface_to_usbdev(intf);
472 	const struct snd_usb_audio_quirk *quirk =
473 		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
474 	struct snd_usb_audio *chip;
475 	int i, err;
476 	struct usb_host_interface *alts;
477 	int ifnum;
478 	u32 id;
479 
480 	alts = &intf->altsetting[0];
481 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
482 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
483 		    le16_to_cpu(dev->descriptor.idProduct));
484 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
485 		return -ENXIO;
486 
487 	err = snd_usb_apply_boot_quirk(dev, intf, quirk);
488 	if (err < 0)
489 		return err;
490 
491 	/*
492 	 * found a config.  now register to ALSA
493 	 */
494 
495 	/* check whether it's already registered */
496 	chip = NULL;
497 	mutex_lock(&register_mutex);
498 	for (i = 0; i < SNDRV_CARDS; i++) {
499 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
500 			if (atomic_read(&usb_chip[i]->shutdown)) {
501 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
502 				err = -EIO;
503 				goto __error;
504 			}
505 			chip = usb_chip[i];
506 			atomic_inc(&chip->active); /* avoid autopm */
507 			break;
508 		}
509 	}
510 	if (! chip) {
511 		/* it's a fresh one.
512 		 * now look for an empty slot and create a new card instance
513 		 */
514 		for (i = 0; i < SNDRV_CARDS; i++)
515 			if (enable[i] && ! usb_chip[i] &&
516 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
517 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
518 				err = snd_usb_audio_create(intf, dev, i, quirk,
519 							   &chip);
520 				if (err < 0)
521 					goto __error;
522 				chip->pm_intf = intf;
523 				break;
524 			}
525 		if (!chip) {
526 			dev_err(&dev->dev, "no available usb audio device\n");
527 			err = -ENODEV;
528 			goto __error;
529 		}
530 	}
531 
532 	/*
533 	 * For devices with more than one control interface, we assume the
534 	 * first contains the audio controls. We might need a more specific
535 	 * check here in the future.
536 	 */
537 	if (!chip->ctrl_intf)
538 		chip->ctrl_intf = alts;
539 
540 	chip->txfr_quirk = 0;
541 	err = 1; /* continue */
542 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
543 		/* need some special handlings */
544 		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
545 		if (err < 0)
546 			goto __error;
547 	}
548 
549 	if (err > 0) {
550 		/* create normal USB audio interfaces */
551 		err = snd_usb_create_streams(chip, ifnum);
552 		if (err < 0)
553 			goto __error;
554 		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
555 		if (err < 0)
556 			goto __error;
557 	}
558 
559 	/* we are allowed to call snd_card_register() many times */
560 	err = snd_card_register(chip->card);
561 	if (err < 0)
562 		goto __error;
563 
564 	usb_chip[chip->index] = chip;
565 	chip->num_interfaces++;
566 	usb_set_intfdata(intf, chip);
567 	atomic_dec(&chip->active);
568 	mutex_unlock(&register_mutex);
569 	return 0;
570 
571  __error:
572 	if (chip) {
573 		if (!chip->num_interfaces)
574 			snd_card_free(chip->card);
575 		atomic_dec(&chip->active);
576 	}
577 	mutex_unlock(&register_mutex);
578 	return err;
579 }
580 
581 /*
582  * we need to take care of counter, since disconnection can be called also
583  * many times as well as usb_audio_probe().
584  */
585 static void usb_audio_disconnect(struct usb_interface *intf)
586 {
587 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
588 	struct snd_card *card;
589 	struct list_head *p;
590 
591 	if (chip == (void *)-1L)
592 		return;
593 
594 	card = chip->card;
595 
596 	mutex_lock(&register_mutex);
597 	if (atomic_inc_return(&chip->shutdown) == 1) {
598 		struct snd_usb_stream *as;
599 		struct snd_usb_endpoint *ep;
600 		struct usb_mixer_interface *mixer;
601 
602 		/* wait until all pending tasks done;
603 		 * they are protected by snd_usb_lock_shutdown()
604 		 */
605 		wait_event(chip->shutdown_wait,
606 			   !atomic_read(&chip->usage_count));
607 		snd_card_disconnect(card);
608 		/* release the pcm resources */
609 		list_for_each_entry(as, &chip->pcm_list, list) {
610 			snd_usb_stream_disconnect(as);
611 		}
612 		/* release the endpoint resources */
613 		list_for_each_entry(ep, &chip->ep_list, list) {
614 			snd_usb_endpoint_release(ep);
615 		}
616 		/* release the midi resources */
617 		list_for_each(p, &chip->midi_list) {
618 			snd_usbmidi_disconnect(p);
619 		}
620 		/* release mixer resources */
621 		list_for_each_entry(mixer, &chip->mixer_list, list) {
622 			snd_usb_mixer_disconnect(mixer);
623 		}
624 	}
625 
626 	chip->num_interfaces--;
627 	if (chip->num_interfaces <= 0) {
628 		usb_chip[chip->index] = NULL;
629 		mutex_unlock(&register_mutex);
630 		snd_card_free_when_closed(card);
631 	} else {
632 		mutex_unlock(&register_mutex);
633 	}
634 }
635 
636 /* lock the shutdown (disconnect) task and autoresume */
637 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
638 {
639 	int err;
640 
641 	atomic_inc(&chip->usage_count);
642 	if (atomic_read(&chip->shutdown)) {
643 		err = -EIO;
644 		goto error;
645 	}
646 	err = snd_usb_autoresume(chip);
647 	if (err < 0)
648 		goto error;
649 	return 0;
650 
651  error:
652 	if (atomic_dec_and_test(&chip->usage_count))
653 		wake_up(&chip->shutdown_wait);
654 	return err;
655 }
656 
657 /* autosuspend and unlock the shutdown */
658 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
659 {
660 	snd_usb_autosuspend(chip);
661 	if (atomic_dec_and_test(&chip->usage_count))
662 		wake_up(&chip->shutdown_wait);
663 }
664 
665 #ifdef CONFIG_PM
666 
667 int snd_usb_autoresume(struct snd_usb_audio *chip)
668 {
669 	if (atomic_read(&chip->shutdown))
670 		return -EIO;
671 	if (atomic_inc_return(&chip->active) == 1)
672 		return usb_autopm_get_interface(chip->pm_intf);
673 	return 0;
674 }
675 
676 void snd_usb_autosuspend(struct snd_usb_audio *chip)
677 {
678 	if (atomic_dec_and_test(&chip->active))
679 		usb_autopm_put_interface(chip->pm_intf);
680 }
681 
682 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
683 {
684 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
685 	struct snd_usb_stream *as;
686 	struct usb_mixer_interface *mixer;
687 	struct list_head *p;
688 
689 	if (chip == (void *)-1L)
690 		return 0;
691 
692 	chip->autosuspended = !!PMSG_IS_AUTO(message);
693 	if (!chip->autosuspended)
694 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
695 	if (!chip->num_suspended_intf++) {
696 		list_for_each_entry(as, &chip->pcm_list, list) {
697 			snd_pcm_suspend_all(as->pcm);
698 			as->substream[0].need_setup_ep =
699 				as->substream[1].need_setup_ep = true;
700 		}
701 		list_for_each(p, &chip->midi_list)
702 			snd_usbmidi_suspend(p);
703 		list_for_each_entry(mixer, &chip->mixer_list, list)
704 			snd_usb_mixer_suspend(mixer);
705 	}
706 
707 	return 0;
708 }
709 
710 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
711 {
712 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
713 	struct usb_mixer_interface *mixer;
714 	struct list_head *p;
715 	int err = 0;
716 
717 	if (chip == (void *)-1L)
718 		return 0;
719 	if (--chip->num_suspended_intf)
720 		return 0;
721 
722 	atomic_inc(&chip->active); /* avoid autopm */
723 	/*
724 	 * ALSA leaves material resumption to user space
725 	 * we just notify and restart the mixers
726 	 */
727 	list_for_each_entry(mixer, &chip->mixer_list, list) {
728 		err = snd_usb_mixer_resume(mixer, reset_resume);
729 		if (err < 0)
730 			goto err_out;
731 	}
732 
733 	list_for_each(p, &chip->midi_list) {
734 		snd_usbmidi_resume(p);
735 	}
736 
737 	if (!chip->autosuspended)
738 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
739 	chip->autosuspended = 0;
740 
741 err_out:
742 	atomic_dec(&chip->active); /* allow autopm after this point */
743 	return err;
744 }
745 
746 static int usb_audio_resume(struct usb_interface *intf)
747 {
748 	return __usb_audio_resume(intf, false);
749 }
750 
751 static int usb_audio_reset_resume(struct usb_interface *intf)
752 {
753 	return __usb_audio_resume(intf, true);
754 }
755 #else
756 #define usb_audio_suspend	NULL
757 #define usb_audio_resume	NULL
758 #define usb_audio_reset_resume	NULL
759 #endif		/* CONFIG_PM */
760 
761 static struct usb_device_id usb_audio_ids [] = {
762 #include "quirks-table.h"
763     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
764       .bInterfaceClass = USB_CLASS_AUDIO,
765       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
766     { }						/* Terminating entry */
767 };
768 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
769 
770 /*
771  * entry point for linux usb interface
772  */
773 
774 static struct usb_driver usb_audio_driver = {
775 	.name =		"snd-usb-audio",
776 	.probe =	usb_audio_probe,
777 	.disconnect =	usb_audio_disconnect,
778 	.suspend =	usb_audio_suspend,
779 	.resume =	usb_audio_resume,
780 	.reset_resume =	usb_audio_reset_resume,
781 	.id_table =	usb_audio_ids,
782 	.supports_autosuspend = 1,
783 };
784 
785 module_usb_driver(usb_audio_driver);
786