xref: /openbmc/linux/sound/usb/card.c (revision b34e08d5)
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 snd_usb_audio_disconnect()
116  */
117 static void snd_usb_stream_disconnect(struct list_head *head)
118 {
119 	int idx;
120 	struct snd_usb_stream *as;
121 	struct snd_usb_substream *subs;
122 
123 	as = list_entry(head, struct snd_usb_stream, list);
124 	for (idx = 0; idx < 2; idx++) {
125 		subs = &as->substream[idx];
126 		if (!subs->num_formats)
127 			continue;
128 		subs->interface = -1;
129 		subs->data_endpoint = NULL;
130 		subs->sync_endpoint = NULL;
131 	}
132 }
133 
134 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
135 {
136 	struct usb_device *dev = chip->dev;
137 	struct usb_host_interface *alts;
138 	struct usb_interface_descriptor *altsd;
139 	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
140 
141 	if (!iface) {
142 		dev_err(&dev->dev, "%u:%d : does not exist\n",
143 			ctrlif, interface);
144 		return -EINVAL;
145 	}
146 
147 	alts = &iface->altsetting[0];
148 	altsd = get_iface_desc(alts);
149 
150 	/*
151 	 * Android with both accessory and audio interfaces enabled gets the
152 	 * interface numbers wrong.
153 	 */
154 	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
155 	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
156 	    interface == 0 &&
157 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
158 	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
159 		interface = 2;
160 		iface = usb_ifnum_to_if(dev, interface);
161 		if (!iface)
162 			return -EINVAL;
163 		alts = &iface->altsetting[0];
164 		altsd = get_iface_desc(alts);
165 	}
166 
167 	if (usb_interface_claimed(iface)) {
168 		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
169 			ctrlif, interface);
170 		return -EINVAL;
171 	}
172 
173 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
174 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
175 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
176 		int err = snd_usbmidi_create(chip->card, iface,
177 					     &chip->midi_list, NULL);
178 		if (err < 0) {
179 			dev_err(&dev->dev,
180 				"%u:%d: cannot create sequencer device\n",
181 				ctrlif, interface);
182 			return -EINVAL;
183 		}
184 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
185 
186 		return 0;
187 	}
188 
189 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
190 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
191 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
192 		dev_dbg(&dev->dev,
193 			"%u:%d: skipping non-supported interface %d\n",
194 			ctrlif, interface, altsd->bInterfaceClass);
195 		/* skip non-supported classes */
196 		return -EINVAL;
197 	}
198 
199 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
200 		dev_err(&dev->dev, "low speed audio streaming not supported\n");
201 		return -EINVAL;
202 	}
203 
204 	if (! snd_usb_parse_audio_interface(chip, interface)) {
205 		usb_set_interface(dev, interface, 0); /* reset the current interface */
206 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
207 		return -EINVAL;
208 	}
209 
210 	return 0;
211 }
212 
213 /*
214  * parse audio control descriptor and create pcm/midi streams
215  */
216 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
217 {
218 	struct usb_device *dev = chip->dev;
219 	struct usb_host_interface *host_iface;
220 	struct usb_interface_descriptor *altsd;
221 	void *control_header;
222 	int i, protocol;
223 
224 	/* find audiocontrol interface */
225 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
226 	control_header = snd_usb_find_csint_desc(host_iface->extra,
227 						 host_iface->extralen,
228 						 NULL, UAC_HEADER);
229 	altsd = get_iface_desc(host_iface);
230 	protocol = altsd->bInterfaceProtocol;
231 
232 	if (!control_header) {
233 		dev_err(&dev->dev, "cannot find UAC_HEADER\n");
234 		return -EINVAL;
235 	}
236 
237 	switch (protocol) {
238 	default:
239 		dev_warn(&dev->dev,
240 			 "unknown interface protocol %#02x, assuming v1\n",
241 			 protocol);
242 		/* fall through */
243 
244 	case UAC_VERSION_1: {
245 		struct uac1_ac_header_descriptor *h1 = control_header;
246 
247 		if (!h1->bInCollection) {
248 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
249 			return -EINVAL;
250 		}
251 
252 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
253 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
254 			return -EINVAL;
255 		}
256 
257 		for (i = 0; i < h1->bInCollection; i++)
258 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
259 
260 		break;
261 	}
262 
263 	case UAC_VERSION_2: {
264 		struct usb_interface_assoc_descriptor *assoc =
265 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
266 
267 		if (!assoc) {
268 			/*
269 			 * Firmware writers cannot count to three.  So to find
270 			 * the IAD on the NuForce UDH-100, also check the next
271 			 * interface.
272 			 */
273 			struct usb_interface *iface =
274 				usb_ifnum_to_if(dev, ctrlif + 1);
275 			if (iface &&
276 			    iface->intf_assoc &&
277 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
278 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
279 				assoc = iface->intf_assoc;
280 		}
281 
282 		if (!assoc) {
283 			dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
284 			return -EINVAL;
285 		}
286 
287 		for (i = 0; i < assoc->bInterfaceCount; i++) {
288 			int intf = assoc->bFirstInterface + i;
289 
290 			if (intf != ctrlif)
291 				snd_usb_create_stream(chip, ctrlif, intf);
292 		}
293 
294 		break;
295 	}
296 	}
297 
298 	return 0;
299 }
300 
301 /*
302  * free the chip instance
303  *
304  * here we have to do not much, since pcm and controls are already freed
305  *
306  */
307 
308 static int snd_usb_audio_free(struct snd_usb_audio *chip)
309 {
310 	mutex_destroy(&chip->mutex);
311 	kfree(chip);
312 	return 0;
313 }
314 
315 static int snd_usb_audio_dev_free(struct snd_device *device)
316 {
317 	struct snd_usb_audio *chip = device->device_data;
318 	return snd_usb_audio_free(chip);
319 }
320 
321 static void remove_trailing_spaces(char *str)
322 {
323 	char *p;
324 
325 	if (!*str)
326 		return;
327 	for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
328 		*p = 0;
329 }
330 
331 /*
332  * create a chip instance and set its names.
333  */
334 static int snd_usb_audio_create(struct usb_interface *intf,
335 				struct usb_device *dev, int idx,
336 				const struct snd_usb_audio_quirk *quirk,
337 				struct snd_usb_audio **rchip)
338 {
339 	struct snd_card *card;
340 	struct snd_usb_audio *chip;
341 	int err, len;
342 	char component[14];
343 	static struct snd_device_ops ops = {
344 		.dev_free =	snd_usb_audio_dev_free,
345 	};
346 
347 	*rchip = NULL;
348 
349 	switch (snd_usb_get_speed(dev)) {
350 	case USB_SPEED_LOW:
351 	case USB_SPEED_FULL:
352 	case USB_SPEED_HIGH:
353 	case USB_SPEED_WIRELESS:
354 	case USB_SPEED_SUPER:
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_rwsem(&chip->shutdown_rwsem);
376 	chip->index = idx;
377 	chip->dev = dev;
378 	chip->card = card;
379 	chip->setup = device_setup[idx];
380 	chip->autoclock = autoclock;
381 	chip->probing = 1;
382 
383 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
384 			      le16_to_cpu(dev->descriptor.idProduct));
385 	INIT_LIST_HEAD(&chip->pcm_list);
386 	INIT_LIST_HEAD(&chip->ep_list);
387 	INIT_LIST_HEAD(&chip->midi_list);
388 	INIT_LIST_HEAD(&chip->mixer_list);
389 
390 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
391 		snd_usb_audio_free(chip);
392 		snd_card_free(card);
393 		return err;
394 	}
395 
396 	strcpy(card->driver, "USB-Audio");
397 	sprintf(component, "USB%04x:%04x",
398 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
399 	snd_component_add(card, component);
400 
401 	/* retrieve the device string as shortname */
402 	if (quirk && quirk->product_name && *quirk->product_name) {
403 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
404 	} else {
405 		if (!dev->descriptor.iProduct ||
406 		    usb_string(dev, dev->descriptor.iProduct,
407 		    card->shortname, sizeof(card->shortname)) <= 0) {
408 			/* no name available from anywhere, so use ID */
409 			sprintf(card->shortname, "USB Device %#04x:%#04x",
410 				USB_ID_VENDOR(chip->usb_id),
411 				USB_ID_PRODUCT(chip->usb_id));
412 		}
413 	}
414 	remove_trailing_spaces(card->shortname);
415 
416 	/* retrieve the vendor and device strings as longname */
417 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
418 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
419 	} else {
420 		if (dev->descriptor.iManufacturer)
421 			len = usb_string(dev, dev->descriptor.iManufacturer,
422 					 card->longname, sizeof(card->longname));
423 		else
424 			len = 0;
425 		/* we don't really care if there isn't any vendor string */
426 	}
427 	if (len > 0) {
428 		remove_trailing_spaces(card->longname);
429 		if (*card->longname)
430 			strlcat(card->longname, " ", sizeof(card->longname));
431 	}
432 
433 	strlcat(card->longname, card->shortname, sizeof(card->longname));
434 
435 	len = strlcat(card->longname, " at ", sizeof(card->longname));
436 
437 	if (len < sizeof(card->longname))
438 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
439 
440 	switch (snd_usb_get_speed(dev)) {
441 	case USB_SPEED_LOW:
442 		strlcat(card->longname, ", low speed", sizeof(card->longname));
443 		break;
444 	case USB_SPEED_FULL:
445 		strlcat(card->longname, ", full speed", sizeof(card->longname));
446 		break;
447 	case USB_SPEED_HIGH:
448 		strlcat(card->longname, ", high speed", sizeof(card->longname));
449 		break;
450 	case USB_SPEED_SUPER:
451 		strlcat(card->longname, ", super speed", sizeof(card->longname));
452 		break;
453 	default:
454 		break;
455 	}
456 
457 	snd_usb_audio_create_proc(chip);
458 
459 	*rchip = chip;
460 	return 0;
461 }
462 
463 /*
464  * probe the active usb device
465  *
466  * note that this can be called multiple times per a device, when it
467  * includes multiple audio control interfaces.
468  *
469  * thus we check the usb device pointer and creates the card instance
470  * only at the first time.  the successive calls of this function will
471  * append the pcm interface to the corresponding card.
472  */
473 static struct snd_usb_audio *
474 snd_usb_audio_probe(struct usb_device *dev,
475 		    struct usb_interface *intf,
476 		    const struct usb_device_id *usb_id)
477 {
478 	const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
479 	int i, err;
480 	struct snd_usb_audio *chip;
481 	struct usb_host_interface *alts;
482 	int ifnum;
483 	u32 id;
484 
485 	alts = &intf->altsetting[0];
486 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
487 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
488 		    le16_to_cpu(dev->descriptor.idProduct));
489 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
490 		goto __err_val;
491 
492 	if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
493 		goto __err_val;
494 
495 	/*
496 	 * found a config.  now register to ALSA
497 	 */
498 
499 	/* check whether it's already registered */
500 	chip = NULL;
501 	mutex_lock(&register_mutex);
502 	for (i = 0; i < SNDRV_CARDS; i++) {
503 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
504 			if (usb_chip[i]->shutdown) {
505 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
506 				goto __error;
507 			}
508 			chip = usb_chip[i];
509 			chip->probing = 1;
510 			break;
511 		}
512 	}
513 	if (! chip) {
514 		/* it's a fresh one.
515 		 * now look for an empty slot and create a new card instance
516 		 */
517 		for (i = 0; i < SNDRV_CARDS; i++)
518 			if (enable[i] && ! usb_chip[i] &&
519 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
520 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
521 				if (snd_usb_audio_create(intf, dev, i, quirk,
522 							 &chip) < 0) {
523 					goto __error;
524 				}
525 				chip->pm_intf = intf;
526 				break;
527 			}
528 		if (!chip) {
529 			dev_err(&dev->dev, "no available usb audio device\n");
530 			goto __error;
531 		}
532 	}
533 
534 	/*
535 	 * For devices with more than one control interface, we assume the
536 	 * first contains the audio controls. We might need a more specific
537 	 * check here in the future.
538 	 */
539 	if (!chip->ctrl_intf)
540 		chip->ctrl_intf = alts;
541 
542 	chip->txfr_quirk = 0;
543 	err = 1; /* continue */
544 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
545 		/* need some special handlings */
546 		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
547 			goto __error;
548 	}
549 
550 	if (err > 0) {
551 		/* create normal USB audio interfaces */
552 		if (snd_usb_create_streams(chip, ifnum) < 0 ||
553 		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
554 			goto __error;
555 		}
556 	}
557 
558 	/* we are allowed to call snd_card_register() many times */
559 	if (snd_card_register(chip->card) < 0) {
560 		goto __error;
561 	}
562 
563 	usb_chip[chip->index] = chip;
564 	chip->num_interfaces++;
565 	chip->probing = 0;
566 	mutex_unlock(&register_mutex);
567 	return chip;
568 
569  __error:
570 	if (chip) {
571 		if (!chip->num_interfaces)
572 			snd_card_free(chip->card);
573 		chip->probing = 0;
574 	}
575 	mutex_unlock(&register_mutex);
576  __err_val:
577 	return NULL;
578 }
579 
580 /*
581  * we need to take care of counter, since disconnection can be called also
582  * many times as well as usb_audio_probe().
583  */
584 static void snd_usb_audio_disconnect(struct usb_device *dev,
585 				     struct snd_usb_audio *chip)
586 {
587 	struct snd_card *card;
588 	struct list_head *p, *n;
589 
590 	if (chip == (void *)-1L)
591 		return;
592 
593 	card = chip->card;
594 	down_write(&chip->shutdown_rwsem);
595 	chip->shutdown = 1;
596 	up_write(&chip->shutdown_rwsem);
597 
598 	mutex_lock(&register_mutex);
599 	chip->num_interfaces--;
600 	if (chip->num_interfaces <= 0) {
601 		snd_card_disconnect(card);
602 		/* release the pcm resources */
603 		list_for_each(p, &chip->pcm_list) {
604 			snd_usb_stream_disconnect(p);
605 		}
606 		/* release the endpoint resources */
607 		list_for_each_safe(p, n, &chip->ep_list) {
608 			snd_usb_endpoint_free(p);
609 		}
610 		/* release the midi resources */
611 		list_for_each(p, &chip->midi_list) {
612 			snd_usbmidi_disconnect(p);
613 		}
614 		/* release mixer resources */
615 		list_for_each(p, &chip->mixer_list) {
616 			snd_usb_mixer_disconnect(p);
617 		}
618 		usb_chip[chip->index] = NULL;
619 		mutex_unlock(&register_mutex);
620 		snd_card_free_when_closed(card);
621 	} else {
622 		mutex_unlock(&register_mutex);
623 	}
624 }
625 
626 /*
627  * new 2.5 USB kernel API
628  */
629 static int usb_audio_probe(struct usb_interface *intf,
630 			   const struct usb_device_id *id)
631 {
632 	struct snd_usb_audio *chip;
633 	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
634 	if (chip) {
635 		usb_set_intfdata(intf, chip);
636 		return 0;
637 	} else
638 		return -EIO;
639 }
640 
641 static void usb_audio_disconnect(struct usb_interface *intf)
642 {
643 	snd_usb_audio_disconnect(interface_to_usbdev(intf),
644 				 usb_get_intfdata(intf));
645 }
646 
647 #ifdef CONFIG_PM
648 
649 int snd_usb_autoresume(struct snd_usb_audio *chip)
650 {
651 	int err = -ENODEV;
652 
653 	down_read(&chip->shutdown_rwsem);
654 	if (chip->probing)
655 		err = 0;
656 	else if (!chip->shutdown)
657 		err = usb_autopm_get_interface(chip->pm_intf);
658 	up_read(&chip->shutdown_rwsem);
659 
660 	return err;
661 }
662 
663 void snd_usb_autosuspend(struct snd_usb_audio *chip)
664 {
665 	down_read(&chip->shutdown_rwsem);
666 	if (!chip->shutdown && !chip->probing)
667 		usb_autopm_put_interface(chip->pm_intf);
668 	up_read(&chip->shutdown_rwsem);
669 }
670 
671 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
672 {
673 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
674 	struct snd_usb_stream *as;
675 	struct usb_mixer_interface *mixer;
676 
677 	if (chip == (void *)-1L)
678 		return 0;
679 
680 	if (!PMSG_IS_AUTO(message)) {
681 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
682 		if (!chip->num_suspended_intf++) {
683 			list_for_each_entry(as, &chip->pcm_list, list) {
684 				snd_pcm_suspend_all(as->pcm);
685 				as->substream[0].need_setup_ep =
686 					as->substream[1].need_setup_ep = true;
687 			}
688 		}
689 	} else {
690 		/*
691 		 * otherwise we keep the rest of the system in the dark
692 		 * to keep this transparent
693 		 */
694 		if (!chip->num_suspended_intf++)
695 			chip->autosuspended = 1;
696 	}
697 
698 	list_for_each_entry(mixer, &chip->mixer_list, list)
699 		snd_usb_mixer_suspend(mixer);
700 
701 	return 0;
702 }
703 
704 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
705 {
706 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
707 	struct usb_mixer_interface *mixer;
708 	int err = 0;
709 
710 	if (chip == (void *)-1L)
711 		return 0;
712 	if (--chip->num_suspended_intf)
713 		return 0;
714 	/*
715 	 * ALSA leaves material resumption to user space
716 	 * we just notify and restart the mixers
717 	 */
718 	list_for_each_entry(mixer, &chip->mixer_list, list) {
719 		err = snd_usb_mixer_resume(mixer, reset_resume);
720 		if (err < 0)
721 			goto err_out;
722 	}
723 
724 	if (!chip->autosuspended)
725 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
726 	chip->autosuspended = 0;
727 
728 err_out:
729 	return err;
730 }
731 
732 static int usb_audio_resume(struct usb_interface *intf)
733 {
734 	return __usb_audio_resume(intf, false);
735 }
736 
737 static int usb_audio_reset_resume(struct usb_interface *intf)
738 {
739 	return __usb_audio_resume(intf, true);
740 }
741 #else
742 #define usb_audio_suspend	NULL
743 #define usb_audio_resume	NULL
744 #define usb_audio_reset_resume	NULL
745 #endif		/* CONFIG_PM */
746 
747 static struct usb_device_id usb_audio_ids [] = {
748 #include "quirks-table.h"
749     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
750       .bInterfaceClass = USB_CLASS_AUDIO,
751       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
752     { }						/* Terminating entry */
753 };
754 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
755 
756 /*
757  * entry point for linux usb interface
758  */
759 
760 static struct usb_driver usb_audio_driver = {
761 	.name =		"snd-usb-audio",
762 	.probe =	usb_audio_probe,
763 	.disconnect =	usb_audio_disconnect,
764 	.suspend =	usb_audio_suspend,
765 	.resume =	usb_audio_resume,
766 	.reset_resume =	usb_audio_reset_resume,
767 	.id_table =	usb_audio_ids,
768 	.supports_autosuspend = 1,
769 };
770 
771 module_usb_driver(usb_audio_driver);
772