xref: /openbmc/linux/sound/usb/card.c (revision 281a6ac0)
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 nrpacks = 8;		/* max. number of packets per urb */
83 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
84 static bool ignore_ctl_error;
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(nrpacks, int, 0644);
97 MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
98 module_param_array(device_setup, int, NULL, 0444);
99 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
100 module_param(ignore_ctl_error, bool, 0444);
101 MODULE_PARM_DESC(ignore_ctl_error,
102 		 "Ignore errors from USB controller for mixer interfaces.");
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 		snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
143 			   dev->devnum, ctrlif, interface);
144 		return -EINVAL;
145 	}
146 
147 	if (usb_interface_claimed(iface)) {
148 		snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
149 						dev->devnum, ctrlif, interface);
150 		return -EINVAL;
151 	}
152 
153 	alts = &iface->altsetting[0];
154 	altsd = get_iface_desc(alts);
155 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
156 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
157 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
158 		int err = snd_usbmidi_create(chip->card, iface,
159 					     &chip->midi_list, NULL);
160 		if (err < 0) {
161 			snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
162 						dev->devnum, ctrlif, interface);
163 			return -EINVAL;
164 		}
165 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
166 
167 		return 0;
168 	}
169 
170 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
171 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
172 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
173 		snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
174 					dev->devnum, ctrlif, interface, altsd->bInterfaceClass);
175 		/* skip non-supported classes */
176 		return -EINVAL;
177 	}
178 
179 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
180 		snd_printk(KERN_ERR "low speed audio streaming not supported\n");
181 		return -EINVAL;
182 	}
183 
184 	if (! snd_usb_parse_audio_interface(chip, interface)) {
185 		usb_set_interface(dev, interface, 0); /* reset the current interface */
186 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
187 		return -EINVAL;
188 	}
189 
190 	return 0;
191 }
192 
193 /*
194  * parse audio control descriptor and create pcm/midi streams
195  */
196 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
197 {
198 	struct usb_device *dev = chip->dev;
199 	struct usb_host_interface *host_iface;
200 	struct usb_interface_descriptor *altsd;
201 	void *control_header;
202 	int i, protocol;
203 
204 	/* find audiocontrol interface */
205 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
206 	control_header = snd_usb_find_csint_desc(host_iface->extra,
207 						 host_iface->extralen,
208 						 NULL, UAC_HEADER);
209 	altsd = get_iface_desc(host_iface);
210 	protocol = altsd->bInterfaceProtocol;
211 
212 	if (!control_header) {
213 		snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
214 		return -EINVAL;
215 	}
216 
217 	switch (protocol) {
218 	default:
219 		snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
220 			    protocol);
221 		/* fall through */
222 
223 	case UAC_VERSION_1: {
224 		struct uac1_ac_header_descriptor *h1 = control_header;
225 
226 		if (!h1->bInCollection) {
227 			snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
228 			return -EINVAL;
229 		}
230 
231 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
232 			snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
233 			return -EINVAL;
234 		}
235 
236 		for (i = 0; i < h1->bInCollection; i++)
237 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
238 
239 		break;
240 	}
241 
242 	case UAC_VERSION_2: {
243 		struct usb_interface_assoc_descriptor *assoc =
244 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
245 
246 		if (!assoc) {
247 			/*
248 			 * Firmware writers cannot count to three.  So to find
249 			 * the IAD on the NuForce UDH-100, also check the next
250 			 * interface.
251 			 */
252 			struct usb_interface *iface =
253 				usb_ifnum_to_if(dev, ctrlif + 1);
254 			if (iface &&
255 			    iface->intf_assoc &&
256 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
257 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
258 				assoc = iface->intf_assoc;
259 		}
260 
261 		if (!assoc) {
262 			snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
263 			return -EINVAL;
264 		}
265 
266 		for (i = 0; i < assoc->bInterfaceCount; i++) {
267 			int intf = assoc->bFirstInterface + i;
268 
269 			if (intf != ctrlif)
270 				snd_usb_create_stream(chip, ctrlif, intf);
271 		}
272 
273 		break;
274 	}
275 	}
276 
277 	return 0;
278 }
279 
280 /*
281  * free the chip instance
282  *
283  * here we have to do not much, since pcm and controls are already freed
284  *
285  */
286 
287 static int snd_usb_audio_free(struct snd_usb_audio *chip)
288 {
289 	mutex_destroy(&chip->mutex);
290 	kfree(chip);
291 	return 0;
292 }
293 
294 static int snd_usb_audio_dev_free(struct snd_device *device)
295 {
296 	struct snd_usb_audio *chip = device->device_data;
297 	return snd_usb_audio_free(chip);
298 }
299 
300 static void remove_trailing_spaces(char *str)
301 {
302 	char *p;
303 
304 	if (!*str)
305 		return;
306 	for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
307 		*p = 0;
308 }
309 
310 /*
311  * create a chip instance and set its names.
312  */
313 static int snd_usb_audio_create(struct usb_device *dev, int idx,
314 				const struct snd_usb_audio_quirk *quirk,
315 				struct snd_usb_audio **rchip)
316 {
317 	struct snd_card *card;
318 	struct snd_usb_audio *chip;
319 	int err, len;
320 	char component[14];
321 	static struct snd_device_ops ops = {
322 		.dev_free =	snd_usb_audio_dev_free,
323 	};
324 
325 	*rchip = NULL;
326 
327 	switch (snd_usb_get_speed(dev)) {
328 	case USB_SPEED_LOW:
329 	case USB_SPEED_FULL:
330 	case USB_SPEED_HIGH:
331 	case USB_SPEED_SUPER:
332 		break;
333 	default:
334 		snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
335 		return -ENXIO;
336 	}
337 
338 	err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
339 	if (err < 0) {
340 		snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
341 		return err;
342 	}
343 
344 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
345 	if (! chip) {
346 		snd_card_free(card);
347 		return -ENOMEM;
348 	}
349 
350 	mutex_init(&chip->mutex);
351 	init_rwsem(&chip->shutdown_rwsem);
352 	chip->index = idx;
353 	chip->dev = dev;
354 	chip->card = card;
355 	chip->setup = device_setup[idx];
356 	chip->nrpacks = nrpacks;
357 	chip->probing = 1;
358 
359 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
360 			      le16_to_cpu(dev->descriptor.idProduct));
361 	INIT_LIST_HEAD(&chip->pcm_list);
362 	INIT_LIST_HEAD(&chip->ep_list);
363 	INIT_LIST_HEAD(&chip->midi_list);
364 	INIT_LIST_HEAD(&chip->mixer_list);
365 
366 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
367 		snd_usb_audio_free(chip);
368 		snd_card_free(card);
369 		return err;
370 	}
371 
372 	strcpy(card->driver, "USB-Audio");
373 	sprintf(component, "USB%04x:%04x",
374 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
375 	snd_component_add(card, component);
376 
377 	/* retrieve the device string as shortname */
378 	if (quirk && quirk->product_name && *quirk->product_name) {
379 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
380 	} else {
381 		if (!dev->descriptor.iProduct ||
382 		    usb_string(dev, dev->descriptor.iProduct,
383 		    card->shortname, sizeof(card->shortname)) <= 0) {
384 			/* no name available from anywhere, so use ID */
385 			sprintf(card->shortname, "USB Device %#04x:%#04x",
386 				USB_ID_VENDOR(chip->usb_id),
387 				USB_ID_PRODUCT(chip->usb_id));
388 		}
389 	}
390 	remove_trailing_spaces(card->shortname);
391 
392 	/* retrieve the vendor and device strings as longname */
393 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
394 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
395 	} else {
396 		if (dev->descriptor.iManufacturer)
397 			len = usb_string(dev, dev->descriptor.iManufacturer,
398 					 card->longname, sizeof(card->longname));
399 		else
400 			len = 0;
401 		/* we don't really care if there isn't any vendor string */
402 	}
403 	if (len > 0) {
404 		remove_trailing_spaces(card->longname);
405 		if (*card->longname)
406 			strlcat(card->longname, " ", sizeof(card->longname));
407 	}
408 
409 	strlcat(card->longname, card->shortname, sizeof(card->longname));
410 
411 	len = strlcat(card->longname, " at ", sizeof(card->longname));
412 
413 	if (len < sizeof(card->longname))
414 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
415 
416 	switch (snd_usb_get_speed(dev)) {
417 	case USB_SPEED_LOW:
418 		strlcat(card->longname, ", low speed", sizeof(card->longname));
419 		break;
420 	case USB_SPEED_FULL:
421 		strlcat(card->longname, ", full speed", sizeof(card->longname));
422 		break;
423 	case USB_SPEED_HIGH:
424 		strlcat(card->longname, ", high speed", sizeof(card->longname));
425 		break;
426 	case USB_SPEED_SUPER:
427 		strlcat(card->longname, ", super speed", sizeof(card->longname));
428 		break;
429 	default:
430 		break;
431 	}
432 
433 	snd_usb_audio_create_proc(chip);
434 
435 	*rchip = chip;
436 	return 0;
437 }
438 
439 /*
440  * probe the active usb device
441  *
442  * note that this can be called multiple times per a device, when it
443  * includes multiple audio control interfaces.
444  *
445  * thus we check the usb device pointer and creates the card instance
446  * only at the first time.  the successive calls of this function will
447  * append the pcm interface to the corresponding card.
448  */
449 static struct snd_usb_audio *
450 snd_usb_audio_probe(struct usb_device *dev,
451 		    struct usb_interface *intf,
452 		    const struct usb_device_id *usb_id)
453 {
454 	const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
455 	int i, err;
456 	struct snd_usb_audio *chip;
457 	struct usb_host_interface *alts;
458 	int ifnum;
459 	u32 id;
460 
461 	alts = &intf->altsetting[0];
462 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
463 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
464 		    le16_to_cpu(dev->descriptor.idProduct));
465 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
466 		goto __err_val;
467 
468 	if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
469 		goto __err_val;
470 
471 	/*
472 	 * found a config.  now register to ALSA
473 	 */
474 
475 	/* check whether it's already registered */
476 	chip = NULL;
477 	mutex_lock(&register_mutex);
478 	for (i = 0; i < SNDRV_CARDS; i++) {
479 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
480 			if (usb_chip[i]->shutdown) {
481 				snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
482 				goto __error;
483 			}
484 			chip = usb_chip[i];
485 			chip->probing = 1;
486 			break;
487 		}
488 	}
489 	if (! chip) {
490 		/* it's a fresh one.
491 		 * now look for an empty slot and create a new card instance
492 		 */
493 		for (i = 0; i < SNDRV_CARDS; i++)
494 			if (enable[i] && ! usb_chip[i] &&
495 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
496 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
497 				if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
498 					goto __error;
499 				}
500 				snd_card_set_dev(chip->card, &intf->dev);
501 				chip->pm_intf = intf;
502 				break;
503 			}
504 		if (!chip) {
505 			printk(KERN_ERR "no available usb audio device\n");
506 			goto __error;
507 		}
508 	}
509 
510 	/*
511 	 * For devices with more than one control interface, we assume the
512 	 * first contains the audio controls. We might need a more specific
513 	 * check here in the future.
514 	 */
515 	if (!chip->ctrl_intf)
516 		chip->ctrl_intf = alts;
517 
518 	chip->txfr_quirk = 0;
519 	err = 1; /* continue */
520 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
521 		/* need some special handlings */
522 		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
523 			goto __error;
524 	}
525 
526 	if (err > 0) {
527 		/* create normal USB audio interfaces */
528 		if (snd_usb_create_streams(chip, ifnum) < 0 ||
529 		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
530 			goto __error;
531 		}
532 	}
533 
534 	/* we are allowed to call snd_card_register() many times */
535 	if (snd_card_register(chip->card) < 0) {
536 		goto __error;
537 	}
538 
539 	usb_chip[chip->index] = chip;
540 	chip->num_interfaces++;
541 	chip->probing = 0;
542 	mutex_unlock(&register_mutex);
543 	return chip;
544 
545  __error:
546 	if (chip) {
547 		if (!chip->num_interfaces)
548 			snd_card_free(chip->card);
549 		chip->probing = 0;
550 	}
551 	mutex_unlock(&register_mutex);
552  __err_val:
553 	return NULL;
554 }
555 
556 /*
557  * we need to take care of counter, since disconnection can be called also
558  * many times as well as usb_audio_probe().
559  */
560 static void snd_usb_audio_disconnect(struct usb_device *dev,
561 				     struct snd_usb_audio *chip)
562 {
563 	struct snd_card *card;
564 	struct list_head *p, *n;
565 
566 	if (chip == (void *)-1L)
567 		return;
568 
569 	card = chip->card;
570 	down_write(&chip->shutdown_rwsem);
571 	chip->shutdown = 1;
572 	up_write(&chip->shutdown_rwsem);
573 
574 	mutex_lock(&register_mutex);
575 	chip->num_interfaces--;
576 	if (chip->num_interfaces <= 0) {
577 		snd_card_disconnect(card);
578 		/* release the pcm resources */
579 		list_for_each(p, &chip->pcm_list) {
580 			snd_usb_stream_disconnect(p);
581 		}
582 		/* release the endpoint resources */
583 		list_for_each_safe(p, n, &chip->ep_list) {
584 			snd_usb_endpoint_free(p);
585 		}
586 		/* release the midi resources */
587 		list_for_each(p, &chip->midi_list) {
588 			snd_usbmidi_disconnect(p);
589 		}
590 		/* release mixer resources */
591 		list_for_each(p, &chip->mixer_list) {
592 			snd_usb_mixer_disconnect(p);
593 		}
594 		usb_chip[chip->index] = NULL;
595 		mutex_unlock(&register_mutex);
596 		snd_card_free_when_closed(card);
597 	} else {
598 		mutex_unlock(&register_mutex);
599 	}
600 }
601 
602 /*
603  * new 2.5 USB kernel API
604  */
605 static int usb_audio_probe(struct usb_interface *intf,
606 			   const struct usb_device_id *id)
607 {
608 	struct snd_usb_audio *chip;
609 	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
610 	if (chip) {
611 		usb_set_intfdata(intf, chip);
612 		return 0;
613 	} else
614 		return -EIO;
615 }
616 
617 static void usb_audio_disconnect(struct usb_interface *intf)
618 {
619 	snd_usb_audio_disconnect(interface_to_usbdev(intf),
620 				 usb_get_intfdata(intf));
621 }
622 
623 #ifdef CONFIG_PM
624 
625 int snd_usb_autoresume(struct snd_usb_audio *chip)
626 {
627 	int err = -ENODEV;
628 
629 	down_read(&chip->shutdown_rwsem);
630 	if (!chip->shutdown && !chip->probing)
631 		err = usb_autopm_get_interface(chip->pm_intf);
632 	up_read(&chip->shutdown_rwsem);
633 
634 	return err;
635 }
636 
637 void snd_usb_autosuspend(struct snd_usb_audio *chip)
638 {
639 	down_read(&chip->shutdown_rwsem);
640 	if (!chip->shutdown && !chip->probing)
641 		usb_autopm_put_interface(chip->pm_intf);
642 	up_read(&chip->shutdown_rwsem);
643 }
644 
645 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
646 {
647 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
648 	struct list_head *p;
649 	struct snd_usb_stream *as;
650 	struct usb_mixer_interface *mixer;
651 
652 	if (chip == (void *)-1L)
653 		return 0;
654 
655 	if (!PMSG_IS_AUTO(message)) {
656 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
657 		if (!chip->num_suspended_intf++) {
658 			list_for_each(p, &chip->pcm_list) {
659 				as = list_entry(p, struct snd_usb_stream, list);
660 				snd_pcm_suspend_all(as->pcm);
661 				as->substream[0].need_setup_ep =
662 					as->substream[1].need_setup_ep = true;
663 			}
664 		}
665 	} else {
666 		/*
667 		 * otherwise we keep the rest of the system in the dark
668 		 * to keep this transparent
669 		 */
670 		if (!chip->num_suspended_intf++)
671 			chip->autosuspended = 1;
672 	}
673 
674 	list_for_each_entry(mixer, &chip->mixer_list, list)
675 		snd_usb_mixer_inactivate(mixer);
676 
677 	return 0;
678 }
679 
680 static int usb_audio_resume(struct usb_interface *intf)
681 {
682 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
683 	struct usb_mixer_interface *mixer;
684 	int err = 0;
685 
686 	if (chip == (void *)-1L)
687 		return 0;
688 	if (--chip->num_suspended_intf)
689 		return 0;
690 	/*
691 	 * ALSA leaves material resumption to user space
692 	 * we just notify and restart the mixers
693 	 */
694 	list_for_each_entry(mixer, &chip->mixer_list, list) {
695 		err = snd_usb_mixer_activate(mixer);
696 		if (err < 0)
697 			goto err_out;
698 	}
699 
700 	if (!chip->autosuspended)
701 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
702 	chip->autosuspended = 0;
703 
704 err_out:
705 	return err;
706 }
707 #else
708 #define usb_audio_suspend	NULL
709 #define usb_audio_resume	NULL
710 #endif		/* CONFIG_PM */
711 
712 static struct usb_device_id usb_audio_ids [] = {
713 #include "quirks-table.h"
714     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
715       .bInterfaceClass = USB_CLASS_AUDIO,
716       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
717     { }						/* Terminating entry */
718 };
719 
720 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
721 
722 /*
723  * entry point for linux usb interface
724  */
725 
726 static struct usb_driver usb_audio_driver = {
727 	.name =		"snd-usb-audio",
728 	.probe =	usb_audio_probe,
729 	.disconnect =	usb_audio_disconnect,
730 	.suspend =	usb_audio_suspend,
731 	.resume =	usb_audio_resume,
732 	.id_table =	usb_audio_ids,
733 	.supports_autosuspend = 1,
734 };
735 
736 static int __init snd_usb_audio_init(void)
737 {
738 	if (nrpacks < 1 || nrpacks > MAX_PACKS) {
739 		printk(KERN_WARNING "invalid nrpacks value.\n");
740 		return -EINVAL;
741 	}
742 	return usb_register(&usb_audio_driver);
743 }
744 
745 static void __exit snd_usb_audio_cleanup(void)
746 {
747 	usb_deregister(&usb_audio_driver);
748 }
749 
750 module_init(snd_usb_audio_init);
751 module_exit(snd_usb_audio_cleanup);
752