xref: /openbmc/linux/sound/usb/card.c (revision 565d76cb)
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  *   - async unlink should be used for avoiding the sleep inside lock.
29  *     2.4.22 usb-uhci seems buggy for async unlinking and results in
30  *     oops.  in such a cse, pass async_unlink=0 option.
31  *   - the linked URBs would be preferred but not used so far because of
32  *     the instability of unlinking.
33  *   - type II is not supported properly.  there is no device which supports
34  *     this type *correctly*.  SB extigy looks as if it supports, but it's
35  *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
36  */
37 
38 
39 #include <linux/bitops.h>
40 #include <linux/init.h>
41 #include <linux/list.h>
42 #include <linux/slab.h>
43 #include <linux/string.h>
44 #include <linux/usb.h>
45 #include <linux/moduleparam.h>
46 #include <linux/mutex.h>
47 #include <linux/usb/audio.h>
48 #include <linux/usb/audio-v2.h>
49 
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 "urb.h"
67 #include "format.h"
68 #include "power.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 int 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 async_unlink = 1;
84 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
85 static int ignore_ctl_error;
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(nrpacks, int, 0644);
98 MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
99 module_param(async_unlink, bool, 0444);
100 MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
101 module_param_array(device_setup, int, NULL, 0444);
102 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
103 module_param(ignore_ctl_error, bool, 0444);
104 MODULE_PARM_DESC(ignore_ctl_error,
105 		 "Ignore errors from USB controller for mixer interfaces.");
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 snd_usb_audio_disconnect()
119  */
120 static void snd_usb_stream_disconnect(struct list_head *head)
121 {
122 	int idx;
123 	struct snd_usb_stream *as;
124 	struct snd_usb_substream *subs;
125 
126 	as = list_entry(head, struct snd_usb_stream, list);
127 	for (idx = 0; idx < 2; idx++) {
128 		subs = &as->substream[idx];
129 		if (!subs->num_formats)
130 			continue;
131 		snd_usb_release_substream_urbs(subs, 1);
132 		subs->interface = -1;
133 	}
134 }
135 
136 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
137 {
138 	struct usb_device *dev = chip->dev;
139 	struct usb_host_interface *alts;
140 	struct usb_interface_descriptor *altsd;
141 	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
142 
143 	if (!iface) {
144 		snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
145 			   dev->devnum, ctrlif, interface);
146 		return -EINVAL;
147 	}
148 
149 	if (usb_interface_claimed(iface)) {
150 		snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
151 						dev->devnum, ctrlif, interface);
152 		return -EINVAL;
153 	}
154 
155 	alts = &iface->altsetting[0];
156 	altsd = get_iface_desc(alts);
157 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
158 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
159 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
160 		int err = snd_usbmidi_create(chip->card, iface,
161 					     &chip->midi_list, NULL);
162 		if (err < 0) {
163 			snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
164 						dev->devnum, ctrlif, interface);
165 			return -EINVAL;
166 		}
167 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
168 
169 		return 0;
170 	}
171 
172 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
173 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
174 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
175 		snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
176 					dev->devnum, ctrlif, interface, altsd->bInterfaceClass);
177 		/* skip non-supported classes */
178 		return -EINVAL;
179 	}
180 
181 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
182 		snd_printk(KERN_ERR "low speed audio streaming not supported\n");
183 		return -EINVAL;
184 	}
185 
186 	if (! snd_usb_parse_audio_endpoints(chip, interface)) {
187 		usb_set_interface(dev, interface, 0); /* reset the current interface */
188 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
189 		return -EINVAL;
190 	}
191 
192 	return 0;
193 }
194 
195 /*
196  * parse audio control descriptor and create pcm/midi streams
197  */
198 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
199 {
200 	struct usb_device *dev = chip->dev;
201 	struct usb_host_interface *host_iface;
202 	struct usb_interface_descriptor *altsd;
203 	void *control_header;
204 	int i, protocol;
205 
206 	/* find audiocontrol interface */
207 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
208 	control_header = snd_usb_find_csint_desc(host_iface->extra,
209 						 host_iface->extralen,
210 						 NULL, UAC_HEADER);
211 	altsd = get_iface_desc(host_iface);
212 	protocol = altsd->bInterfaceProtocol;
213 
214 	if (!control_header) {
215 		snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
216 		return -EINVAL;
217 	}
218 
219 	switch (protocol) {
220 	default:
221 		snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
222 			    protocol);
223 		/* fall through */
224 
225 	case UAC_VERSION_1: {
226 		struct uac1_ac_header_descriptor *h1 = control_header;
227 
228 		if (!h1->bInCollection) {
229 			snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
230 			return -EINVAL;
231 		}
232 
233 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
234 			snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
235 			return -EINVAL;
236 		}
237 
238 		for (i = 0; i < h1->bInCollection; i++)
239 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
240 
241 		break;
242 	}
243 
244 	case UAC_VERSION_2: {
245 		struct usb_interface_assoc_descriptor *assoc =
246 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
247 
248 		if (!assoc) {
249 			snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
250 			return -EINVAL;
251 		}
252 
253 		for (i = 0; i < assoc->bInterfaceCount; i++) {
254 			int intf = assoc->bFirstInterface + i;
255 
256 			if (intf != ctrlif)
257 				snd_usb_create_stream(chip, ctrlif, intf);
258 		}
259 
260 		break;
261 	}
262 	}
263 
264 	return 0;
265 }
266 
267 /*
268  * free the chip instance
269  *
270  * here we have to do not much, since pcm and controls are already freed
271  *
272  */
273 
274 static int snd_usb_audio_free(struct snd_usb_audio *chip)
275 {
276 	kfree(chip);
277 	return 0;
278 }
279 
280 static int snd_usb_audio_dev_free(struct snd_device *device)
281 {
282 	struct snd_usb_audio *chip = device->device_data;
283 	return snd_usb_audio_free(chip);
284 }
285 
286 
287 /*
288  * create a chip instance and set its names.
289  */
290 static int snd_usb_audio_create(struct usb_device *dev, int idx,
291 				const struct snd_usb_audio_quirk *quirk,
292 				struct snd_usb_audio **rchip)
293 {
294 	struct snd_card *card;
295 	struct snd_usb_audio *chip;
296 	int err, len;
297 	char component[14];
298 	static struct snd_device_ops ops = {
299 		.dev_free =	snd_usb_audio_dev_free,
300 	};
301 
302 	*rchip = NULL;
303 
304 	switch (snd_usb_get_speed(dev)) {
305 	case USB_SPEED_LOW:
306 	case USB_SPEED_FULL:
307 	case USB_SPEED_HIGH:
308 	case USB_SPEED_SUPER:
309 		break;
310 	default:
311 		snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
312 		return -ENXIO;
313 	}
314 
315 	err = snd_card_create(index[idx], id[idx], THIS_MODULE, 0, &card);
316 	if (err < 0) {
317 		snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
318 		return err;
319 	}
320 
321 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
322 	if (! chip) {
323 		snd_card_free(card);
324 		return -ENOMEM;
325 	}
326 
327 	mutex_init(&chip->shutdown_mutex);
328 	chip->index = idx;
329 	chip->dev = dev;
330 	chip->card = card;
331 	chip->setup = device_setup[idx];
332 	chip->nrpacks = nrpacks;
333 	chip->async_unlink = async_unlink;
334 	chip->probing = 1;
335 
336 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
337 			      le16_to_cpu(dev->descriptor.idProduct));
338 	INIT_LIST_HEAD(&chip->pcm_list);
339 	INIT_LIST_HEAD(&chip->midi_list);
340 	INIT_LIST_HEAD(&chip->mixer_list);
341 
342 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
343 		snd_usb_audio_free(chip);
344 		snd_card_free(card);
345 		return err;
346 	}
347 
348 	strcpy(card->driver, "USB-Audio");
349 	sprintf(component, "USB%04x:%04x",
350 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
351 	snd_component_add(card, component);
352 
353 	/* retrieve the device string as shortname */
354 	if (quirk && quirk->product_name) {
355 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
356 	} else {
357 		if (!dev->descriptor.iProduct ||
358 		    usb_string(dev, dev->descriptor.iProduct,
359 		    card->shortname, sizeof(card->shortname)) <= 0) {
360 			/* no name available from anywhere, so use ID */
361 			sprintf(card->shortname, "USB Device %#04x:%#04x",
362 				USB_ID_VENDOR(chip->usb_id),
363 				USB_ID_PRODUCT(chip->usb_id));
364 		}
365 	}
366 
367 	/* retrieve the vendor and device strings as longname */
368 	if (quirk && quirk->vendor_name) {
369 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
370 	} else {
371 		if (dev->descriptor.iManufacturer)
372 			len = usb_string(dev, dev->descriptor.iManufacturer,
373 					 card->longname, sizeof(card->longname));
374 		else
375 			len = 0;
376 		/* we don't really care if there isn't any vendor string */
377 	}
378 	if (len > 0)
379 		strlcat(card->longname, " ", sizeof(card->longname));
380 
381 	strlcat(card->longname, card->shortname, sizeof(card->longname));
382 
383 	len = strlcat(card->longname, " at ", sizeof(card->longname));
384 
385 	if (len < sizeof(card->longname))
386 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
387 
388 	switch (snd_usb_get_speed(dev)) {
389 	case USB_SPEED_LOW:
390 		strlcat(card->longname, ", low speed", sizeof(card->longname));
391 		break;
392 	case USB_SPEED_FULL:
393 		strlcat(card->longname, ", full speed", sizeof(card->longname));
394 		break;
395 	case USB_SPEED_HIGH:
396 		strlcat(card->longname, ", high speed", sizeof(card->longname));
397 		break;
398 	case USB_SPEED_SUPER:
399 		strlcat(card->longname, ", super speed", sizeof(card->longname));
400 		break;
401 	default:
402 		break;
403 	}
404 
405 	snd_usb_audio_create_proc(chip);
406 
407 	*rchip = chip;
408 	return 0;
409 }
410 
411 /*
412  * probe the active usb device
413  *
414  * note that this can be called multiple times per a device, when it
415  * includes multiple audio control interfaces.
416  *
417  * thus we check the usb device pointer and creates the card instance
418  * only at the first time.  the successive calls of this function will
419  * append the pcm interface to the corresponding card.
420  */
421 static void *snd_usb_audio_probe(struct usb_device *dev,
422 				 struct usb_interface *intf,
423 				 const struct usb_device_id *usb_id)
424 {
425 	const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
426 	int i, err;
427 	struct snd_usb_audio *chip;
428 	struct usb_host_interface *alts;
429 	int ifnum;
430 	u32 id;
431 
432 	alts = &intf->altsetting[0];
433 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
434 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
435 		    le16_to_cpu(dev->descriptor.idProduct));
436 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
437 		goto __err_val;
438 
439 	if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
440 		goto __err_val;
441 
442 	/*
443 	 * found a config.  now register to ALSA
444 	 */
445 
446 	/* check whether it's already registered */
447 	chip = NULL;
448 	mutex_lock(&register_mutex);
449 	for (i = 0; i < SNDRV_CARDS; i++) {
450 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
451 			if (usb_chip[i]->shutdown) {
452 				snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
453 				goto __error;
454 			}
455 			chip = usb_chip[i];
456 			chip->probing = 1;
457 			break;
458 		}
459 	}
460 	if (! chip) {
461 		/* it's a fresh one.
462 		 * now look for an empty slot and create a new card instance
463 		 */
464 		for (i = 0; i < SNDRV_CARDS; i++)
465 			if (enable[i] && ! usb_chip[i] &&
466 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
467 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
468 				if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
469 					goto __error;
470 				}
471 				snd_card_set_dev(chip->card, &intf->dev);
472 				chip->pm_intf = intf;
473 				break;
474 			}
475 		if (!chip) {
476 			printk(KERN_ERR "no available usb audio device\n");
477 			goto __error;
478 		}
479 	}
480 
481 	chip->txfr_quirk = 0;
482 	err = 1; /* continue */
483 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
484 		/* need some special handlings */
485 		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
486 			goto __error;
487 	}
488 
489 	/*
490 	 * For devices with more than one control interface, we assume the
491 	 * first contains the audio controls. We might need a more specific
492 	 * check here in the future.
493 	 */
494 	if (!chip->ctrl_intf)
495 		chip->ctrl_intf = alts;
496 
497 	if (err > 0) {
498 		/* create normal USB audio interfaces */
499 		if (snd_usb_create_streams(chip, ifnum) < 0 ||
500 		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
501 			goto __error;
502 		}
503 	}
504 
505 	/* we are allowed to call snd_card_register() many times */
506 	if (snd_card_register(chip->card) < 0) {
507 		goto __error;
508 	}
509 
510 	usb_chip[chip->index] = chip;
511 	chip->num_interfaces++;
512 	chip->probing = 0;
513 	mutex_unlock(&register_mutex);
514 	return chip;
515 
516  __error:
517 	if (chip && !chip->num_interfaces)
518 		snd_card_free(chip->card);
519 	mutex_unlock(&register_mutex);
520  __err_val:
521 	return NULL;
522 }
523 
524 /*
525  * we need to take care of counter, since disconnection can be called also
526  * many times as well as usb_audio_probe().
527  */
528 static void snd_usb_audio_disconnect(struct usb_device *dev, void *ptr)
529 {
530 	struct snd_usb_audio *chip;
531 	struct snd_card *card;
532 	struct list_head *p;
533 
534 	if (ptr == (void *)-1L)
535 		return;
536 
537 	chip = ptr;
538 	card = chip->card;
539 	mutex_lock(&register_mutex);
540 	mutex_lock(&chip->shutdown_mutex);
541 	chip->shutdown = 1;
542 	chip->num_interfaces--;
543 	if (chip->num_interfaces <= 0) {
544 		snd_card_disconnect(card);
545 		/* release the pcm resources */
546 		list_for_each(p, &chip->pcm_list) {
547 			snd_usb_stream_disconnect(p);
548 		}
549 		/* release the midi resources */
550 		list_for_each(p, &chip->midi_list) {
551 			snd_usbmidi_disconnect(p);
552 		}
553 		/* release mixer resources */
554 		list_for_each(p, &chip->mixer_list) {
555 			snd_usb_mixer_disconnect(p);
556 		}
557 		usb_chip[chip->index] = NULL;
558 		mutex_unlock(&chip->shutdown_mutex);
559 		mutex_unlock(&register_mutex);
560 		snd_card_free_when_closed(card);
561 	} else {
562 		mutex_unlock(&chip->shutdown_mutex);
563 		mutex_unlock(&register_mutex);
564 	}
565 }
566 
567 /*
568  * new 2.5 USB kernel API
569  */
570 static int usb_audio_probe(struct usb_interface *intf,
571 			   const struct usb_device_id *id)
572 {
573 	void *chip;
574 	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
575 	if (chip) {
576 		usb_set_intfdata(intf, chip);
577 		return 0;
578 	} else
579 		return -EIO;
580 }
581 
582 static void usb_audio_disconnect(struct usb_interface *intf)
583 {
584 	snd_usb_audio_disconnect(interface_to_usbdev(intf),
585 				 usb_get_intfdata(intf));
586 }
587 
588 #ifdef CONFIG_PM
589 
590 int snd_usb_autoresume(struct snd_usb_audio *chip)
591 {
592 	int err = -ENODEV;
593 
594 	if (!chip->shutdown && !chip->probing)
595 		err = usb_autopm_get_interface(chip->pm_intf);
596 
597 	return err;
598 }
599 
600 void snd_usb_autosuspend(struct snd_usb_audio *chip)
601 {
602 	if (!chip->shutdown && !chip->probing)
603 		usb_autopm_put_interface(chip->pm_intf);
604 }
605 
606 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
607 {
608 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
609 	struct list_head *p;
610 	struct snd_usb_stream *as;
611 	struct usb_mixer_interface *mixer;
612 
613 	if (chip == (void *)-1L)
614 		return 0;
615 
616 	if (!(message.event & PM_EVENT_AUTO)) {
617 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
618 		if (!chip->num_suspended_intf++) {
619 			list_for_each(p, &chip->pcm_list) {
620 				as = list_entry(p, struct snd_usb_stream, list);
621 				snd_pcm_suspend_all(as->pcm);
622 			}
623  		}
624 	} else {
625 		/*
626 		 * otherwise we keep the rest of the system in the dark
627 		 * to keep this transparent
628 		 */
629 		if (!chip->num_suspended_intf++)
630 			chip->autosuspended = 1;
631 	}
632 
633 	list_for_each_entry(mixer, &chip->mixer_list, list)
634 		snd_usb_mixer_inactivate(mixer);
635 
636 	return 0;
637 }
638 
639 static int usb_audio_resume(struct usb_interface *intf)
640 {
641 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
642 	struct usb_mixer_interface *mixer;
643 	int err = 0;
644 
645 	if (chip == (void *)-1L)
646 		return 0;
647 	if (--chip->num_suspended_intf)
648 		return 0;
649 	/*
650 	 * ALSA leaves material resumption to user space
651 	 * we just notify and restart the mixers
652 	 */
653 	list_for_each_entry(mixer, &chip->mixer_list, list) {
654 		err = snd_usb_mixer_activate(mixer);
655 		if (err < 0)
656 			goto err_out;
657 	}
658 
659 	if (!chip->autosuspended)
660 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
661 	chip->autosuspended = 0;
662 
663 err_out:
664 	return err;
665 }
666 #else
667 #define usb_audio_suspend	NULL
668 #define usb_audio_resume	NULL
669 #endif		/* CONFIG_PM */
670 
671 static struct usb_device_id usb_audio_ids [] = {
672 #include "quirks-table.h"
673     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
674       .bInterfaceClass = USB_CLASS_AUDIO,
675       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
676     { }						/* Terminating entry */
677 };
678 
679 MODULE_DEVICE_TABLE (usb, usb_audio_ids);
680 
681 /*
682  * entry point for linux usb interface
683  */
684 
685 static struct usb_driver usb_audio_driver = {
686 	.name =		"snd-usb-audio",
687 	.probe =	usb_audio_probe,
688 	.disconnect =	usb_audio_disconnect,
689 	.suspend =	usb_audio_suspend,
690 	.resume =	usb_audio_resume,
691 	.id_table =	usb_audio_ids,
692 	.supports_autosuspend = 1,
693 };
694 
695 static int __init snd_usb_audio_init(void)
696 {
697 	if (nrpacks < 1 || nrpacks > MAX_PACKS) {
698 		printk(KERN_WARNING "invalid nrpacks value.\n");
699 		return -EINVAL;
700 	}
701 	return usb_register(&usb_audio_driver);
702 }
703 
704 static void __exit snd_usb_audio_cleanup(void)
705 {
706 	usb_deregister(&usb_audio_driver);
707 }
708 
709 module_init(snd_usb_audio_init);
710 module_exit(snd_usb_audio_cleanup);
711