xref: /openbmc/linux/sound/usb/card.c (revision 483eb062)
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 		snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
143 			   dev->devnum, 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 		snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n",
169 						dev->devnum, 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 			snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n",
180 						dev->devnum, ctrlif, interface);
181 			return -EINVAL;
182 		}
183 		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
184 
185 		return 0;
186 	}
187 
188 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
189 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
190 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
191 		snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n",
192 					dev->devnum, 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 		snd_printk(KERN_ERR "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 		snd_printk(KERN_ERR "cannot find UAC_HEADER\n");
232 		return -EINVAL;
233 	}
234 
235 	switch (protocol) {
236 	default:
237 		snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
238 			    protocol);
239 		/* fall through */
240 
241 	case UAC_VERSION_1: {
242 		struct uac1_ac_header_descriptor *h1 = control_header;
243 
244 		if (!h1->bInCollection) {
245 			snd_printk(KERN_INFO "skipping empty audio interface (v1)\n");
246 			return -EINVAL;
247 		}
248 
249 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
250 			snd_printk(KERN_ERR "invalid UAC_HEADER (v1)\n");
251 			return -EINVAL;
252 		}
253 
254 		for (i = 0; i < h1->bInCollection; i++)
255 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
256 
257 		break;
258 	}
259 
260 	case UAC_VERSION_2: {
261 		struct usb_interface_assoc_descriptor *assoc =
262 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
263 
264 		if (!assoc) {
265 			/*
266 			 * Firmware writers cannot count to three.  So to find
267 			 * the IAD on the NuForce UDH-100, also check the next
268 			 * interface.
269 			 */
270 			struct usb_interface *iface =
271 				usb_ifnum_to_if(dev, ctrlif + 1);
272 			if (iface &&
273 			    iface->intf_assoc &&
274 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
275 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
276 				assoc = iface->intf_assoc;
277 		}
278 
279 		if (!assoc) {
280 			snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
281 			return -EINVAL;
282 		}
283 
284 		for (i = 0; i < assoc->bInterfaceCount; i++) {
285 			int intf = assoc->bFirstInterface + i;
286 
287 			if (intf != ctrlif)
288 				snd_usb_create_stream(chip, ctrlif, intf);
289 		}
290 
291 		break;
292 	}
293 	}
294 
295 	return 0;
296 }
297 
298 /*
299  * free the chip instance
300  *
301  * here we have to do not much, since pcm and controls are already freed
302  *
303  */
304 
305 static int snd_usb_audio_free(struct snd_usb_audio *chip)
306 {
307 	mutex_destroy(&chip->mutex);
308 	kfree(chip);
309 	return 0;
310 }
311 
312 static int snd_usb_audio_dev_free(struct snd_device *device)
313 {
314 	struct snd_usb_audio *chip = device->device_data;
315 	return snd_usb_audio_free(chip);
316 }
317 
318 static void remove_trailing_spaces(char *str)
319 {
320 	char *p;
321 
322 	if (!*str)
323 		return;
324 	for (p = str + strlen(str) - 1; p >= str && isspace(*p); p--)
325 		*p = 0;
326 }
327 
328 /*
329  * create a chip instance and set its names.
330  */
331 static int snd_usb_audio_create(struct usb_interface *intf,
332 				struct usb_device *dev, int idx,
333 				const struct snd_usb_audio_quirk *quirk,
334 				struct snd_usb_audio **rchip)
335 {
336 	struct snd_card *card;
337 	struct snd_usb_audio *chip;
338 	int err, len;
339 	char component[14];
340 	static struct snd_device_ops ops = {
341 		.dev_free =	snd_usb_audio_dev_free,
342 	};
343 
344 	*rchip = NULL;
345 
346 	switch (snd_usb_get_speed(dev)) {
347 	case USB_SPEED_LOW:
348 	case USB_SPEED_FULL:
349 	case USB_SPEED_HIGH:
350 	case USB_SPEED_WIRELESS:
351 	case USB_SPEED_SUPER:
352 		break;
353 	default:
354 		snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
355 		return -ENXIO;
356 	}
357 
358 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
359 			   0, &card);
360 	if (err < 0) {
361 		snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
362 		return err;
363 	}
364 
365 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
366 	if (! chip) {
367 		snd_card_free(card);
368 		return -ENOMEM;
369 	}
370 
371 	mutex_init(&chip->mutex);
372 	init_rwsem(&chip->shutdown_rwsem);
373 	chip->index = idx;
374 	chip->dev = dev;
375 	chip->card = card;
376 	chip->setup = device_setup[idx];
377 	chip->autoclock = autoclock;
378 	chip->probing = 1;
379 
380 	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
381 			      le16_to_cpu(dev->descriptor.idProduct));
382 	INIT_LIST_HEAD(&chip->pcm_list);
383 	INIT_LIST_HEAD(&chip->ep_list);
384 	INIT_LIST_HEAD(&chip->midi_list);
385 	INIT_LIST_HEAD(&chip->mixer_list);
386 
387 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
388 		snd_usb_audio_free(chip);
389 		snd_card_free(card);
390 		return err;
391 	}
392 
393 	strcpy(card->driver, "USB-Audio");
394 	sprintf(component, "USB%04x:%04x",
395 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
396 	snd_component_add(card, component);
397 
398 	/* retrieve the device string as shortname */
399 	if (quirk && quirk->product_name && *quirk->product_name) {
400 		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
401 	} else {
402 		if (!dev->descriptor.iProduct ||
403 		    usb_string(dev, dev->descriptor.iProduct,
404 		    card->shortname, sizeof(card->shortname)) <= 0) {
405 			/* no name available from anywhere, so use ID */
406 			sprintf(card->shortname, "USB Device %#04x:%#04x",
407 				USB_ID_VENDOR(chip->usb_id),
408 				USB_ID_PRODUCT(chip->usb_id));
409 		}
410 	}
411 	remove_trailing_spaces(card->shortname);
412 
413 	/* retrieve the vendor and device strings as longname */
414 	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
415 		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
416 	} else {
417 		if (dev->descriptor.iManufacturer)
418 			len = usb_string(dev, dev->descriptor.iManufacturer,
419 					 card->longname, sizeof(card->longname));
420 		else
421 			len = 0;
422 		/* we don't really care if there isn't any vendor string */
423 	}
424 	if (len > 0) {
425 		remove_trailing_spaces(card->longname);
426 		if (*card->longname)
427 			strlcat(card->longname, " ", sizeof(card->longname));
428 	}
429 
430 	strlcat(card->longname, card->shortname, sizeof(card->longname));
431 
432 	len = strlcat(card->longname, " at ", sizeof(card->longname));
433 
434 	if (len < sizeof(card->longname))
435 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
436 
437 	switch (snd_usb_get_speed(dev)) {
438 	case USB_SPEED_LOW:
439 		strlcat(card->longname, ", low speed", sizeof(card->longname));
440 		break;
441 	case USB_SPEED_FULL:
442 		strlcat(card->longname, ", full speed", sizeof(card->longname));
443 		break;
444 	case USB_SPEED_HIGH:
445 		strlcat(card->longname, ", high speed", sizeof(card->longname));
446 		break;
447 	case USB_SPEED_SUPER:
448 		strlcat(card->longname, ", super speed", sizeof(card->longname));
449 		break;
450 	default:
451 		break;
452 	}
453 
454 	snd_usb_audio_create_proc(chip);
455 
456 	*rchip = chip;
457 	return 0;
458 }
459 
460 /*
461  * probe the active usb device
462  *
463  * note that this can be called multiple times per a device, when it
464  * includes multiple audio control interfaces.
465  *
466  * thus we check the usb device pointer and creates the card instance
467  * only at the first time.  the successive calls of this function will
468  * append the pcm interface to the corresponding card.
469  */
470 static struct snd_usb_audio *
471 snd_usb_audio_probe(struct usb_device *dev,
472 		    struct usb_interface *intf,
473 		    const struct usb_device_id *usb_id)
474 {
475 	const struct snd_usb_audio_quirk *quirk = (const struct snd_usb_audio_quirk *)usb_id->driver_info;
476 	int i, err;
477 	struct snd_usb_audio *chip;
478 	struct usb_host_interface *alts;
479 	int ifnum;
480 	u32 id;
481 
482 	alts = &intf->altsetting[0];
483 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
484 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
485 		    le16_to_cpu(dev->descriptor.idProduct));
486 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
487 		goto __err_val;
488 
489 	if (snd_usb_apply_boot_quirk(dev, intf, quirk) < 0)
490 		goto __err_val;
491 
492 	/*
493 	 * found a config.  now register to ALSA
494 	 */
495 
496 	/* check whether it's already registered */
497 	chip = NULL;
498 	mutex_lock(&register_mutex);
499 	for (i = 0; i < SNDRV_CARDS; i++) {
500 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
501 			if (usb_chip[i]->shutdown) {
502 				snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
503 				goto __error;
504 			}
505 			chip = usb_chip[i];
506 			chip->probing = 1;
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 				if (snd_usb_audio_create(intf, dev, i, quirk,
519 							 &chip) < 0) {
520 					goto __error;
521 				}
522 				chip->pm_intf = intf;
523 				break;
524 			}
525 		if (!chip) {
526 			printk(KERN_ERR "no available usb audio device\n");
527 			goto __error;
528 		}
529 	}
530 
531 	/*
532 	 * For devices with more than one control interface, we assume the
533 	 * first contains the audio controls. We might need a more specific
534 	 * check here in the future.
535 	 */
536 	if (!chip->ctrl_intf)
537 		chip->ctrl_intf = alts;
538 
539 	chip->txfr_quirk = 0;
540 	err = 1; /* continue */
541 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
542 		/* need some special handlings */
543 		if ((err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk)) < 0)
544 			goto __error;
545 	}
546 
547 	if (err > 0) {
548 		/* create normal USB audio interfaces */
549 		if (snd_usb_create_streams(chip, ifnum) < 0 ||
550 		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
551 			goto __error;
552 		}
553 	}
554 
555 	/* we are allowed to call snd_card_register() many times */
556 	if (snd_card_register(chip->card) < 0) {
557 		goto __error;
558 	}
559 
560 	usb_chip[chip->index] = chip;
561 	chip->num_interfaces++;
562 	chip->probing = 0;
563 	mutex_unlock(&register_mutex);
564 	return chip;
565 
566  __error:
567 	if (chip) {
568 		if (!chip->num_interfaces)
569 			snd_card_free(chip->card);
570 		chip->probing = 0;
571 	}
572 	mutex_unlock(&register_mutex);
573  __err_val:
574 	return NULL;
575 }
576 
577 /*
578  * we need to take care of counter, since disconnection can be called also
579  * many times as well as usb_audio_probe().
580  */
581 static void snd_usb_audio_disconnect(struct usb_device *dev,
582 				     struct snd_usb_audio *chip)
583 {
584 	struct snd_card *card;
585 	struct list_head *p, *n;
586 
587 	if (chip == (void *)-1L)
588 		return;
589 
590 	card = chip->card;
591 	down_write(&chip->shutdown_rwsem);
592 	chip->shutdown = 1;
593 	up_write(&chip->shutdown_rwsem);
594 
595 	mutex_lock(&register_mutex);
596 	chip->num_interfaces--;
597 	if (chip->num_interfaces <= 0) {
598 		snd_card_disconnect(card);
599 		/* release the pcm resources */
600 		list_for_each(p, &chip->pcm_list) {
601 			snd_usb_stream_disconnect(p);
602 		}
603 		/* release the endpoint resources */
604 		list_for_each_safe(p, n, &chip->ep_list) {
605 			snd_usb_endpoint_free(p);
606 		}
607 		/* release the midi resources */
608 		list_for_each(p, &chip->midi_list) {
609 			snd_usbmidi_disconnect(p);
610 		}
611 		/* release mixer resources */
612 		list_for_each(p, &chip->mixer_list) {
613 			snd_usb_mixer_disconnect(p);
614 		}
615 		usb_chip[chip->index] = NULL;
616 		mutex_unlock(&register_mutex);
617 		snd_card_free_when_closed(card);
618 	} else {
619 		mutex_unlock(&register_mutex);
620 	}
621 }
622 
623 /*
624  * new 2.5 USB kernel API
625  */
626 static int usb_audio_probe(struct usb_interface *intf,
627 			   const struct usb_device_id *id)
628 {
629 	struct snd_usb_audio *chip;
630 	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
631 	if (chip) {
632 		usb_set_intfdata(intf, chip);
633 		return 0;
634 	} else
635 		return -EIO;
636 }
637 
638 static void usb_audio_disconnect(struct usb_interface *intf)
639 {
640 	snd_usb_audio_disconnect(interface_to_usbdev(intf),
641 				 usb_get_intfdata(intf));
642 }
643 
644 #ifdef CONFIG_PM
645 
646 int snd_usb_autoresume(struct snd_usb_audio *chip)
647 {
648 	int err = -ENODEV;
649 
650 	down_read(&chip->shutdown_rwsem);
651 	if (chip->probing)
652 		err = 0;
653 	else if (!chip->shutdown)
654 		err = usb_autopm_get_interface(chip->pm_intf);
655 	up_read(&chip->shutdown_rwsem);
656 
657 	return err;
658 }
659 
660 void snd_usb_autosuspend(struct snd_usb_audio *chip)
661 {
662 	down_read(&chip->shutdown_rwsem);
663 	if (!chip->shutdown && !chip->probing)
664 		usb_autopm_put_interface(chip->pm_intf);
665 	up_read(&chip->shutdown_rwsem);
666 }
667 
668 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
669 {
670 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
671 	struct snd_usb_stream *as;
672 	struct usb_mixer_interface *mixer;
673 
674 	if (chip == (void *)-1L)
675 		return 0;
676 
677 	if (!PMSG_IS_AUTO(message)) {
678 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
679 		if (!chip->num_suspended_intf++) {
680 			list_for_each_entry(as, &chip->pcm_list, list) {
681 				snd_pcm_suspend_all(as->pcm);
682 				as->substream[0].need_setup_ep =
683 					as->substream[1].need_setup_ep = true;
684 			}
685 		}
686 	} else {
687 		/*
688 		 * otherwise we keep the rest of the system in the dark
689 		 * to keep this transparent
690 		 */
691 		if (!chip->num_suspended_intf++)
692 			chip->autosuspended = 1;
693 	}
694 
695 	list_for_each_entry(mixer, &chip->mixer_list, list)
696 		snd_usb_mixer_suspend(mixer);
697 
698 	return 0;
699 }
700 
701 static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
702 {
703 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
704 	struct usb_mixer_interface *mixer;
705 	int err = 0;
706 
707 	if (chip == (void *)-1L)
708 		return 0;
709 	if (--chip->num_suspended_intf)
710 		return 0;
711 	/*
712 	 * ALSA leaves material resumption to user space
713 	 * we just notify and restart the mixers
714 	 */
715 	list_for_each_entry(mixer, &chip->mixer_list, list) {
716 		err = snd_usb_mixer_resume(mixer, reset_resume);
717 		if (err < 0)
718 			goto err_out;
719 	}
720 
721 	if (!chip->autosuspended)
722 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
723 	chip->autosuspended = 0;
724 
725 err_out:
726 	return err;
727 }
728 
729 static int usb_audio_resume(struct usb_interface *intf)
730 {
731 	return __usb_audio_resume(intf, false);
732 }
733 
734 static int usb_audio_reset_resume(struct usb_interface *intf)
735 {
736 	return __usb_audio_resume(intf, true);
737 }
738 #else
739 #define usb_audio_suspend	NULL
740 #define usb_audio_resume	NULL
741 #define usb_audio_reset_resume	NULL
742 #endif		/* CONFIG_PM */
743 
744 static struct usb_device_id usb_audio_ids [] = {
745 #include "quirks-table.h"
746     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
747       .bInterfaceClass = USB_CLASS_AUDIO,
748       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
749     { }						/* Terminating entry */
750 };
751 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
752 
753 /*
754  * entry point for linux usb interface
755  */
756 
757 static struct usb_driver usb_audio_driver = {
758 	.name =		"snd-usb-audio",
759 	.probe =	usb_audio_probe,
760 	.disconnect =	usb_audio_disconnect,
761 	.suspend =	usb_audio_suspend,
762 	.resume =	usb_audio_resume,
763 	.reset_resume =	usb_audio_reset_resume,
764 	.id_table =	usb_audio_ids,
765 	.supports_autosuspend = 1,
766 };
767 
768 module_usb_driver(usb_audio_driver);
769