xref: /openbmc/linux/sound/usb/card.c (revision 2f4e3926)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   (Tentative) USB Audio Driver for ALSA
4  *
5  *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
6  *
7  *   Many codes borrowed from audio.c by
8  *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
9  *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
10  *
11  *   Audio Class 3.0 support by Ruslan Bilovol <ruslan.bilovol@gmail.com>
12  *
13  *  NOTES:
14  *
15  *   - the linked URBs would be preferred but not used so far because of
16  *     the instability of unlinking.
17  *   - type II is not supported properly.  there is no device which supports
18  *     this type *correctly*.  SB extigy looks as if it supports, but it's
19  *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
20  */
21 
22 
23 #include <linux/bitops.h>
24 #include <linux/init.h>
25 #include <linux/list.h>
26 #include <linux/slab.h>
27 #include <linux/string.h>
28 #include <linux/ctype.h>
29 #include <linux/usb.h>
30 #include <linux/moduleparam.h>
31 #include <linux/mutex.h>
32 #include <linux/usb/audio.h>
33 #include <linux/usb/audio-v2.h>
34 #include <linux/usb/audio-v3.h>
35 #include <linux/module.h>
36 
37 #include <sound/control.h>
38 #include <sound/core.h>
39 #include <sound/info.h>
40 #include <sound/pcm.h>
41 #include <sound/pcm_params.h>
42 #include <sound/initval.h>
43 
44 #include "usbaudio.h"
45 #include "card.h"
46 #include "midi.h"
47 #include "midi2.h"
48 #include "mixer.h"
49 #include "proc.h"
50 #include "quirks.h"
51 #include "endpoint.h"
52 #include "helper.h"
53 #include "pcm.h"
54 #include "format.h"
55 #include "power.h"
56 #include "stream.h"
57 #include "media.h"
58 
59 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
60 MODULE_DESCRIPTION("USB Audio");
61 MODULE_LICENSE("GPL");
62 
63 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
64 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
65 static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
66 /* Vendor/product IDs for this card */
67 static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
68 static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
69 static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
70 static bool ignore_ctl_error;
71 static bool autoclock = true;
72 static bool lowlatency = true;
73 static char *quirk_alias[SNDRV_CARDS];
74 static char *delayed_register[SNDRV_CARDS];
75 static bool implicit_fb[SNDRV_CARDS];
76 static unsigned int quirk_flags[SNDRV_CARDS];
77 
78 bool snd_usb_use_vmalloc = true;
79 bool snd_usb_skip_validation;
80 
81 module_param_array(index, int, NULL, 0444);
82 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
83 module_param_array(id, charp, NULL, 0444);
84 MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
85 module_param_array(enable, bool, NULL, 0444);
86 MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
87 module_param_array(vid, int, NULL, 0444);
88 MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
89 module_param_array(pid, int, NULL, 0444);
90 MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
91 module_param_array(device_setup, int, NULL, 0444);
92 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
93 module_param(ignore_ctl_error, bool, 0444);
94 MODULE_PARM_DESC(ignore_ctl_error,
95 		 "Ignore errors from USB controller for mixer interfaces.");
96 module_param(autoclock, bool, 0444);
97 MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
98 module_param(lowlatency, bool, 0444);
99 MODULE_PARM_DESC(lowlatency, "Enable low latency playback (default: yes).");
100 module_param_array(quirk_alias, charp, NULL, 0444);
101 MODULE_PARM_DESC(quirk_alias, "Quirk aliases, e.g. 0123abcd:5678beef.");
102 module_param_array(delayed_register, charp, NULL, 0444);
103 MODULE_PARM_DESC(delayed_register, "Quirk for delayed registration, given by id:iface, e.g. 0123abcd:4.");
104 module_param_array(implicit_fb, bool, NULL, 0444);
105 MODULE_PARM_DESC(implicit_fb, "Apply generic implicit feedback sync mode.");
106 module_param_array(quirk_flags, uint, NULL, 0444);
107 MODULE_PARM_DESC(quirk_flags, "Driver quirk bit flags.");
108 module_param_named(use_vmalloc, snd_usb_use_vmalloc, bool, 0444);
109 MODULE_PARM_DESC(use_vmalloc, "Use vmalloc for PCM intermediate buffers (default: yes).");
110 module_param_named(skip_validation, snd_usb_skip_validation, bool, 0444);
111 MODULE_PARM_DESC(skip_validation, "Skip unit descriptor validation (default: no).");
112 
113 /*
114  * we keep the snd_usb_audio_t instances by ourselves for merging
115  * the all interfaces on the same card as one sound device.
116  */
117 
118 static DEFINE_MUTEX(register_mutex);
119 static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
120 static struct usb_driver usb_audio_driver;
121 
122 /*
123  * disconnect streams
124  * called from usb_audio_disconnect()
125  */
126 static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
127 {
128 	int idx;
129 	struct snd_usb_substream *subs;
130 
131 	for (idx = 0; idx < 2; idx++) {
132 		subs = &as->substream[idx];
133 		if (!subs->num_formats)
134 			continue;
135 		subs->data_endpoint = NULL;
136 		subs->sync_endpoint = NULL;
137 	}
138 }
139 
140 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
141 {
142 	struct usb_device *dev = chip->dev;
143 	struct usb_host_interface *alts;
144 	struct usb_interface_descriptor *altsd;
145 	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
146 
147 	if (!iface) {
148 		dev_err(&dev->dev, "%u:%d : does not exist\n",
149 			ctrlif, interface);
150 		return -EINVAL;
151 	}
152 
153 	alts = &iface->altsetting[0];
154 	altsd = get_iface_desc(alts);
155 
156 	/*
157 	 * Android with both accessory and audio interfaces enabled gets the
158 	 * interface numbers wrong.
159 	 */
160 	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
161 	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
162 	    interface == 0 &&
163 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
164 	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
165 		interface = 2;
166 		iface = usb_ifnum_to_if(dev, interface);
167 		if (!iface)
168 			return -EINVAL;
169 		alts = &iface->altsetting[0];
170 		altsd = get_iface_desc(alts);
171 	}
172 
173 	if (usb_interface_claimed(iface)) {
174 		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
175 			ctrlif, interface);
176 		return -EINVAL;
177 	}
178 
179 	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
180 	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
181 	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
182 		int err = snd_usb_midi_v2_create(chip, iface, NULL,
183 						 chip->usb_id);
184 		if (err < 0) {
185 			dev_err(&dev->dev,
186 				"%u:%d: cannot create sequencer device\n",
187 				ctrlif, interface);
188 			return -EINVAL;
189 		}
190 		return usb_driver_claim_interface(&usb_audio_driver, iface,
191 						  USB_AUDIO_IFACE_UNUSED);
192 	}
193 
194 	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
195 	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
196 	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
197 		dev_dbg(&dev->dev,
198 			"%u:%d: skipping non-supported interface %d\n",
199 			ctrlif, interface, altsd->bInterfaceClass);
200 		/* skip non-supported classes */
201 		return -EINVAL;
202 	}
203 
204 	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
205 		dev_err(&dev->dev, "low speed audio streaming not supported\n");
206 		return -EINVAL;
207 	}
208 
209 	if (! snd_usb_parse_audio_interface(chip, interface)) {
210 		usb_set_interface(dev, interface, 0); /* reset the current interface */
211 		return usb_driver_claim_interface(&usb_audio_driver, iface,
212 						  USB_AUDIO_IFACE_UNUSED);
213 	}
214 
215 	return 0;
216 }
217 
218 /*
219  * parse audio control descriptor and create pcm/midi streams
220  */
221 static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
222 {
223 	struct usb_device *dev = chip->dev;
224 	struct usb_host_interface *host_iface;
225 	struct usb_interface_descriptor *altsd;
226 	int i, protocol;
227 
228 	/* find audiocontrol interface */
229 	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
230 	altsd = get_iface_desc(host_iface);
231 	protocol = altsd->bInterfaceProtocol;
232 
233 	switch (protocol) {
234 	default:
235 		dev_warn(&dev->dev,
236 			 "unknown interface protocol %#02x, assuming v1\n",
237 			 protocol);
238 		fallthrough;
239 
240 	case UAC_VERSION_1: {
241 		struct uac1_ac_header_descriptor *h1;
242 		int rest_bytes;
243 
244 		h1 = snd_usb_find_csint_desc(host_iface->extra,
245 							 host_iface->extralen,
246 							 NULL, UAC_HEADER);
247 		if (!h1 || h1->bLength < sizeof(*h1)) {
248 			dev_err(&dev->dev, "cannot find UAC_HEADER\n");
249 			return -EINVAL;
250 		}
251 
252 		rest_bytes = (void *)(host_iface->extra +
253 				host_iface->extralen) - (void *)h1;
254 
255 		/* just to be sure -- this shouldn't hit at all */
256 		if (rest_bytes <= 0) {
257 			dev_err(&dev->dev, "invalid control header\n");
258 			return -EINVAL;
259 		}
260 
261 		if (rest_bytes < sizeof(*h1)) {
262 			dev_err(&dev->dev, "too short v1 buffer descriptor\n");
263 			return -EINVAL;
264 		}
265 
266 		if (!h1->bInCollection) {
267 			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
268 			return -EINVAL;
269 		}
270 
271 		if (rest_bytes < h1->bLength) {
272 			dev_err(&dev->dev, "invalid buffer length (v1)\n");
273 			return -EINVAL;
274 		}
275 
276 		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
277 			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
278 			return -EINVAL;
279 		}
280 
281 		for (i = 0; i < h1->bInCollection; i++)
282 			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
283 
284 		break;
285 	}
286 
287 	case UAC_VERSION_2:
288 	case UAC_VERSION_3: {
289 		struct usb_interface_assoc_descriptor *assoc =
290 			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
291 
292 		if (!assoc) {
293 			/*
294 			 * Firmware writers cannot count to three.  So to find
295 			 * the IAD on the NuForce UDH-100, also check the next
296 			 * interface.
297 			 */
298 			struct usb_interface *iface =
299 				usb_ifnum_to_if(dev, ctrlif + 1);
300 			if (iface &&
301 			    iface->intf_assoc &&
302 			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
303 			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
304 				assoc = iface->intf_assoc;
305 		}
306 
307 		if (!assoc) {
308 			dev_err(&dev->dev, "Audio class v2/v3 interfaces need an interface association\n");
309 			return -EINVAL;
310 		}
311 
312 		if (protocol == UAC_VERSION_3) {
313 			int badd = assoc->bFunctionSubClass;
314 
315 			if (badd != UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0 &&
316 			    (badd < UAC3_FUNCTION_SUBCLASS_GENERIC_IO ||
317 			     badd > UAC3_FUNCTION_SUBCLASS_SPEAKERPHONE)) {
318 				dev_err(&dev->dev,
319 					"Unsupported UAC3 BADD profile\n");
320 				return -EINVAL;
321 			}
322 
323 			chip->badd_profile = badd;
324 		}
325 
326 		for (i = 0; i < assoc->bInterfaceCount; i++) {
327 			int intf = assoc->bFirstInterface + i;
328 
329 			if (intf != ctrlif)
330 				snd_usb_create_stream(chip, ctrlif, intf);
331 		}
332 
333 		break;
334 	}
335 	}
336 
337 	return 0;
338 }
339 
340 /*
341  * Profile name preset table
342  */
343 struct usb_audio_device_name {
344 	u32 id;
345 	const char *vendor_name;
346 	const char *product_name;
347 	const char *profile_name;	/* override card->longname */
348 };
349 
350 #define PROFILE_NAME(vid, pid, vendor, product, profile)	 \
351 	{ .id = USB_ID(vid, pid), .vendor_name = (vendor),	 \
352 	  .product_name = (product), .profile_name = (profile) }
353 #define DEVICE_NAME(vid, pid, vendor, product) \
354 	PROFILE_NAME(vid, pid, vendor, product, NULL)
355 
356 /* vendor/product and profile name presets, sorted in device id order */
357 static const struct usb_audio_device_name usb_audio_names[] = {
358 	/* HP Thunderbolt Dock Audio Headset */
359 	PROFILE_NAME(0x03f0, 0x0269, "HP", "Thunderbolt Dock Audio Headset",
360 		     "HP-Thunderbolt-Dock-Audio-Headset"),
361 	/* HP Thunderbolt Dock Audio Module */
362 	PROFILE_NAME(0x03f0, 0x0567, "HP", "Thunderbolt Dock Audio Module",
363 		     "HP-Thunderbolt-Dock-Audio-Module"),
364 
365 	/* Two entries for Gigabyte TRX40 Aorus Master:
366 	 * TRX40 Aorus Master has two USB-audio devices, one for the front
367 	 * headphone with ESS SABRE9218 DAC chip, while another for the rest
368 	 * I/O (the rear panel and the front mic) with Realtek ALC1220-VB.
369 	 * Here we provide two distinct names for making UCM profiles easier.
370 	 */
371 	PROFILE_NAME(0x0414, 0xa000, "Gigabyte", "Aorus Master Front Headphone",
372 		     "Gigabyte-Aorus-Master-Front-Headphone"),
373 	PROFILE_NAME(0x0414, 0xa001, "Gigabyte", "Aorus Master Main Audio",
374 		     "Gigabyte-Aorus-Master-Main-Audio"),
375 
376 	/* Gigabyte TRX40 Aorus Pro WiFi */
377 	PROFILE_NAME(0x0414, 0xa002,
378 		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
379 
380 	/* Creative/E-Mu devices */
381 	DEVICE_NAME(0x041e, 0x3010, "Creative Labs", "Sound Blaster MP3+"),
382 	/* Creative/Toshiba Multimedia Center SB-0500 */
383 	DEVICE_NAME(0x041e, 0x3048, "Toshiba", "SB-0500"),
384 
385 	/* Logitech Audio Devices */
386 	DEVICE_NAME(0x046d, 0x0867, "Logitech, Inc.", "Logi-MeetUp"),
387 	DEVICE_NAME(0x046d, 0x0874, "Logitech, Inc.", "Logi-Tap-Audio"),
388 	DEVICE_NAME(0x046d, 0x087c, "Logitech, Inc.", "Logi-Huddle"),
389 	DEVICE_NAME(0x046d, 0x0898, "Logitech, Inc.", "Logi-RB-Audio"),
390 	DEVICE_NAME(0x046d, 0x08d2, "Logitech, Inc.", "Logi-RBM-Audio"),
391 	DEVICE_NAME(0x046d, 0x0990, "Logitech, Inc.", "QuickCam Pro 9000"),
392 
393 	DEVICE_NAME(0x05e1, 0x0408, "Syntek", "STK1160"),
394 	DEVICE_NAME(0x05e1, 0x0480, "Hauppauge", "Woodbury"),
395 
396 	/* ASUS ROG Zenith II: this machine has also two devices, one for
397 	 * the front headphone and another for the rest
398 	 */
399 	PROFILE_NAME(0x0b05, 0x1915, "ASUS", "Zenith II Front Headphone",
400 		     "Zenith-II-Front-Headphone"),
401 	PROFILE_NAME(0x0b05, 0x1916, "ASUS", "Zenith II Main Audio",
402 		     "Zenith-II-Main-Audio"),
403 
404 	/* ASUS ROG Strix */
405 	PROFILE_NAME(0x0b05, 0x1917,
406 		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
407 	/* ASUS PRIME TRX40 PRO-S */
408 	PROFILE_NAME(0x0b05, 0x1918,
409 		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
410 
411 	/* Dell WD15 Dock */
412 	PROFILE_NAME(0x0bda, 0x4014, "Dell", "WD15 Dock", "Dell-WD15-Dock"),
413 	/* Dell WD19 Dock */
414 	PROFILE_NAME(0x0bda, 0x402e, "Dell", "WD19 Dock", "Dell-WD15-Dock"),
415 
416 	DEVICE_NAME(0x0ccd, 0x0028, "TerraTec", "Aureon5.1MkII"),
417 
418 	/*
419 	 * The original product_name is "USB Sound Device", however this name
420 	 * is also used by the CM106 based cards, so make it unique.
421 	 */
422 	DEVICE_NAME(0x0d8c, 0x0102, NULL, "ICUSBAUDIO7D"),
423 	DEVICE_NAME(0x0d8c, 0x0103, NULL, "Audio Advantage MicroII"),
424 
425 	/* MSI TRX40 Creator */
426 	PROFILE_NAME(0x0db0, 0x0d64,
427 		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
428 	/* MSI TRX40 */
429 	PROFILE_NAME(0x0db0, 0x543d,
430 		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
431 
432 	DEVICE_NAME(0x0fd9, 0x0008, "Hauppauge", "HVR-950Q"),
433 
434 	/* Stanton/N2IT Final Scratch v1 device ('Scratchamp') */
435 	DEVICE_NAME(0x103d, 0x0100, "Stanton", "ScratchAmp"),
436 	DEVICE_NAME(0x103d, 0x0101, "Stanton", "ScratchAmp"),
437 
438 	/* aka. Serato Scratch Live DJ Box */
439 	DEVICE_NAME(0x13e5, 0x0001, "Rane", "SL-1"),
440 
441 	/* Lenovo ThinkStation P620 Rear Line-in, Line-out and Microphone */
442 	PROFILE_NAME(0x17aa, 0x1046, "Lenovo", "ThinkStation P620 Rear",
443 		     "Lenovo-ThinkStation-P620-Rear"),
444 	/* Lenovo ThinkStation P620 Internal Speaker + Front Headset */
445 	PROFILE_NAME(0x17aa, 0x104d, "Lenovo", "ThinkStation P620 Main",
446 		     "Lenovo-ThinkStation-P620-Main"),
447 
448 	/* Asrock TRX40 Creator */
449 	PROFILE_NAME(0x26ce, 0x0a01,
450 		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
451 
452 	DEVICE_NAME(0x2040, 0x7200, "Hauppauge", "HVR-950Q"),
453 	DEVICE_NAME(0x2040, 0x7201, "Hauppauge", "HVR-950Q-MXL"),
454 	DEVICE_NAME(0x2040, 0x7210, "Hauppauge", "HVR-950Q"),
455 	DEVICE_NAME(0x2040, 0x7211, "Hauppauge", "HVR-950Q-MXL"),
456 	DEVICE_NAME(0x2040, 0x7213, "Hauppauge", "HVR-950Q"),
457 	DEVICE_NAME(0x2040, 0x7217, "Hauppauge", "HVR-950Q"),
458 	DEVICE_NAME(0x2040, 0x721b, "Hauppauge", "HVR-950Q"),
459 	DEVICE_NAME(0x2040, 0x721e, "Hauppauge", "HVR-950Q"),
460 	DEVICE_NAME(0x2040, 0x721f, "Hauppauge", "HVR-950Q"),
461 	DEVICE_NAME(0x2040, 0x7240, "Hauppauge", "HVR-850"),
462 	DEVICE_NAME(0x2040, 0x7260, "Hauppauge", "HVR-950Q"),
463 	DEVICE_NAME(0x2040, 0x7270, "Hauppauge", "HVR-950Q"),
464 	DEVICE_NAME(0x2040, 0x7280, "Hauppauge", "HVR-950Q"),
465 	DEVICE_NAME(0x2040, 0x7281, "Hauppauge", "HVR-950Q-MXL"),
466 	DEVICE_NAME(0x2040, 0x8200, "Hauppauge", "Woodbury"),
467 
468 	{ } /* terminator */
469 };
470 
471 static const struct usb_audio_device_name *
472 lookup_device_name(u32 id)
473 {
474 	static const struct usb_audio_device_name *p;
475 
476 	for (p = usb_audio_names; p->id; p++)
477 		if (p->id == id)
478 			return p;
479 	return NULL;
480 }
481 
482 /*
483  * free the chip instance
484  *
485  * here we have to do not much, since pcm and controls are already freed
486  *
487  */
488 
489 static void snd_usb_audio_free(struct snd_card *card)
490 {
491 	struct snd_usb_audio *chip = card->private_data;
492 
493 	snd_usb_endpoint_free_all(chip);
494 	snd_usb_midi_v2_free_all(chip);
495 
496 	mutex_destroy(&chip->mutex);
497 	if (!atomic_read(&chip->shutdown))
498 		dev_set_drvdata(&chip->dev->dev, NULL);
499 }
500 
501 static void usb_audio_make_shortname(struct usb_device *dev,
502 				     struct snd_usb_audio *chip,
503 				     const struct snd_usb_audio_quirk *quirk)
504 {
505 	struct snd_card *card = chip->card;
506 	const struct usb_audio_device_name *preset;
507 	const char *s = NULL;
508 
509 	preset = lookup_device_name(chip->usb_id);
510 	if (preset && preset->product_name)
511 		s = preset->product_name;
512 	else if (quirk && quirk->product_name)
513 		s = quirk->product_name;
514 	if (s && *s) {
515 		strscpy(card->shortname, s, sizeof(card->shortname));
516 		return;
517 	}
518 
519 	/* retrieve the device string as shortname */
520 	if (!dev->descriptor.iProduct ||
521 	    usb_string(dev, dev->descriptor.iProduct,
522 		       card->shortname, sizeof(card->shortname)) <= 0) {
523 		/* no name available from anywhere, so use ID */
524 		sprintf(card->shortname, "USB Device %#04x:%#04x",
525 			USB_ID_VENDOR(chip->usb_id),
526 			USB_ID_PRODUCT(chip->usb_id));
527 	}
528 
529 	strim(card->shortname);
530 }
531 
532 static void usb_audio_make_longname(struct usb_device *dev,
533 				    struct snd_usb_audio *chip,
534 				    const struct snd_usb_audio_quirk *quirk)
535 {
536 	struct snd_card *card = chip->card;
537 	const struct usb_audio_device_name *preset;
538 	const char *s = NULL;
539 	int len;
540 
541 	preset = lookup_device_name(chip->usb_id);
542 
543 	/* shortcut - if any pre-defined string is given, use it */
544 	if (preset && preset->profile_name)
545 		s = preset->profile_name;
546 	if (s && *s) {
547 		strscpy(card->longname, s, sizeof(card->longname));
548 		return;
549 	}
550 
551 	if (preset && preset->vendor_name)
552 		s = preset->vendor_name;
553 	else if (quirk && quirk->vendor_name)
554 		s = quirk->vendor_name;
555 	*card->longname = 0;
556 	if (s && *s) {
557 		strscpy(card->longname, s, sizeof(card->longname));
558 	} else {
559 		/* retrieve the vendor and device strings as longname */
560 		if (dev->descriptor.iManufacturer)
561 			usb_string(dev, dev->descriptor.iManufacturer,
562 				   card->longname, sizeof(card->longname));
563 		/* we don't really care if there isn't any vendor string */
564 	}
565 	if (*card->longname) {
566 		strim(card->longname);
567 		if (*card->longname)
568 			strlcat(card->longname, " ", sizeof(card->longname));
569 	}
570 
571 	strlcat(card->longname, card->shortname, sizeof(card->longname));
572 
573 	len = strlcat(card->longname, " at ", sizeof(card->longname));
574 
575 	if (len < sizeof(card->longname))
576 		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
577 
578 	switch (snd_usb_get_speed(dev)) {
579 	case USB_SPEED_LOW:
580 		strlcat(card->longname, ", low speed", sizeof(card->longname));
581 		break;
582 	case USB_SPEED_FULL:
583 		strlcat(card->longname, ", full speed", sizeof(card->longname));
584 		break;
585 	case USB_SPEED_HIGH:
586 		strlcat(card->longname, ", high speed", sizeof(card->longname));
587 		break;
588 	case USB_SPEED_SUPER:
589 		strlcat(card->longname, ", super speed", sizeof(card->longname));
590 		break;
591 	case USB_SPEED_SUPER_PLUS:
592 		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
593 		break;
594 	default:
595 		break;
596 	}
597 }
598 
599 /*
600  * create a chip instance and set its names.
601  */
602 static int snd_usb_audio_create(struct usb_interface *intf,
603 				struct usb_device *dev, int idx,
604 				const struct snd_usb_audio_quirk *quirk,
605 				unsigned int usb_id,
606 				struct snd_usb_audio **rchip)
607 {
608 	struct snd_card *card;
609 	struct snd_usb_audio *chip;
610 	int err;
611 	char component[14];
612 
613 	*rchip = NULL;
614 
615 	switch (snd_usb_get_speed(dev)) {
616 	case USB_SPEED_LOW:
617 	case USB_SPEED_FULL:
618 	case USB_SPEED_HIGH:
619 	case USB_SPEED_SUPER:
620 	case USB_SPEED_SUPER_PLUS:
621 		break;
622 	default:
623 		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
624 		return -ENXIO;
625 	}
626 
627 	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
628 			   sizeof(*chip), &card);
629 	if (err < 0) {
630 		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
631 		return err;
632 	}
633 
634 	chip = card->private_data;
635 	mutex_init(&chip->mutex);
636 	init_waitqueue_head(&chip->shutdown_wait);
637 	chip->index = idx;
638 	chip->dev = dev;
639 	chip->card = card;
640 	chip->setup = device_setup[idx];
641 	chip->generic_implicit_fb = implicit_fb[idx];
642 	chip->autoclock = autoclock;
643 	chip->lowlatency = lowlatency;
644 	atomic_set(&chip->active, 1); /* avoid autopm during probing */
645 	atomic_set(&chip->usage_count, 0);
646 	atomic_set(&chip->shutdown, 0);
647 
648 	chip->usb_id = usb_id;
649 	INIT_LIST_HEAD(&chip->pcm_list);
650 	INIT_LIST_HEAD(&chip->ep_list);
651 	INIT_LIST_HEAD(&chip->iface_ref_list);
652 	INIT_LIST_HEAD(&chip->clock_ref_list);
653 	INIT_LIST_HEAD(&chip->midi_list);
654 	INIT_LIST_HEAD(&chip->midi_v2_list);
655 	INIT_LIST_HEAD(&chip->mixer_list);
656 
657 	if (quirk_flags[idx])
658 		chip->quirk_flags = quirk_flags[idx];
659 	else
660 		snd_usb_init_quirk_flags(chip);
661 
662 	card->private_free = snd_usb_audio_free;
663 
664 	strcpy(card->driver, "USB-Audio");
665 	sprintf(component, "USB%04x:%04x",
666 		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
667 	snd_component_add(card, component);
668 
669 	usb_audio_make_shortname(dev, chip, quirk);
670 	usb_audio_make_longname(dev, chip, quirk);
671 
672 	snd_usb_audio_create_proc(chip);
673 
674 	*rchip = chip;
675 	return 0;
676 }
677 
678 /* look for a matching quirk alias id */
679 static bool get_alias_id(struct usb_device *dev, unsigned int *id)
680 {
681 	int i;
682 	unsigned int src, dst;
683 
684 	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
685 		if (!quirk_alias[i] ||
686 		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
687 		    src != *id)
688 			continue;
689 		dev_info(&dev->dev,
690 			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
691 			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
692 			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
693 		*id = dst;
694 		return true;
695 	}
696 
697 	return false;
698 }
699 
700 static int check_delayed_register_option(struct snd_usb_audio *chip)
701 {
702 	int i;
703 	unsigned int id, inum;
704 
705 	for (i = 0; i < ARRAY_SIZE(delayed_register); i++) {
706 		if (delayed_register[i] &&
707 		    sscanf(delayed_register[i], "%x:%x", &id, &inum) == 2 &&
708 		    id == chip->usb_id)
709 			return inum;
710 	}
711 
712 	return -1;
713 }
714 
715 static const struct usb_device_id usb_audio_ids[]; /* defined below */
716 
717 /* look for the last interface that matches with our ids and remember it */
718 static void find_last_interface(struct snd_usb_audio *chip)
719 {
720 	struct usb_host_config *config = chip->dev->actconfig;
721 	struct usb_interface *intf;
722 	int i;
723 
724 	if (!config)
725 		return;
726 	for (i = 0; i < config->desc.bNumInterfaces; i++) {
727 		intf = config->interface[i];
728 		if (usb_match_id(intf, usb_audio_ids))
729 			chip->last_iface = intf->altsetting[0].desc.bInterfaceNumber;
730 	}
731 	usb_audio_dbg(chip, "Found last interface = %d\n", chip->last_iface);
732 }
733 
734 /* look for the corresponding quirk */
735 static const struct snd_usb_audio_quirk *
736 get_alias_quirk(struct usb_device *dev, unsigned int id)
737 {
738 	const struct usb_device_id *p;
739 
740 	for (p = usb_audio_ids; p->match_flags; p++) {
741 		/* FIXME: this checks only vendor:product pair in the list */
742 		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) ==
743 		    USB_DEVICE_ID_MATCH_DEVICE &&
744 		    p->idVendor == USB_ID_VENDOR(id) &&
745 		    p->idProduct == USB_ID_PRODUCT(id))
746 			return (const struct snd_usb_audio_quirk *)p->driver_info;
747 	}
748 
749 	return NULL;
750 }
751 
752 /* register card if we reach to the last interface or to the specified
753  * one given via option
754  */
755 static int try_to_register_card(struct snd_usb_audio *chip, int ifnum)
756 {
757 	if (check_delayed_register_option(chip) == ifnum ||
758 	    chip->last_iface == ifnum ||
759 	    usb_interface_claimed(usb_ifnum_to_if(chip->dev, chip->last_iface)))
760 		return snd_card_register(chip->card);
761 	return 0;
762 }
763 
764 /*
765  * probe the active usb device
766  *
767  * note that this can be called multiple times per a device, when it
768  * includes multiple audio control interfaces.
769  *
770  * thus we check the usb device pointer and creates the card instance
771  * only at the first time.  the successive calls of this function will
772  * append the pcm interface to the corresponding card.
773  */
774 static int usb_audio_probe(struct usb_interface *intf,
775 			   const struct usb_device_id *usb_id)
776 {
777 	struct usb_device *dev = interface_to_usbdev(intf);
778 	const struct snd_usb_audio_quirk *quirk =
779 		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
780 	struct snd_usb_audio *chip;
781 	int i, err;
782 	struct usb_host_interface *alts;
783 	int ifnum;
784 	u32 id;
785 
786 	alts = &intf->altsetting[0];
787 	ifnum = get_iface_desc(alts)->bInterfaceNumber;
788 	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
789 		    le16_to_cpu(dev->descriptor.idProduct));
790 	if (get_alias_id(dev, &id))
791 		quirk = get_alias_quirk(dev, id);
792 	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
793 		return -ENXIO;
794 	if (quirk && quirk->ifnum == QUIRK_NODEV_INTERFACE)
795 		return -ENODEV;
796 
797 	err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
798 	if (err < 0)
799 		return err;
800 
801 	/*
802 	 * found a config.  now register to ALSA
803 	 */
804 
805 	/* check whether it's already registered */
806 	chip = NULL;
807 	mutex_lock(&register_mutex);
808 	for (i = 0; i < SNDRV_CARDS; i++) {
809 		if (usb_chip[i] && usb_chip[i]->dev == dev) {
810 			if (atomic_read(&usb_chip[i]->shutdown)) {
811 				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
812 				err = -EIO;
813 				goto __error;
814 			}
815 			chip = usb_chip[i];
816 			atomic_inc(&chip->active); /* avoid autopm */
817 			break;
818 		}
819 	}
820 	if (! chip) {
821 		err = snd_usb_apply_boot_quirk_once(dev, intf, quirk, id);
822 		if (err < 0)
823 			goto __error;
824 
825 		/* it's a fresh one.
826 		 * now look for an empty slot and create a new card instance
827 		 */
828 		for (i = 0; i < SNDRV_CARDS; i++)
829 			if (!usb_chip[i] &&
830 			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
831 			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
832 				if (enable[i]) {
833 					err = snd_usb_audio_create(intf, dev, i, quirk,
834 								   id, &chip);
835 					if (err < 0)
836 						goto __error;
837 					break;
838 				} else if (vid[i] != -1 || pid[i] != -1) {
839 					dev_info(&dev->dev,
840 						 "device (%04x:%04x) is disabled\n",
841 						 USB_ID_VENDOR(id),
842 						 USB_ID_PRODUCT(id));
843 					err = -ENOENT;
844 					goto __error;
845 				}
846 			}
847 		if (!chip) {
848 			dev_err(&dev->dev, "no available usb audio device\n");
849 			err = -ENODEV;
850 			goto __error;
851 		}
852 		find_last_interface(chip);
853 	}
854 
855 	if (chip->num_interfaces >= MAX_CARD_INTERFACES) {
856 		dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");
857 		err = -EINVAL;
858 		goto __error;
859 	}
860 
861 	dev_set_drvdata(&dev->dev, chip);
862 
863 	if (ignore_ctl_error)
864 		chip->quirk_flags |= QUIRK_FLAG_IGNORE_CTL_ERROR;
865 
866 	if (chip->quirk_flags & QUIRK_FLAG_DISABLE_AUTOSUSPEND)
867 		usb_disable_autosuspend(interface_to_usbdev(intf));
868 
869 	/*
870 	 * For devices with more than one control interface, we assume the
871 	 * first contains the audio controls. We might need a more specific
872 	 * check here in the future.
873 	 */
874 	if (!chip->ctrl_intf)
875 		chip->ctrl_intf = alts;
876 
877 	err = 1; /* continue */
878 	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
879 		/* need some special handlings */
880 		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
881 		if (err < 0)
882 			goto __error;
883 	}
884 
885 	if (err > 0) {
886 		/* create normal USB audio interfaces */
887 		err = snd_usb_create_streams(chip, ifnum);
888 		if (err < 0)
889 			goto __error;
890 		err = snd_usb_create_mixer(chip, ifnum);
891 		if (err < 0)
892 			goto __error;
893 	}
894 
895 	if (chip->need_delayed_register) {
896 		dev_info(&dev->dev,
897 			 "Found post-registration device assignment: %08x:%02x\n",
898 			 chip->usb_id, ifnum);
899 		chip->need_delayed_register = false; /* clear again */
900 	}
901 
902 	err = try_to_register_card(chip, ifnum);
903 	if (err < 0)
904 		goto __error_no_register;
905 
906 	if (chip->quirk_flags & QUIRK_FLAG_SHARE_MEDIA_DEVICE) {
907 		/* don't want to fail when snd_media_device_create() fails */
908 		snd_media_device_create(chip, intf);
909 	}
910 
911 	if (quirk)
912 		chip->quirk_type = quirk->type;
913 
914 	usb_chip[chip->index] = chip;
915 	chip->intf[chip->num_interfaces] = intf;
916 	chip->num_interfaces++;
917 	usb_set_intfdata(intf, chip);
918 	atomic_dec(&chip->active);
919 	mutex_unlock(&register_mutex);
920 	return 0;
921 
922  __error:
923 	/* in the case of error in secondary interface, still try to register */
924 	if (chip)
925 		try_to_register_card(chip, ifnum);
926 
927  __error_no_register:
928 	if (chip) {
929 		/* chip->active is inside the chip->card object,
930 		 * decrement before memory is possibly returned.
931 		 */
932 		atomic_dec(&chip->active);
933 		if (!chip->num_interfaces)
934 			snd_card_free(chip->card);
935 	}
936 	mutex_unlock(&register_mutex);
937 	return err;
938 }
939 
940 /*
941  * we need to take care of counter, since disconnection can be called also
942  * many times as well as usb_audio_probe().
943  */
944 static void usb_audio_disconnect(struct usb_interface *intf)
945 {
946 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
947 	struct snd_card *card;
948 	struct list_head *p;
949 
950 	if (chip == USB_AUDIO_IFACE_UNUSED)
951 		return;
952 
953 	card = chip->card;
954 
955 	mutex_lock(&register_mutex);
956 	if (atomic_inc_return(&chip->shutdown) == 1) {
957 		struct snd_usb_stream *as;
958 		struct snd_usb_endpoint *ep;
959 		struct usb_mixer_interface *mixer;
960 
961 		/* wait until all pending tasks done;
962 		 * they are protected by snd_usb_lock_shutdown()
963 		 */
964 		wait_event(chip->shutdown_wait,
965 			   !atomic_read(&chip->usage_count));
966 		snd_card_disconnect(card);
967 		/* release the pcm resources */
968 		list_for_each_entry(as, &chip->pcm_list, list) {
969 			snd_usb_stream_disconnect(as);
970 		}
971 		/* release the endpoint resources */
972 		list_for_each_entry(ep, &chip->ep_list, list) {
973 			snd_usb_endpoint_release(ep);
974 		}
975 		/* release the midi resources */
976 		list_for_each(p, &chip->midi_list) {
977 			snd_usbmidi_disconnect(p);
978 		}
979 		snd_usb_midi_v2_disconnect_all(chip);
980 		/*
981 		 * Nice to check quirk && quirk->shares_media_device and
982 		 * then call the snd_media_device_delete(). Don't have
983 		 * access to the quirk here. snd_media_device_delete()
984 		 * accesses mixer_list
985 		 */
986 		snd_media_device_delete(chip);
987 
988 		/* release mixer resources */
989 		list_for_each_entry(mixer, &chip->mixer_list, list) {
990 			snd_usb_mixer_disconnect(mixer);
991 		}
992 	}
993 
994 	if (chip->quirk_flags & QUIRK_FLAG_DISABLE_AUTOSUSPEND)
995 		usb_enable_autosuspend(interface_to_usbdev(intf));
996 
997 	chip->num_interfaces--;
998 	if (chip->num_interfaces <= 0) {
999 		usb_chip[chip->index] = NULL;
1000 		mutex_unlock(&register_mutex);
1001 		snd_card_free_when_closed(card);
1002 	} else {
1003 		mutex_unlock(&register_mutex);
1004 	}
1005 }
1006 
1007 /* lock the shutdown (disconnect) task and autoresume */
1008 int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
1009 {
1010 	int err;
1011 
1012 	atomic_inc(&chip->usage_count);
1013 	if (atomic_read(&chip->shutdown)) {
1014 		err = -EIO;
1015 		goto error;
1016 	}
1017 	err = snd_usb_autoresume(chip);
1018 	if (err < 0)
1019 		goto error;
1020 	return 0;
1021 
1022  error:
1023 	if (atomic_dec_and_test(&chip->usage_count))
1024 		wake_up(&chip->shutdown_wait);
1025 	return err;
1026 }
1027 
1028 /* autosuspend and unlock the shutdown */
1029 void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
1030 {
1031 	snd_usb_autosuspend(chip);
1032 	if (atomic_dec_and_test(&chip->usage_count))
1033 		wake_up(&chip->shutdown_wait);
1034 }
1035 
1036 int snd_usb_autoresume(struct snd_usb_audio *chip)
1037 {
1038 	int i, err;
1039 
1040 	if (atomic_read(&chip->shutdown))
1041 		return -EIO;
1042 	if (atomic_inc_return(&chip->active) != 1)
1043 		return 0;
1044 
1045 	for (i = 0; i < chip->num_interfaces; i++) {
1046 		err = usb_autopm_get_interface(chip->intf[i]);
1047 		if (err < 0) {
1048 			/* rollback */
1049 			while (--i >= 0)
1050 				usb_autopm_put_interface(chip->intf[i]);
1051 			atomic_dec(&chip->active);
1052 			return err;
1053 		}
1054 	}
1055 	return 0;
1056 }
1057 
1058 void snd_usb_autosuspend(struct snd_usb_audio *chip)
1059 {
1060 	int i;
1061 
1062 	if (atomic_read(&chip->shutdown))
1063 		return;
1064 	if (!atomic_dec_and_test(&chip->active))
1065 		return;
1066 
1067 	for (i = 0; i < chip->num_interfaces; i++)
1068 		usb_autopm_put_interface(chip->intf[i]);
1069 }
1070 
1071 static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
1072 {
1073 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
1074 	struct snd_usb_stream *as;
1075 	struct snd_usb_endpoint *ep;
1076 	struct usb_mixer_interface *mixer;
1077 	struct list_head *p;
1078 
1079 	if (chip == USB_AUDIO_IFACE_UNUSED)
1080 		return 0;
1081 
1082 	if (!chip->num_suspended_intf++) {
1083 		list_for_each_entry(as, &chip->pcm_list, list)
1084 			snd_usb_pcm_suspend(as);
1085 		list_for_each_entry(ep, &chip->ep_list, list)
1086 			snd_usb_endpoint_suspend(ep);
1087 		list_for_each(p, &chip->midi_list)
1088 			snd_usbmidi_suspend(p);
1089 		list_for_each_entry(mixer, &chip->mixer_list, list)
1090 			snd_usb_mixer_suspend(mixer);
1091 		snd_usb_midi_v2_suspend_all(chip);
1092 	}
1093 
1094 	if (!PMSG_IS_AUTO(message) && !chip->system_suspend) {
1095 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
1096 		chip->system_suspend = chip->num_suspended_intf;
1097 	}
1098 
1099 	return 0;
1100 }
1101 
1102 static int usb_audio_resume(struct usb_interface *intf)
1103 {
1104 	struct snd_usb_audio *chip = usb_get_intfdata(intf);
1105 	struct snd_usb_stream *as;
1106 	struct usb_mixer_interface *mixer;
1107 	struct list_head *p;
1108 	int err = 0;
1109 
1110 	if (chip == USB_AUDIO_IFACE_UNUSED)
1111 		return 0;
1112 
1113 	atomic_inc(&chip->active); /* avoid autopm */
1114 	if (chip->num_suspended_intf > 1)
1115 		goto out;
1116 
1117 	list_for_each_entry(as, &chip->pcm_list, list) {
1118 		err = snd_usb_pcm_resume(as);
1119 		if (err < 0)
1120 			goto err_out;
1121 	}
1122 
1123 	/*
1124 	 * ALSA leaves material resumption to user space
1125 	 * we just notify and restart the mixers
1126 	 */
1127 	list_for_each_entry(mixer, &chip->mixer_list, list) {
1128 		err = snd_usb_mixer_resume(mixer);
1129 		if (err < 0)
1130 			goto err_out;
1131 	}
1132 
1133 	list_for_each(p, &chip->midi_list) {
1134 		snd_usbmidi_resume(p);
1135 	}
1136 
1137 	snd_usb_midi_v2_resume_all(chip);
1138 
1139  out:
1140 	if (chip->num_suspended_intf == chip->system_suspend) {
1141 		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
1142 		chip->system_suspend = 0;
1143 	}
1144 	chip->num_suspended_intf--;
1145 
1146 err_out:
1147 	atomic_dec(&chip->active); /* allow autopm after this point */
1148 	return err;
1149 }
1150 
1151 static const struct usb_device_id usb_audio_ids [] = {
1152 #include "quirks-table.h"
1153     { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
1154       .bInterfaceClass = USB_CLASS_AUDIO,
1155       .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
1156     { }						/* Terminating entry */
1157 };
1158 MODULE_DEVICE_TABLE(usb, usb_audio_ids);
1159 
1160 /*
1161  * entry point for linux usb interface
1162  */
1163 
1164 static struct usb_driver usb_audio_driver = {
1165 	.name =		"snd-usb-audio",
1166 	.probe =	usb_audio_probe,
1167 	.disconnect =	usb_audio_disconnect,
1168 	.suspend =	usb_audio_suspend,
1169 	.resume =	usb_audio_resume,
1170 	.reset_resume =	usb_audio_resume,
1171 	.id_table =	usb_audio_ids,
1172 	.supports_autosuspend = 1,
1173 };
1174 
1175 module_usb_driver(usb_audio_driver);
1176