xref: /linux/sound/usb/stream.c (revision c0c914eca7f251c70facc37dfebeaf176601918d)
1 /*
2  *   This program is free software; you can redistribute it and/or modify
3  *   it under the terms of the GNU General Public License as published by
4  *   the Free Software Foundation; either version 2 of the License, or
5  *   (at your option) any later version.
6  *
7  *   This program is distributed in the hope that it will be useful,
8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  *   GNU General Public License for more details.
11  *
12  *   You should have received a copy of the GNU General Public License
13  *   along with this program; if not, write to the Free Software
14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
15  */
16 
17 
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/usb.h>
21 #include <linux/usb/audio.h>
22 #include <linux/usb/audio-v2.h>
23 
24 #include <sound/core.h>
25 #include <sound/pcm.h>
26 #include <sound/control.h>
27 #include <sound/tlv.h>
28 
29 #include "usbaudio.h"
30 #include "card.h"
31 #include "proc.h"
32 #include "quirks.h"
33 #include "endpoint.h"
34 #include "pcm.h"
35 #include "helper.h"
36 #include "format.h"
37 #include "clock.h"
38 #include "stream.h"
39 
40 /*
41  * free a substream
42  */
43 static void free_substream(struct snd_usb_substream *subs)
44 {
45 	struct audioformat *fp, *n;
46 
47 	if (!subs->num_formats)
48 		return; /* not initialized */
49 	list_for_each_entry_safe(fp, n, &subs->fmt_list, list) {
50 		kfree(fp->rate_table);
51 		kfree(fp->chmap);
52 		kfree(fp);
53 	}
54 	kfree(subs->rate_list.list);
55 }
56 
57 
58 /*
59  * free a usb stream instance
60  */
61 static void snd_usb_audio_stream_free(struct snd_usb_stream *stream)
62 {
63 	free_substream(&stream->substream[0]);
64 	free_substream(&stream->substream[1]);
65 	list_del(&stream->list);
66 	kfree(stream);
67 }
68 
69 static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
70 {
71 	struct snd_usb_stream *stream = pcm->private_data;
72 	if (stream) {
73 		stream->pcm = NULL;
74 		snd_usb_audio_stream_free(stream);
75 	}
76 }
77 
78 /*
79  * initialize the substream instance.
80  */
81 
82 static void snd_usb_init_substream(struct snd_usb_stream *as,
83 				   int stream,
84 				   struct audioformat *fp)
85 {
86 	struct snd_usb_substream *subs = &as->substream[stream];
87 
88 	INIT_LIST_HEAD(&subs->fmt_list);
89 	spin_lock_init(&subs->lock);
90 
91 	subs->stream = as;
92 	subs->direction = stream;
93 	subs->dev = as->chip->dev;
94 	subs->txfr_quirk = as->chip->txfr_quirk;
95 	subs->tx_length_quirk = as->chip->tx_length_quirk;
96 	subs->speed = snd_usb_get_speed(subs->dev);
97 	subs->pkt_offset_adj = 0;
98 
99 	snd_usb_set_pcm_ops(as->pcm, stream);
100 
101 	list_add_tail(&fp->list, &subs->fmt_list);
102 	subs->formats |= fp->formats;
103 	subs->num_formats++;
104 	subs->fmt_type = fp->fmt_type;
105 	subs->ep_num = fp->endpoint;
106 	if (fp->channels > subs->channels_max)
107 		subs->channels_max = fp->channels;
108 }
109 
110 /* kctl callbacks for usb-audio channel maps */
111 static int usb_chmap_ctl_info(struct snd_kcontrol *kcontrol,
112 			      struct snd_ctl_elem_info *uinfo)
113 {
114 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
115 	struct snd_usb_substream *subs = info->private_data;
116 
117 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
118 	uinfo->count = subs->channels_max;
119 	uinfo->value.integer.min = 0;
120 	uinfo->value.integer.max = SNDRV_CHMAP_LAST;
121 	return 0;
122 }
123 
124 /* check whether a duplicated entry exists in the audiofmt list */
125 static bool have_dup_chmap(struct snd_usb_substream *subs,
126 			   struct audioformat *fp)
127 {
128 	struct audioformat *prev = fp;
129 
130 	list_for_each_entry_continue_reverse(prev, &subs->fmt_list, list) {
131 		if (prev->chmap &&
132 		    !memcmp(prev->chmap, fp->chmap, sizeof(*fp->chmap)))
133 			return true;
134 	}
135 	return false;
136 }
137 
138 static int usb_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
139 			     unsigned int size, unsigned int __user *tlv)
140 {
141 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
142 	struct snd_usb_substream *subs = info->private_data;
143 	struct audioformat *fp;
144 	unsigned int __user *dst;
145 	int count = 0;
146 
147 	if (size < 8)
148 		return -ENOMEM;
149 	if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
150 		return -EFAULT;
151 	size -= 8;
152 	dst = tlv + 2;
153 	list_for_each_entry(fp, &subs->fmt_list, list) {
154 		int i, ch_bytes;
155 
156 		if (!fp->chmap)
157 			continue;
158 		if (have_dup_chmap(subs, fp))
159 			continue;
160 		/* copy the entry */
161 		ch_bytes = fp->chmap->channels * 4;
162 		if (size < 8 + ch_bytes)
163 			return -ENOMEM;
164 		if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
165 		    put_user(ch_bytes, dst + 1))
166 			return -EFAULT;
167 		dst += 2;
168 		for (i = 0; i < fp->chmap->channels; i++, dst++) {
169 			if (put_user(fp->chmap->map[i], dst))
170 				return -EFAULT;
171 		}
172 
173 		count += 8 + ch_bytes;
174 		size -= 8 + ch_bytes;
175 	}
176 	if (put_user(count, tlv + 1))
177 		return -EFAULT;
178 	return 0;
179 }
180 
181 static int usb_chmap_ctl_get(struct snd_kcontrol *kcontrol,
182 			     struct snd_ctl_elem_value *ucontrol)
183 {
184 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
185 	struct snd_usb_substream *subs = info->private_data;
186 	struct snd_pcm_chmap_elem *chmap = NULL;
187 	int i;
188 
189 	memset(ucontrol->value.integer.value, 0,
190 	       sizeof(ucontrol->value.integer.value));
191 	if (subs->cur_audiofmt)
192 		chmap = subs->cur_audiofmt->chmap;
193 	if (chmap) {
194 		for (i = 0; i < chmap->channels; i++)
195 			ucontrol->value.integer.value[i] = chmap->map[i];
196 	}
197 	return 0;
198 }
199 
200 /* create a chmap kctl assigned to the given USB substream */
201 static int add_chmap(struct snd_pcm *pcm, int stream,
202 		     struct snd_usb_substream *subs)
203 {
204 	struct audioformat *fp;
205 	struct snd_pcm_chmap *chmap;
206 	struct snd_kcontrol *kctl;
207 	int err;
208 
209 	list_for_each_entry(fp, &subs->fmt_list, list)
210 		if (fp->chmap)
211 			goto ok;
212 	/* no chmap is found */
213 	return 0;
214 
215  ok:
216 	err = snd_pcm_add_chmap_ctls(pcm, stream, NULL, 0, 0, &chmap);
217 	if (err < 0)
218 		return err;
219 
220 	/* override handlers */
221 	chmap->private_data = subs;
222 	kctl = chmap->kctl;
223 	kctl->info = usb_chmap_ctl_info;
224 	kctl->get = usb_chmap_ctl_get;
225 	kctl->tlv.c = usb_chmap_ctl_tlv;
226 
227 	return 0;
228 }
229 
230 /* convert from USB ChannelConfig bits to ALSA chmap element */
231 static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
232 						int protocol)
233 {
234 	static unsigned int uac1_maps[] = {
235 		SNDRV_CHMAP_FL,		/* left front */
236 		SNDRV_CHMAP_FR,		/* right front */
237 		SNDRV_CHMAP_FC,		/* center front */
238 		SNDRV_CHMAP_LFE,	/* LFE */
239 		SNDRV_CHMAP_SL,		/* left surround */
240 		SNDRV_CHMAP_SR,		/* right surround */
241 		SNDRV_CHMAP_FLC,	/* left of center */
242 		SNDRV_CHMAP_FRC,	/* right of center */
243 		SNDRV_CHMAP_RC,		/* surround */
244 		SNDRV_CHMAP_SL,		/* side left */
245 		SNDRV_CHMAP_SR,		/* side right */
246 		SNDRV_CHMAP_TC,		/* top */
247 		0 /* terminator */
248 	};
249 	static unsigned int uac2_maps[] = {
250 		SNDRV_CHMAP_FL,		/* front left */
251 		SNDRV_CHMAP_FR,		/* front right */
252 		SNDRV_CHMAP_FC,		/* front center */
253 		SNDRV_CHMAP_LFE,	/* LFE */
254 		SNDRV_CHMAP_RL,		/* back left */
255 		SNDRV_CHMAP_RR,		/* back right */
256 		SNDRV_CHMAP_FLC,	/* front left of center */
257 		SNDRV_CHMAP_FRC,	/* front right of center */
258 		SNDRV_CHMAP_RC,		/* back center */
259 		SNDRV_CHMAP_SL,		/* side left */
260 		SNDRV_CHMAP_SR,		/* side right */
261 		SNDRV_CHMAP_TC,		/* top center */
262 		SNDRV_CHMAP_TFL,	/* top front left */
263 		SNDRV_CHMAP_TFC,	/* top front center */
264 		SNDRV_CHMAP_TFR,	/* top front right */
265 		SNDRV_CHMAP_TRL,	/* top back left */
266 		SNDRV_CHMAP_TRC,	/* top back center */
267 		SNDRV_CHMAP_TRR,	/* top back right */
268 		SNDRV_CHMAP_TFLC,	/* top front left of center */
269 		SNDRV_CHMAP_TFRC,	/* top front right of center */
270 		SNDRV_CHMAP_LLFE,	/* left LFE */
271 		SNDRV_CHMAP_RLFE,	/* right LFE */
272 		SNDRV_CHMAP_TSL,	/* top side left */
273 		SNDRV_CHMAP_TSR,	/* top side right */
274 		SNDRV_CHMAP_BC,		/* bottom center */
275 		SNDRV_CHMAP_RLC,	/* back left of center */
276 		SNDRV_CHMAP_RRC,	/* back right of center */
277 		0 /* terminator */
278 	};
279 	struct snd_pcm_chmap_elem *chmap;
280 	const unsigned int *maps;
281 	int c;
282 
283 	if (channels > ARRAY_SIZE(chmap->map))
284 		return NULL;
285 
286 	chmap = kzalloc(sizeof(*chmap), GFP_KERNEL);
287 	if (!chmap)
288 		return NULL;
289 
290 	maps = protocol == UAC_VERSION_2 ? uac2_maps : uac1_maps;
291 	chmap->channels = channels;
292 	c = 0;
293 
294 	if (bits) {
295 		for (; bits && *maps; maps++, bits >>= 1)
296 			if (bits & 1)
297 				chmap->map[c++] = *maps;
298 	} else {
299 		/* If we're missing wChannelConfig, then guess something
300 		    to make sure the channel map is not skipped entirely */
301 		if (channels == 1)
302 			chmap->map[c++] = SNDRV_CHMAP_MONO;
303 		else
304 			for (; c < channels && *maps; maps++)
305 				chmap->map[c++] = *maps;
306 	}
307 
308 	for (; c < channels; c++)
309 		chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
310 
311 	return chmap;
312 }
313 
314 /*
315  * add this endpoint to the chip instance.
316  * if a stream with the same endpoint already exists, append to it.
317  * if not, create a new pcm stream.
318  */
319 int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
320 			     int stream,
321 			     struct audioformat *fp)
322 {
323 	struct snd_usb_stream *as;
324 	struct snd_usb_substream *subs;
325 	struct snd_pcm *pcm;
326 	int err;
327 
328 	list_for_each_entry(as, &chip->pcm_list, list) {
329 		if (as->fmt_type != fp->fmt_type)
330 			continue;
331 		subs = &as->substream[stream];
332 		if (subs->ep_num == fp->endpoint) {
333 			list_add_tail(&fp->list, &subs->fmt_list);
334 			subs->num_formats++;
335 			subs->formats |= fp->formats;
336 			return 0;
337 		}
338 	}
339 	/* look for an empty stream */
340 	list_for_each_entry(as, &chip->pcm_list, list) {
341 		if (as->fmt_type != fp->fmt_type)
342 			continue;
343 		subs = &as->substream[stream];
344 		if (subs->ep_num)
345 			continue;
346 		err = snd_pcm_new_stream(as->pcm, stream, 1);
347 		if (err < 0)
348 			return err;
349 		snd_usb_init_substream(as, stream, fp);
350 		return add_chmap(as->pcm, stream, subs);
351 	}
352 
353 	/* create a new pcm */
354 	as = kzalloc(sizeof(*as), GFP_KERNEL);
355 	if (!as)
356 		return -ENOMEM;
357 	as->pcm_index = chip->pcm_devs;
358 	as->chip = chip;
359 	as->fmt_type = fp->fmt_type;
360 	err = snd_pcm_new(chip->card, "USB Audio", chip->pcm_devs,
361 			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 1 : 0,
362 			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1,
363 			  &pcm);
364 	if (err < 0) {
365 		kfree(as);
366 		return err;
367 	}
368 	as->pcm = pcm;
369 	pcm->private_data = as;
370 	pcm->private_free = snd_usb_audio_pcm_free;
371 	pcm->info_flags = 0;
372 	if (chip->pcm_devs > 0)
373 		sprintf(pcm->name, "USB Audio #%d", chip->pcm_devs);
374 	else
375 		strcpy(pcm->name, "USB Audio");
376 
377 	snd_usb_init_substream(as, stream, fp);
378 
379 	/*
380 	 * Keep using head insertion for M-Audio Audiophile USB (tm) which has a
381 	 * fix to swap capture stream order in conf/cards/USB-audio.conf
382 	 */
383 	if (chip->usb_id == USB_ID(0x0763, 0x2003))
384 		list_add(&as->list, &chip->pcm_list);
385 	else
386 		list_add_tail(&as->list, &chip->pcm_list);
387 
388 	chip->pcm_devs++;
389 
390 	snd_usb_proc_pcm_format_add(as);
391 
392 	return add_chmap(pcm, stream, &as->substream[stream]);
393 }
394 
395 static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
396 					 struct usb_host_interface *alts,
397 					 int protocol, int iface_no)
398 {
399 	/* parsed with a v1 header here. that's ok as we only look at the
400 	 * header first which is the same for both versions */
401 	struct uac_iso_endpoint_descriptor *csep;
402 	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
403 	int attributes = 0;
404 
405 	csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
406 
407 	/* Creamware Noah has this descriptor after the 2nd endpoint */
408 	if (!csep && altsd->bNumEndpoints >= 2)
409 		csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
410 
411 	/*
412 	 * If we can't locate the USB_DT_CS_ENDPOINT descriptor in the extra
413 	 * bytes after the first endpoint, go search the entire interface.
414 	 * Some devices have it directly *before* the standard endpoint.
415 	 */
416 	if (!csep)
417 		csep = snd_usb_find_desc(alts->extra, alts->extralen, NULL, USB_DT_CS_ENDPOINT);
418 
419 	if (!csep || csep->bLength < 7 ||
420 	    csep->bDescriptorSubtype != UAC_EP_GENERAL) {
421 		usb_audio_warn(chip,
422 			       "%u:%d : no or invalid class specific endpoint descriptor\n",
423 			       iface_no, altsd->bAlternateSetting);
424 		return 0;
425 	}
426 
427 	if (protocol == UAC_VERSION_1) {
428 		attributes = csep->bmAttributes;
429 	} else {
430 		struct uac2_iso_endpoint_descriptor *csep2 =
431 			(struct uac2_iso_endpoint_descriptor *) csep;
432 
433 		attributes = csep->bmAttributes & UAC_EP_CS_ATTR_FILL_MAX;
434 
435 		/* emulate the endpoint attributes of a v1 device */
436 		if (csep2->bmControls & UAC2_CONTROL_PITCH)
437 			attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
438 	}
439 
440 	return attributes;
441 }
442 
443 /* find an input terminal descriptor (either UAC1 or UAC2) with the given
444  * terminal id
445  */
446 static void *
447 snd_usb_find_input_terminal_descriptor(struct usb_host_interface *ctrl_iface,
448 					       int terminal_id)
449 {
450 	struct uac2_input_terminal_descriptor *term = NULL;
451 
452 	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
453 					       ctrl_iface->extralen,
454 					       term, UAC_INPUT_TERMINAL))) {
455 		if (term->bTerminalID == terminal_id)
456 			return term;
457 	}
458 
459 	return NULL;
460 }
461 
462 static struct uac2_output_terminal_descriptor *
463 	snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
464 						int terminal_id)
465 {
466 	struct uac2_output_terminal_descriptor *term = NULL;
467 
468 	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
469 					       ctrl_iface->extralen,
470 					       term, UAC_OUTPUT_TERMINAL))) {
471 		if (term->bTerminalID == terminal_id)
472 			return term;
473 	}
474 
475 	return NULL;
476 }
477 
478 int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
479 {
480 	struct usb_device *dev;
481 	struct usb_interface *iface;
482 	struct usb_host_interface *alts;
483 	struct usb_interface_descriptor *altsd;
484 	int i, altno, err, stream;
485 	unsigned int format = 0, num_channels = 0;
486 	struct audioformat *fp = NULL;
487 	int num, protocol, clock = 0;
488 	struct uac_format_type_i_continuous_descriptor *fmt;
489 	unsigned int chconfig;
490 
491 	dev = chip->dev;
492 
493 	/* parse the interface's altsettings */
494 	iface = usb_ifnum_to_if(dev, iface_no);
495 
496 	num = iface->num_altsetting;
497 
498 	/*
499 	 * Dallas DS4201 workaround: It presents 5 altsettings, but the last
500 	 * one misses syncpipe, and does not produce any sound.
501 	 */
502 	if (chip->usb_id == USB_ID(0x04fa, 0x4201))
503 		num = 4;
504 
505 	for (i = 0; i < num; i++) {
506 		alts = &iface->altsetting[i];
507 		altsd = get_iface_desc(alts);
508 		protocol = altsd->bInterfaceProtocol;
509 		/* skip invalid one */
510 		if (((altsd->bInterfaceClass != USB_CLASS_AUDIO ||
511 		      (altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING &&
512 		       altsd->bInterfaceSubClass != USB_SUBCLASS_VENDOR_SPEC)) &&
513 		     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
514 		    altsd->bNumEndpoints < 1 ||
515 		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == 0)
516 			continue;
517 		/* must be isochronous */
518 		if ((get_endpoint(alts, 0)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
519 		    USB_ENDPOINT_XFER_ISOC)
520 			continue;
521 		/* check direction */
522 		stream = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN) ?
523 			SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
524 		altno = altsd->bAlternateSetting;
525 
526 		if (snd_usb_apply_interface_quirk(chip, iface_no, altno))
527 			continue;
528 
529 		/*
530 		 * Roland audio streaming interfaces are marked with protocols
531 		 * 0/1/2, but are UAC 1 compatible.
532 		 */
533 		if (USB_ID_VENDOR(chip->usb_id) == 0x0582 &&
534 		    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
535 		    protocol <= 2)
536 			protocol = UAC_VERSION_1;
537 
538 		chconfig = 0;
539 		/* get audio formats */
540 		switch (protocol) {
541 		default:
542 			dev_dbg(&dev->dev, "%u:%d: unknown interface protocol %#02x, assuming v1\n",
543 				iface_no, altno, protocol);
544 			protocol = UAC_VERSION_1;
545 			/* fall through */
546 
547 		case UAC_VERSION_1: {
548 			struct uac1_as_header_descriptor *as =
549 				snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
550 			struct uac_input_terminal_descriptor *iterm;
551 
552 			if (!as) {
553 				dev_err(&dev->dev,
554 					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
555 					iface_no, altno);
556 				continue;
557 			}
558 
559 			if (as->bLength < sizeof(*as)) {
560 				dev_err(&dev->dev,
561 					"%u:%d : invalid UAC_AS_GENERAL desc\n",
562 					iface_no, altno);
563 				continue;
564 			}
565 
566 			format = le16_to_cpu(as->wFormatTag); /* remember the format value */
567 
568 			iterm = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
569 								       as->bTerminalLink);
570 			if (iterm) {
571 				num_channels = iterm->bNrChannels;
572 				chconfig = le16_to_cpu(iterm->wChannelConfig);
573 			}
574 
575 			break;
576 		}
577 
578 		case UAC_VERSION_2: {
579 			struct uac2_input_terminal_descriptor *input_term;
580 			struct uac2_output_terminal_descriptor *output_term;
581 			struct uac2_as_header_descriptor *as =
582 				snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
583 
584 			if (!as) {
585 				dev_err(&dev->dev,
586 					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
587 					iface_no, altno);
588 				continue;
589 			}
590 
591 			if (as->bLength < sizeof(*as)) {
592 				dev_err(&dev->dev,
593 					"%u:%d : invalid UAC_AS_GENERAL desc\n",
594 					iface_no, altno);
595 				continue;
596 			}
597 
598 			num_channels = as->bNrChannels;
599 			format = le32_to_cpu(as->bmFormats);
600 			chconfig = le32_to_cpu(as->bmChannelConfig);
601 
602 			/* lookup the terminal associated to this interface
603 			 * to extract the clock */
604 			input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
605 									    as->bTerminalLink);
606 			if (input_term) {
607 				clock = input_term->bCSourceID;
608 				if (!chconfig && (num_channels == input_term->bNrChannels))
609 					chconfig = le32_to_cpu(input_term->bmChannelConfig);
610 				break;
611 			}
612 
613 			output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
614 									      as->bTerminalLink);
615 			if (output_term) {
616 				clock = output_term->bCSourceID;
617 				break;
618 			}
619 
620 			dev_err(&dev->dev,
621 				"%u:%d : bogus bTerminalLink %d\n",
622 				iface_no, altno, as->bTerminalLink);
623 			continue;
624 		}
625 		}
626 
627 		/* get format type */
628 		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_FORMAT_TYPE);
629 		if (!fmt) {
630 			dev_err(&dev->dev,
631 				"%u:%d : no UAC_FORMAT_TYPE desc\n",
632 				iface_no, altno);
633 			continue;
634 		}
635 		if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8)) ||
636 		    ((protocol == UAC_VERSION_2) && (fmt->bLength < 6))) {
637 			dev_err(&dev->dev,
638 				"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
639 				iface_no, altno);
640 			continue;
641 		}
642 
643 		/*
644 		 * Blue Microphones workaround: The last altsetting is identical
645 		 * with the previous one, except for a larger packet size, but
646 		 * is actually a mislabeled two-channel setting; ignore it.
647 		 */
648 		if (fmt->bNrChannels == 1 &&
649 		    fmt->bSubframeSize == 2 &&
650 		    altno == 2 && num == 3 &&
651 		    fp && fp->altsetting == 1 && fp->channels == 1 &&
652 		    fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
653 		    protocol == UAC_VERSION_1 &&
654 		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
655 							fp->maxpacksize * 2)
656 			continue;
657 
658 		fp = kzalloc(sizeof(*fp), GFP_KERNEL);
659 		if (! fp) {
660 			dev_err(&dev->dev, "cannot malloc\n");
661 			return -ENOMEM;
662 		}
663 
664 		fp->iface = iface_no;
665 		fp->altsetting = altno;
666 		fp->altset_idx = i;
667 		fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
668 		fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
669 		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
670 		fp->protocol = protocol;
671 		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
672 		fp->channels = num_channels;
673 		if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
674 			fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
675 					* (fp->maxpacksize & 0x7ff);
676 		fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
677 		fp->clock = clock;
678 
679 		/* some quirks for attributes here */
680 
681 		switch (chip->usb_id) {
682 		case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
683 			/* Optoplay sets the sample rate attribute although
684 			 * it seems not supporting it in fact.
685 			 */
686 			fp->attributes &= ~UAC_EP_CS_ATTR_SAMPLE_RATE;
687 			break;
688 		case USB_ID(0x041e, 0x3020): /* Creative SB Audigy 2 NX */
689 		case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
690 			/* doesn't set the sample rate attribute, but supports it */
691 			fp->attributes |= UAC_EP_CS_ATTR_SAMPLE_RATE;
692 			break;
693 		case USB_ID(0x0763, 0x2001):  /* M-Audio Quattro USB */
694 		case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
695 		case USB_ID(0x047f, 0x0ca1): /* plantronics headset */
696 		case USB_ID(0x077d, 0x07af): /* Griffin iMic (note that there is
697 						an older model 77d:223) */
698 		/*
699 		 * plantronics headset and Griffin iMic have set adaptive-in
700 		 * although it's really not...
701 		 */
702 			fp->ep_attr &= ~USB_ENDPOINT_SYNCTYPE;
703 			if (stream == SNDRV_PCM_STREAM_PLAYBACK)
704 				fp->ep_attr |= USB_ENDPOINT_SYNC_ADAPTIVE;
705 			else
706 				fp->ep_attr |= USB_ENDPOINT_SYNC_SYNC;
707 			break;
708 		}
709 
710 		/* ok, let's parse further... */
711 		if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream) < 0) {
712 			kfree(fp->rate_table);
713 			kfree(fp);
714 			fp = NULL;
715 			continue;
716 		}
717 
718 		/* Create chmap */
719 		if (fp->channels != num_channels)
720 			chconfig = 0;
721 		fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
722 
723 		dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
724 		err = snd_usb_add_audio_stream(chip, stream, fp);
725 		if (err < 0) {
726 			kfree(fp->rate_table);
727 			kfree(fp->chmap);
728 			kfree(fp);
729 			return err;
730 		}
731 		/* try to set the interface... */
732 		usb_set_interface(chip->dev, iface_no, altno);
733 		snd_usb_init_pitch(chip, iface_no, alts, fp);
734 		snd_usb_init_sample_rate(chip, iface_no, alts, fp, fp->rate_max);
735 	}
736 	return 0;
737 }
738 
739