xref: /openbmc/linux/sound/usb/stream.c (revision b96fc2f3)
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->speed = snd_usb_get_speed(subs->dev);
96 	subs->pkt_offset_adj = 0;
97 
98 	snd_usb_set_pcm_ops(as->pcm, stream);
99 
100 	list_add_tail(&fp->list, &subs->fmt_list);
101 	subs->formats |= fp->formats;
102 	subs->num_formats++;
103 	subs->fmt_type = fp->fmt_type;
104 	subs->ep_num = fp->endpoint;
105 	if (fp->channels > subs->channels_max)
106 		subs->channels_max = fp->channels;
107 }
108 
109 /* kctl callbacks for usb-audio channel maps */
110 static int usb_chmap_ctl_info(struct snd_kcontrol *kcontrol,
111 			      struct snd_ctl_elem_info *uinfo)
112 {
113 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
114 	struct snd_usb_substream *subs = info->private_data;
115 
116 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
117 	uinfo->count = subs->channels_max;
118 	uinfo->value.integer.min = 0;
119 	uinfo->value.integer.max = SNDRV_CHMAP_LAST;
120 	return 0;
121 }
122 
123 /* check whether a duplicated entry exists in the audiofmt list */
124 static bool have_dup_chmap(struct snd_usb_substream *subs,
125 			   struct audioformat *fp)
126 {
127 	struct list_head *p;
128 
129 	for (p = fp->list.prev; p != &subs->fmt_list; p = p->prev) {
130 		struct audioformat *prev;
131 		prev = list_entry(p, struct audioformat, list);
132 		if (prev->chmap &&
133 		    !memcmp(prev->chmap, fp->chmap, sizeof(*fp->chmap)))
134 			return true;
135 	}
136 	return false;
137 }
138 
139 static int usb_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
140 			     unsigned int size, unsigned int __user *tlv)
141 {
142 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
143 	struct snd_usb_substream *subs = info->private_data;
144 	struct audioformat *fp;
145 	unsigned int __user *dst;
146 	int count = 0;
147 
148 	if (size < 8)
149 		return -ENOMEM;
150 	if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
151 		return -EFAULT;
152 	size -= 8;
153 	dst = tlv + 2;
154 	list_for_each_entry(fp, &subs->fmt_list, list) {
155 		int i, ch_bytes;
156 
157 		if (!fp->chmap)
158 			continue;
159 		if (have_dup_chmap(subs, fp))
160 			continue;
161 		/* copy the entry */
162 		ch_bytes = fp->chmap->channels * 4;
163 		if (size < 8 + ch_bytes)
164 			return -ENOMEM;
165 		if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
166 		    put_user(ch_bytes, dst + 1))
167 			return -EFAULT;
168 		dst += 2;
169 		for (i = 0; i < fp->chmap->channels; i++, dst++) {
170 			if (put_user(fp->chmap->map[i], dst))
171 				return -EFAULT;
172 		}
173 
174 		count += 8 + ch_bytes;
175 		size -= 8 + ch_bytes;
176 	}
177 	if (put_user(count, tlv + 1))
178 		return -EFAULT;
179 	return 0;
180 }
181 
182 static int usb_chmap_ctl_get(struct snd_kcontrol *kcontrol,
183 			     struct snd_ctl_elem_value *ucontrol)
184 {
185 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
186 	struct snd_usb_substream *subs = info->private_data;
187 	struct snd_pcm_chmap_elem *chmap = NULL;
188 	int i;
189 
190 	memset(ucontrol->value.integer.value, 0,
191 	       sizeof(ucontrol->value.integer.value));
192 	if (subs->cur_audiofmt)
193 		chmap = subs->cur_audiofmt->chmap;
194 	if (chmap) {
195 		for (i = 0; i < chmap->channels; i++)
196 			ucontrol->value.integer.value[i] = chmap->map[i];
197 	}
198 	return 0;
199 }
200 
201 /* create a chmap kctl assigned to the given USB substream */
202 static int add_chmap(struct snd_pcm *pcm, int stream,
203 		     struct snd_usb_substream *subs)
204 {
205 	struct audioformat *fp;
206 	struct snd_pcm_chmap *chmap;
207 	struct snd_kcontrol *kctl;
208 	int err;
209 
210 	list_for_each_entry(fp, &subs->fmt_list, list)
211 		if (fp->chmap)
212 			goto ok;
213 	/* no chmap is found */
214 	return 0;
215 
216  ok:
217 	err = snd_pcm_add_chmap_ctls(pcm, stream, NULL, 0, 0, &chmap);
218 	if (err < 0)
219 		return err;
220 
221 	/* override handlers */
222 	chmap->private_data = subs;
223 	kctl = chmap->kctl;
224 	kctl->info = usb_chmap_ctl_info;
225 	kctl->get = usb_chmap_ctl_get;
226 	kctl->tlv.c = usb_chmap_ctl_tlv;
227 
228 	return 0;
229 }
230 
231 /* convert from USB ChannelConfig bits to ALSA chmap element */
232 static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
233 						int protocol)
234 {
235 	static unsigned int uac1_maps[] = {
236 		SNDRV_CHMAP_FL,		/* left front */
237 		SNDRV_CHMAP_FR,		/* right front */
238 		SNDRV_CHMAP_FC,		/* center front */
239 		SNDRV_CHMAP_LFE,	/* LFE */
240 		SNDRV_CHMAP_SL,		/* left surround */
241 		SNDRV_CHMAP_SR,		/* right surround */
242 		SNDRV_CHMAP_FLC,	/* left of center */
243 		SNDRV_CHMAP_FRC,	/* right of center */
244 		SNDRV_CHMAP_RC,		/* surround */
245 		SNDRV_CHMAP_SL,		/* side left */
246 		SNDRV_CHMAP_SR,		/* side right */
247 		SNDRV_CHMAP_TC,		/* top */
248 		0 /* terminator */
249 	};
250 	static unsigned int uac2_maps[] = {
251 		SNDRV_CHMAP_FL,		/* front left */
252 		SNDRV_CHMAP_FR,		/* front right */
253 		SNDRV_CHMAP_FC,		/* front center */
254 		SNDRV_CHMAP_LFE,	/* LFE */
255 		SNDRV_CHMAP_RL,		/* back left */
256 		SNDRV_CHMAP_RR,		/* back right */
257 		SNDRV_CHMAP_FLC,	/* front left of center */
258 		SNDRV_CHMAP_FRC,	/* front right of center */
259 		SNDRV_CHMAP_RC,		/* back center */
260 		SNDRV_CHMAP_SL,		/* side left */
261 		SNDRV_CHMAP_SR,		/* side right */
262 		SNDRV_CHMAP_TC,		/* top center */
263 		SNDRV_CHMAP_TFL,	/* top front left */
264 		SNDRV_CHMAP_TFC,	/* top front center */
265 		SNDRV_CHMAP_TFR,	/* top front right */
266 		SNDRV_CHMAP_TRL,	/* top back left */
267 		SNDRV_CHMAP_TRC,	/* top back center */
268 		SNDRV_CHMAP_TRR,	/* top back right */
269 		SNDRV_CHMAP_TFLC,	/* top front left of center */
270 		SNDRV_CHMAP_TFRC,	/* top front right of center */
271 		SNDRV_CHMAP_LLFE,	/* left LFE */
272 		SNDRV_CHMAP_RLFE,	/* right LFE */
273 		SNDRV_CHMAP_TSL,	/* top side left */
274 		SNDRV_CHMAP_TSR,	/* top side right */
275 		SNDRV_CHMAP_BC,		/* bottom center */
276 		SNDRV_CHMAP_RLC,	/* back left of center */
277 		SNDRV_CHMAP_RRC,	/* back right of center */
278 		0 /* terminator */
279 	};
280 	struct snd_pcm_chmap_elem *chmap;
281 	const unsigned int *maps;
282 	int c;
283 
284 	if (channels > ARRAY_SIZE(chmap->map))
285 		return NULL;
286 
287 	chmap = kzalloc(sizeof(*chmap), GFP_KERNEL);
288 	if (!chmap)
289 		return NULL;
290 
291 	maps = protocol == UAC_VERSION_2 ? uac2_maps : uac1_maps;
292 	chmap->channels = channels;
293 	c = 0;
294 
295 	if (bits) {
296 		for (; bits && *maps; maps++, bits >>= 1)
297 			if (bits & 1)
298 				chmap->map[c++] = *maps;
299 	} else {
300 		/* If we're missing wChannelConfig, then guess something
301 		    to make sure the channel map is not skipped entirely */
302 		if (channels == 1)
303 			chmap->map[c++] = SNDRV_CHMAP_MONO;
304 		else
305 			for (; c < channels && *maps; maps++)
306 				chmap->map[c++] = *maps;
307 	}
308 
309 	for (; c < channels; c++)
310 		chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
311 
312 	return chmap;
313 }
314 
315 /*
316  * add this endpoint to the chip instance.
317  * if a stream with the same endpoint already exists, append to it.
318  * if not, create a new pcm stream.
319  */
320 int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
321 			     int stream,
322 			     struct audioformat *fp)
323 {
324 	struct snd_usb_stream *as;
325 	struct snd_usb_substream *subs;
326 	struct snd_pcm *pcm;
327 	int err;
328 
329 	list_for_each_entry(as, &chip->pcm_list, list) {
330 		if (as->fmt_type != fp->fmt_type)
331 			continue;
332 		subs = &as->substream[stream];
333 		if (subs->ep_num == fp->endpoint) {
334 			list_add_tail(&fp->list, &subs->fmt_list);
335 			subs->num_formats++;
336 			subs->formats |= fp->formats;
337 			return 0;
338 		}
339 	}
340 	/* look for an empty stream */
341 	list_for_each_entry(as, &chip->pcm_list, list) {
342 		if (as->fmt_type != fp->fmt_type)
343 			continue;
344 		subs = &as->substream[stream];
345 		if (subs->ep_num)
346 			continue;
347 		err = snd_pcm_new_stream(as->pcm, stream, 1);
348 		if (err < 0)
349 			return err;
350 		snd_usb_init_substream(as, stream, fp);
351 		return add_chmap(as->pcm, stream, subs);
352 	}
353 
354 	/* create a new pcm */
355 	as = kzalloc(sizeof(*as), GFP_KERNEL);
356 	if (!as)
357 		return -ENOMEM;
358 	as->pcm_index = chip->pcm_devs;
359 	as->chip = chip;
360 	as->fmt_type = fp->fmt_type;
361 	err = snd_pcm_new(chip->card, "USB Audio", chip->pcm_devs,
362 			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 1 : 0,
363 			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1,
364 			  &pcm);
365 	if (err < 0) {
366 		kfree(as);
367 		return err;
368 	}
369 	as->pcm = pcm;
370 	pcm->private_data = as;
371 	pcm->private_free = snd_usb_audio_pcm_free;
372 	pcm->info_flags = 0;
373 	if (chip->pcm_devs > 0)
374 		sprintf(pcm->name, "USB Audio #%d", chip->pcm_devs);
375 	else
376 		strcpy(pcm->name, "USB Audio");
377 
378 	snd_usb_init_substream(as, stream, fp);
379 
380 	/*
381 	 * Keep using head insertion for M-Audio Audiophile USB (tm) which has a
382 	 * fix to swap capture stream order in conf/cards/USB-audio.conf
383 	 */
384 	if (chip->usb_id == USB_ID(0x0763, 0x2003))
385 		list_add(&as->list, &chip->pcm_list);
386 	else
387 		list_add_tail(&as->list, &chip->pcm_list);
388 
389 	chip->pcm_devs++;
390 
391 	snd_usb_proc_pcm_format_add(as);
392 
393 	return add_chmap(pcm, stream, &as->substream[stream]);
394 }
395 
396 static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
397 					 struct usb_host_interface *alts,
398 					 int protocol, int iface_no)
399 {
400 	/* parsed with a v1 header here. that's ok as we only look at the
401 	 * header first which is the same for both versions */
402 	struct uac_iso_endpoint_descriptor *csep;
403 	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
404 	int attributes = 0;
405 
406 	csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
407 
408 	/* Creamware Noah has this descriptor after the 2nd endpoint */
409 	if (!csep && altsd->bNumEndpoints >= 2)
410 		csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
411 
412 	/*
413 	 * If we can't locate the USB_DT_CS_ENDPOINT descriptor in the extra
414 	 * bytes after the first endpoint, go search the entire interface.
415 	 * Some devices have it directly *before* the standard endpoint.
416 	 */
417 	if (!csep)
418 		csep = snd_usb_find_desc(alts->extra, alts->extralen, NULL, USB_DT_CS_ENDPOINT);
419 
420 	if (!csep || csep->bLength < 7 ||
421 	    csep->bDescriptorSubtype != UAC_EP_GENERAL) {
422 		usb_audio_warn(chip,
423 			       "%u:%d : no or invalid class specific endpoint descriptor\n",
424 			       iface_no, altsd->bAlternateSetting);
425 		return 0;
426 	}
427 
428 	if (protocol == UAC_VERSION_1) {
429 		attributes = csep->bmAttributes;
430 	} else {
431 		struct uac2_iso_endpoint_descriptor *csep2 =
432 			(struct uac2_iso_endpoint_descriptor *) csep;
433 
434 		attributes = csep->bmAttributes & UAC_EP_CS_ATTR_FILL_MAX;
435 
436 		/* emulate the endpoint attributes of a v1 device */
437 		if (csep2->bmControls & UAC2_CONTROL_PITCH)
438 			attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
439 	}
440 
441 	return attributes;
442 }
443 
444 /* find an input terminal descriptor (either UAC1 or UAC2) with the given
445  * terminal id
446  */
447 static void *
448 snd_usb_find_input_terminal_descriptor(struct usb_host_interface *ctrl_iface,
449 					       int terminal_id)
450 {
451 	struct uac2_input_terminal_descriptor *term = NULL;
452 
453 	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
454 					       ctrl_iface->extralen,
455 					       term, UAC_INPUT_TERMINAL))) {
456 		if (term->bTerminalID == terminal_id)
457 			return term;
458 	}
459 
460 	return NULL;
461 }
462 
463 static struct uac2_output_terminal_descriptor *
464 	snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
465 						int terminal_id)
466 {
467 	struct uac2_output_terminal_descriptor *term = NULL;
468 
469 	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
470 					       ctrl_iface->extralen,
471 					       term, UAC_OUTPUT_TERMINAL))) {
472 		if (term->bTerminalID == terminal_id)
473 			return term;
474 	}
475 
476 	return NULL;
477 }
478 
479 int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
480 {
481 	struct usb_device *dev;
482 	struct usb_interface *iface;
483 	struct usb_host_interface *alts;
484 	struct usb_interface_descriptor *altsd;
485 	int i, altno, err, stream;
486 	unsigned int format = 0, num_channels = 0;
487 	struct audioformat *fp = NULL;
488 	int num, protocol, clock = 0;
489 	struct uac_format_type_i_continuous_descriptor *fmt;
490 	unsigned int chconfig;
491 
492 	dev = chip->dev;
493 
494 	/* parse the interface's altsettings */
495 	iface = usb_ifnum_to_if(dev, iface_no);
496 
497 	num = iface->num_altsetting;
498 
499 	/*
500 	 * Dallas DS4201 workaround: It presents 5 altsettings, but the last
501 	 * one misses syncpipe, and does not produce any sound.
502 	 */
503 	if (chip->usb_id == USB_ID(0x04fa, 0x4201))
504 		num = 4;
505 
506 	for (i = 0; i < num; i++) {
507 		alts = &iface->altsetting[i];
508 		altsd = get_iface_desc(alts);
509 		protocol = altsd->bInterfaceProtocol;
510 		/* skip invalid one */
511 		if (((altsd->bInterfaceClass != USB_CLASS_AUDIO ||
512 		      (altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING &&
513 		       altsd->bInterfaceSubClass != USB_SUBCLASS_VENDOR_SPEC)) &&
514 		     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
515 		    altsd->bNumEndpoints < 1 ||
516 		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == 0)
517 			continue;
518 		/* must be isochronous */
519 		if ((get_endpoint(alts, 0)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
520 		    USB_ENDPOINT_XFER_ISOC)
521 			continue;
522 		/* check direction */
523 		stream = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN) ?
524 			SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
525 		altno = altsd->bAlternateSetting;
526 
527 		if (snd_usb_apply_interface_quirk(chip, iface_no, altno))
528 			continue;
529 
530 		/*
531 		 * Roland audio streaming interfaces are marked with protocols
532 		 * 0/1/2, but are UAC 1 compatible.
533 		 */
534 		if (USB_ID_VENDOR(chip->usb_id) == 0x0582 &&
535 		    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
536 		    protocol <= 2)
537 			protocol = UAC_VERSION_1;
538 
539 		chconfig = 0;
540 		/* get audio formats */
541 		switch (protocol) {
542 		default:
543 			dev_dbg(&dev->dev, "%u:%d: unknown interface protocol %#02x, assuming v1\n",
544 				iface_no, altno, protocol);
545 			protocol = UAC_VERSION_1;
546 			/* fall through */
547 
548 		case UAC_VERSION_1: {
549 			struct uac1_as_header_descriptor *as =
550 				snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
551 			struct uac_input_terminal_descriptor *iterm;
552 
553 			if (!as) {
554 				dev_err(&dev->dev,
555 					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
556 					iface_no, altno);
557 				continue;
558 			}
559 
560 			if (as->bLength < sizeof(*as)) {
561 				dev_err(&dev->dev,
562 					"%u:%d : invalid UAC_AS_GENERAL desc\n",
563 					iface_no, altno);
564 				continue;
565 			}
566 
567 			format = le16_to_cpu(as->wFormatTag); /* remember the format value */
568 
569 			iterm = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
570 								       as->bTerminalLink);
571 			if (iterm) {
572 				num_channels = iterm->bNrChannels;
573 				chconfig = le16_to_cpu(iterm->wChannelConfig);
574 			}
575 
576 			break;
577 		}
578 
579 		case UAC_VERSION_2: {
580 			struct uac2_input_terminal_descriptor *input_term;
581 			struct uac2_output_terminal_descriptor *output_term;
582 			struct uac2_as_header_descriptor *as =
583 				snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
584 
585 			if (!as) {
586 				dev_err(&dev->dev,
587 					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
588 					iface_no, altno);
589 				continue;
590 			}
591 
592 			if (as->bLength < sizeof(*as)) {
593 				dev_err(&dev->dev,
594 					"%u:%d : invalid UAC_AS_GENERAL desc\n",
595 					iface_no, altno);
596 				continue;
597 			}
598 
599 			num_channels = as->bNrChannels;
600 			format = le32_to_cpu(as->bmFormats);
601 			chconfig = le32_to_cpu(as->bmChannelConfig);
602 
603 			/* lookup the terminal associated to this interface
604 			 * to extract the clock */
605 			input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
606 									    as->bTerminalLink);
607 			if (input_term) {
608 				clock = input_term->bCSourceID;
609 				if (!chconfig && (num_channels == input_term->bNrChannels))
610 					chconfig = le32_to_cpu(input_term->bmChannelConfig);
611 				break;
612 			}
613 
614 			output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
615 									      as->bTerminalLink);
616 			if (output_term) {
617 				clock = output_term->bCSourceID;
618 				break;
619 			}
620 
621 			dev_err(&dev->dev,
622 				"%u:%d : bogus bTerminalLink %d\n",
623 				iface_no, altno, as->bTerminalLink);
624 			continue;
625 		}
626 		}
627 
628 		/* get format type */
629 		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_FORMAT_TYPE);
630 		if (!fmt) {
631 			dev_err(&dev->dev,
632 				"%u:%d : no UAC_FORMAT_TYPE desc\n",
633 				iface_no, altno);
634 			continue;
635 		}
636 		if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8)) ||
637 		    ((protocol == UAC_VERSION_2) && (fmt->bLength < 6))) {
638 			dev_err(&dev->dev,
639 				"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
640 				iface_no, altno);
641 			continue;
642 		}
643 
644 		/*
645 		 * Blue Microphones workaround: The last altsetting is identical
646 		 * with the previous one, except for a larger packet size, but
647 		 * is actually a mislabeled two-channel setting; ignore it.
648 		 */
649 		if (fmt->bNrChannels == 1 &&
650 		    fmt->bSubframeSize == 2 &&
651 		    altno == 2 && num == 3 &&
652 		    fp && fp->altsetting == 1 && fp->channels == 1 &&
653 		    fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
654 		    protocol == UAC_VERSION_1 &&
655 		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
656 							fp->maxpacksize * 2)
657 			continue;
658 
659 		fp = kzalloc(sizeof(*fp), GFP_KERNEL);
660 		if (! fp) {
661 			dev_err(&dev->dev, "cannot malloc\n");
662 			return -ENOMEM;
663 		}
664 
665 		fp->iface = iface_no;
666 		fp->altsetting = altno;
667 		fp->altset_idx = i;
668 		fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
669 		fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
670 		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
671 		fp->protocol = protocol;
672 		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
673 		fp->channels = num_channels;
674 		if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
675 			fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
676 					* (fp->maxpacksize & 0x7ff);
677 		fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
678 		fp->clock = clock;
679 
680 		/* some quirks for attributes here */
681 
682 		switch (chip->usb_id) {
683 		case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
684 			/* Optoplay sets the sample rate attribute although
685 			 * it seems not supporting it in fact.
686 			 */
687 			fp->attributes &= ~UAC_EP_CS_ATTR_SAMPLE_RATE;
688 			break;
689 		case USB_ID(0x041e, 0x3020): /* Creative SB Audigy 2 NX */
690 		case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
691 			/* doesn't set the sample rate attribute, but supports it */
692 			fp->attributes |= UAC_EP_CS_ATTR_SAMPLE_RATE;
693 			break;
694 		case USB_ID(0x0763, 0x2001):  /* M-Audio Quattro USB */
695 		case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
696 		case USB_ID(0x047f, 0x0ca1): /* plantronics headset */
697 		case USB_ID(0x077d, 0x07af): /* Griffin iMic (note that there is
698 						an older model 77d:223) */
699 		/*
700 		 * plantronics headset and Griffin iMic have set adaptive-in
701 		 * although it's really not...
702 		 */
703 			fp->ep_attr &= ~USB_ENDPOINT_SYNCTYPE;
704 			if (stream == SNDRV_PCM_STREAM_PLAYBACK)
705 				fp->ep_attr |= USB_ENDPOINT_SYNC_ADAPTIVE;
706 			else
707 				fp->ep_attr |= USB_ENDPOINT_SYNC_SYNC;
708 			break;
709 		}
710 
711 		/* ok, let's parse further... */
712 		if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream) < 0) {
713 			kfree(fp->rate_table);
714 			kfree(fp);
715 			fp = NULL;
716 			continue;
717 		}
718 
719 		/* Create chmap */
720 		if (fp->channels != num_channels)
721 			chconfig = 0;
722 		fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
723 
724 		dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
725 		err = snd_usb_add_audio_stream(chip, stream, fp);
726 		if (err < 0) {
727 			kfree(fp->rate_table);
728 			kfree(fp->chmap);
729 			kfree(fp);
730 			return err;
731 		}
732 		/* try to set the interface... */
733 		usb_set_interface(chip->dev, iface_no, altno);
734 		snd_usb_init_pitch(chip, iface_no, alts, fp);
735 		snd_usb_init_sample_rate(chip, iface_no, alts, fp, fp->rate_max);
736 	}
737 	return 0;
738 }
739 
740