xref: /linux/sound/usb/pcm.c (revision 0526b56cbc3c489642bd6a5fe4b718dea7ef0ee8)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  */
4 
5 #include <linux/init.h>
6 #include <linux/slab.h>
7 #include <linux/bitrev.h>
8 #include <linux/ratelimit.h>
9 #include <linux/usb.h>
10 #include <linux/usb/audio.h>
11 #include <linux/usb/audio-v2.h>
12 
13 #include <sound/core.h>
14 #include <sound/pcm.h>
15 #include <sound/pcm_params.h>
16 
17 #include "usbaudio.h"
18 #include "card.h"
19 #include "quirks.h"
20 #include "endpoint.h"
21 #include "helper.h"
22 #include "pcm.h"
23 #include "clock.h"
24 #include "power.h"
25 #include "media.h"
26 #include "implicit.h"
27 
28 #define SUBSTREAM_FLAG_DATA_EP_STARTED	0
29 #define SUBSTREAM_FLAG_SYNC_EP_STARTED	1
30 
31 /* return the estimated delay based on USB frame counters */
32 static snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
33 					   struct snd_pcm_runtime *runtime)
34 {
35 	unsigned int current_frame_number;
36 	unsigned int frame_diff;
37 	int est_delay;
38 	int queued;
39 
40 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
41 		queued = bytes_to_frames(runtime, subs->inflight_bytes);
42 		if (!queued)
43 			return 0;
44 	} else if (!subs->running) {
45 		return 0;
46 	}
47 
48 	current_frame_number = usb_get_current_frame_number(subs->dev);
49 	/*
50 	 * HCD implementations use different widths, use lower 8 bits.
51 	 * The delay will be managed up to 256ms, which is more than
52 	 * enough
53 	 */
54 	frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
55 
56 	/* Approximation based on number of samples per USB frame (ms),
57 	   some truncation for 44.1 but the estimate is good enough */
58 	est_delay = frame_diff * runtime->rate / 1000;
59 
60 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
61 		est_delay = queued - est_delay;
62 		if (est_delay < 0)
63 			est_delay = 0;
64 	}
65 
66 	return est_delay;
67 }
68 
69 /*
70  * return the current pcm pointer.  just based on the hwptr_done value.
71  */
72 static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
73 {
74 	struct snd_pcm_runtime *runtime = substream->runtime;
75 	struct snd_usb_substream *subs = runtime->private_data;
76 	unsigned int hwptr_done;
77 
78 	if (atomic_read(&subs->stream->chip->shutdown))
79 		return SNDRV_PCM_POS_XRUN;
80 	spin_lock(&subs->lock);
81 	hwptr_done = subs->hwptr_done;
82 	runtime->delay = snd_usb_pcm_delay(subs, runtime);
83 	spin_unlock(&subs->lock);
84 	return bytes_to_frames(runtime, hwptr_done);
85 }
86 
87 /*
88  * find a matching audio format
89  */
90 static const struct audioformat *
91 find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
92 	    unsigned int rate, unsigned int channels, bool strict_match,
93 	    struct snd_usb_substream *subs)
94 {
95 	const struct audioformat *fp;
96 	const struct audioformat *found = NULL;
97 	int cur_attr = 0, attr;
98 
99 	list_for_each_entry(fp, fmt_list_head, list) {
100 		if (strict_match) {
101 			if (!(fp->formats & pcm_format_to_bits(format)))
102 				continue;
103 			if (fp->channels != channels)
104 				continue;
105 		}
106 		if (rate < fp->rate_min || rate > fp->rate_max)
107 			continue;
108 		if (!(fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
109 			unsigned int i;
110 			for (i = 0; i < fp->nr_rates; i++)
111 				if (fp->rate_table[i] == rate)
112 					break;
113 			if (i >= fp->nr_rates)
114 				continue;
115 		}
116 		attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
117 		if (!found) {
118 			found = fp;
119 			cur_attr = attr;
120 			continue;
121 		}
122 		/* avoid async out and adaptive in if the other method
123 		 * supports the same format.
124 		 * this is a workaround for the case like
125 		 * M-audio audiophile USB.
126 		 */
127 		if (subs && attr != cur_attr) {
128 			if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
129 			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
130 			    (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
131 			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
132 				continue;
133 			if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
134 			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
135 			    (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
136 			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
137 				found = fp;
138 				cur_attr = attr;
139 				continue;
140 			}
141 		}
142 		/* find the format with the largest max. packet size */
143 		if (fp->maxpacksize > found->maxpacksize) {
144 			found = fp;
145 			cur_attr = attr;
146 		}
147 	}
148 	return found;
149 }
150 
151 static const struct audioformat *
152 find_substream_format(struct snd_usb_substream *subs,
153 		      const struct snd_pcm_hw_params *params)
154 {
155 	return find_format(&subs->fmt_list, params_format(params),
156 			   params_rate(params), params_channels(params),
157 			   true, subs);
158 }
159 
160 bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs)
161 {
162 	const struct audioformat *fp;
163 	struct snd_usb_audio *chip;
164 	int rate = -1;
165 
166 	if (!subs)
167 		return false;
168 	chip = subs->stream->chip;
169 	if (!(chip->quirk_flags & QUIRK_FLAG_FIXED_RATE))
170 		return false;
171 	list_for_each_entry(fp, &subs->fmt_list, list) {
172 		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
173 			return false;
174 		if (fp->nr_rates < 1)
175 			continue;
176 		if (fp->nr_rates > 1)
177 			return false;
178 		if (rate < 0) {
179 			rate = fp->rate_table[0];
180 			continue;
181 		}
182 		if (rate != fp->rate_table[0])
183 			return false;
184 	}
185 	return true;
186 }
187 
188 static int init_pitch_v1(struct snd_usb_audio *chip, int ep)
189 {
190 	struct usb_device *dev = chip->dev;
191 	unsigned char data[1];
192 	int err;
193 
194 	data[0] = 1;
195 	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
196 			      USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
197 			      UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
198 			      data, sizeof(data));
199 	return err;
200 }
201 
202 static int init_pitch_v2(struct snd_usb_audio *chip, int ep)
203 {
204 	struct usb_device *dev = chip->dev;
205 	unsigned char data[1];
206 	int err;
207 
208 	data[0] = 1;
209 	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
210 			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
211 			      UAC2_EP_CS_PITCH << 8, 0,
212 			      data, sizeof(data));
213 	return err;
214 }
215 
216 /*
217  * initialize the pitch control and sample rate
218  */
219 int snd_usb_init_pitch(struct snd_usb_audio *chip,
220 		       const struct audioformat *fmt)
221 {
222 	int err;
223 
224 	/* if endpoint doesn't have pitch control, bail out */
225 	if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
226 		return 0;
227 
228 	usb_audio_dbg(chip, "enable PITCH for EP 0x%x\n", fmt->endpoint);
229 
230 	switch (fmt->protocol) {
231 	case UAC_VERSION_1:
232 		err = init_pitch_v1(chip, fmt->endpoint);
233 		break;
234 	case UAC_VERSION_2:
235 		err = init_pitch_v2(chip, fmt->endpoint);
236 		break;
237 	default:
238 		return 0;
239 	}
240 
241 	if (err < 0) {
242 		usb_audio_err(chip, "failed to enable PITCH for EP 0x%x\n",
243 			      fmt->endpoint);
244 		return err;
245 	}
246 
247 	return 0;
248 }
249 
250 static bool stop_endpoints(struct snd_usb_substream *subs, bool keep_pending)
251 {
252 	bool stopped = 0;
253 
254 	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
255 		snd_usb_endpoint_stop(subs->sync_endpoint, keep_pending);
256 		stopped = true;
257 	}
258 	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
259 		snd_usb_endpoint_stop(subs->data_endpoint, keep_pending);
260 		stopped = true;
261 	}
262 	return stopped;
263 }
264 
265 static int start_endpoints(struct snd_usb_substream *subs)
266 {
267 	int err;
268 
269 	if (!subs->data_endpoint)
270 		return -EINVAL;
271 
272 	if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
273 		err = snd_usb_endpoint_start(subs->data_endpoint);
274 		if (err < 0) {
275 			clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
276 			goto error;
277 		}
278 	}
279 
280 	if (subs->sync_endpoint &&
281 	    !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
282 		err = snd_usb_endpoint_start(subs->sync_endpoint);
283 		if (err < 0) {
284 			clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
285 			goto error;
286 		}
287 	}
288 
289 	return 0;
290 
291  error:
292 	stop_endpoints(subs, false);
293 	return err;
294 }
295 
296 static void sync_pending_stops(struct snd_usb_substream *subs)
297 {
298 	snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
299 	snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
300 }
301 
302 /* PCM sync_stop callback */
303 static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream)
304 {
305 	struct snd_usb_substream *subs = substream->runtime->private_data;
306 
307 	sync_pending_stops(subs);
308 	return 0;
309 }
310 
311 /* Set up sync endpoint */
312 int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip,
313 				    struct audioformat *fmt)
314 {
315 	struct usb_device *dev = chip->dev;
316 	struct usb_host_interface *alts;
317 	struct usb_interface_descriptor *altsd;
318 	unsigned int ep, attr, sync_attr;
319 	bool is_playback;
320 	int err;
321 
322 	if (fmt->sync_ep)
323 		return 0; /* already set up */
324 
325 	alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);
326 	if (!alts)
327 		return 0;
328 	altsd = get_iface_desc(alts);
329 
330 	err = snd_usb_parse_implicit_fb_quirk(chip, fmt, alts);
331 	if (err > 0)
332 		return 0; /* matched */
333 
334 	/*
335 	 * Generic sync EP handling
336 	 */
337 
338 	if (fmt->ep_idx > 0 || altsd->bNumEndpoints < 2)
339 		return 0;
340 
341 	is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
342 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
343 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
344 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
345 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
346 		return 0;
347 
348 	sync_attr = get_endpoint(alts, 1)->bmAttributes;
349 
350 	/*
351 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
352 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
353 	 * error fall back to SYNC mode and don't create sync endpoint
354 	 */
355 
356 	/* check sync-pipe endpoint */
357 	/* ... and check descriptor size before accessing bSynchAddress
358 	   because there is a version of the SB Audigy 2 NX firmware lacking
359 	   the audio fields in the endpoint descriptors */
360 	if ((sync_attr & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
361 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
362 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
363 		dev_err(&dev->dev,
364 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
365 			   fmt->iface, fmt->altsetting,
366 			   get_endpoint(alts, 1)->bmAttributes,
367 			   get_endpoint(alts, 1)->bLength,
368 			   get_endpoint(alts, 1)->bSynchAddress);
369 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
370 			return 0;
371 		return -EINVAL;
372 	}
373 	ep = get_endpoint(alts, 1)->bEndpointAddress;
374 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
375 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
376 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
377 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
378 		dev_err(&dev->dev,
379 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
380 			   fmt->iface, fmt->altsetting,
381 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
382 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
383 			return 0;
384 		return -EINVAL;
385 	}
386 
387 	fmt->sync_ep = ep;
388 	fmt->sync_iface = altsd->bInterfaceNumber;
389 	fmt->sync_altsetting = altsd->bAlternateSetting;
390 	fmt->sync_ep_idx = 1;
391 	if ((sync_attr & USB_ENDPOINT_USAGE_MASK) == USB_ENDPOINT_USAGE_IMPLICIT_FB)
392 		fmt->implicit_fb = 1;
393 
394 	dev_dbg(&dev->dev, "%d:%d: found sync_ep=0x%x, iface=%d, alt=%d, implicit_fb=%d\n",
395 		fmt->iface, fmt->altsetting, fmt->sync_ep, fmt->sync_iface,
396 		fmt->sync_altsetting, fmt->implicit_fb);
397 
398 	return 0;
399 }
400 
401 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
402 {
403 	int ret;
404 
405 	if (!subs->str_pd)
406 		return 0;
407 
408 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
409 	if (ret < 0) {
410 		dev_err(&subs->dev->dev,
411 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
412 			subs->str_pd->pd_id, state, ret);
413 		return ret;
414 	}
415 
416 	return 0;
417 }
418 
419 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
420 {
421 	int ret;
422 
423 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
424 	if (ret < 0)
425 		return ret;
426 
427 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
428 	if (ret < 0)
429 		return ret;
430 
431 	return 0;
432 }
433 
434 int snd_usb_pcm_resume(struct snd_usb_stream *as)
435 {
436 	int ret;
437 
438 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
439 	if (ret < 0)
440 		return ret;
441 
442 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
443 	if (ret < 0)
444 		return ret;
445 
446 	return 0;
447 }
448 
449 static void close_endpoints(struct snd_usb_audio *chip,
450 			    struct snd_usb_substream *subs)
451 {
452 	if (subs->data_endpoint) {
453 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint, NULL);
454 		snd_usb_endpoint_close(chip, subs->data_endpoint);
455 		subs->data_endpoint = NULL;
456 	}
457 
458 	if (subs->sync_endpoint) {
459 		snd_usb_endpoint_close(chip, subs->sync_endpoint);
460 		subs->sync_endpoint = NULL;
461 	}
462 }
463 
464 /*
465  * hw_params callback
466  *
467  * allocate a buffer and set the given audio format.
468  *
469  * so far we use a physically linear buffer although packetize transfer
470  * doesn't need a continuous area.
471  * if sg buffer is supported on the later version of alsa, we'll follow
472  * that.
473  */
474 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
475 			     struct snd_pcm_hw_params *hw_params)
476 {
477 	struct snd_usb_substream *subs = substream->runtime->private_data;
478 	struct snd_usb_audio *chip = subs->stream->chip;
479 	const struct audioformat *fmt;
480 	const struct audioformat *sync_fmt;
481 	bool fixed_rate, sync_fixed_rate;
482 	int ret;
483 
484 	ret = snd_media_start_pipeline(subs);
485 	if (ret)
486 		return ret;
487 
488 	fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
489 	fmt = find_substream_format(subs, hw_params);
490 	if (!fmt) {
491 		usb_audio_dbg(chip,
492 			      "cannot find format: format=%s, rate=%d, channels=%d\n",
493 			      snd_pcm_format_name(params_format(hw_params)),
494 			      params_rate(hw_params), params_channels(hw_params));
495 		ret = -EINVAL;
496 		goto stop_pipeline;
497 	}
498 
499 	if (fmt->implicit_fb) {
500 		sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
501 								hw_params,
502 								!substream->stream,
503 								&sync_fixed_rate);
504 		if (!sync_fmt) {
505 			usb_audio_dbg(chip,
506 				      "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
507 				      fmt->sync_ep, fmt->sync_iface,
508 				      fmt->sync_altsetting,
509 				      snd_pcm_format_name(params_format(hw_params)),
510 				      params_rate(hw_params), params_channels(hw_params));
511 			ret = -EINVAL;
512 			goto stop_pipeline;
513 		}
514 	} else {
515 		sync_fmt = fmt;
516 		sync_fixed_rate = fixed_rate;
517 	}
518 
519 	ret = snd_usb_lock_shutdown(chip);
520 	if (ret < 0)
521 		goto stop_pipeline;
522 
523 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
524 	if (ret < 0)
525 		goto unlock;
526 
527 	if (subs->data_endpoint) {
528 		if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
529 						fmt, hw_params))
530 			goto unlock;
531 		if (stop_endpoints(subs, false))
532 			sync_pending_stops(subs);
533 		close_endpoints(chip, subs);
534 	}
535 
536 	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false, fixed_rate);
537 	if (!subs->data_endpoint) {
538 		ret = -EINVAL;
539 		goto unlock;
540 	}
541 
542 	if (fmt->sync_ep) {
543 		subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
544 							    hw_params,
545 							    fmt == sync_fmt,
546 							    sync_fixed_rate);
547 		if (!subs->sync_endpoint) {
548 			ret = -EINVAL;
549 			goto unlock;
550 		}
551 
552 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
553 					  subs->sync_endpoint);
554 	}
555 
556 	mutex_lock(&chip->mutex);
557 	subs->cur_audiofmt = fmt;
558 	mutex_unlock(&chip->mutex);
559 
560 	if (!subs->data_endpoint->need_setup)
561 		goto unlock;
562 
563 	if (subs->sync_endpoint) {
564 		ret = snd_usb_endpoint_set_params(chip, subs->sync_endpoint);
565 		if (ret < 0)
566 			goto unlock;
567 	}
568 
569 	ret = snd_usb_endpoint_set_params(chip, subs->data_endpoint);
570 
571  unlock:
572 	if (ret < 0)
573 		close_endpoints(chip, subs);
574 
575 	snd_usb_unlock_shutdown(chip);
576  stop_pipeline:
577 	if (ret < 0)
578 		snd_media_stop_pipeline(subs);
579 
580 	return ret;
581 }
582 
583 /*
584  * hw_free callback
585  *
586  * reset the audio format and release the buffer
587  */
588 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
589 {
590 	struct snd_usb_substream *subs = substream->runtime->private_data;
591 	struct snd_usb_audio *chip = subs->stream->chip;
592 
593 	snd_media_stop_pipeline(subs);
594 	mutex_lock(&chip->mutex);
595 	subs->cur_audiofmt = NULL;
596 	mutex_unlock(&chip->mutex);
597 	if (!snd_usb_lock_shutdown(chip)) {
598 		if (stop_endpoints(subs, false))
599 			sync_pending_stops(subs);
600 		close_endpoints(chip, subs);
601 		snd_usb_unlock_shutdown(chip);
602 	}
603 
604 	return 0;
605 }
606 
607 /* free-wheeling mode? (e.g. dmix) */
608 static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
609 {
610 	return runtime->stop_threshold > runtime->buffer_size;
611 }
612 
613 /* check whether early start is needed for playback stream */
614 static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
615 					 struct snd_usb_substream *subs)
616 {
617 	struct snd_usb_audio *chip = subs->stream->chip;
618 
619 	if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
620 		return false;
621 	/* disabled via module option? */
622 	if (!chip->lowlatency)
623 		return false;
624 	if (in_free_wheeling_mode(runtime))
625 		return false;
626 	/* implicit feedback mode has own operation mode */
627 	if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
628 		return false;
629 	return true;
630 }
631 
632 /*
633  * prepare callback
634  *
635  * only a few subtle things...
636  */
637 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
638 {
639 	struct snd_pcm_runtime *runtime = substream->runtime;
640 	struct snd_usb_substream *subs = runtime->private_data;
641 	struct snd_usb_audio *chip = subs->stream->chip;
642 	int retry = 0;
643 	int ret;
644 
645 	ret = snd_usb_lock_shutdown(chip);
646 	if (ret < 0)
647 		return ret;
648 	if (snd_BUG_ON(!subs->data_endpoint)) {
649 		ret = -EIO;
650 		goto unlock;
651 	}
652 
653  again:
654 	if (subs->sync_endpoint) {
655 		ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
656 		if (ret < 0)
657 			goto unlock;
658 	}
659 
660 	ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
661 	if (ret < 0)
662 		goto unlock;
663 	else if (ret > 0)
664 		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
665 	ret = 0;
666 
667 	/* reset the pointer */
668 	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
669 	subs->inflight_bytes = 0;
670 	subs->hwptr_done = 0;
671 	subs->transfer_done = 0;
672 	subs->last_frame_number = 0;
673 	subs->period_elapsed_pending = 0;
674 	runtime->delay = 0;
675 
676 	subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
677 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
678 	    !subs->lowlatency_playback) {
679 		ret = start_endpoints(subs);
680 		/* if XRUN happens at starting streams (possibly with implicit
681 		 * fb case), restart again, but only try once.
682 		 */
683 		if (ret == -EPIPE && !retry++) {
684 			sync_pending_stops(subs);
685 			goto again;
686 		}
687 	}
688  unlock:
689 	snd_usb_unlock_shutdown(chip);
690 	return ret;
691 }
692 
693 /*
694  * h/w constraints
695  */
696 
697 #ifdef HW_CONST_DEBUG
698 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
699 #else
700 #define hwc_debug(fmt, args...) do { } while(0)
701 #endif
702 
703 static const struct snd_pcm_hardware snd_usb_hardware =
704 {
705 	.info =			SNDRV_PCM_INFO_MMAP |
706 				SNDRV_PCM_INFO_MMAP_VALID |
707 				SNDRV_PCM_INFO_BATCH |
708 				SNDRV_PCM_INFO_INTERLEAVED |
709 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
710 				SNDRV_PCM_INFO_PAUSE,
711 	.channels_min =		1,
712 	.channels_max =		256,
713 	.buffer_bytes_max =	INT_MAX, /* limited by BUFFER_TIME later */
714 	.period_bytes_min =	64,
715 	.period_bytes_max =	INT_MAX, /* limited by PERIOD_TIME later */
716 	.periods_min =		2,
717 	.periods_max =		1024,
718 };
719 
720 static int hw_check_valid_format(struct snd_usb_substream *subs,
721 				 struct snd_pcm_hw_params *params,
722 				 const struct audioformat *fp)
723 {
724 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
725 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
726 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
727 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
728 	struct snd_mask check_fmts;
729 	unsigned int ptime;
730 
731 	/* check the format */
732 	snd_mask_none(&check_fmts);
733 	check_fmts.bits[0] = (u32)fp->formats;
734 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
735 	snd_mask_intersect(&check_fmts, fmts);
736 	if (snd_mask_empty(&check_fmts)) {
737 		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
738 		return 0;
739 	}
740 	/* check the channels */
741 	if (fp->channels < ct->min || fp->channels > ct->max) {
742 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
743 		return 0;
744 	}
745 	/* check the rate is within the range */
746 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
747 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
748 		return 0;
749 	}
750 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
751 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
752 		return 0;
753 	}
754 	/* check whether the period time is >= the data packet interval */
755 	if (subs->speed != USB_SPEED_FULL) {
756 		ptime = 125 * (1 << fp->datainterval);
757 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
758 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
759 			return 0;
760 		}
761 	}
762 	return 1;
763 }
764 
765 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
766 				  unsigned int rmax)
767 {
768 	int changed;
769 
770 	if (rmin > rmax) {
771 		hwc_debug("  --> get empty\n");
772 		it->empty = 1;
773 		return -EINVAL;
774 	}
775 
776 	changed = 0;
777 	if (it->min < rmin) {
778 		it->min = rmin;
779 		it->openmin = 0;
780 		changed = 1;
781 	}
782 	if (it->max > rmax) {
783 		it->max = rmax;
784 		it->openmax = 0;
785 		changed = 1;
786 	}
787 	if (snd_interval_checkempty(it)) {
788 		it->empty = 1;
789 		return -EINVAL;
790 	}
791 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
792 	return changed;
793 }
794 
795 /* get the specified endpoint object that is being used by other streams
796  * (i.e. the parameter is locked)
797  */
798 static const struct snd_usb_endpoint *
799 get_endpoint_in_use(struct snd_usb_audio *chip, int endpoint,
800 		    const struct snd_usb_endpoint *ref_ep)
801 {
802 	const struct snd_usb_endpoint *ep;
803 
804 	ep = snd_usb_get_endpoint(chip, endpoint);
805 	if (ep && ep->cur_audiofmt && (ep != ref_ep || ep->opened > 1))
806 		return ep;
807 	return NULL;
808 }
809 
810 static int hw_rule_rate(struct snd_pcm_hw_params *params,
811 			struct snd_pcm_hw_rule *rule)
812 {
813 	struct snd_usb_substream *subs = rule->private;
814 	struct snd_usb_audio *chip = subs->stream->chip;
815 	const struct snd_usb_endpoint *ep;
816 	const struct audioformat *fp;
817 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
818 	unsigned int rmin, rmax, r;
819 	int i;
820 
821 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
822 	rmin = UINT_MAX;
823 	rmax = 0;
824 	list_for_each_entry(fp, &subs->fmt_list, list) {
825 		if (!hw_check_valid_format(subs, params, fp))
826 			continue;
827 
828 		ep = get_endpoint_in_use(chip, fp->endpoint,
829 					 subs->data_endpoint);
830 		if (ep) {
831 			hwc_debug("rate limit %d for ep#%x\n",
832 				  ep->cur_rate, fp->endpoint);
833 			rmin = min(rmin, ep->cur_rate);
834 			rmax = max(rmax, ep->cur_rate);
835 			continue;
836 		}
837 
838 		if (fp->implicit_fb) {
839 			ep = get_endpoint_in_use(chip, fp->sync_ep,
840 						 subs->sync_endpoint);
841 			if (ep) {
842 				hwc_debug("rate limit %d for sync_ep#%x\n",
843 					  ep->cur_rate, fp->sync_ep);
844 				rmin = min(rmin, ep->cur_rate);
845 				rmax = max(rmax, ep->cur_rate);
846 				continue;
847 			}
848 		}
849 
850 		r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
851 		if (r > 0) {
852 			if (!snd_interval_test(it, r))
853 				continue;
854 			rmin = min(rmin, r);
855 			rmax = max(rmax, r);
856 			continue;
857 		}
858 		if (fp->rate_table && fp->nr_rates) {
859 			for (i = 0; i < fp->nr_rates; i++) {
860 				r = fp->rate_table[i];
861 				if (!snd_interval_test(it, r))
862 					continue;
863 				rmin = min(rmin, r);
864 				rmax = max(rmax, r);
865 			}
866 		} else {
867 			rmin = min(rmin, fp->rate_min);
868 			rmax = max(rmax, fp->rate_max);
869 		}
870 	}
871 
872 	return apply_hw_params_minmax(it, rmin, rmax);
873 }
874 
875 
876 static int hw_rule_channels(struct snd_pcm_hw_params *params,
877 			    struct snd_pcm_hw_rule *rule)
878 {
879 	struct snd_usb_substream *subs = rule->private;
880 	const struct audioformat *fp;
881 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
882 	unsigned int rmin, rmax;
883 
884 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
885 	rmin = UINT_MAX;
886 	rmax = 0;
887 	list_for_each_entry(fp, &subs->fmt_list, list) {
888 		if (!hw_check_valid_format(subs, params, fp))
889 			continue;
890 		rmin = min(rmin, fp->channels);
891 		rmax = max(rmax, fp->channels);
892 	}
893 
894 	return apply_hw_params_minmax(it, rmin, rmax);
895 }
896 
897 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
898 {
899 	u32 oldbits[2];
900 	int changed;
901 
902 	oldbits[0] = fmt->bits[0];
903 	oldbits[1] = fmt->bits[1];
904 	fmt->bits[0] &= (u32)fbits;
905 	fmt->bits[1] &= (u32)(fbits >> 32);
906 	if (!fmt->bits[0] && !fmt->bits[1]) {
907 		hwc_debug("  --> get empty\n");
908 		return -EINVAL;
909 	}
910 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
911 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
912 	return changed;
913 }
914 
915 static int hw_rule_format(struct snd_pcm_hw_params *params,
916 			  struct snd_pcm_hw_rule *rule)
917 {
918 	struct snd_usb_substream *subs = rule->private;
919 	struct snd_usb_audio *chip = subs->stream->chip;
920 	const struct snd_usb_endpoint *ep;
921 	const struct audioformat *fp;
922 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
923 	u64 fbits;
924 
925 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
926 	fbits = 0;
927 	list_for_each_entry(fp, &subs->fmt_list, list) {
928 		if (!hw_check_valid_format(subs, params, fp))
929 			continue;
930 
931 		ep = get_endpoint_in_use(chip, fp->endpoint,
932 					 subs->data_endpoint);
933 		if (ep) {
934 			hwc_debug("format limit %d for ep#%x\n",
935 				  ep->cur_format, fp->endpoint);
936 			fbits |= pcm_format_to_bits(ep->cur_format);
937 			continue;
938 		}
939 
940 		if (fp->implicit_fb) {
941 			ep = get_endpoint_in_use(chip, fp->sync_ep,
942 						 subs->sync_endpoint);
943 			if (ep) {
944 				hwc_debug("format limit %d for sync_ep#%x\n",
945 					  ep->cur_format, fp->sync_ep);
946 				fbits |= pcm_format_to_bits(ep->cur_format);
947 				continue;
948 			}
949 		}
950 
951 		fbits |= fp->formats;
952 	}
953 	return apply_hw_params_format_bits(fmt, fbits);
954 }
955 
956 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
957 			       struct snd_pcm_hw_rule *rule)
958 {
959 	struct snd_usb_substream *subs = rule->private;
960 	const struct audioformat *fp;
961 	struct snd_interval *it;
962 	unsigned char min_datainterval;
963 	unsigned int pmin;
964 
965 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
966 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
967 	min_datainterval = 0xff;
968 	list_for_each_entry(fp, &subs->fmt_list, list) {
969 		if (!hw_check_valid_format(subs, params, fp))
970 			continue;
971 		min_datainterval = min(min_datainterval, fp->datainterval);
972 	}
973 	if (min_datainterval == 0xff) {
974 		hwc_debug("  --> get empty\n");
975 		it->empty = 1;
976 		return -EINVAL;
977 	}
978 	pmin = 125 * (1 << min_datainterval);
979 
980 	return apply_hw_params_minmax(it, pmin, UINT_MAX);
981 }
982 
983 /* additional hw constraints for implicit feedback mode */
984 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
985 					   struct snd_pcm_hw_rule *rule)
986 {
987 	struct snd_usb_substream *subs = rule->private;
988 	struct snd_usb_audio *chip = subs->stream->chip;
989 	const struct audioformat *fp;
990 	const struct snd_usb_endpoint *ep;
991 	struct snd_interval *it;
992 	unsigned int rmin, rmax;
993 
994 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
995 	hwc_debug("hw_rule_period_size: (%u,%u)\n", it->min, it->max);
996 	rmin = UINT_MAX;
997 	rmax = 0;
998 	list_for_each_entry(fp, &subs->fmt_list, list) {
999 		if (!hw_check_valid_format(subs, params, fp))
1000 			continue;
1001 		ep = get_endpoint_in_use(chip, fp->endpoint,
1002 					 subs->data_endpoint);
1003 		if (ep) {
1004 			hwc_debug("period size limit %d for ep#%x\n",
1005 				  ep->cur_period_frames, fp->endpoint);
1006 			rmin = min(rmin, ep->cur_period_frames);
1007 			rmax = max(rmax, ep->cur_period_frames);
1008 			continue;
1009 		}
1010 
1011 		if (fp->implicit_fb) {
1012 			ep = get_endpoint_in_use(chip, fp->sync_ep,
1013 						 subs->sync_endpoint);
1014 			if (ep) {
1015 				hwc_debug("period size limit %d for sync_ep#%x\n",
1016 					  ep->cur_period_frames, fp->sync_ep);
1017 				rmin = min(rmin, ep->cur_period_frames);
1018 				rmax = max(rmax, ep->cur_period_frames);
1019 				continue;
1020 			}
1021 		}
1022 	}
1023 
1024 	if (!rmax)
1025 		return 0; /* no limit by implicit fb */
1026 	return apply_hw_params_minmax(it, rmin, rmax);
1027 }
1028 
1029 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
1030 				       struct snd_pcm_hw_rule *rule)
1031 {
1032 	struct snd_usb_substream *subs = rule->private;
1033 	struct snd_usb_audio *chip = subs->stream->chip;
1034 	const struct audioformat *fp;
1035 	const struct snd_usb_endpoint *ep;
1036 	struct snd_interval *it;
1037 	unsigned int rmin, rmax;
1038 
1039 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
1040 	hwc_debug("hw_rule_periods: (%u,%u)\n", it->min, it->max);
1041 	rmin = UINT_MAX;
1042 	rmax = 0;
1043 	list_for_each_entry(fp, &subs->fmt_list, list) {
1044 		if (!hw_check_valid_format(subs, params, fp))
1045 			continue;
1046 		ep = get_endpoint_in_use(chip, fp->endpoint,
1047 					 subs->data_endpoint);
1048 		if (ep) {
1049 			hwc_debug("periods limit %d for ep#%x\n",
1050 				  ep->cur_buffer_periods, fp->endpoint);
1051 			rmin = min(rmin, ep->cur_buffer_periods);
1052 			rmax = max(rmax, ep->cur_buffer_periods);
1053 			continue;
1054 		}
1055 
1056 		if (fp->implicit_fb) {
1057 			ep = get_endpoint_in_use(chip, fp->sync_ep,
1058 						 subs->sync_endpoint);
1059 			if (ep) {
1060 				hwc_debug("periods limit %d for sync_ep#%x\n",
1061 					  ep->cur_buffer_periods, fp->sync_ep);
1062 				rmin = min(rmin, ep->cur_buffer_periods);
1063 				rmax = max(rmax, ep->cur_buffer_periods);
1064 				continue;
1065 			}
1066 		}
1067 	}
1068 
1069 	if (!rmax)
1070 		return 0; /* no limit by implicit fb */
1071 	return apply_hw_params_minmax(it, rmin, rmax);
1072 }
1073 
1074 /*
1075  * set up the runtime hardware information.
1076  */
1077 
1078 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1079 {
1080 	const struct audioformat *fp;
1081 	unsigned int pt, ptmin;
1082 	int param_period_time_if_needed = -1;
1083 	int err;
1084 
1085 	runtime->hw.formats = subs->formats;
1086 
1087 	runtime->hw.rate_min = 0x7fffffff;
1088 	runtime->hw.rate_max = 0;
1089 	runtime->hw.channels_min = 256;
1090 	runtime->hw.channels_max = 0;
1091 	runtime->hw.rates = 0;
1092 	ptmin = UINT_MAX;
1093 	/* check min/max rates and channels */
1094 	list_for_each_entry(fp, &subs->fmt_list, list) {
1095 		runtime->hw.rates |= fp->rates;
1096 		if (runtime->hw.rate_min > fp->rate_min)
1097 			runtime->hw.rate_min = fp->rate_min;
1098 		if (runtime->hw.rate_max < fp->rate_max)
1099 			runtime->hw.rate_max = fp->rate_max;
1100 		if (runtime->hw.channels_min > fp->channels)
1101 			runtime->hw.channels_min = fp->channels;
1102 		if (runtime->hw.channels_max < fp->channels)
1103 			runtime->hw.channels_max = fp->channels;
1104 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1105 			/* FIXME: there might be more than one audio formats... */
1106 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1107 				fp->frame_size;
1108 		}
1109 		pt = 125 * (1 << fp->datainterval);
1110 		ptmin = min(ptmin, pt);
1111 	}
1112 
1113 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1114 	if (subs->speed == USB_SPEED_FULL)
1115 		/* full speed devices have fixed data packet interval */
1116 		ptmin = 1000;
1117 	if (ptmin == 1000)
1118 		/* if period time doesn't go below 1 ms, no rules needed */
1119 		param_period_time_if_needed = -1;
1120 
1121 	err = snd_pcm_hw_constraint_minmax(runtime,
1122 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1123 					   ptmin, UINT_MAX);
1124 	if (err < 0)
1125 		return err;
1126 
1127 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1128 				  hw_rule_rate, subs,
1129 				  SNDRV_PCM_HW_PARAM_RATE,
1130 				  SNDRV_PCM_HW_PARAM_FORMAT,
1131 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1132 				  param_period_time_if_needed,
1133 				  -1);
1134 	if (err < 0)
1135 		return err;
1136 
1137 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1138 				  hw_rule_channels, subs,
1139 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1140 				  SNDRV_PCM_HW_PARAM_FORMAT,
1141 				  SNDRV_PCM_HW_PARAM_RATE,
1142 				  param_period_time_if_needed,
1143 				  -1);
1144 	if (err < 0)
1145 		return err;
1146 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1147 				  hw_rule_format, subs,
1148 				  SNDRV_PCM_HW_PARAM_FORMAT,
1149 				  SNDRV_PCM_HW_PARAM_RATE,
1150 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1151 				  param_period_time_if_needed,
1152 				  -1);
1153 	if (err < 0)
1154 		return err;
1155 	if (param_period_time_if_needed >= 0) {
1156 		err = snd_pcm_hw_rule_add(runtime, 0,
1157 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1158 					  hw_rule_period_time, subs,
1159 					  SNDRV_PCM_HW_PARAM_FORMAT,
1160 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1161 					  SNDRV_PCM_HW_PARAM_RATE,
1162 					  -1);
1163 		if (err < 0)
1164 			return err;
1165 	}
1166 
1167 	/* set max period and buffer sizes for 1 and 2 seconds, respectively */
1168 	err = snd_pcm_hw_constraint_minmax(runtime,
1169 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1170 					   0, 1000000);
1171 	if (err < 0)
1172 		return err;
1173 	err = snd_pcm_hw_constraint_minmax(runtime,
1174 					   SNDRV_PCM_HW_PARAM_BUFFER_TIME,
1175 					   0, 2000000);
1176 	if (err < 0)
1177 		return err;
1178 
1179 	/* additional hw constraints for implicit fb */
1180 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1181 				  hw_rule_period_size_implicit_fb, subs,
1182 				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1183 	if (err < 0)
1184 		return err;
1185 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1186 				  hw_rule_periods_implicit_fb, subs,
1187 				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
1188 	if (err < 0)
1189 		return err;
1190 
1191 	list_for_each_entry(fp, &subs->fmt_list, list) {
1192 		if (fp->implicit_fb) {
1193 			runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1194 			break;
1195 		}
1196 	}
1197 
1198 	return 0;
1199 }
1200 
1201 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1202 {
1203 	int direction = substream->stream;
1204 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1205 	struct snd_pcm_runtime *runtime = substream->runtime;
1206 	struct snd_usb_substream *subs = &as->substream[direction];
1207 	int ret;
1208 
1209 	runtime->hw = snd_usb_hardware;
1210 	/* need an explicit sync to catch applptr update in low-latency mode */
1211 	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1212 	    as->chip->lowlatency)
1213 		runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1214 	runtime->private_data = subs;
1215 	subs->pcm_substream = substream;
1216 	/* runtime PM is also done there */
1217 
1218 	/* initialize DSD/DOP context */
1219 	subs->dsd_dop.byte_idx = 0;
1220 	subs->dsd_dop.channel = 0;
1221 	subs->dsd_dop.marker = 1;
1222 
1223 	ret = setup_hw_info(runtime, subs);
1224 	if (ret < 0)
1225 		return ret;
1226 	ret = snd_usb_autoresume(subs->stream->chip);
1227 	if (ret < 0)
1228 		return ret;
1229 	ret = snd_media_stream_init(subs, as->pcm, direction);
1230 	if (ret < 0)
1231 		snd_usb_autosuspend(subs->stream->chip);
1232 	return ret;
1233 }
1234 
1235 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1236 {
1237 	int direction = substream->stream;
1238 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1239 	struct snd_usb_substream *subs = &as->substream[direction];
1240 	int ret;
1241 
1242 	snd_media_stop_pipeline(subs);
1243 
1244 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1245 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1246 		snd_usb_unlock_shutdown(subs->stream->chip);
1247 		if (ret < 0)
1248 			return ret;
1249 	}
1250 
1251 	subs->pcm_substream = NULL;
1252 	snd_usb_autosuspend(subs->stream->chip);
1253 
1254 	return 0;
1255 }
1256 
1257 /* Since a URB can handle only a single linear buffer, we must use double
1258  * buffering when the data to be transferred overflows the buffer boundary.
1259  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1260  * for all URBs.
1261  */
1262 static void retire_capture_urb(struct snd_usb_substream *subs,
1263 			       struct urb *urb)
1264 {
1265 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1266 	unsigned int stride, frames, bytes, oldptr;
1267 	int i, period_elapsed = 0;
1268 	unsigned long flags;
1269 	unsigned char *cp;
1270 	int current_frame_number;
1271 
1272 	/* read frame number here, update pointer in critical section */
1273 	current_frame_number = usb_get_current_frame_number(subs->dev);
1274 
1275 	stride = runtime->frame_bits >> 3;
1276 
1277 	for (i = 0; i < urb->number_of_packets; i++) {
1278 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1279 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1280 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1281 				i, urb->iso_frame_desc[i].status);
1282 			// continue;
1283 		}
1284 		bytes = urb->iso_frame_desc[i].actual_length;
1285 		if (subs->stream_offset_adj > 0) {
1286 			unsigned int adj = min(subs->stream_offset_adj, bytes);
1287 			cp += adj;
1288 			bytes -= adj;
1289 			subs->stream_offset_adj -= adj;
1290 		}
1291 		frames = bytes / stride;
1292 		if (!subs->txfr_quirk)
1293 			bytes = frames * stride;
1294 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1295 			int oldbytes = bytes;
1296 			bytes = frames * stride;
1297 			dev_warn_ratelimited(&subs->dev->dev,
1298 				 "Corrected urb data len. %d->%d\n",
1299 							oldbytes, bytes);
1300 		}
1301 		/* update the current pointer */
1302 		spin_lock_irqsave(&subs->lock, flags);
1303 		oldptr = subs->hwptr_done;
1304 		subs->hwptr_done += bytes;
1305 		if (subs->hwptr_done >= subs->buffer_bytes)
1306 			subs->hwptr_done -= subs->buffer_bytes;
1307 		frames = (bytes + (oldptr % stride)) / stride;
1308 		subs->transfer_done += frames;
1309 		if (subs->transfer_done >= runtime->period_size) {
1310 			subs->transfer_done -= runtime->period_size;
1311 			period_elapsed = 1;
1312 		}
1313 
1314 		/* realign last_frame_number */
1315 		subs->last_frame_number = current_frame_number;
1316 
1317 		spin_unlock_irqrestore(&subs->lock, flags);
1318 		/* copy a data chunk */
1319 		if (oldptr + bytes > subs->buffer_bytes) {
1320 			unsigned int bytes1 = subs->buffer_bytes - oldptr;
1321 
1322 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1323 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1324 		} else {
1325 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1326 		}
1327 	}
1328 
1329 	if (period_elapsed)
1330 		snd_pcm_period_elapsed(subs->pcm_substream);
1331 }
1332 
1333 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1334 				  struct urb *urb, unsigned int bytes)
1335 {
1336 	struct snd_urb_ctx *ctx = urb->context;
1337 
1338 	ctx->queued += bytes;
1339 	subs->inflight_bytes += bytes;
1340 	subs->hwptr_done += bytes;
1341 	if (subs->hwptr_done >= subs->buffer_bytes)
1342 		subs->hwptr_done -= subs->buffer_bytes;
1343 }
1344 
1345 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1346 					     struct urb *urb, unsigned int bytes)
1347 {
1348 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1349 	unsigned int dst_idx = 0;
1350 	unsigned int src_idx = subs->hwptr_done;
1351 	unsigned int wrap = subs->buffer_bytes;
1352 	u8 *dst = urb->transfer_buffer;
1353 	u8 *src = runtime->dma_area;
1354 	static const u8 marker[] = { 0x05, 0xfa };
1355 	unsigned int queued = 0;
1356 
1357 	/*
1358 	 * The DSP DOP format defines a way to transport DSD samples over
1359 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1360 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1361 	 * 2 additional bytes of actual payload. The whole frame is stored
1362 	 * LSB.
1363 	 *
1364 	 * Hence, for a stereo transport, the buffer layout looks like this,
1365 	 * where L refers to left channel samples and R to right.
1366 	 *
1367 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1368 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1369 	 *   .....
1370 	 *
1371 	 */
1372 
1373 	while (bytes--) {
1374 		if (++subs->dsd_dop.byte_idx == 3) {
1375 			/* frame boundary? */
1376 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1377 			src_idx += 2;
1378 			subs->dsd_dop.byte_idx = 0;
1379 
1380 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1381 				/* alternate the marker */
1382 				subs->dsd_dop.marker++;
1383 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1384 				subs->dsd_dop.channel = 0;
1385 			}
1386 		} else {
1387 			/* stuff the DSD payload */
1388 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1389 
1390 			if (subs->cur_audiofmt->dsd_bitrev)
1391 				dst[dst_idx++] = bitrev8(src[idx]);
1392 			else
1393 				dst[dst_idx++] = src[idx];
1394 			queued++;
1395 		}
1396 	}
1397 
1398 	urb_ctx_queue_advance(subs, urb, queued);
1399 }
1400 
1401 /* copy bit-reversed bytes onto transfer buffer */
1402 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1403 					 struct urb *urb, unsigned int bytes)
1404 {
1405 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1406 	const u8 *src = runtime->dma_area;
1407 	u8 *buf = urb->transfer_buffer;
1408 	int i, ofs = subs->hwptr_done;
1409 
1410 	for (i = 0; i < bytes; i++) {
1411 		*buf++ = bitrev8(src[ofs]);
1412 		if (++ofs >= subs->buffer_bytes)
1413 			ofs = 0;
1414 	}
1415 
1416 	urb_ctx_queue_advance(subs, urb, bytes);
1417 }
1418 
1419 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1420 			int offset, int stride, unsigned int bytes)
1421 {
1422 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1423 
1424 	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1425 		/* err, the transferred area goes over buffer boundary. */
1426 		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1427 
1428 		memcpy(urb->transfer_buffer + offset,
1429 		       runtime->dma_area + subs->hwptr_done, bytes1);
1430 		memcpy(urb->transfer_buffer + offset + bytes1,
1431 		       runtime->dma_area, bytes - bytes1);
1432 	} else {
1433 		memcpy(urb->transfer_buffer + offset,
1434 		       runtime->dma_area + subs->hwptr_done, bytes);
1435 	}
1436 
1437 	urb_ctx_queue_advance(subs, urb, bytes);
1438 }
1439 
1440 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1441 				      struct urb *urb, int stride,
1442 				      unsigned int bytes)
1443 {
1444 	__le32 packet_length;
1445 	int i;
1446 
1447 	/* Put __le32 length descriptor at start of each packet. */
1448 	for (i = 0; i < urb->number_of_packets; i++) {
1449 		unsigned int length = urb->iso_frame_desc[i].length;
1450 		unsigned int offset = urb->iso_frame_desc[i].offset;
1451 
1452 		packet_length = cpu_to_le32(length);
1453 		offset += i * sizeof(packet_length);
1454 		urb->iso_frame_desc[i].offset = offset;
1455 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1456 		memcpy(urb->transfer_buffer + offset,
1457 		       &packet_length, sizeof(packet_length));
1458 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1459 			    stride, length);
1460 	}
1461 	/* Adjust transfer size accordingly. */
1462 	bytes += urb->number_of_packets * sizeof(packet_length);
1463 	return bytes;
1464 }
1465 
1466 static int prepare_playback_urb(struct snd_usb_substream *subs,
1467 				struct urb *urb,
1468 				bool in_stream_lock)
1469 {
1470 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1471 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1472 	struct snd_urb_ctx *ctx = urb->context;
1473 	unsigned int frames, bytes;
1474 	int counts;
1475 	unsigned int transfer_done, frame_limit, avail = 0;
1476 	int i, stride, period_elapsed = 0;
1477 	unsigned long flags;
1478 	int err = 0;
1479 
1480 	stride = ep->stride;
1481 
1482 	frames = 0;
1483 	ctx->queued = 0;
1484 	urb->number_of_packets = 0;
1485 
1486 	spin_lock_irqsave(&subs->lock, flags);
1487 	frame_limit = subs->frame_limit + ep->max_urb_frames;
1488 	transfer_done = subs->transfer_done;
1489 
1490 	if (subs->lowlatency_playback &&
1491 	    runtime->state != SNDRV_PCM_STATE_DRAINING) {
1492 		unsigned int hwptr = subs->hwptr_done / stride;
1493 
1494 		/* calculate the byte offset-in-buffer of the appl_ptr */
1495 		avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1496 			% runtime->buffer_size;
1497 		if (avail <= hwptr)
1498 			avail += runtime->buffer_size;
1499 		avail -= hwptr;
1500 	}
1501 
1502 	for (i = 0; i < ctx->packets; i++) {
1503 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1504 		if (counts < 0)
1505 			break;
1506 		/* set up descriptor */
1507 		urb->iso_frame_desc[i].offset = frames * stride;
1508 		urb->iso_frame_desc[i].length = counts * stride;
1509 		frames += counts;
1510 		avail -= counts;
1511 		urb->number_of_packets++;
1512 		transfer_done += counts;
1513 		if (transfer_done >= runtime->period_size) {
1514 			transfer_done -= runtime->period_size;
1515 			frame_limit = 0;
1516 			period_elapsed = 1;
1517 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1518 				if (transfer_done > 0) {
1519 					/* FIXME: fill-max mode is not
1520 					 * supported yet */
1521 					frames -= transfer_done;
1522 					counts -= transfer_done;
1523 					urb->iso_frame_desc[i].length =
1524 						counts * stride;
1525 					transfer_done = 0;
1526 				}
1527 				i++;
1528 				if (i < ctx->packets) {
1529 					/* add a transfer delimiter */
1530 					urb->iso_frame_desc[i].offset =
1531 						frames * stride;
1532 					urb->iso_frame_desc[i].length = 0;
1533 					urb->number_of_packets++;
1534 				}
1535 				break;
1536 			}
1537 		}
1538 		/* finish at the period boundary or after enough frames */
1539 		if ((period_elapsed || transfer_done >= frame_limit) &&
1540 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1541 			break;
1542 	}
1543 
1544 	if (!frames) {
1545 		err = -EAGAIN;
1546 		goto unlock;
1547 	}
1548 
1549 	bytes = frames * stride;
1550 	subs->transfer_done = transfer_done;
1551 	subs->frame_limit = frame_limit;
1552 	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1553 		     subs->cur_audiofmt->dsd_dop)) {
1554 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1555 	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1556 			   subs->cur_audiofmt->dsd_bitrev)) {
1557 		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1558 	} else {
1559 		/* usual PCM */
1560 		if (!subs->tx_length_quirk)
1561 			copy_to_urb(subs, urb, 0, stride, bytes);
1562 		else
1563 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1564 			/* bytes is now amount of outgoing data */
1565 	}
1566 
1567 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1568 
1569 	if (subs->trigger_tstamp_pending_update) {
1570 		/* this is the first actual URB submitted,
1571 		 * update trigger timestamp to reflect actual start time
1572 		 */
1573 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1574 		subs->trigger_tstamp_pending_update = false;
1575 	}
1576 
1577 	if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1578 		subs->period_elapsed_pending = 1;
1579 		period_elapsed = 0;
1580 	}
1581 
1582  unlock:
1583 	spin_unlock_irqrestore(&subs->lock, flags);
1584 	if (err < 0)
1585 		return err;
1586 	urb->transfer_buffer_length = bytes;
1587 	if (period_elapsed) {
1588 		if (in_stream_lock)
1589 			snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1590 		else
1591 			snd_pcm_period_elapsed(subs->pcm_substream);
1592 	}
1593 	return 0;
1594 }
1595 
1596 /*
1597  * process after playback data complete
1598  * - decrease the delay count again
1599  */
1600 static void retire_playback_urb(struct snd_usb_substream *subs,
1601 			       struct urb *urb)
1602 {
1603 	unsigned long flags;
1604 	struct snd_urb_ctx *ctx = urb->context;
1605 	bool period_elapsed = false;
1606 
1607 	spin_lock_irqsave(&subs->lock, flags);
1608 	if (ctx->queued) {
1609 		if (subs->inflight_bytes >= ctx->queued)
1610 			subs->inflight_bytes -= ctx->queued;
1611 		else
1612 			subs->inflight_bytes = 0;
1613 	}
1614 
1615 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1616 	if (subs->running) {
1617 		period_elapsed = subs->period_elapsed_pending;
1618 		subs->period_elapsed_pending = 0;
1619 	}
1620 	spin_unlock_irqrestore(&subs->lock, flags);
1621 	if (period_elapsed)
1622 		snd_pcm_period_elapsed(subs->pcm_substream);
1623 }
1624 
1625 /* PCM ack callback for the playback stream;
1626  * this plays a role only when the stream is running in low-latency mode.
1627  */
1628 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1629 {
1630 	struct snd_usb_substream *subs = substream->runtime->private_data;
1631 	struct snd_usb_endpoint *ep;
1632 
1633 	if (!subs->lowlatency_playback || !subs->running)
1634 		return 0;
1635 	ep = subs->data_endpoint;
1636 	if (!ep)
1637 		return 0;
1638 	/* When no more in-flight URBs available, try to process the pending
1639 	 * outputs here
1640 	 */
1641 	if (!ep->active_mask)
1642 		return snd_usb_queue_pending_output_urbs(ep, true);
1643 	return 0;
1644 }
1645 
1646 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1647 					      int cmd)
1648 {
1649 	struct snd_usb_substream *subs = substream->runtime->private_data;
1650 	int err;
1651 
1652 	switch (cmd) {
1653 	case SNDRV_PCM_TRIGGER_START:
1654 		subs->trigger_tstamp_pending_update = true;
1655 		fallthrough;
1656 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1657 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1658 					      prepare_playback_urb,
1659 					      retire_playback_urb,
1660 					      subs);
1661 		if (subs->lowlatency_playback &&
1662 		    cmd == SNDRV_PCM_TRIGGER_START) {
1663 			if (in_free_wheeling_mode(substream->runtime))
1664 				subs->lowlatency_playback = false;
1665 			err = start_endpoints(subs);
1666 			if (err < 0) {
1667 				snd_usb_endpoint_set_callback(subs->data_endpoint,
1668 							      NULL, NULL, NULL);
1669 				return err;
1670 			}
1671 		}
1672 		subs->running = 1;
1673 		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1674 			subs->cur_audiofmt->iface,
1675 			subs->cur_audiofmt->altsetting);
1676 		return 0;
1677 	case SNDRV_PCM_TRIGGER_SUSPEND:
1678 	case SNDRV_PCM_TRIGGER_STOP:
1679 		stop_endpoints(subs, substream->runtime->state == SNDRV_PCM_STATE_DRAINING);
1680 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1681 					      NULL, NULL, NULL);
1682 		subs->running = 0;
1683 		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1684 			subs->cur_audiofmt->iface,
1685 			subs->cur_audiofmt->altsetting);
1686 		return 0;
1687 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1688 		/* keep retire_data_urb for delay calculation */
1689 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1690 					      NULL,
1691 					      retire_playback_urb,
1692 					      subs);
1693 		subs->running = 0;
1694 		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1695 			subs->cur_audiofmt->iface,
1696 			subs->cur_audiofmt->altsetting);
1697 		return 0;
1698 	}
1699 
1700 	return -EINVAL;
1701 }
1702 
1703 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1704 					     int cmd)
1705 {
1706 	int err;
1707 	struct snd_usb_substream *subs = substream->runtime->private_data;
1708 
1709 	switch (cmd) {
1710 	case SNDRV_PCM_TRIGGER_START:
1711 		err = start_endpoints(subs);
1712 		if (err < 0)
1713 			return err;
1714 		fallthrough;
1715 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1716 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1717 					      NULL, retire_capture_urb,
1718 					      subs);
1719 		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1720 		subs->running = 1;
1721 		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1722 			subs->cur_audiofmt->iface,
1723 			subs->cur_audiofmt->altsetting);
1724 		return 0;
1725 	case SNDRV_PCM_TRIGGER_SUSPEND:
1726 	case SNDRV_PCM_TRIGGER_STOP:
1727 		stop_endpoints(subs, false);
1728 		fallthrough;
1729 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1730 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1731 					      NULL, NULL, NULL);
1732 		subs->running = 0;
1733 		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1734 			subs->cur_audiofmt->iface,
1735 			subs->cur_audiofmt->altsetting);
1736 		return 0;
1737 	}
1738 
1739 	return -EINVAL;
1740 }
1741 
1742 static const struct snd_pcm_ops snd_usb_playback_ops = {
1743 	.open =		snd_usb_pcm_open,
1744 	.close =	snd_usb_pcm_close,
1745 	.hw_params =	snd_usb_hw_params,
1746 	.hw_free =	snd_usb_hw_free,
1747 	.prepare =	snd_usb_pcm_prepare,
1748 	.trigger =	snd_usb_substream_playback_trigger,
1749 	.sync_stop =	snd_usb_pcm_sync_stop,
1750 	.pointer =	snd_usb_pcm_pointer,
1751 	.ack =		snd_usb_pcm_playback_ack,
1752 };
1753 
1754 static const struct snd_pcm_ops snd_usb_capture_ops = {
1755 	.open =		snd_usb_pcm_open,
1756 	.close =	snd_usb_pcm_close,
1757 	.hw_params =	snd_usb_hw_params,
1758 	.hw_free =	snd_usb_hw_free,
1759 	.prepare =	snd_usb_pcm_prepare,
1760 	.trigger =	snd_usb_substream_capture_trigger,
1761 	.sync_stop =	snd_usb_pcm_sync_stop,
1762 	.pointer =	snd_usb_pcm_pointer,
1763 };
1764 
1765 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1766 {
1767 	const struct snd_pcm_ops *ops;
1768 
1769 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1770 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1771 	snd_pcm_set_ops(pcm, stream, ops);
1772 }
1773 
1774 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1775 {
1776 	struct snd_pcm *pcm = subs->stream->pcm;
1777 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1778 	struct device *dev = subs->dev->bus->sysdev;
1779 
1780 	if (snd_usb_use_vmalloc)
1781 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1782 					   NULL, 0, 0);
1783 	else
1784 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1785 					   dev, 64*1024, 512*1024);
1786 }
1787