1/*
2 * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the
6 * Free Software Foundation; either version 2 of the License, or (at your
7 * option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software Foundation,
16 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19#include <linux/usb.h>
20#include <linux/gfp.h>
21
22#include "usb_stream.h"
23
24
25/*                             setup                                  */
26
27static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
28{
29	struct usb_stream *s = sk->s;
30	sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
31	return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
32}
33
34static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
35{
36	struct usb_stream *s = sk->s;
37	int pack, lb = 0;
38
39	for (pack = 0; pack < sk->n_o_ps; pack++) {
40		int l = usb_stream_next_packet_size(sk);
41		if (s->idle_outsize + lb + l > s->period_size)
42			goto check;
43
44		sk->out_phase = sk->out_phase_peeked;
45		urb->iso_frame_desc[pack].offset = lb;
46		urb->iso_frame_desc[pack].length = l;
47		lb += l;
48	}
49	snd_printdd(KERN_DEBUG "%i\n", lb);
50
51check:
52	urb->number_of_packets = pack;
53	urb->transfer_buffer_length = lb;
54	s->idle_outsize += lb - s->period_size;
55	snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
56		    lb, s->period_size);
57}
58
59static void init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
60			   struct urb **urbs, char *transfer,
61			   struct usb_device *dev, int pipe)
62{
63	int u, p;
64	int maxpacket = use_packsize ?
65		use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
66	int transfer_length = maxpacket * sk->n_o_ps;
67
68	for (u = 0; u < USB_STREAM_NURBS;
69	     ++u, transfer += transfer_length) {
70		struct urb *urb = urbs[u];
71		struct usb_iso_packet_descriptor *desc;
72		urb->transfer_buffer = transfer;
73		urb->dev = dev;
74		urb->pipe = pipe;
75		urb->number_of_packets = sk->n_o_ps;
76		urb->context = sk;
77		urb->interval = 1;
78		if (usb_pipeout(pipe))
79			continue;
80
81		urb->transfer_buffer_length = transfer_length;
82		desc = urb->iso_frame_desc;
83		desc->offset = 0;
84		desc->length = maxpacket;
85		for (p = 1; p < sk->n_o_ps; ++p) {
86			desc[p].offset = desc[p - 1].offset + maxpacket;
87			desc[p].length = maxpacket;
88		}
89	}
90}
91
92static void init_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
93		      struct usb_device *dev, int in_pipe, int out_pipe)
94{
95	struct usb_stream	*s = sk->s;
96	char			*indata = (char *)s + sizeof(*s) +
97					sizeof(struct usb_stream_packet) *
98					s->inpackets;
99	int			u;
100
101	for (u = 0; u < USB_STREAM_NURBS; ++u) {
102		sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
103		sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
104	}
105
106	init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe);
107	init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
108		       out_pipe);
109}
110
111
112/*
113 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
114 * this will overflow at approx 524 kHz
115 */
116static inline unsigned get_usb_full_speed_rate(unsigned rate)
117{
118	return ((rate << 13) + 62) / 125;
119}
120
121/*
122 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
123 * this will overflow at approx 4 MHz
124 */
125static inline unsigned get_usb_high_speed_rate(unsigned rate)
126{
127	return ((rate << 10) + 62) / 125;
128}
129
130void usb_stream_free(struct usb_stream_kernel *sk)
131{
132	struct usb_stream *s;
133	unsigned u;
134
135	for (u = 0; u < USB_STREAM_NURBS; ++u) {
136		usb_free_urb(sk->inurb[u]);
137		sk->inurb[u] = NULL;
138		usb_free_urb(sk->outurb[u]);
139		sk->outurb[u] = NULL;
140	}
141
142	s = sk->s;
143	if (!s)
144		return;
145
146	free_pages((unsigned long)sk->write_page, get_order(s->write_size));
147	sk->write_page = NULL;
148	free_pages((unsigned long)s, get_order(s->read_size));
149	sk->s = NULL;
150}
151
152struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
153				  struct usb_device *dev,
154				  unsigned in_endpoint, unsigned out_endpoint,
155				  unsigned sample_rate, unsigned use_packsize,
156				  unsigned period_frames, unsigned frame_size)
157{
158	int packets, max_packsize;
159	int in_pipe, out_pipe;
160	int read_size = sizeof(struct usb_stream);
161	int write_size;
162	int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
163	int pg;
164
165	in_pipe = usb_rcvisocpipe(dev, in_endpoint);
166	out_pipe = usb_sndisocpipe(dev, out_endpoint);
167
168	max_packsize = use_packsize ?
169		use_packsize : usb_maxpacket(dev, in_pipe, 0);
170
171	/*
172		t_period = period_frames / sample_rate
173		iso_packs = t_period / t_iso_frame
174			= (period_frames / sample_rate) * (1 / t_iso_frame)
175	*/
176
177	packets = period_frames * usb_frames / sample_rate + 1;
178
179	if (dev->speed == USB_SPEED_HIGH)
180		packets = (packets + 7) & ~7;
181
182	read_size += packets * USB_STREAM_URBDEPTH *
183		(max_packsize + sizeof(struct usb_stream_packet));
184
185	max_packsize = usb_maxpacket(dev, out_pipe, 1);
186	write_size = max_packsize * packets * USB_STREAM_URBDEPTH;
187
188	if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
189		snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
190		goto out;
191	}
192
193	pg = get_order(read_size);
194	sk->s = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
195	if (!sk->s) {
196		snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
197		goto out;
198	}
199	sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;
200
201	sk->s->read_size = read_size;
202
203	sk->s->cfg.sample_rate = sample_rate;
204	sk->s->cfg.frame_size = frame_size;
205	sk->n_o_ps = packets;
206	sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
207	sk->s->cfg.period_frames = period_frames;
208	sk->s->period_size = frame_size * period_frames;
209
210	sk->s->write_size = write_size;
211	pg = get_order(write_size);
212
213	sk->write_page =
214		(void *)__get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
215	if (!sk->write_page) {
216		snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
217		usb_stream_free(sk);
218		return NULL;
219	}
220
221	/* calculate the frequency in 16.16 format */
222	if (dev->speed == USB_SPEED_FULL)
223		sk->freqn = get_usb_full_speed_rate(sample_rate);
224	else
225		sk->freqn = get_usb_high_speed_rate(sample_rate);
226
227	init_urbs(sk, use_packsize, dev, in_pipe, out_pipe);
228	sk->s->state = usb_stream_stopped;
229out:
230	return sk->s;
231}
232
233
234/*                             start                                  */
235
236static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
237{
238	bool r;
239	if (unlikely(urb->status)) {
240		if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
241			snd_printk(KERN_WARNING "status=%i\n", urb->status);
242		sk->iso_frame_balance = 0x7FFFFFFF;
243		return false;
244	}
245	r = sk->iso_frame_balance == 0;
246	if (!r)
247		sk->i_urb = urb;
248	return r;
249}
250
251static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
252{
253	sk->iso_frame_balance += urb->number_of_packets;
254	return balance_check(sk, urb);
255}
256
257static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
258{
259	sk->iso_frame_balance -= urb->number_of_packets;
260	return balance_check(sk, urb);
261}
262
263static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
264{
265	int u;
266
267	for (u = 0; u < USB_STREAM_NURBS; u++) {
268		struct urb *urb = urbs[u];
269		urb->complete = complete;
270	}
271}
272
273static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
274		struct urb *inurb)
275{
276	struct usb_stream *s = sk->s;
277	struct urb *io;
278	struct usb_iso_packet_descriptor *id, *od;
279	int p = 0, lb = 0, l = 0;
280
281	io = sk->idle_outurb;
282	od = io->iso_frame_desc;
283
284	for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
285		struct urb *ii = sk->completed_inurb;
286		id = ii->iso_frame_desc +
287			ii->number_of_packets + s->sync_packet;
288		l = id->actual_length;
289
290		od[p].length = l;
291		od[p].offset = lb;
292		lb += l;
293	}
294
295	for (;
296	     s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
297	     ++p, ++s->sync_packet) {
298		l = inurb->iso_frame_desc[s->sync_packet].actual_length;
299
300		if (s->idle_outsize + lb + l > s->period_size)
301			goto check_ok;
302
303		od[p].length = l;
304		od[p].offset = lb;
305		lb += l;
306	}
307
308check_ok:
309	s->sync_packet -= inurb->number_of_packets;
310	if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
311		snd_printk(KERN_WARNING "invalid sync_packet = %i;"
312			   " p=%i nop=%i %i %x %x %x > %x\n",
313			   s->sync_packet, p, inurb->number_of_packets,
314			   s->idle_outsize + lb + l,
315			   s->idle_outsize, lb,  l,
316			   s->period_size);
317		return -1;
318	}
319	if (unlikely(lb % s->cfg.frame_size)) {
320		snd_printk(KERN_WARNING"invalid outsize = %i\n",
321			   lb);
322		return -1;
323	}
324	s->idle_outsize += lb - s->period_size;
325	io->number_of_packets = p;
326	io->transfer_buffer_length = lb;
327	if (s->idle_outsize <= 0)
328		return 0;
329
330	snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
331	return -1;
332}
333
334static void prepare_inurb(int number_of_packets, struct urb *iu)
335{
336	struct usb_iso_packet_descriptor *id;
337	int p;
338
339	iu->number_of_packets = number_of_packets;
340	id = iu->iso_frame_desc;
341	id->offset = 0;
342	for (p = 0; p < iu->number_of_packets - 1; ++p)
343		id[p + 1].offset = id[p].offset + id[p].length;
344
345	iu->transfer_buffer_length =
346		id[0].length * iu->number_of_packets;
347}
348
349static int submit_urbs(struct usb_stream_kernel *sk,
350		       struct urb *inurb, struct urb *outurb)
351{
352	int err;
353	prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
354	err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
355	if (err < 0) {
356		snd_printk(KERN_ERR "%i\n", err);
357		return err;
358	}
359	sk->idle_inurb = sk->completed_inurb;
360	sk->completed_inurb = inurb;
361	err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
362	if (err < 0) {
363		snd_printk(KERN_ERR "%i\n", err);
364		return err;
365	}
366	sk->idle_outurb = sk->completed_outurb;
367	sk->completed_outurb = outurb;
368	return 0;
369}
370
371#ifdef DEBUG_LOOP_BACK
372/*
373  This loop_back() shows how to read/write the period data.
374 */
375static void loop_back(struct usb_stream *s)
376{
377	char *i, *o;
378	int il, ol, l, p;
379	struct urb *iu;
380	struct usb_iso_packet_descriptor *id;
381
382	o = s->playback1st_to;
383	ol = s->playback1st_size;
384	l = 0;
385
386	if (s->insplit_pack >= 0) {
387		iu = sk->idle_inurb;
388		id = iu->iso_frame_desc;
389		p = s->insplit_pack;
390	} else
391		goto second;
392loop:
393	for (; p < iu->number_of_packets && l < s->period_size; ++p) {
394		i = iu->transfer_buffer + id[p].offset;
395		il = id[p].actual_length;
396		if (l + il > s->period_size)
397			il = s->period_size - l;
398		if (il <= ol) {
399			memcpy(o, i, il);
400			o += il;
401			ol -= il;
402		} else {
403			memcpy(o, i, ol);
404			singen_6pack(o, ol);
405			o = s->playback_to;
406			memcpy(o, i + ol, il - ol);
407			o += il - ol;
408			ol = s->period_size - s->playback1st_size;
409		}
410		l += il;
411	}
412	if (iu == sk->completed_inurb) {
413		if (l != s->period_size)
414			printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
415			       l/(int)s->cfg.frame_size);
416
417		return;
418	}
419second:
420	iu = sk->completed_inurb;
421	id = iu->iso_frame_desc;
422	p = 0;
423	goto loop;
424
425}
426#else
427static void loop_back(struct usb_stream *s)
428{
429}
430#endif
431
432static void stream_idle(struct usb_stream_kernel *sk,
433			struct urb *inurb, struct urb *outurb)
434{
435	struct usb_stream *s = sk->s;
436	int l, p;
437	int insize = s->idle_insize;
438	int urb_size = 0;
439
440	s->inpacket_split = s->next_inpacket_split;
441	s->inpacket_split_at = s->next_inpacket_split_at;
442	s->next_inpacket_split = -1;
443	s->next_inpacket_split_at = 0;
444
445	for (p = 0; p < inurb->number_of_packets; ++p) {
446		struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
447		l = id[p].actual_length;
448		if (unlikely(l == 0 || id[p].status)) {
449			snd_printk(KERN_WARNING "underrun, status=%u\n",
450				   id[p].status);
451			goto err_out;
452		}
453		s->inpacket_head++;
454		s->inpacket_head %= s->inpackets;
455		if (s->inpacket_split == -1)
456			s->inpacket_split = s->inpacket_head;
457
458		s->inpacket[s->inpacket_head].offset =
459			id[p].offset + (inurb->transfer_buffer - (void *)s);
460		s->inpacket[s->inpacket_head].length = l;
461		if (insize + l > s->period_size &&
462		    s->next_inpacket_split == -1) {
463			s->next_inpacket_split = s->inpacket_head;
464			s->next_inpacket_split_at = s->period_size - insize;
465		}
466		insize += l;
467		urb_size += l;
468	}
469	s->idle_insize += urb_size - s->period_size;
470	if (s->idle_insize < 0) {
471		snd_printk(KERN_WARNING "%i\n",
472			   (s->idle_insize)/(int)s->cfg.frame_size);
473		goto err_out;
474	}
475	s->insize_done += urb_size;
476
477	l = s->idle_outsize;
478	s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
479				  sk->write_page) - l;
480
481	if (usb_stream_prepare_playback(sk, inurb) < 0)
482		goto err_out;
483
484	s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
485	s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
486		sk->write_page;
487
488	if (submit_urbs(sk, inurb, outurb) < 0)
489		goto err_out;
490
491	loop_back(s);
492	s->periods_done++;
493	wake_up_all(&sk->sleep);
494	return;
495err_out:
496	s->state = usb_stream_xrun;
497	wake_up_all(&sk->sleep);
498}
499
500static void i_capture_idle(struct urb *urb)
501{
502	struct usb_stream_kernel *sk = urb->context;
503	if (balance_capture(sk, urb))
504		stream_idle(sk, urb, sk->i_urb);
505}
506
507static void i_playback_idle(struct urb *urb)
508{
509	struct usb_stream_kernel *sk = urb->context;
510	if (balance_playback(sk, urb))
511		stream_idle(sk, sk->i_urb, urb);
512}
513
514static void stream_start(struct usb_stream_kernel *sk,
515			 struct urb *inurb, struct urb *outurb)
516{
517	struct usb_stream *s = sk->s;
518	if (s->state >= usb_stream_sync1) {
519		int l, p, max_diff, max_diff_0;
520		int urb_size = 0;
521		unsigned frames_per_packet, min_frames = 0;
522		frames_per_packet = (s->period_size - s->idle_insize);
523		frames_per_packet <<= 8;
524		frames_per_packet /=
525			s->cfg.frame_size * inurb->number_of_packets;
526		frames_per_packet++;
527
528		max_diff_0 = s->cfg.frame_size;
529		if (s->cfg.period_frames >= 256)
530			max_diff_0 <<= 1;
531		if (s->cfg.period_frames >= 1024)
532			max_diff_0 <<= 1;
533		max_diff = max_diff_0;
534		for (p = 0; p < inurb->number_of_packets; ++p) {
535			int diff;
536			l = inurb->iso_frame_desc[p].actual_length;
537			urb_size += l;
538
539			min_frames += frames_per_packet;
540			diff = urb_size -
541				(min_frames >> 8) * s->cfg.frame_size;
542			if (diff < max_diff) {
543				snd_printdd(KERN_DEBUG "%i %i %i %i\n",
544					    s->insize_done,
545					    urb_size / (int)s->cfg.frame_size,
546					    inurb->number_of_packets, diff);
547				max_diff = diff;
548			}
549		}
550		s->idle_insize -= max_diff - max_diff_0;
551		s->idle_insize += urb_size - s->period_size;
552		if (s->idle_insize < 0) {
553			snd_printk(KERN_WARNING "%i %i %i\n",
554				   s->idle_insize, urb_size, s->period_size);
555			return;
556		} else if (s->idle_insize == 0) {
557			s->next_inpacket_split =
558				(s->inpacket_head + 1) % s->inpackets;
559			s->next_inpacket_split_at = 0;
560		} else {
561			unsigned split = s->inpacket_head;
562			l = s->idle_insize;
563			while (l > s->inpacket[split].length) {
564				l -= s->inpacket[split].length;
565				if (split == 0)
566					split = s->inpackets - 1;
567				else
568					split--;
569			}
570			s->next_inpacket_split = split;
571			s->next_inpacket_split_at =
572				s->inpacket[split].length - l;
573		}
574
575		s->insize_done += urb_size;
576
577		if (usb_stream_prepare_playback(sk, inurb) < 0)
578			return;
579
580	} else
581		playback_prep_freqn(sk, sk->idle_outurb);
582
583	if (submit_urbs(sk, inurb, outurb) < 0)
584		return;
585
586	if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
587		/* just guesswork                            ^^^^^^ */
588		s->state = usb_stream_ready;
589		subs_set_complete(sk->inurb, i_capture_idle);
590		subs_set_complete(sk->outurb, i_playback_idle);
591	}
592}
593
594static void i_capture_start(struct urb *urb)
595{
596	struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
597	struct usb_stream_kernel *sk = urb->context;
598	struct usb_stream *s = sk->s;
599	int p;
600	int empty = 0;
601
602	if (urb->status) {
603		snd_printk(KERN_WARNING "status=%i\n", urb->status);
604		return;
605	}
606
607	for (p = 0; p < urb->number_of_packets; ++p) {
608		int l = id[p].actual_length;
609		if (l < s->cfg.frame_size) {
610			++empty;
611			if (s->state >= usb_stream_sync0) {
612				snd_printk(KERN_WARNING "%i\n", l);
613				return;
614			}
615		}
616		s->inpacket_head++;
617		s->inpacket_head %= s->inpackets;
618		s->inpacket[s->inpacket_head].offset =
619			id[p].offset + (urb->transfer_buffer - (void *)s);
620		s->inpacket[s->inpacket_head].length = l;
621	}
622#ifdef SHOW_EMPTY
623	if (empty) {
624		printk(KERN_DEBUG"%s:%i: %i", __func__, __LINE__,
625		       urb->iso_frame_desc[0].actual_length);
626		for (pack = 1; pack < urb->number_of_packets; ++pack) {
627			int l = urb->iso_frame_desc[pack].actual_length;
628			printk(" %i", l);
629		}
630		printk("\n");
631	}
632#endif
633	if (!empty && s->state < usb_stream_sync1)
634		++s->state;
635
636	if (balance_capture(sk, urb))
637		stream_start(sk, urb, sk->i_urb);
638}
639
640static void i_playback_start(struct urb *urb)
641{
642	struct usb_stream_kernel *sk = urb->context;
643	if (balance_playback(sk, urb))
644		stream_start(sk, sk->i_urb, urb);
645}
646
647int usb_stream_start(struct usb_stream_kernel *sk)
648{
649	struct usb_stream *s = sk->s;
650	int frame = 0, iters = 0;
651	int u, err;
652	int try = 0;
653
654	if (s->state != usb_stream_stopped)
655		return -EAGAIN;
656
657	subs_set_complete(sk->inurb, i_capture_start);
658	subs_set_complete(sk->outurb, i_playback_start);
659	memset(sk->write_page, 0, s->write_size);
660dotry:
661	s->insize_done = 0;
662	s->idle_insize = 0;
663	s->idle_outsize = 0;
664	s->sync_packet = -1;
665	s->inpacket_head = -1;
666	sk->iso_frame_balance = 0;
667	++try;
668	for (u = 0; u < 2; u++) {
669		struct urb *inurb = sk->inurb[u];
670		struct urb *outurb = sk->outurb[u];
671		playback_prep_freqn(sk, outurb);
672		inurb->number_of_packets = outurb->number_of_packets;
673		inurb->transfer_buffer_length =
674			inurb->number_of_packets *
675			inurb->iso_frame_desc[0].length;
676
677		if (u == 0) {
678			int now;
679			struct usb_device *dev = inurb->dev;
680			frame = usb_get_current_frame_number(dev);
681			do {
682				now = usb_get_current_frame_number(dev);
683				++iters;
684			} while (now > -1 && now == frame);
685		}
686		err = usb_submit_urb(inurb, GFP_ATOMIC);
687		if (err < 0) {
688			snd_printk(KERN_ERR"usb_submit_urb(sk->inurb[%i])"
689				   " returned %i\n", u, err);
690			return err;
691		}
692		err = usb_submit_urb(outurb, GFP_ATOMIC);
693		if (err < 0) {
694			snd_printk(KERN_ERR"usb_submit_urb(sk->outurb[%i])"
695				   " returned %i\n", u, err);
696			return err;
697		}
698
699		if (inurb->start_frame != outurb->start_frame) {
700			snd_printd(KERN_DEBUG
701				   "u[%i] start_frames differ in:%u out:%u\n",
702				   u, inurb->start_frame, outurb->start_frame);
703			goto check_retry;
704		}
705	}
706	snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
707	try = 0;
708check_retry:
709	if (try) {
710		usb_stream_stop(sk);
711		if (try < 5) {
712			msleep(1500);
713			snd_printd(KERN_DEBUG "goto dotry;\n");
714			goto dotry;
715		}
716		snd_printk(KERN_WARNING"couldn't start"
717			   " all urbs on the same start_frame.\n");
718		return -EFAULT;
719	}
720
721	sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
722	sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
723	sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
724	sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
725
726/* wait, check */
727	{
728		int wait_ms = 3000;
729		while (s->state != usb_stream_ready && wait_ms > 0) {
730			snd_printdd(KERN_DEBUG "%i\n", s->state);
731			msleep(200);
732			wait_ms -= 200;
733		}
734	}
735
736	return s->state == usb_stream_ready ? 0 : -EFAULT;
737}
738
739
740/*                             stop                                   */
741
742void usb_stream_stop(struct usb_stream_kernel *sk)
743{
744	int u;
745	if (!sk->s)
746		return;
747	for (u = 0; u < USB_STREAM_NURBS; ++u) {
748		usb_kill_urb(sk->inurb[u]);
749		usb_kill_urb(sk->outurb[u]);
750	}
751	sk->s->state = usb_stream_stopped;
752	msleep(400);
753}
754