Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / sound / usb / usx2y / usb_stream.c
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
21 #include "usb_stream.h"
22
23
24 /*                             setup                                  */
25
26 static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
27 {
28         struct usb_stream *s = sk->s;
29         sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
30         return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
31 }
32
33 static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
34 {
35         struct usb_stream *s = sk->s;
36         int pack, lb = 0;
37
38         for (pack = 0; pack < sk->n_o_ps; pack++) {
39                 int l = usb_stream_next_packet_size(sk);
40                 if (s->idle_outsize + lb + l > s->period_size)
41                         goto check;
42
43                 sk->out_phase = sk->out_phase_peeked;
44                 urb->iso_frame_desc[pack].offset = lb;
45                 urb->iso_frame_desc[pack].length = l;
46                 lb += l;
47         }
48         snd_printdd(KERN_DEBUG "%i\n", lb);
49
50 check:
51         urb->number_of_packets = pack;
52         urb->transfer_buffer_length = lb;
53         s->idle_outsize += lb - s->period_size;
54         snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
55                     lb, s->period_size);
56 }
57
58 static void init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
59                            struct urb **urbs, char *transfer,
60                            struct usb_device *dev, int pipe)
61 {
62         int u, p;
63         int maxpacket = use_packsize ?
64                 use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
65         int transfer_length = maxpacket * sk->n_o_ps;
66
67         for (u = 0; u < USB_STREAM_NURBS;
68              ++u, transfer += transfer_length) {
69                 struct urb *urb = urbs[u];
70                 struct usb_iso_packet_descriptor *desc;
71                 urb->transfer_flags = URB_ISO_ASAP;
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
92 static 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  */
116 static 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  */
125 static inline unsigned get_usb_high_speed_rate(unsigned rate)
126 {
127         return ((rate << 10) + 62) / 125;
128 }
129
130 void 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
152 struct 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;
229 out:
230         return sk->s;
231 }
232
233
234 /*                             start                                  */
235
236 static 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
251 static 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
257 static 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
263 static 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
273 static 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
308 check_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
334 static 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
349 static 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  */
375 static 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;
392 loop:
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         }
419 second:
420         iu = sk->completed_inurb;
421         id = iu->iso_frame_desc;
422         p = 0;
423         goto loop;
424
425 }
426 #else
427 static void loop_back(struct usb_stream *s)
428 {
429 }
430 #endif
431
432 static 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;
495 err_out:
496         s->state = usb_stream_xrun;
497         wake_up_all(&sk->sleep);
498 }
499
500 static 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
507 static 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
514 static 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
594 static 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
640 static 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
647 int 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);
660 dotry:
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                 preempt_disable();
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                         preempt_enable();
689                         snd_printk(KERN_ERR"usb_submit_urb(sk->inurb[%i])"
690                                    " returned %i\n", u, err);
691                         return err;
692                 }
693                 err = usb_submit_urb(outurb, GFP_ATOMIC);
694                 if (err < 0) {
695                         preempt_enable();
696                         snd_printk(KERN_ERR"usb_submit_urb(sk->outurb[%i])"
697                                    " returned %i\n", u, err);
698                         return err;
699                 }
700                 preempt_enable();
701                 if (inurb->start_frame != outurb->start_frame) {
702                         snd_printd(KERN_DEBUG
703                                    "u[%i] start_frames differ in:%u out:%u\n",
704                                    u, inurb->start_frame, outurb->start_frame);
705                         goto check_retry;
706                 }
707         }
708         snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
709         try = 0;
710 check_retry:
711         if (try) {
712                 usb_stream_stop(sk);
713                 if (try < 5) {
714                         msleep(1500);
715                         snd_printd(KERN_DEBUG "goto dotry;\n");
716                         goto dotry;
717                 }
718                 snd_printk(KERN_WARNING"couldn't start"
719                            " all urbs on the same start_frame.\n");
720                 return -EFAULT;
721         }
722
723         sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
724         sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
725         sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
726         sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
727
728 /* wait, check */
729         {
730                 int wait_ms = 3000;
731                 while (s->state != usb_stream_ready && wait_ms > 0) {
732                         snd_printdd(KERN_DEBUG "%i\n", s->state);
733                         msleep(200);
734                         wait_ms -= 200;
735                 }
736         }
737
738         return s->state == usb_stream_ready ? 0 : -EFAULT;
739 }
740
741
742 /*                             stop                                   */
743
744 void usb_stream_stop(struct usb_stream_kernel *sk)
745 {
746         int u;
747         if (!sk->s)
748                 return;
749         for (u = 0; u < USB_STREAM_NURBS; ++u) {
750                 usb_kill_urb(sk->inurb[u]);
751                 usb_kill_urb(sk->outurb[u]);
752         }
753         sk->s->state = usb_stream_stopped;
754         msleep(400);
755 }