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   1 /*
   2  * Helper functions for indirect PCM data transfer to a simple FIFO in
   3  * hardware (small, no possibility to read "hardware io position",
   4  * updating position done by interrupt, ...)
   5  *
   6  *  Copyright (c) by 2007  Joachim Foerster <JOFT@gmx.de>
   7  *
   8  *  Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
   9  *
  10  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
  11  *                   Jaroslav Kysela <perex@suse.cz>
  12  *
  13  *   This program is free software; you can redistribute it and/or modify
  14  *   it under the terms of the GNU General Public License as published by
  15  *   the Free Software Foundation; either version 2 of the License, or
  16  *   (at your option) any later version.
  17  *
  18  *   This program is distributed in the hope that it will be useful,
  19  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  *   GNU General Public License for more details.
  22  *
  23  *   You should have received a copy of the GNU General Public License
  24  *   along with this program; if not, write to the Free Software
  25  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26  */
  27
  28 /* #dependency of sound/core.h# */
  29 #include <sound/driver.h>
  30 /* snd_printk/d() */
  31 #include <sound/core.h>
  32 /* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t
  33  * snd_pcm_period_elapsed() */
  34 #include <sound/pcm.h>
  35
  36 #include "pcm-indirect2.h"
  37
  38 #ifdef SND_PCM_INDIRECT2_STAT
  39 /* jiffies */
  40 #include <linux/jiffies.h>
  41
  42 void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
  43                             struct snd_pcm_indirect2 *rec)
  44 {
  45         struct snd_pcm_runtime *runtime = substream->runtime;
  46         int i;
  47         int j;
  48         int k;
  49         int seconds = (rec->lastbytetime - rec->firstbytetime) / HZ;
  50
  51         snd_printk(KERN_DEBUG "STAT: mul_elapsed: %u, mul_elapsed_real: %d, "
  52                    "irq_occured: %d\n",
  53                    rec->mul_elapsed, rec->mul_elapsed_real, rec->irq_occured);
  54         snd_printk(KERN_DEBUG "STAT: min_multiple: %d (irqs/period)\n",
  55                    rec->min_multiple);
  56         snd_printk(KERN_DEBUG "STAT: firstbytetime: %lu, lastbytetime: %lu, "
  57                    "firstzerotime: %lu\n",
  58                  rec->firstbytetime, rec->lastbytetime, rec->firstzerotime);
  59         snd_printk(KERN_DEBUG "STAT: bytes2hw: %u Bytes => (by runtime->rate) "
  60                    "length: %d s\n",
  61                  rec->bytes2hw, rec->bytes2hw / 2 / 2 / runtime->rate);
  62         snd_printk(KERN_DEBUG "STAT: (by measurement) length: %d => "
  63                    "rate: %d Bytes/s = %d Frames/s|Hz\n",
  64                    seconds, rec->bytes2hw / seconds,
  65                    rec->bytes2hw / 2 / 2 / seconds);
  66         snd_printk(KERN_DEBUG
  67                    "STAT: zeros2hw: %u = %d ms ~ %d * %d zero copies\n",
  68                    rec->zeros2hw, ((rec->zeros2hw / 2 / 2) * 1000) /
  69                    runtime->rate,
  70                    rec->zeros2hw / (rec->hw_buffer_size / 2),
  71                    (rec->hw_buffer_size / 2));
  72         snd_printk(KERN_DEBUG "STAT: pointer_calls: %u, lastdifftime: %u\n",
  73                    rec->pointer_calls, rec->lastdifftime);
  74         snd_printk(KERN_DEBUG "STAT: sw_io: %d, sw_data: %d\n", rec->sw_io,
  75                    rec->sw_data);
  76         snd_printk(KERN_DEBUG "STAT: byte_sizes[]:\n");
  77         k = 0;
  78         for (j = 0; j < 8; j++) {
  79                 for (i = j * 8; i < (j + 1) * 8; i++)
  80                         if (rec->byte_sizes[i] != 0) {
  81                                 snd_printk(KERN_DEBUG "%u: %u",
  82                                            i, rec->byte_sizes[i]);
  83                                 k++;
  84                         }
  85                 if (((k % 8) == 0) && (k != 0)) {
  86                         snd_printk(KERN_DEBUG "\n");
  87                         k = 0;
  88                 }
  89         }
  90         snd_printk(KERN_DEBUG "\n");
  91         snd_printk(KERN_DEBUG "STAT: zero_sizes[]:\n");
  92         for (j = 0; j < 8; j++) {
  93                 k = 0;
  94                 for (i = j * 8; i < (j + 1) * 8; i++)
  95                         if (rec->zero_sizes[i] != 0)
  96                                 snd_printk(KERN_DEBUG "%u: %u",
  97                                            i, rec->zero_sizes[i]);
  98                         else
  99                                 k++;
 100                 if (!k)
 101                         snd_printk(KERN_DEBUG "\n");
 102         }
 103         snd_printk(KERN_DEBUG "\n");
 104         snd_printk(KERN_DEBUG "STAT: min_adds[]:\n");
 105         for (j = 0; j < 8; j++) {
 106                 if (rec->min_adds[j] != 0)
 107                         snd_printk(KERN_DEBUG "%u: %u", j, rec->min_adds[j]);
 108         }
 109         snd_printk(KERN_DEBUG "\n");
 110         snd_printk(KERN_DEBUG "STAT: mul_adds[]:\n");
 111         for (j = 0; j < 8; j++) {
 112                 if (rec->mul_adds[j] != 0)
 113                         snd_printk(KERN_DEBUG "%u: %u", j, rec->mul_adds[j]);
 114         }
 115         snd_printk(KERN_DEBUG "\n");
 116         snd_printk(KERN_DEBUG
 117                    "STAT: zero_times_saved: %d, zero_times_notsaved: %d\n",
 118                    rec->zero_times_saved, rec->zero_times_notsaved);
 119         /* snd_printk(KERN_DEBUG "STAT: zero_times[]\n");
 120         i = 0;
 121         for (j = 0; j < 3750; j++) {
 122                 if (rec->zero_times[j] != 0) {
 123                         snd_printk(KERN_DEBUG "%u: %u", j, rec->zero_times[j]);
 124                         i++;
 125                 }
 126                 if (((i % 8) == 0) && (i != 0))
 127                         snd_printk(KERN_DEBUG "\n");
 128         }
 129         snd_printk(KERN_DEBUG "\n"); */
 130         return;
 131 }
 132 #endif
 133
 134 /*
 135  * _internal_ helper function for playback/capture transfer function
 136  */
 137 static void
 138 snd_pcm_indirect2_increase_min_periods(struct snd_pcm_substream *substream,
 139                                        struct snd_pcm_indirect2 *rec,
 140                                        int isplay, int iscopy,
 141                                        unsigned int bytes)
 142 {
 143         if (rec->min_periods >= 0) {
 144                 if (iscopy) {
 145                         rec->sw_io += bytes;
 146                         if (rec->sw_io >= rec->sw_buffer_size)
 147                                 rec->sw_io -= rec->sw_buffer_size;
 148                 } else if (isplay) {
 149                         /* If application does not write data in multiples of
 150                          * a period, move sw_data to the next correctly aligned
 151                          * position, so that sw_io can converge to it (in the
 152                          * next step).
 153                          */
 154                         if (!rec->check_alignment) {
 155                                 if (rec->bytes2hw %
 156                                     snd_pcm_lib_period_bytes(substream)) {
 157                                         unsigned bytes2hw_aligned =
 158                                             (1 +
 159                                              (rec->bytes2hw /
 160                                               snd_pcm_lib_period_bytes
 161                                               (substream))) *
 162                                             snd_pcm_lib_period_bytes
 163                                             (substream);
 164                                         rec->sw_data =
 165                                             bytes2hw_aligned %
 166                                             rec->sw_buffer_size;
 167 #ifdef SND_PCM_INDIRECT2_STAT
 168                                         snd_printk(KERN_DEBUG
 169                                                    "STAT: @re-align: aligned "
 170                                                    "bytes2hw to next period "
 171                                                    "size boundary: %d "
 172                                                    "(instead of %d)\n",
 173                                                    bytes2hw_aligned,
 174                                                    rec->bytes2hw);
 175                                         snd_printk(KERN_DEBUG
 176                                                    "STAT: @re-align: sw_data "
 177                                                    "moves to: %d\n",
 178                                                    rec->sw_data);
 179 #endif
 180                                 }
 181                                 rec->check_alignment = 1;
 182                         }
 183                         /* We are at the end and are copying zeros into the
 184                          * fifo.
 185                          * Now, we have to make sure that sw_io is increased
 186                          * until the position of sw_data: Filling the fifo with
 187                          * the first zeros means, the last bytes were played.
 188                          */
 189                         if (rec->sw_io != rec->sw_data) {
 190                                 unsigned int diff;
 191                                 if (rec->sw_data > rec->sw_io)
 192                                         diff = rec->sw_data - rec->sw_io;
 193                                 else
 194                                         diff = (rec->sw_buffer_size -
 195                                                 rec->sw_io) +
 196                                                 rec->sw_data;
 197                                 if (bytes >= diff)
 198                                         rec->sw_io = rec->sw_data;
 199                                 else {
 200                                         rec->sw_io += bytes;
 201                                         if (rec->sw_io >= rec->sw_buffer_size)
 202                                                 rec->sw_io -=
 203                                                     rec->sw_buffer_size;
 204                                 }
 205                         }
 206                 }
 207                 rec->min_period_count += bytes;
 208                 if (rec->min_period_count >= (rec->hw_buffer_size / 2)) {
 209                         rec->min_periods += (rec->min_period_count /
 210                                              (rec->hw_buffer_size / 2));
 211 #ifdef SND_PCM_INDIRECT2_STAT
 212                         if ((rec->min_period_count /
 213                              (rec->hw_buffer_size / 2)) > 7)
 214                                 snd_printk(KERN_DEBUG
 215                                            "STAT: more than 7 (%d) min_adds "
 216                                            "at once - too big to save!\n",
 217                                            (rec->min_period_count /
 218                                             (rec->hw_buffer_size / 2)));
 219                         else
 220                                 rec->min_adds[(rec->min_period_count /
 221                                                (rec->hw_buffer_size / 2))]++;
 222 #endif
 223                         rec->min_period_count = (rec->min_period_count %
 224                                                  (rec->hw_buffer_size / 2));
 225                 }
 226         } else if (isplay && iscopy)
 227                 rec->min_periods = 0;
 228 }
 229
 230 /*
 231  * helper function for playback/capture pointer callback
 232  */
 233 snd_pcm_uframes_t
 234 snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
 235                           struct snd_pcm_indirect2 *rec)
 236 {
 237 #ifdef SND_PCM_INDIRECT2_STAT
 238         rec->pointer_calls++;
 239 #endif
 240         return bytes_to_frames(substream->runtime, rec->sw_io);
 241 }
 242
 243 /*
 244  * _internal_ helper function for playback interrupt callback
 245  */
 246 static void
 247 snd_pcm_indirect2_playback_transfer(struct snd_pcm_substream *substream,
 248                                     struct snd_pcm_indirect2 *rec,
 249                                     snd_pcm_indirect2_copy_t copy,
 250                                     snd_pcm_indirect2_zero_t zero)
 251 {
 252         struct snd_pcm_runtime *runtime = substream->runtime;
 253         snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
 254
 255         /* runtime->control->appl_ptr: position where ALSA will write next time
 256          * rec->appl_ptr: position where ALSA was last time
 257          * diff: obviously ALSA wrote that much bytes into the intermediate
 258          * buffer since we checked last time
 259          */
 260         snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;
 261
 262         if (diff) {
 263 #ifdef SND_PCM_INDIRECT2_STAT
 264                 rec->lastdifftime = jiffies;
 265 #endif
 266                 if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
 267                         diff += runtime->boundary;
 268                 /* number of bytes "added" by ALSA increases the number of
 269                  * bytes which are ready to "be transfered to HW"/"played"
 270                  * Then, set rec->appl_ptr to not count bytes twice next time.
 271                  */
 272                 rec->sw_ready += (int)frames_to_bytes(runtime, diff);
 273                 rec->appl_ptr = appl_ptr;
 274         }
 275         if (rec->hw_ready && (rec->sw_ready <= 0)) {
 276                 unsigned int bytes;
 277
 278 #ifdef SND_PCM_INDIRECT2_STAT
 279                 if (rec->firstzerotime == 0) {
 280                         rec->firstzerotime = jiffies;
 281                         snd_printk(KERN_DEBUG
 282                                    "STAT: @firstzerotime: mul_elapsed: %d, "
 283                                    "min_period_count: %d\n",
 284                                    rec->mul_elapsed, rec->min_period_count);
 285                         snd_printk(KERN_DEBUG
 286                                    "STAT: @firstzerotime: sw_io: %d, "
 287                                    "sw_data: %d, appl_ptr: %u\n",
 288                                    rec->sw_io, rec->sw_data,
 289                                    (unsigned int)appl_ptr);
 290                 }
 291                 if ((jiffies - rec->firstzerotime) < 3750) {
 292                         rec->zero_times[(jiffies - rec->firstzerotime)]++;
 293                         rec->zero_times_saved++;
 294                 } else
 295                         rec->zero_times_notsaved++;
 296 #endif
 297                 bytes = zero(substream, rec);
 298
 299 #ifdef SND_PCM_INDIRECT2_STAT
 300                 rec->zeros2hw += bytes;
 301                 if (bytes < 64)
 302                         rec->zero_sizes[bytes]++;
 303                 else
 304                         snd_printk(KERN_DEBUG
 305                                    "STAT: %d zero Bytes copied to hardware at "
 306                                    "once - too big to save!\n",
 307                                    bytes);
 308 #endif
 309                 snd_pcm_indirect2_increase_min_periods(substream, rec, 1, 0,
 310                                                        bytes);
 311                 return;
 312         }
 313         while (rec->hw_ready && (rec->sw_ready > 0)) {
 314                 /* sw_to_end: max. number of bytes that can be read/take from
 315                  * the current position (sw_data) in _one_ step
 316                  */
 317                 unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data;
 318
 319                 /* bytes: number of bytes we have available (for reading) */
 320                 unsigned int bytes = rec->sw_ready;
 321
 322                 if (sw_to_end < bytes)
 323                         bytes = sw_to_end;
 324                 if (!bytes)
 325                         break;
 326
 327 #ifdef SND_PCM_INDIRECT2_STAT
 328                 if (rec->firstbytetime == 0)
 329                         rec->firstbytetime = jiffies;
 330                 rec->lastbytetime = jiffies;
 331 #endif
 332                 /* copy bytes from intermediate buffer position sw_data to the
 333                  * HW and return number of bytes actually written
 334                  * Furthermore, set hw_ready to 0, if the fifo isn't empty
 335                  * now => more could be transfered to fifo
 336                  */
 337                 bytes = copy(substream, rec, bytes);
 338                 rec->bytes2hw += bytes;
 339
 340 #ifdef SND_PCM_INDIRECT2_STAT
 341                 if (bytes < 64)
 342                         rec->byte_sizes[bytes]++;
 343                 else
 344                         snd_printk(KERN_DEBUG
 345                                    "STAT: %d Bytes copied to hardware at once "
 346                                    "- too big to save!\n",
 347                                    bytes);
 348 #endif
 349                 /* increase sw_data by the number of actually written bytes
 350                  * (= number of taken bytes from intermediate buffer)
 351                  */
 352                 rec->sw_data += bytes;
 353                 if (rec->sw_data == rec->sw_buffer_size)
 354                         rec->sw_data = 0;
 355                 /* now sw_data is the position where ALSA is going to write
 356                  * in the intermediate buffer next time = position we are going
 357                  * to read from next time
 358                  */
 359
 360                 snd_pcm_indirect2_increase_min_periods(substream, rec, 1, 1,
 361                                                        bytes);
 362
 363                 /* we read bytes from intermediate buffer, so we need to say
 364                  * that the number of bytes ready for transfer are decreased
 365                  * now
 366                  */
 367                 rec->sw_ready -= bytes;
 368         }
 369         return;
 370 }
 371
 372 /*
 373  * helper function for playback interrupt routine
 374  */
 375 void
 376 snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
 377                                      struct snd_pcm_indirect2 *rec,
 378                                      snd_pcm_indirect2_copy_t copy,
 379                                      snd_pcm_indirect2_zero_t zero)
 380 {
 381 #ifdef SND_PCM_INDIRECT2_STAT
 382         rec->irq_occured++;
 383 #endif
 384         /* hardware played some bytes, so there is room again (in fifo) */
 385         rec->hw_ready = 1;
 386
 387         /* don't call ack() now, instead call transfer() function directly
 388          * (normally called by ack() )
 389          */
 390         snd_pcm_indirect2_playback_transfer(substream, rec, copy, zero);
 391
 392         if (rec->min_periods >= rec->min_multiple) {
 393 #ifdef SND_PCM_INDIRECT2_STAT
 394                 if ((rec->min_periods / rec->min_multiple) > 7)
 395                         snd_printk(KERN_DEBUG
 396                                    "STAT: more than 7 (%d) mul_adds - too big "
 397                                    "to save!\n",
 398                                    (rec->min_periods / rec->min_multiple));
 399                 else
 400                         rec->mul_adds[(rec->min_periods /
 401                                        rec->min_multiple)]++;
 402                 rec->mul_elapsed_real += (rec->min_periods /
 403                                           rec->min_multiple);
 404                 rec->mul_elapsed++;
 405 #endif
 406                 rec->min_periods = (rec->min_periods % rec->min_multiple);
 407                 snd_pcm_period_elapsed(substream);
 408         }
 409 }
 410
 411 /*
 412  * _internal_ helper function for capture interrupt callback
 413  */
 414 static void
 415 snd_pcm_indirect2_capture_transfer(struct snd_pcm_substream *substream,
 416                                    struct snd_pcm_indirect2 *rec,
 417                                    snd_pcm_indirect2_copy_t copy,
 418                                    snd_pcm_indirect2_zero_t null)
 419 {
 420         struct snd_pcm_runtime *runtime = substream->runtime;
 421         snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
 422         snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;
 423
 424         if (diff) {
 425 #ifdef SND_PCM_INDIRECT2_STAT
 426                 rec->lastdifftime = jiffies;
 427 #endif
 428                 if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
 429                         diff += runtime->boundary;
 430                 rec->sw_ready -= frames_to_bytes(runtime, diff);
 431                 rec->appl_ptr = appl_ptr;
 432         }
 433         /* if hardware has something, but the intermediate buffer is full
 434          * => skip contents of buffer
 435          */
 436         if (rec->hw_ready && (rec->sw_ready >= (int)rec->sw_buffer_size)) {
 437                 unsigned int bytes;
 438
 439 #ifdef SND_PCM_INDIRECT2_STAT
 440                 if (rec->firstzerotime == 0) {
 441                         rec->firstzerotime = jiffies;
 442                         snd_printk(KERN_DEBUG "STAT: (capture) "
 443                                    "@firstzerotime: mul_elapsed: %d, "
 444                                    "min_period_count: %d\n",
 445                                    rec->mul_elapsed, rec->min_period_count);
 446                         snd_printk(KERN_DEBUG "STAT: (capture) "
 447                                    "@firstzerotime: sw_io: %d, sw_data: %d, "
 448                                    "appl_ptr: %u\n",
 449                                    rec->sw_io, rec->sw_data,
 450                                    (unsigned int)appl_ptr);
 451                 }
 452                 if ((jiffies - rec->firstzerotime) < 3750) {
 453                         rec->zero_times[(jiffies - rec->firstzerotime)]++;
 454                         rec->zero_times_saved++;
 455                 } else
 456                         rec->zero_times_notsaved++;
 457 #endif
 458                 bytes = null(substream, rec);
 459
 460 #ifdef SND_PCM_INDIRECT2_STAT
 461                 rec->zeros2hw += bytes;
 462                 if (bytes < 64)
 463                         rec->zero_sizes[bytes]++;
 464                 else
 465                         snd_printk(KERN_DEBUG
 466                                    "STAT: (capture) %d zero Bytes copied to "
 467                                    "hardware at once - too big to save!\n",
 468                                    bytes);
 469 #endif
 470                 snd_pcm_indirect2_increase_min_periods(substream, rec, 0, 0,
 471                                                        bytes);
 472                 /* report an overrun */
 473                 rec->sw_io = SNDRV_PCM_POS_XRUN;
 474                 return;
 475         }
 476         while (rec->hw_ready && (rec->sw_ready < (int)rec->sw_buffer_size)) {
 477                 /* sw_to_end: max. number of bytes that we can write to the
 478                  *  intermediate buffer (until it's end)
 479                  */
 480                 size_t sw_to_end = rec->sw_buffer_size - rec->sw_data;
 481
 482                 /* bytes: max. number of bytes, which may be copied to the
 483                  *  intermediate buffer without overflow (in _one_ step)
 484                  */
 485                 size_t bytes = rec->sw_buffer_size - rec->sw_ready;
 486
 487                 /* limit number of bytes (for transfer) by available room in
 488                  * the intermediate buffer
 489                  */
 490                 if (sw_to_end < bytes)
 491                         bytes = sw_to_end;
 492                 if (!bytes)
 493                         break;
 494
 495 #ifdef SND_PCM_INDIRECT2_STAT
 496                 if (rec->firstbytetime == 0)
 497                         rec->firstbytetime = jiffies;
 498                 rec->lastbytetime = jiffies;
 499 #endif
 500                 /* copy bytes from the intermediate buffer (position sw_data)
 501                  * to the HW at most and return number of bytes actually copied
 502                  * from HW
 503                  * Furthermore, set hw_ready to 0, if the fifo is empty now.
 504                  */
 505                 bytes = copy(substream, rec, bytes);
 506                 rec->bytes2hw += bytes;
 507
 508 #ifdef SND_PCM_INDIRECT2_STAT
 509                 if (bytes < 64)
 510                         rec->byte_sizes[bytes]++;
 511                 else
 512                         snd_printk(KERN_DEBUG
 513                                    "STAT: (capture) %d Bytes copied to "
 514                                    "hardware at once - too big to save!\n",
 515                                    bytes);
 516 #endif
 517                 /* increase sw_data by the number of actually copied bytes from
 518                  * HW
 519                  */
 520                 rec->sw_data += bytes;
 521                 if (rec->sw_data == rec->sw_buffer_size)
 522                         rec->sw_data = 0;
 523
 524                 snd_pcm_indirect2_increase_min_periods(substream, rec, 0, 1,
 525                                                        bytes);
 526
 527                 /* number of bytes in the intermediate buffer, which haven't
 528                  * been fetched by ALSA yet.
 529                  */
 530                 rec->sw_ready += bytes;
 531         }
 532         return;
 533 }
 534
 535 /*
 536  * helper function for capture interrupt routine
 537  */
 538 void
 539 snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
 540                                     struct snd_pcm_indirect2 *rec,
 541                                     snd_pcm_indirect2_copy_t copy,
 542                                     snd_pcm_indirect2_zero_t null)
 543 {
 544 #ifdef SND_PCM_INDIRECT2_STAT
 545         rec->irq_occured++;
 546 #endif
 547         /* hardware recorded some bytes, so there is something to read from the
 548          * record fifo:
 549          */
 550         rec->hw_ready = 1;
 551
 552         /* don't call ack() now, instead call transfer() function directly
 553          * (normally called by ack() )
 554          */
 555         snd_pcm_indirect2_capture_transfer(substream, rec, copy, null);
 556
 557         if (rec->min_periods >= rec->min_multiple) {
 558
 559 #ifdef SND_PCM_INDIRECT2_STAT
 560                 if ((rec->min_periods / rec->min_multiple) > 7)
 561                         snd_printk(KERN_DEBUG
 562                                    "STAT: more than 7 (%d) mul_adds - "
 563                                    "too big to save!\n",
 564                                    (rec->min_periods / rec->min_multiple));
 565                 else
 566                         rec->mul_adds[(rec->min_periods /
 567                                        rec->min_multiple)]++;
 568                 rec->mul_elapsed_real += (rec->min_periods /
 569                                           rec->min_multiple);
 570                 rec->mul_elapsed++;
 571 #endif
 572                 rec->min_periods = (rec->min_periods % rec->min_multiple);
 573                 snd_pcm_period_elapsed(substream);
 574         }
 575 }