sound/core/init.c

   1 /*
   2  *  Initialization routines
   3  *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <sound/driver.h>
  23 #include <linux/init.h>
  24 #include <linux/sched.h>
  25 #include <linux/file.h>
  26 #include <linux/slab.h>
  27 #include <linux/time.h>
  28 #include <linux/ctype.h>
  29 #include <linux/pci.h>
  30 #include <linux/pm.h>
  31
  32 #include <sound/core.h>
  33 #include <sound/control.h>
  34 #include <sound/info.h>
  35
  36 struct snd_shutdown_f_ops {
  37         struct file_operations f_ops;
  38         struct snd_shutdown_f_ops *next;
  39 };
  40
  41 unsigned int snd_cards_lock = 0;        /* locked for registering/using */
  42 struct snd_card *snd_cards[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = NULL};
  43 DEFINE_RWLOCK(snd_card_rwlock);
  44
  45 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
  46 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
  47 #endif
  48
  49 static void snd_card_id_read(struct snd_info_entry *entry,
  50                              struct snd_info_buffer *buffer)
  51 {
  52         snd_iprintf(buffer, "%s\n", entry->card->id);
  53 }
  54
  55 static void snd_card_free_thread(void * __card);
  56
  57 /**
  58  *  snd_card_new - create and initialize a soundcard structure
  59  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
  60  *  @xid: card identification (ASCII string)
  61  *  @module: top level module for locking
  62  *  @extra_size: allocate this extra size after the main soundcard structure
  63  *
  64  *  Creates and initializes a soundcard structure.
  65  *
  66  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
  67  *  (which is blocked until snd_card_register function is called).
  68  */
  69 struct snd_card *snd_card_new(int idx, const char *xid,
  70                          struct module *module, int extra_size)
  71 {
  72         struct snd_card *card;
  73         int err;
  74
  75         if (extra_size < 0)
  76                 extra_size = 0;
  77         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
  78         if (card == NULL)
  79                 return NULL;
  80         if (xid) {
  81                 if (!snd_info_check_reserved_words(xid))
  82                         goto __error;
  83                 strlcpy(card->id, xid, sizeof(card->id));
  84         }
  85         err = 0;
  86         write_lock(&snd_card_rwlock);
  87         if (idx < 0) {
  88                 int idx2;
  89                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
  90                         if (~snd_cards_lock & idx & 1<<idx2) {
  91                                 idx = idx2;
  92                                 if (idx >= snd_ecards_limit)
  93                                         snd_ecards_limit = idx + 1;
  94                                 break;
  95                         }
  96         } else if (idx < snd_ecards_limit) {
  97                 if (snd_cards_lock & (1 << idx))
  98                         err = -ENODEV;  /* invalid */
  99         } else if (idx < SNDRV_CARDS)
 100                 snd_ecards_limit = idx + 1; /* increase the limit */
 101         else
 102                 err = -ENODEV;
 103         if (idx < 0 || err < 0) {
 104                 write_unlock(&snd_card_rwlock);
 105                 snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);
 106                 goto __error;
 107         }
 108         snd_cards_lock |= 1 << idx;             /* lock it */
 109         write_unlock(&snd_card_rwlock);
 110         card->number = idx;
 111         card->module = module;
 112         INIT_LIST_HEAD(&card->devices);
 113         init_rwsem(&card->controls_rwsem);
 114         rwlock_init(&card->ctl_files_rwlock);
 115         INIT_LIST_HEAD(&card->controls);
 116         INIT_LIST_HEAD(&card->ctl_files);
 117         spin_lock_init(&card->files_lock);
 118         init_waitqueue_head(&card->shutdown_sleep);
 119         INIT_WORK(&card->free_workq, snd_card_free_thread, card);
 120 #ifdef CONFIG_PM
 121         init_MUTEX(&card->power_lock);
 122         init_waitqueue_head(&card->power_sleep);
 123 #endif
 124         /* the control interface cannot be accessed from the user space until */
 125         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
 126         if ((err = snd_ctl_create(card)) < 0) {
 127                 snd_printd("unable to register control minors\n");
 128                 goto __error;
 129         }
 130         if ((err = snd_info_card_create(card)) < 0) {
 131                 snd_printd("unable to create card info\n");
 132                 goto __error_ctl;
 133         }
 134         if (extra_size > 0)
 135                 card->private_data = (char *)card + sizeof(struct snd_card);
 136         return card;
 137
 138       __error_ctl:
 139         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
 140       __error:
 141         kfree(card);
 142         return NULL;
 143 }
 144
 145 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
 146 {
 147         return POLLERR | POLLNVAL;
 148 }
 149
 150 /**
 151  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 152  *  @card: soundcard structure
 153  *
 154  *  Disconnects all APIs from the file-operations (user space).
 155  *
 156  *  Returns zero, otherwise a negative error code.
 157  *
 158  *  Note: The current implementation replaces all active file->f_op with special
 159  *        dummy file operations (they do nothing except release).
 160  */
 161 int snd_card_disconnect(struct snd_card *card)
 162 {
 163         struct snd_monitor_file *mfile;
 164         struct file *file;
 165         struct snd_shutdown_f_ops *s_f_ops;
 166         struct file_operations *f_ops, *old_f_ops;
 167         int err;
 168
 169         spin_lock(&card->files_lock);
 170         if (card->shutdown) {
 171                 spin_unlock(&card->files_lock);
 172                 return 0;
 173         }
 174         card->shutdown = 1;
 175         spin_unlock(&card->files_lock);
 176
 177         /* phase 1: disable fops (user space) operations for ALSA API */
 178         write_lock(&snd_card_rwlock);
 179         snd_cards[card->number] = NULL;
 180         write_unlock(&snd_card_rwlock);
 181
 182         /* phase 2: replace file->f_op with special dummy operations */
 183
 184         spin_lock(&card->files_lock);
 185         mfile = card->files;
 186         while (mfile) {
 187                 file = mfile->file;
 188
 189                 /* it's critical part, use endless loop */
 190                 /* we have no room to fail */
 191                 s_f_ops = kmalloc(sizeof(struct snd_shutdown_f_ops), GFP_ATOMIC);
 192                 if (s_f_ops == NULL)
 193                         panic("Atomic allocation failed for snd_shutdown_f_ops!");
 194
 195                 f_ops = &s_f_ops->f_ops;
 196
 197                 memset(f_ops, 0, sizeof(*f_ops));
 198                 f_ops->owner = file->f_op->owner;
 199                 f_ops->release = file->f_op->release;
 200                 f_ops->poll = snd_disconnect_poll;
 201
 202                 s_f_ops->next = card->s_f_ops;
 203                 card->s_f_ops = s_f_ops;
 204
 205                 f_ops = fops_get(f_ops);
 206
 207                 old_f_ops = file->f_op;
 208                 file->f_op = f_ops;     /* must be atomic */
 209                 fops_put(old_f_ops);
 210
 211                 mfile = mfile->next;
 212         }
 213         spin_unlock(&card->files_lock);
 214
 215         /* phase 3: notify all connected devices about disconnection */
 216         /* at this point, they cannot respond to any calls except release() */
 217
 218 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 219         if (snd_mixer_oss_notify_callback)
 220                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 221 #endif
 222
 223         /* notify all devices that we are disconnected */
 224         err = snd_device_disconnect_all(card);
 225         if (err < 0)
 226                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 227
 228         return 0;
 229 }
 230
 231 /**
 232  *  snd_card_free - frees given soundcard structure
 233  *  @card: soundcard structure
 234  *
 235  *  This function releases the soundcard structure and the all assigned
 236  *  devices automatically.  That is, you don't have to release the devices
 237  *  by yourself.
 238  *
 239  *  Returns zero. Frees all associated devices and frees the control
 240  *  interface associated to given soundcard.
 241  */
 242 int snd_card_free(struct snd_card *card)
 243 {
 244         struct snd_shutdown_f_ops *s_f_ops;
 245
 246         if (card == NULL)
 247                 return -EINVAL;
 248         write_lock(&snd_card_rwlock);
 249         snd_cards[card->number] = NULL;
 250         write_unlock(&snd_card_rwlock);
 251
 252 #ifdef CONFIG_PM
 253         wake_up(&card->power_sleep);
 254 #endif
 255         /* wait, until all devices are ready for the free operation */
 256         wait_event(card->shutdown_sleep, card->files == NULL);
 257
 258 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 259         if (snd_mixer_oss_notify_callback)
 260                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 261 #endif
 262         if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
 263                 snd_printk(KERN_ERR "unable to free all devices (pre)\n");
 264                 /* Fatal, but this situation should never occur */
 265         }
 266         if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
 267                 snd_printk(KERN_ERR "unable to free all devices (normal)\n");
 268                 /* Fatal, but this situation should never occur */
 269         }
 270         if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
 271                 snd_printk(KERN_ERR "unable to free all devices (post)\n");
 272                 /* Fatal, but this situation should never occur */
 273         }
 274         if (card->private_free)
 275                 card->private_free(card);
 276         if (card->proc_id)
 277                 snd_info_unregister(card->proc_id);
 278         if (snd_info_card_free(card) < 0) {
 279                 snd_printk(KERN_WARNING "unable to free card info\n");
 280                 /* Not fatal error */
 281         }
 282         while (card->s_f_ops) {
 283                 s_f_ops = card->s_f_ops;
 284                 card->s_f_ops = s_f_ops->next;
 285                 kfree(s_f_ops);
 286         }
 287         write_lock(&snd_card_rwlock);
 288         snd_cards_lock &= ~(1 << card->number);
 289         write_unlock(&snd_card_rwlock);
 290         kfree(card);
 291         return 0;
 292 }
 293
 294 static void snd_card_free_thread(void * __card)
 295 {
 296         struct snd_card *card = __card;
 297         struct module * module = card->module;
 298
 299         if (!try_module_get(module)) {
 300                 snd_printk(KERN_ERR "unable to lock toplevel module for card %i in free thread\n", card->number);
 301                 module = NULL;
 302         }
 303
 304         snd_card_free(card);
 305
 306         module_put(module);
 307 }
 308
 309 /**
 310  *  snd_card_free_in_thread - call snd_card_free() in thread
 311  *  @card: soundcard structure
 312  *
 313  *  This function schedules the call of snd_card_free() function in a
 314  *  work queue.  When all devices are released (non-busy), the work
 315  *  is woken up and calls snd_card_free().
 316  *
 317  *  When a card can be disconnected at any time by hotplug service,
 318  *  this function should be used in disconnect (or detach) callback
 319  *  instead of calling snd_card_free() directly.
 320  *
 321  *  Returns - zero otherwise a negative error code if the start of thread failed.
 322  */
 323 int snd_card_free_in_thread(struct snd_card *card)
 324 {
 325         if (card->files == NULL) {
 326                 snd_card_free(card);
 327                 return 0;
 328         }
 329
 330         if (schedule_work(&card->free_workq))
 331                 return 0;
 332
 333         snd_printk(KERN_ERR "schedule_work() failed in snd_card_free_in_thread for card %i\n", card->number);
 334         /* try to free the structure immediately */
 335         snd_card_free(card);
 336         return -EFAULT;
 337 }
 338
 339 static void choose_default_id(struct snd_card *card)
 340 {
 341         int i, len, idx_flag = 0, loops = 8;
 342         char *id, *spos;
 343
 344         id = spos = card->shortname;
 345         while (*id != '\0') {
 346                 if (*id == ' ')
 347                         spos = id + 1;
 348                 id++;
 349         }
 350         id = card->id;
 351         while (*spos != '\0' && !isalnum(*spos))
 352                 spos++;
 353         if (isdigit(*spos))
 354                 *id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
 355         while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
 356                 if (isalnum(*spos))
 357                         *id++ = *spos;
 358                 spos++;
 359         }
 360         *id = '\0';
 361
 362         id = card->id;
 363
 364         if (*id == '\0')
 365                 strcpy(id, "default");
 366
 367         while (1) {
 368                 if (loops-- == 0) {
 369                         snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
 370                         strcpy(card->id, card->proc_root->name);
 371                         return;
 372                 }
 373                 if (!snd_info_check_reserved_words(id))
 374                         goto __change;
 375                 for (i = 0; i < snd_ecards_limit; i++) {
 376                         if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
 377                                 goto __change;
 378                 }
 379                 break;
 380
 381               __change:
 382                 len = strlen(id);
 383                 if (idx_flag)
 384                         id[len-1]++;
 385                 else if ((size_t)len <= sizeof(card->id) - 3) {
 386                         strcat(id, "_1");
 387                         idx_flag++;
 388                 } else {
 389                         spos = id + len - 2;
 390                         if ((size_t)len <= sizeof(card->id) - 2)
 391                                 spos++;
 392                         *spos++ = '_';
 393                         *spos++ = '1';
 394                         *spos++ = '\0';
 395                         idx_flag++;
 396                 }
 397         }
 398 }
 399
 400 /**
 401  *  snd_card_register - register the soundcard
 402  *  @card: soundcard structure
 403  *
 404  *  This function registers all the devices assigned to the soundcard.
 405  *  Until calling this, the ALSA control interface is blocked from the
 406  *  external accesses.  Thus, you should call this function at the end
 407  *  of the initialization of the card.
 408  *
 409  *  Returns zero otherwise a negative error code if the registrain failed.
 410  */
 411 int snd_card_register(struct snd_card *card)
 412 {
 413         int err;
 414         struct snd_info_entry *entry;
 415
 416         snd_assert(card != NULL, return -EINVAL);
 417         if ((err = snd_device_register_all(card)) < 0)
 418                 return err;
 419         write_lock(&snd_card_rwlock);
 420         if (snd_cards[card->number]) {
 421                 /* already registered */
 422                 write_unlock(&snd_card_rwlock);
 423                 return 0;
 424         }
 425         if (card->id[0] == '\0')
 426                 choose_default_id(card);
 427         snd_cards[card->number] = card;
 428         write_unlock(&snd_card_rwlock);
 429         if ((err = snd_info_card_register(card)) < 0) {
 430                 snd_printd("unable to create card info\n");
 431                 goto __skip_info;
 432         }
 433         if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
 434                 snd_printd("unable to create card entry\n");
 435                 goto __skip_info;
 436         }
 437         entry->c.text.read_size = PAGE_SIZE;
 438         entry->c.text.read = snd_card_id_read;
 439         if (snd_info_register(entry) < 0) {
 440                 snd_info_free_entry(entry);
 441                 entry = NULL;
 442         }
 443         card->proc_id = entry;
 444       __skip_info:
 445 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 446         if (snd_mixer_oss_notify_callback)
 447                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 448 #endif
 449         return 0;
 450 }
 451
 452 static struct snd_info_entry *snd_card_info_entry = NULL;
 453
 454 static void snd_card_info_read(struct snd_info_entry *entry,
 455                                struct snd_info_buffer *buffer)
 456 {
 457         int idx, count;
 458         struct snd_card *card;
 459
 460         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 461                 read_lock(&snd_card_rwlock);
 462                 if ((card = snd_cards[idx]) != NULL) {
 463                         count++;
 464                         snd_iprintf(buffer, "%i [%-15s]: %s - %s\n",
 465                                         idx,
 466                                         card->id,
 467                                         card->driver,
 468                                         card->shortname);
 469                         snd_iprintf(buffer, "                     %s\n",
 470                                         card->longname);
 471                 }
 472                 read_unlock(&snd_card_rwlock);
 473         }
 474         if (!count)
 475                 snd_iprintf(buffer, "--- no soundcards ---\n");
 476 }
 477
 478 #if defined(CONFIG_SND_OSSEMUL) && defined(CONFIG_PROC_FS)
 479
 480 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 481 {
 482         int idx, count;
 483         struct snd_card *card;
 484
 485         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 486                 read_lock(&snd_card_rwlock);
 487                 if ((card = snd_cards[idx]) != NULL) {
 488                         count++;
 489                         snd_iprintf(buffer, "%s\n", card->longname);
 490                 }
 491                 read_unlock(&snd_card_rwlock);
 492         }
 493         if (!count) {
 494                 snd_iprintf(buffer, "--- no soundcards ---\n");
 495         }
 496 }
 497
 498 #endif
 499
 500 #ifdef MODULE
 501 static struct snd_info_entry *snd_card_module_info_entry;
 502 static void snd_card_module_info_read(struct snd_info_entry *entry,
 503                                       struct snd_info_buffer *buffer)
 504 {
 505         int idx;
 506         struct snd_card *card;
 507
 508         for (idx = 0; idx < SNDRV_CARDS; idx++) {
 509                 read_lock(&snd_card_rwlock);
 510                 if ((card = snd_cards[idx]) != NULL)
 511                         snd_iprintf(buffer, "%i %s\n", idx, card->module->name);
 512                 read_unlock(&snd_card_rwlock);
 513         }
 514 }
 515 #endif
 516
 517 int __init snd_card_info_init(void)
 518 {
 519         struct snd_info_entry *entry;
 520
 521         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
 522         if (! entry)
 523                 return -ENOMEM;
 524         entry->c.text.read_size = PAGE_SIZE;
 525         entry->c.text.read = snd_card_info_read;
 526         if (snd_info_register(entry) < 0) {
 527                 snd_info_free_entry(entry);
 528                 return -ENOMEM;
 529         }
 530         snd_card_info_entry = entry;
 531
 532 #ifdef MODULE
 533         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
 534         if (entry) {
 535                 entry->c.text.read_size = PAGE_SIZE;
 536                 entry->c.text.read = snd_card_module_info_read;
 537                 if (snd_info_register(entry) < 0)
 538                         snd_info_free_entry(entry);
 539                 else
 540                         snd_card_module_info_entry = entry;
 541         }
 542 #endif
 543
 544         return 0;
 545 }
 546
 547 int __exit snd_card_info_done(void)
 548 {
 549         if (snd_card_info_entry)
 550                 snd_info_unregister(snd_card_info_entry);
 551 #ifdef MODULE
 552         if (snd_card_module_info_entry)
 553                 snd_info_unregister(snd_card_module_info_entry);
 554 #endif
 555         return 0;
 556 }
 557
 558 /**
 559  *  snd_component_add - add a component string
 560  *  @card: soundcard structure
 561  *  @component: the component id string
 562  *
 563  *  This function adds the component id string to the supported list.
 564  *  The component can be referred from the alsa-lib.
 565  *
 566  *  Returns zero otherwise a negative error code.
 567  */
 568
 569 int snd_component_add(struct snd_card *card, const char *component)
 570 {
 571         char *ptr;
 572         int len = strlen(component);
 573
 574         ptr = strstr(card->components, component);
 575         if (ptr != NULL) {
 576                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
 577                         return 1;
 578         }
 579         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
 580                 snd_BUG();
 581                 return -ENOMEM;
 582         }
 583         if (card->components[0] != '\0')
 584                 strcat(card->components, " ");
 585         strcat(card->components, component);
 586         return 0;
 587 }
 588
 589 /**
 590  *  snd_card_file_add - add the file to the file list of the card
 591  *  @card: soundcard structure
 592  *  @file: file pointer
 593  *
 594  *  This function adds the file to the file linked-list of the card.
 595  *  This linked-list is used to keep tracking the connection state,
 596  *  and to avoid the release of busy resources by hotplug.
 597  *
 598  *  Returns zero or a negative error code.
 599  */
 600 int snd_card_file_add(struct snd_card *card, struct file *file)
 601 {
 602         struct snd_monitor_file *mfile;
 603
 604         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
 605         if (mfile == NULL)
 606                 return -ENOMEM;
 607         mfile->file = file;
 608         mfile->next = NULL;
 609         spin_lock(&card->files_lock);
 610         if (card->shutdown) {
 611                 spin_unlock(&card->files_lock);
 612                 kfree(mfile);
 613                 return -ENODEV;
 614         }
 615         mfile->next = card->files;
 616         card->files = mfile;
 617         spin_unlock(&card->files_lock);
 618         return 0;
 619 }
 620
 621 /**
 622  *  snd_card_file_remove - remove the file from the file list
 623  *  @card: soundcard structure
 624  *  @file: file pointer
 625  *
 626  *  This function removes the file formerly added to the card via
 627  *  snd_card_file_add() function.
 628  *  If all files are removed and the release of the card is
 629  *  scheduled, it will wake up the the thread to call snd_card_free()
 630  *  (see snd_card_free_in_thread() function).
 631  *
 632  *  Returns zero or a negative error code.
 633  */
 634 int snd_card_file_remove(struct snd_card *card, struct file *file)
 635 {
 636         struct snd_monitor_file *mfile, *pfile = NULL;
 637
 638         spin_lock(&card->files_lock);
 639         mfile = card->files;
 640         while (mfile) {
 641                 if (mfile->file == file) {
 642                         if (pfile)
 643                                 pfile->next = mfile->next;
 644                         else
 645                                 card->files = mfile->next;
 646                         break;
 647                 }
 648                 pfile = mfile;
 649                 mfile = mfile->next;
 650         }
 651         spin_unlock(&card->files_lock);
 652         if (card->files == NULL)
 653                 wake_up(&card->shutdown_sleep);
 654         if (!mfile) {
 655                 snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
 656                 return -ENOENT;
 657         }
 658         kfree(mfile);
 659         return 0;
 660 }
 661
 662 #ifdef CONFIG_PM
 663 /**
 664  *  snd_power_wait - wait until the power-state is changed.
 665  *  @card: soundcard structure
 666  *  @power_state: expected power state
 667  *  @file: file structure for the O_NONBLOCK check (optional)
 668  *
 669  *  Waits until the power-state is changed.
 670  *
 671  *  Note: the power lock must be active before call.
 672  */
 673 int snd_power_wait(struct snd_card *card, unsigned int power_state, struct file *file)
 674 {
 675         wait_queue_t wait;
 676         int result = 0;
 677
 678         /* fastpath */
 679         if (snd_power_get_state(card) == power_state)
 680                 return 0;
 681         init_waitqueue_entry(&wait, current);
 682         add_wait_queue(&card->power_sleep, &wait);
 683         while (1) {
 684                 if (card->shutdown) {
 685                         result = -ENODEV;
 686                         break;
 687                 }
 688                 if (snd_power_get_state(card) == power_state)
 689                         break;
 690 #if 0 /* block all devices */
 691                 if (file && (file->f_flags & O_NONBLOCK)) {
 692                         result = -EAGAIN;
 693                         break;
 694                 }
 695 #endif
 696                 set_current_state(TASK_UNINTERRUPTIBLE);
 697                 snd_power_unlock(card);
 698                 schedule_timeout(30 * HZ);
 699                 snd_power_lock(card);
 700         }
 701         remove_wait_queue(&card->power_sleep, &wait);
 702         return result;
 703 }
 704
 705 #endif /* CONFIG_PM */