git.oblomov.eu Git - linux-2.6/blob - 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 #ifdef CONFIG_PROC_FS
  50 static void snd_card_id_read(struct snd_info_entry *entry,
  51                              struct snd_info_buffer *buffer)
  52 {
  53         snd_iprintf(buffer, "%s\n", entry->card->id);
  54 }
  55
  56 static inline int init_info_for_card(struct snd_card *card)
  57 {
  58         int err;
  59         struct snd_info_entry *entry;
  60
  61         if ((err = snd_info_card_register(card)) < 0) {
  62                 snd_printd("unable to create card info\n");
  63                 return err;
  64         }
  65         if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
  66                 snd_printd("unable to create card entry\n");
  67                 return err;
  68         }
  69         entry->c.text.read_size = PAGE_SIZE;
  70         entry->c.text.read = snd_card_id_read;
  71         if (snd_info_register(entry) < 0) {
  72                 snd_info_free_entry(entry);
  73                 entry = NULL;
  74         }
  75         card->proc_id = entry;
  76         return 0;
  77 }
  78 #else /* !CONFIG_PROC_FS */
  79 #define init_info_for_card(card)
  80 #endif
  81
  82 static void snd_card_free_thread(void * __card);
  83
  84 /**
  85  *  snd_card_new - create and initialize a soundcard structure
  86  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
  87  *  @xid: card identification (ASCII string)
  88  *  @module: top level module for locking
  89  *  @extra_size: allocate this extra size after the main soundcard structure
  90  *
  91  *  Creates and initializes a soundcard structure.
  92  *
  93  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
  94  *  (which is blocked until snd_card_register function is called).
  95  */
  96 struct snd_card *snd_card_new(int idx, const char *xid,
  97                          struct module *module, int extra_size)
  98 {
  99         struct snd_card *card;
 100         int err;
 101
 102         if (extra_size < 0)
 103                 extra_size = 0;
 104         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
 105         if (card == NULL)
 106                 return NULL;
 107         if (xid) {
 108                 if (!snd_info_check_reserved_words(xid))
 109                         goto __error;
 110                 strlcpy(card->id, xid, sizeof(card->id));
 111         }
 112         err = 0;
 113         write_lock(&snd_card_rwlock);
 114         if (idx < 0) {
 115                 int idx2;
 116                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
 117                         if (~snd_cards_lock & idx & 1<<idx2) {
 118                                 idx = idx2;
 119                                 if (idx >= snd_ecards_limit)
 120                                         snd_ecards_limit = idx + 1;
 121                                 break;
 122                         }
 123         } else if (idx < snd_ecards_limit) {
 124                 if (snd_cards_lock & (1 << idx))
 125                         err = -ENODEV;  /* invalid */
 126         } else if (idx < SNDRV_CARDS)
 127                 snd_ecards_limit = idx + 1; /* increase the limit */
 128         else
 129                 err = -ENODEV;
 130         if (idx < 0 || err < 0) {
 131                 write_unlock(&snd_card_rwlock);
 132                 snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);
 133                 goto __error;
 134         }
 135         snd_cards_lock |= 1 << idx;             /* lock it */
 136         write_unlock(&snd_card_rwlock);
 137         card->number = idx;
 138         card->module = module;
 139         INIT_LIST_HEAD(&card->devices);
 140         init_rwsem(&card->controls_rwsem);
 141         rwlock_init(&card->ctl_files_rwlock);
 142         INIT_LIST_HEAD(&card->controls);
 143         INIT_LIST_HEAD(&card->ctl_files);
 144         spin_lock_init(&card->files_lock);
 145         init_waitqueue_head(&card->shutdown_sleep);
 146         INIT_WORK(&card->free_workq, snd_card_free_thread, card);
 147 #ifdef CONFIG_PM
 148         mutex_init(&card->power_lock);
 149         init_waitqueue_head(&card->power_sleep);
 150 #endif
 151         /* the control interface cannot be accessed from the user space until */
 152         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
 153         if ((err = snd_ctl_create(card)) < 0) {
 154                 snd_printd("unable to register control minors\n");
 155                 goto __error;
 156         }
 157         if ((err = snd_info_card_create(card)) < 0) {
 158                 snd_printd("unable to create card info\n");
 159                 goto __error_ctl;
 160         }
 161         if (extra_size > 0)
 162                 card->private_data = (char *)card + sizeof(struct snd_card);
 163         return card;
 164
 165       __error_ctl:
 166         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
 167       __error:
 168         kfree(card);
 169         return NULL;
 170 }
 171
 172 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
 173 {
 174         return POLLERR | POLLNVAL;
 175 }
 176
 177 /**
 178  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
 179  *  @card: soundcard structure
 180  *
 181  *  Disconnects all APIs from the file-operations (user space).
 182  *
 183  *  Returns zero, otherwise a negative error code.
 184  *
 185  *  Note: The current implementation replaces all active file->f_op with special
 186  *        dummy file operations (they do nothing except release).
 187  */
 188 int snd_card_disconnect(struct snd_card *card)
 189 {
 190         struct snd_monitor_file *mfile;
 191         struct file *file;
 192         struct snd_shutdown_f_ops *s_f_ops;
 193         struct file_operations *f_ops, *old_f_ops;
 194         int err;
 195
 196         spin_lock(&card->files_lock);
 197         if (card->shutdown) {
 198                 spin_unlock(&card->files_lock);
 199                 return 0;
 200         }
 201         card->shutdown = 1;
 202         spin_unlock(&card->files_lock);
 203
 204         /* phase 1: disable fops (user space) operations for ALSA API */
 205         write_lock(&snd_card_rwlock);
 206         snd_cards[card->number] = NULL;
 207         write_unlock(&snd_card_rwlock);
 208
 209         /* phase 2: replace file->f_op with special dummy operations */
 210
 211         spin_lock(&card->files_lock);
 212         mfile = card->files;
 213         while (mfile) {
 214                 file = mfile->file;
 215
 216                 /* it's critical part, use endless loop */
 217                 /* we have no room to fail */
 218                 s_f_ops = kmalloc(sizeof(struct snd_shutdown_f_ops), GFP_ATOMIC);
 219                 if (s_f_ops == NULL)
 220                         panic("Atomic allocation failed for snd_shutdown_f_ops!");
 221
 222                 f_ops = &s_f_ops->f_ops;
 223
 224                 memset(f_ops, 0, sizeof(*f_ops));
 225                 f_ops->owner = file->f_op->owner;
 226                 f_ops->release = file->f_op->release;
 227                 f_ops->poll = snd_disconnect_poll;
 228
 229                 s_f_ops->next = card->s_f_ops;
 230                 card->s_f_ops = s_f_ops;
 231
 232                 f_ops = fops_get(f_ops);
 233
 234                 old_f_ops = file->f_op;
 235                 file->f_op = f_ops;     /* must be atomic */
 236                 fops_put(old_f_ops);
 237
 238                 mfile = mfile->next;
 239         }
 240         spin_unlock(&card->files_lock);
 241
 242         /* phase 3: notify all connected devices about disconnection */
 243         /* at this point, they cannot respond to any calls except release() */
 244
 245 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 246         if (snd_mixer_oss_notify_callback)
 247                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 248 #endif
 249
 250         /* notify all devices that we are disconnected */
 251         err = snd_device_disconnect_all(card);
 252         if (err < 0)
 253                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
 254
 255         return 0;
 256 }
 257
 258 /**
 259  *  snd_card_free - frees given soundcard structure
 260  *  @card: soundcard structure
 261  *
 262  *  This function releases the soundcard structure and the all assigned
 263  *  devices automatically.  That is, you don't have to release the devices
 264  *  by yourself.
 265  *
 266  *  Returns zero. Frees all associated devices and frees the control
 267  *  interface associated to given soundcard.
 268  */
 269 int snd_card_free(struct snd_card *card)
 270 {
 271         struct snd_shutdown_f_ops *s_f_ops;
 272
 273         if (card == NULL)
 274                 return -EINVAL;
 275         write_lock(&snd_card_rwlock);
 276         snd_cards[card->number] = NULL;
 277         write_unlock(&snd_card_rwlock);
 278
 279 #ifdef CONFIG_PM
 280         wake_up(&card->power_sleep);
 281 #endif
 282         /* wait, until all devices are ready for the free operation */
 283         wait_event(card->shutdown_sleep, card->files == NULL);
 284
 285 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 286         if (snd_mixer_oss_notify_callback)
 287                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
 288 #endif
 289         if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
 290                 snd_printk(KERN_ERR "unable to free all devices (pre)\n");
 291                 /* Fatal, but this situation should never occur */
 292         }
 293         if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
 294                 snd_printk(KERN_ERR "unable to free all devices (normal)\n");
 295                 /* Fatal, but this situation should never occur */
 296         }
 297         if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
 298                 snd_printk(KERN_ERR "unable to free all devices (post)\n");
 299                 /* Fatal, but this situation should never occur */
 300         }
 301         if (card->private_free)
 302                 card->private_free(card);
 303         snd_info_unregister(card->proc_id);
 304         if (snd_info_card_free(card) < 0) {
 305                 snd_printk(KERN_WARNING "unable to free card info\n");
 306                 /* Not fatal error */
 307         }
 308         while (card->s_f_ops) {
 309                 s_f_ops = card->s_f_ops;
 310                 card->s_f_ops = s_f_ops->next;
 311                 kfree(s_f_ops);
 312         }
 313         write_lock(&snd_card_rwlock);
 314         snd_cards_lock &= ~(1 << card->number);
 315         write_unlock(&snd_card_rwlock);
 316         kfree(card);
 317         return 0;
 318 }
 319
 320 static void snd_card_free_thread(void * __card)
 321 {
 322         struct snd_card *card = __card;
 323         struct module * module = card->module;
 324
 325         if (!try_module_get(module)) {
 326                 snd_printk(KERN_ERR "unable to lock toplevel module for card %i in free thread\n", card->number);
 327                 module = NULL;
 328         }
 329
 330         snd_card_free(card);
 331
 332         module_put(module);
 333 }
 334
 335 /**
 336  *  snd_card_free_in_thread - call snd_card_free() in thread
 337  *  @card: soundcard structure
 338  *
 339  *  This function schedules the call of snd_card_free() function in a
 340  *  work queue.  When all devices are released (non-busy), the work
 341  *  is woken up and calls snd_card_free().
 342  *
 343  *  When a card can be disconnected at any time by hotplug service,
 344  *  this function should be used in disconnect (or detach) callback
 345  *  instead of calling snd_card_free() directly.
 346  *
 347  *  Returns - zero otherwise a negative error code if the start of thread failed.
 348  */
 349 int snd_card_free_in_thread(struct snd_card *card)
 350 {
 351         if (card->files == NULL) {
 352                 snd_card_free(card);
 353                 return 0;
 354         }
 355
 356         if (schedule_work(&card->free_workq))
 357                 return 0;
 358
 359         snd_printk(KERN_ERR "schedule_work() failed in snd_card_free_in_thread for card %i\n", card->number);
 360         /* try to free the structure immediately */
 361         snd_card_free(card);
 362         return -EFAULT;
 363 }
 364
 365 static void choose_default_id(struct snd_card *card)
 366 {
 367         int i, len, idx_flag = 0, loops = SNDRV_CARDS;
 368         char *id, *spos;
 369
 370         id = spos = card->shortname;
 371         while (*id != '\0') {
 372                 if (*id == ' ')
 373                         spos = id + 1;
 374                 id++;
 375         }
 376         id = card->id;
 377         while (*spos != '\0' && !isalnum(*spos))
 378                 spos++;
 379         if (isdigit(*spos))
 380                 *id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
 381         while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
 382                 if (isalnum(*spos))
 383                         *id++ = *spos;
 384                 spos++;
 385         }
 386         *id = '\0';
 387
 388         id = card->id;
 389
 390         if (*id == '\0')
 391                 strcpy(id, "default");
 392
 393         while (1) {
 394                 if (loops-- == 0) {
 395                         snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
 396                         strcpy(card->id, card->proc_root->name);
 397                         return;
 398                 }
 399                 if (!snd_info_check_reserved_words(id))
 400                         goto __change;
 401                 for (i = 0; i < snd_ecards_limit; i++) {
 402                         if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
 403                                 goto __change;
 404                 }
 405                 break;
 406
 407               __change:
 408                 len = strlen(id);
 409                 if (idx_flag) {
 410                         if (id[len-1] != '9')
 411                                 id[len-1]++;
 412                         else
 413                                 id[len-1] = 'A';
 414                 } else if ((size_t)len <= sizeof(card->id) - 3) {
 415                         strcat(id, "_1");
 416                         idx_flag++;
 417                 } else {
 418                         spos = id + len - 2;
 419                         if ((size_t)len <= sizeof(card->id) - 2)
 420                                 spos++;
 421                         *spos++ = '_';
 422                         *spos++ = '1';
 423                         *spos++ = '\0';
 424                         idx_flag++;
 425                 }
 426         }
 427 }
 428
 429 /**
 430  *  snd_card_register - register the soundcard
 431  *  @card: soundcard structure
 432  *
 433  *  This function registers all the devices assigned to the soundcard.
 434  *  Until calling this, the ALSA control interface is blocked from the
 435  *  external accesses.  Thus, you should call this function at the end
 436  *  of the initialization of the card.
 437  *
 438  *  Returns zero otherwise a negative error code if the registrain failed.
 439  */
 440 int snd_card_register(struct snd_card *card)
 441 {
 442         int err;
 443
 444         snd_assert(card != NULL, return -EINVAL);
 445         if ((err = snd_device_register_all(card)) < 0)
 446                 return err;
 447         write_lock(&snd_card_rwlock);
 448         if (snd_cards[card->number]) {
 449                 /* already registered */
 450                 write_unlock(&snd_card_rwlock);
 451                 return 0;
 452         }
 453         if (card->id[0] == '\0')
 454                 choose_default_id(card);
 455         snd_cards[card->number] = card;
 456         write_unlock(&snd_card_rwlock);
 457         init_info_for_card(card);
 458 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 459         if (snd_mixer_oss_notify_callback)
 460                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 461 #endif
 462         return 0;
 463 }
 464
 465 #ifdef CONFIG_PROC_FS
 466 static struct snd_info_entry *snd_card_info_entry = NULL;
 467
 468 static void snd_card_info_read(struct snd_info_entry *entry,
 469                                struct snd_info_buffer *buffer)
 470 {
 471         int idx, count;
 472         struct snd_card *card;
 473
 474         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 475                 read_lock(&snd_card_rwlock);
 476                 if ((card = snd_cards[idx]) != NULL) {
 477                         count++;
 478                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
 479                                         idx,
 480                                         card->id,
 481                                         card->driver,
 482                                         card->shortname);
 483                         snd_iprintf(buffer, "                      %s\n",
 484                                         card->longname);
 485                 }
 486                 read_unlock(&snd_card_rwlock);
 487         }
 488         if (!count)
 489                 snd_iprintf(buffer, "--- no soundcards ---\n");
 490 }
 491
 492 #ifdef CONFIG_SND_OSSEMUL
 493
 494 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
 495 {
 496         int idx, count;
 497         struct snd_card *card;
 498
 499         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
 500                 read_lock(&snd_card_rwlock);
 501                 if ((card = snd_cards[idx]) != NULL) {
 502                         count++;
 503                         snd_iprintf(buffer, "%s\n", card->longname);
 504                 }
 505                 read_unlock(&snd_card_rwlock);
 506         }
 507         if (!count) {
 508                 snd_iprintf(buffer, "--- no soundcards ---\n");
 509         }
 510 }
 511
 512 #endif
 513
 514 #ifdef MODULE
 515 static struct snd_info_entry *snd_card_module_info_entry;
 516 static void snd_card_module_info_read(struct snd_info_entry *entry,
 517                                       struct snd_info_buffer *buffer)
 518 {
 519         int idx;
 520         struct snd_card *card;
 521
 522         for (idx = 0; idx < SNDRV_CARDS; idx++) {
 523                 read_lock(&snd_card_rwlock);
 524                 if ((card = snd_cards[idx]) != NULL)
 525                         snd_iprintf(buffer, "%2i %s\n",
 526                                     idx, card->module->name);
 527                 read_unlock(&snd_card_rwlock);
 528         }
 529 }
 530 #endif
 531
 532 int __init snd_card_info_init(void)
 533 {
 534         struct snd_info_entry *entry;
 535
 536         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
 537         if (! entry)
 538                 return -ENOMEM;
 539         entry->c.text.read_size = PAGE_SIZE;
 540         entry->c.text.read = snd_card_info_read;
 541         if (snd_info_register(entry) < 0) {
 542                 snd_info_free_entry(entry);
 543                 return -ENOMEM;
 544         }
 545         snd_card_info_entry = entry;
 546
 547 #ifdef MODULE
 548         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
 549         if (entry) {
 550                 entry->c.text.read_size = PAGE_SIZE;
 551                 entry->c.text.read = snd_card_module_info_read;
 552                 if (snd_info_register(entry) < 0)
 553                         snd_info_free_entry(entry);
 554                 else
 555                         snd_card_module_info_entry = entry;
 556         }
 557 #endif
 558
 559         return 0;
 560 }
 561
 562 int __exit snd_card_info_done(void)
 563 {
 564         snd_info_unregister(snd_card_info_entry);
 565 #ifdef MODULE
 566         snd_info_unregister(snd_card_module_info_entry);
 567 #endif
 568         return 0;
 569 }
 570
 571 #endif /* CONFIG_PROC_FS */
 572
 573 /**
 574  *  snd_component_add - add a component string
 575  *  @card: soundcard structure
 576  *  @component: the component id string
 577  *
 578  *  This function adds the component id string to the supported list.
 579  *  The component can be referred from the alsa-lib.
 580  *
 581  *  Returns zero otherwise a negative error code.
 582  */
 583
 584 int snd_component_add(struct snd_card *card, const char *component)
 585 {
 586         char *ptr;
 587         int len = strlen(component);
 588
 589         ptr = strstr(card->components, component);
 590         if (ptr != NULL) {
 591                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
 592                         return 1;
 593         }
 594         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
 595                 snd_BUG();
 596                 return -ENOMEM;
 597         }
 598         if (card->components[0] != '\0')
 599                 strcat(card->components, " ");
 600         strcat(card->components, component);
 601         return 0;
 602 }
 603
 604 /**
 605  *  snd_card_file_add - add the file to the file list of the card
 606  *  @card: soundcard structure
 607  *  @file: file pointer
 608  *
 609  *  This function adds the file to the file linked-list of the card.
 610  *  This linked-list is used to keep tracking the connection state,
 611  *  and to avoid the release of busy resources by hotplug.
 612  *
 613  *  Returns zero or a negative error code.
 614  */
 615 int snd_card_file_add(struct snd_card *card, struct file *file)
 616 {
 617         struct snd_monitor_file *mfile;
 618
 619         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
 620         if (mfile == NULL)
 621                 return -ENOMEM;
 622         mfile->file = file;
 623         mfile->next = NULL;
 624         spin_lock(&card->files_lock);
 625         if (card->shutdown) {
 626                 spin_unlock(&card->files_lock);
 627                 kfree(mfile);
 628                 return -ENODEV;
 629         }
 630         mfile->next = card->files;
 631         card->files = mfile;
 632         spin_unlock(&card->files_lock);
 633         return 0;
 634 }
 635
 636 /**
 637  *  snd_card_file_remove - remove the file from the file list
 638  *  @card: soundcard structure
 639  *  @file: file pointer
 640  *
 641  *  This function removes the file formerly added to the card via
 642  *  snd_card_file_add() function.
 643  *  If all files are removed and the release of the card is
 644  *  scheduled, it will wake up the the thread to call snd_card_free()
 645  *  (see snd_card_free_in_thread() function).
 646  *
 647  *  Returns zero or a negative error code.
 648  */
 649 int snd_card_file_remove(struct snd_card *card, struct file *file)
 650 {
 651         struct snd_monitor_file *mfile, *pfile = NULL;
 652
 653         spin_lock(&card->files_lock);
 654         mfile = card->files;
 655         while (mfile) {
 656                 if (mfile->file == file) {
 657                         if (pfile)
 658                                 pfile->next = mfile->next;
 659                         else
 660                                 card->files = mfile->next;
 661                         break;
 662                 }
 663                 pfile = mfile;
 664                 mfile = mfile->next;
 665         }
 666         spin_unlock(&card->files_lock);
 667         if (card->files == NULL)
 668                 wake_up(&card->shutdown_sleep);
 669         if (!mfile) {
 670                 snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
 671                 return -ENOENT;
 672         }
 673         kfree(mfile);
 674         return 0;
 675 }
 676
 677 #ifdef CONFIG_PM
 678 /**
 679  *  snd_power_wait - wait until the power-state is changed.
 680  *  @card: soundcard structure
 681  *  @power_state: expected power state
 682  *  @file: file structure for the O_NONBLOCK check (optional)
 683  *
 684  *  Waits until the power-state is changed.
 685  *
 686  *  Note: the power lock must be active before call.
 687  */
 688 int snd_power_wait(struct snd_card *card, unsigned int power_state, struct file *file)
 689 {
 690         wait_queue_t wait;
 691         int result = 0;
 692
 693         /* fastpath */
 694         if (snd_power_get_state(card) == power_state)
 695                 return 0;
 696         init_waitqueue_entry(&wait, current);
 697         add_wait_queue(&card->power_sleep, &wait);
 698         while (1) {
 699                 if (card->shutdown) {
 700                         result = -ENODEV;
 701                         break;
 702                 }
 703                 if (snd_power_get_state(card) == power_state)
 704                         break;
 705 #if 0 /* block all devices */
 706                 if (file && (file->f_flags & O_NONBLOCK)) {
 707                         result = -EAGAIN;
 708                         break;
 709                 }
 710 #endif
 711                 set_current_state(TASK_UNINTERRUPTIBLE);
 712                 snd_power_unlock(card);
 713                 schedule_timeout(30 * HZ);
 714                 snd_power_lock(card);
 715         }
 716         remove_wait_queue(&card->power_sleep, &wait);
 717         return result;
 718 }
 719
 720 #endif /* CONFIG_PM */