2 * Initialization routines
3 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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.
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.
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
22 #include <linux/init.h>
23 #include <linux/sched.h>
24 #include <linux/module.h>
25 #include <linux/device.h>
26 #include <linux/file.h>
27 #include <linux/slab.h>
28 #include <linux/time.h>
29 #include <linux/ctype.h>
31 #include <linux/completion.h>
33 #include <sound/core.h>
34 #include <sound/control.h>
35 #include <sound/info.h>
37 /* monitor files for graceful shutdown (hotplug) */
38 struct snd_monitor_file {
40 const struct file_operations *disconnected_f_op;
41 struct list_head shutdown_list; /* still need to shutdown */
42 struct list_head list; /* link of monitor files */
45 static DEFINE_SPINLOCK(shutdown_lock);
46 static LIST_HEAD(shutdown_files);
48 static const struct file_operations snd_shutdown_f_ops;
50 /* locked for registering/using */
51 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
52 struct snd_card *snd_cards[SNDRV_CARDS];
53 EXPORT_SYMBOL(snd_cards);
55 static DEFINE_MUTEX(snd_card_mutex);
57 static char *slots[SNDRV_CARDS];
58 module_param_array(slots, charp, NULL, 0444);
59 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
61 /* return non-zero if the given index is reserved for the given
62 * module via slots option
64 static int module_slot_match(struct module *module, int idx)
70 if (!module || !*module->name || !slots[idx])
76 match = 0; /* negative match */
79 /* compare module name strings
80 * hyphens are handled as equivalent with underscore
98 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
99 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
100 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
103 #ifdef CONFIG_PROC_FS
104 static void snd_card_id_read(struct snd_info_entry *entry,
105 struct snd_info_buffer *buffer)
107 snd_iprintf(buffer, "%s\n", entry->card->id);
110 static inline int init_info_for_card(struct snd_card *card)
113 struct snd_info_entry *entry;
115 if ((err = snd_info_card_register(card)) < 0) {
116 dev_dbg(card->dev, "unable to create card info\n");
119 if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
120 dev_dbg(card->dev, "unable to create card entry\n");
123 entry->c.text.read = snd_card_id_read;
124 if (snd_info_register(entry) < 0) {
125 snd_info_free_entry(entry);
128 card->proc_id = entry;
131 #else /* !CONFIG_PROC_FS */
132 #define init_info_for_card(card)
135 static int check_empty_slot(struct module *module, int slot)
137 return !slots[slot] || !*slots[slot];
140 /* return an empty slot number (>= 0) found in the given bitmask @mask.
141 * @mask == -1 == 0xffffffff means: take any free slot up to 32
142 * when no slot is available, return the original @mask as is.
144 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
145 struct module *module)
149 for (slot = 0; slot < SNDRV_CARDS; slot++) {
150 if (slot < 32 && !(mask & (1U << slot)))
152 if (!test_bit(slot, snd_cards_lock)) {
153 if (check(module, slot))
154 return slot; /* found */
157 return mask; /* unchanged */
160 static int snd_card_do_free(struct snd_card *card);
161 static const struct attribute_group *card_dev_attr_groups[];
163 static void release_card_device(struct device *dev)
165 snd_card_do_free(dev_to_snd_card(dev));
169 * snd_card_new - create and initialize a soundcard structure
170 * @parent: the parent device object
171 * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
172 * @xid: card identification (ASCII string)
173 * @module: top level module for locking
174 * @extra_size: allocate this extra size after the main soundcard structure
175 * @card_ret: the pointer to store the created card instance
177 * Creates and initializes a soundcard structure.
179 * The function allocates snd_card instance via kzalloc with the given
180 * space for the driver to use freely. The allocated struct is stored
181 * in the given card_ret pointer.
183 * Return: Zero if successful or a negative error code.
185 int snd_card_new(struct device *parent, int idx, const char *xid,
186 struct module *module, int extra_size,
187 struct snd_card **card_ret)
189 struct snd_card *card;
192 if (snd_BUG_ON(!card_ret))
198 card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
202 card->private_data = (char *)card + sizeof(struct snd_card);
204 strlcpy(card->id, xid, sizeof(card->id));
206 mutex_lock(&snd_card_mutex);
207 if (idx < 0) /* first check the matching module-name slot */
208 idx = get_slot_from_bitmask(idx, module_slot_match, module);
209 if (idx < 0) /* if not matched, assign an empty slot */
210 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
213 else if (idx < snd_ecards_limit) {
214 if (test_bit(idx, snd_cards_lock))
215 err = -EBUSY; /* invalid */
216 } else if (idx >= SNDRV_CARDS)
219 mutex_unlock(&snd_card_mutex);
220 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
221 idx, snd_ecards_limit - 1, err);
225 set_bit(idx, snd_cards_lock); /* lock it */
226 if (idx >= snd_ecards_limit)
227 snd_ecards_limit = idx + 1; /* increase the limit */
228 mutex_unlock(&snd_card_mutex);
231 card->module = module;
232 INIT_LIST_HEAD(&card->devices);
233 init_rwsem(&card->controls_rwsem);
234 rwlock_init(&card->ctl_files_rwlock);
235 mutex_init(&card->user_ctl_lock);
236 INIT_LIST_HEAD(&card->controls);
237 INIT_LIST_HEAD(&card->ctl_files);
238 spin_lock_init(&card->files_lock);
239 INIT_LIST_HEAD(&card->files_list);
241 mutex_init(&card->power_lock);
242 init_waitqueue_head(&card->power_sleep);
245 device_initialize(&card->card_dev);
246 card->card_dev.parent = parent;
247 card->card_dev.class = sound_class;
248 card->card_dev.release = release_card_device;
249 card->card_dev.groups = card_dev_attr_groups;
250 err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
254 /* the control interface cannot be accessed from the user space until */
255 /* snd_cards_bitmask and snd_cards are set with snd_card_register */
256 err = snd_ctl_create(card);
258 dev_err(parent, "unable to register control minors\n");
261 err = snd_info_card_create(card);
263 dev_err(parent, "unable to create card info\n");
270 snd_device_free_all(card);
272 put_device(&card->card_dev);
275 EXPORT_SYMBOL(snd_card_new);
277 /* return non-zero if a card is already locked */
278 int snd_card_locked(int card)
282 mutex_lock(&snd_card_mutex);
283 locked = test_bit(card, snd_cards_lock);
284 mutex_unlock(&snd_card_mutex);
288 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
293 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
294 size_t count, loff_t *offset)
299 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
300 size_t count, loff_t *offset)
305 static int snd_disconnect_release(struct inode *inode, struct file *file)
307 struct snd_monitor_file *df = NULL, *_df;
309 spin_lock(&shutdown_lock);
310 list_for_each_entry(_df, &shutdown_files, shutdown_list) {
311 if (_df->file == file) {
313 list_del_init(&df->shutdown_list);
317 spin_unlock(&shutdown_lock);
320 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
321 df->disconnected_f_op->fasync(-1, file, 0);
322 return df->disconnected_f_op->release(inode, file);
325 panic("%s(%p, %p) failed!", __func__, inode, file);
328 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
330 return POLLERR | POLLNVAL;
333 static long snd_disconnect_ioctl(struct file *file,
334 unsigned int cmd, unsigned long arg)
339 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
344 static int snd_disconnect_fasync(int fd, struct file *file, int on)
349 static const struct file_operations snd_shutdown_f_ops =
351 .owner = THIS_MODULE,
352 .llseek = snd_disconnect_llseek,
353 .read = snd_disconnect_read,
354 .write = snd_disconnect_write,
355 .release = snd_disconnect_release,
356 .poll = snd_disconnect_poll,
357 .unlocked_ioctl = snd_disconnect_ioctl,
359 .compat_ioctl = snd_disconnect_ioctl,
361 .mmap = snd_disconnect_mmap,
362 .fasync = snd_disconnect_fasync
366 * snd_card_disconnect - disconnect all APIs from the file-operations (user space)
367 * @card: soundcard structure
369 * Disconnects all APIs from the file-operations (user space).
371 * Return: Zero, otherwise a negative error code.
373 * Note: The current implementation replaces all active file->f_op with special
374 * dummy file operations (they do nothing except release).
376 int snd_card_disconnect(struct snd_card *card)
378 struct snd_monitor_file *mfile;
384 spin_lock(&card->files_lock);
385 if (card->shutdown) {
386 spin_unlock(&card->files_lock);
390 spin_unlock(&card->files_lock);
392 /* phase 1: disable fops (user space) operations for ALSA API */
393 mutex_lock(&snd_card_mutex);
394 snd_cards[card->number] = NULL;
395 clear_bit(card->number, snd_cards_lock);
396 mutex_unlock(&snd_card_mutex);
398 /* phase 2: replace file->f_op with special dummy operations */
400 spin_lock(&card->files_lock);
401 list_for_each_entry(mfile, &card->files_list, list) {
402 /* it's critical part, use endless loop */
403 /* we have no room to fail */
404 mfile->disconnected_f_op = mfile->file->f_op;
406 spin_lock(&shutdown_lock);
407 list_add(&mfile->shutdown_list, &shutdown_files);
408 spin_unlock(&shutdown_lock);
410 mfile->file->f_op = &snd_shutdown_f_ops;
411 fops_get(mfile->file->f_op);
413 spin_unlock(&card->files_lock);
415 /* phase 3: notify all connected devices about disconnection */
416 /* at this point, they cannot respond to any calls except release() */
418 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
419 if (snd_mixer_oss_notify_callback)
420 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
423 /* notify all devices that we are disconnected */
424 err = snd_device_disconnect_all(card);
426 dev_err(card->dev, "not all devices for card %i can be disconnected\n", card->number);
428 snd_info_card_disconnect(card);
429 if (card->registered) {
430 device_del(&card->card_dev);
431 card->registered = false;
434 wake_up(&card->power_sleep);
439 EXPORT_SYMBOL(snd_card_disconnect);
441 static int snd_card_do_free(struct snd_card *card)
443 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
444 if (snd_mixer_oss_notify_callback)
445 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
447 snd_device_free_all(card);
448 if (card->private_free)
449 card->private_free(card);
450 snd_info_free_entry(card->proc_id);
451 if (snd_info_card_free(card) < 0) {
452 dev_warn(card->dev, "unable to free card info\n");
453 /* Not fatal error */
455 if (card->release_completion)
456 complete(card->release_completion);
462 * snd_card_free_when_closed - Disconnect the card, free it later eventually
463 * @card: soundcard structure
465 * Unlike snd_card_free(), this function doesn't try to release the card
466 * resource immediately, but tries to disconnect at first. When the card
467 * is still in use, the function returns before freeing the resources.
468 * The card resources will be freed when the refcount gets to zero.
470 int snd_card_free_when_closed(struct snd_card *card)
472 int ret = snd_card_disconnect(card);
475 put_device(&card->card_dev);
478 EXPORT_SYMBOL(snd_card_free_when_closed);
481 * snd_card_free - frees given soundcard structure
482 * @card: soundcard structure
484 * This function releases the soundcard structure and the all assigned
485 * devices automatically. That is, you don't have to release the devices
488 * This function waits until the all resources are properly released.
490 * Return: Zero. Frees all associated devices and frees the control
491 * interface associated to given soundcard.
493 int snd_card_free(struct snd_card *card)
495 struct completion released;
498 init_completion(&released);
499 card->release_completion = &released;
500 ret = snd_card_free_when_closed(card);
503 /* wait, until all devices are ready for the free operation */
504 wait_for_completion(&released);
507 EXPORT_SYMBOL(snd_card_free);
509 /* retrieve the last word of shortname or longname */
510 static const char *retrieve_id_from_card_name(const char *name)
512 const char *spos = name;
515 if (isspace(*name) && isalnum(name[1]))
522 /* return true if the given id string doesn't conflict any other card ids */
523 static bool card_id_ok(struct snd_card *card, const char *id)
526 if (!snd_info_check_reserved_words(id))
528 for (i = 0; i < snd_ecards_limit; i++) {
529 if (snd_cards[i] && snd_cards[i] != card &&
530 !strcmp(snd_cards[i]->id, id))
536 /* copy to card->id only with valid letters from nid */
537 static void copy_valid_id_string(struct snd_card *card, const char *src,
542 while (*nid && !isalnum(*nid))
545 *id++ = isalpha(*src) ? *src : 'D';
546 while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
554 /* Set card->id from the given string
555 * If the string conflicts with other ids, add a suffix to make it unique.
557 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
561 bool is_default = false;
564 copy_valid_id_string(card, src, nid);
568 /* use "Default" for obviously invalid strings
569 * ("card" conflicts with proc directories)
571 if (!*id || !strncmp(id, "card", 4)) {
572 strcpy(id, "Default");
577 for (loops = 0; loops < SNDRV_CARDS; loops++) {
579 char sfxstr[5]; /* "_012" */
582 if (card_id_ok(card, id))
585 /* Add _XYZ suffix */
586 sprintf(sfxstr, "_%X", loops + 1);
587 sfxlen = strlen(sfxstr);
588 if (len + sfxlen >= sizeof(card->id))
589 spos = id + sizeof(card->id) - sfxlen - 1;
592 strcpy(spos, sfxstr);
594 /* fallback to the default id */
600 dev_err(card->dev, "unable to set card id (%s)\n", id);
601 if (card->proc_root->name)
602 strlcpy(card->id, card->proc_root->name, sizeof(card->id));
606 * snd_card_set_id - set card identification name
607 * @card: soundcard structure
608 * @nid: new identification string
610 * This function sets the card identification and checks for name
613 void snd_card_set_id(struct snd_card *card, const char *nid)
615 /* check if user specified own card->id */
616 if (card->id[0] != '\0')
618 mutex_lock(&snd_card_mutex);
619 snd_card_set_id_no_lock(card, nid, nid);
620 mutex_unlock(&snd_card_mutex);
622 EXPORT_SYMBOL(snd_card_set_id);
625 card_id_show_attr(struct device *dev,
626 struct device_attribute *attr, char *buf)
628 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
629 return snprintf(buf, PAGE_SIZE, "%s\n", card->id);
633 card_id_store_attr(struct device *dev, struct device_attribute *attr,
634 const char *buf, size_t count)
636 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
637 char buf1[sizeof(card->id)];
638 size_t copy = count > sizeof(card->id) - 1 ?
639 sizeof(card->id) - 1 : count;
643 for (idx = 0; idx < copy; idx++) {
645 if (!isalnum(c) && c != '_' && c != '-')
648 memcpy(buf1, buf, copy);
650 mutex_lock(&snd_card_mutex);
651 if (!card_id_ok(NULL, buf1)) {
652 mutex_unlock(&snd_card_mutex);
655 strcpy(card->id, buf1);
656 snd_info_card_id_change(card);
657 mutex_unlock(&snd_card_mutex);
662 static DEVICE_ATTR(id, S_IRUGO | S_IWUSR, card_id_show_attr, card_id_store_attr);
665 card_number_show_attr(struct device *dev,
666 struct device_attribute *attr, char *buf)
668 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
669 return snprintf(buf, PAGE_SIZE, "%i\n", card->number);
672 static DEVICE_ATTR(number, S_IRUGO, card_number_show_attr, NULL);
674 static struct attribute *card_dev_attrs[] = {
676 &dev_attr_number.attr,
680 static struct attribute_group card_dev_attr_group = {
681 .attrs = card_dev_attrs,
684 static const struct attribute_group *card_dev_attr_groups[] = {
685 &card_dev_attr_group,
690 * snd_card_register - register the soundcard
691 * @card: soundcard structure
693 * This function registers all the devices assigned to the soundcard.
694 * Until calling this, the ALSA control interface is blocked from the
695 * external accesses. Thus, you should call this function at the end
696 * of the initialization of the card.
698 * Return: Zero otherwise a negative error code if the registration failed.
700 int snd_card_register(struct snd_card *card)
704 if (snd_BUG_ON(!card))
707 if (!card->registered) {
708 err = device_add(&card->card_dev);
711 card->registered = true;
714 if ((err = snd_device_register_all(card)) < 0)
716 mutex_lock(&snd_card_mutex);
717 if (snd_cards[card->number]) {
718 /* already registered */
719 mutex_unlock(&snd_card_mutex);
723 /* make a unique id name from the given string */
724 char tmpid[sizeof(card->id)];
725 memcpy(tmpid, card->id, sizeof(card->id));
726 snd_card_set_id_no_lock(card, tmpid, tmpid);
728 /* create an id from either shortname or longname */
730 src = *card->shortname ? card->shortname : card->longname;
731 snd_card_set_id_no_lock(card, src,
732 retrieve_id_from_card_name(src));
734 snd_cards[card->number] = card;
735 mutex_unlock(&snd_card_mutex);
736 init_info_for_card(card);
737 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
738 if (snd_mixer_oss_notify_callback)
739 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
744 EXPORT_SYMBOL(snd_card_register);
746 #ifdef CONFIG_PROC_FS
747 static struct snd_info_entry *snd_card_info_entry;
749 static void snd_card_info_read(struct snd_info_entry *entry,
750 struct snd_info_buffer *buffer)
753 struct snd_card *card;
755 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
756 mutex_lock(&snd_card_mutex);
757 if ((card = snd_cards[idx]) != NULL) {
759 snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
764 snd_iprintf(buffer, " %s\n",
767 mutex_unlock(&snd_card_mutex);
770 snd_iprintf(buffer, "--- no soundcards ---\n");
773 #ifdef CONFIG_SND_OSSEMUL
775 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
778 struct snd_card *card;
780 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
781 mutex_lock(&snd_card_mutex);
782 if ((card = snd_cards[idx]) != NULL) {
784 snd_iprintf(buffer, "%s\n", card->longname);
786 mutex_unlock(&snd_card_mutex);
789 snd_iprintf(buffer, "--- no soundcards ---\n");
796 static struct snd_info_entry *snd_card_module_info_entry;
797 static void snd_card_module_info_read(struct snd_info_entry *entry,
798 struct snd_info_buffer *buffer)
801 struct snd_card *card;
803 for (idx = 0; idx < SNDRV_CARDS; idx++) {
804 mutex_lock(&snd_card_mutex);
805 if ((card = snd_cards[idx]) != NULL)
806 snd_iprintf(buffer, "%2i %s\n",
807 idx, card->module->name);
808 mutex_unlock(&snd_card_mutex);
813 int __init snd_card_info_init(void)
815 struct snd_info_entry *entry;
817 entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
820 entry->c.text.read = snd_card_info_read;
821 if (snd_info_register(entry) < 0) {
822 snd_info_free_entry(entry);
825 snd_card_info_entry = entry;
828 entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
830 entry->c.text.read = snd_card_module_info_read;
831 if (snd_info_register(entry) < 0)
832 snd_info_free_entry(entry);
834 snd_card_module_info_entry = entry;
841 int __exit snd_card_info_done(void)
843 snd_info_free_entry(snd_card_info_entry);
845 snd_info_free_entry(snd_card_module_info_entry);
850 #endif /* CONFIG_PROC_FS */
853 * snd_component_add - add a component string
854 * @card: soundcard structure
855 * @component: the component id string
857 * This function adds the component id string to the supported list.
858 * The component can be referred from the alsa-lib.
860 * Return: Zero otherwise a negative error code.
863 int snd_component_add(struct snd_card *card, const char *component)
866 int len = strlen(component);
868 ptr = strstr(card->components, component);
870 if (ptr[len] == '\0' || ptr[len] == ' ') /* already there */
873 if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
877 if (card->components[0] != '\0')
878 strcat(card->components, " ");
879 strcat(card->components, component);
883 EXPORT_SYMBOL(snd_component_add);
886 * snd_card_file_add - add the file to the file list of the card
887 * @card: soundcard structure
888 * @file: file pointer
890 * This function adds the file to the file linked-list of the card.
891 * This linked-list is used to keep tracking the connection state,
892 * and to avoid the release of busy resources by hotplug.
894 * Return: zero or a negative error code.
896 int snd_card_file_add(struct snd_card *card, struct file *file)
898 struct snd_monitor_file *mfile;
900 mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
904 mfile->disconnected_f_op = NULL;
905 INIT_LIST_HEAD(&mfile->shutdown_list);
906 spin_lock(&card->files_lock);
907 if (card->shutdown) {
908 spin_unlock(&card->files_lock);
912 list_add(&mfile->list, &card->files_list);
913 get_device(&card->card_dev);
914 spin_unlock(&card->files_lock);
918 EXPORT_SYMBOL(snd_card_file_add);
921 * snd_card_file_remove - remove the file from the file list
922 * @card: soundcard structure
923 * @file: file pointer
925 * This function removes the file formerly added to the card via
926 * snd_card_file_add() function.
927 * If all files are removed and snd_card_free_when_closed() was
928 * called beforehand, it processes the pending release of
931 * Return: Zero or a negative error code.
933 int snd_card_file_remove(struct snd_card *card, struct file *file)
935 struct snd_monitor_file *mfile, *found = NULL;
937 spin_lock(&card->files_lock);
938 list_for_each_entry(mfile, &card->files_list, list) {
939 if (mfile->file == file) {
940 list_del(&mfile->list);
941 spin_lock(&shutdown_lock);
942 list_del(&mfile->shutdown_list);
943 spin_unlock(&shutdown_lock);
944 if (mfile->disconnected_f_op)
945 fops_put(mfile->disconnected_f_op);
950 spin_unlock(&card->files_lock);
952 dev_err(card->dev, "card file remove problem (%p)\n", file);
956 put_device(&card->card_dev);
960 EXPORT_SYMBOL(snd_card_file_remove);
964 * snd_power_wait - wait until the power-state is changed.
965 * @card: soundcard structure
966 * @power_state: expected power state
968 * Waits until the power-state is changed.
970 * Return: Zero if successful, or a negative error code.
972 * Note: the power lock must be active before call.
974 int snd_power_wait(struct snd_card *card, unsigned int power_state)
980 if (snd_power_get_state(card) == power_state)
982 init_waitqueue_entry(&wait, current);
983 add_wait_queue(&card->power_sleep, &wait);
985 if (card->shutdown) {
989 if (snd_power_get_state(card) == power_state)
991 set_current_state(TASK_UNINTERRUPTIBLE);
992 snd_power_unlock(card);
993 schedule_timeout(30 * HZ);
994 snd_power_lock(card);
996 remove_wait_queue(&card->power_sleep, &wait);
1000 EXPORT_SYMBOL(snd_power_wait);
1001 #endif /* CONFIG_PM */