2 * Routines for driver control interface
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/threads.h>
23 #include <linux/interrupt.h>
24 #include <linux/module.h>
25 #include <linux/slab.h>
26 #include <linux/vmalloc.h>
27 #include <linux/time.h>
28 #include <sound/core.h>
29 #include <sound/minors.h>
30 #include <sound/info.h>
31 #include <sound/control.h>
33 /* max number of user-defined controls */
34 #define MAX_USER_CONTROLS 32
35 #define MAX_CONTROL_COUNT 1028
37 struct snd_kctl_ioctl {
38 struct list_head list; /* list of all ioctls */
39 snd_kctl_ioctl_func_t fioctl;
42 static DECLARE_RWSEM(snd_ioctl_rwsem);
43 static LIST_HEAD(snd_control_ioctls);
45 static LIST_HEAD(snd_control_compat_ioctls);
48 static int snd_ctl_open(struct inode *inode, struct file *file)
51 struct snd_card *card;
52 struct snd_ctl_file *ctl;
55 err = nonseekable_open(inode, file);
59 card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
64 err = snd_card_file_add(card, file);
69 if (!try_module_get(card->module)) {
73 ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
78 INIT_LIST_HEAD(&ctl->events);
79 init_waitqueue_head(&ctl->change_sleep);
80 spin_lock_init(&ctl->read_lock);
82 ctl->prefer_pcm_subdevice = -1;
83 ctl->prefer_rawmidi_subdevice = -1;
84 ctl->pid = get_pid(task_pid(current));
85 file->private_data = ctl;
86 write_lock_irqsave(&card->ctl_files_rwlock, flags);
87 list_add_tail(&ctl->list, &card->ctl_files);
88 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
93 module_put(card->module);
95 snd_card_file_remove(card, file);
102 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
105 struct snd_kctl_event *cread;
107 spin_lock_irqsave(&ctl->read_lock, flags);
108 while (!list_empty(&ctl->events)) {
109 cread = snd_kctl_event(ctl->events.next);
110 list_del(&cread->list);
113 spin_unlock_irqrestore(&ctl->read_lock, flags);
116 static int snd_ctl_release(struct inode *inode, struct file *file)
119 struct snd_card *card;
120 struct snd_ctl_file *ctl;
121 struct snd_kcontrol *control;
124 ctl = file->private_data;
125 file->private_data = NULL;
127 write_lock_irqsave(&card->ctl_files_rwlock, flags);
128 list_del(&ctl->list);
129 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
130 down_write(&card->controls_rwsem);
131 list_for_each_entry(control, &card->controls, list)
132 for (idx = 0; idx < control->count; idx++)
133 if (control->vd[idx].owner == ctl)
134 control->vd[idx].owner = NULL;
135 up_write(&card->controls_rwsem);
136 snd_ctl_empty_read_queue(ctl);
139 module_put(card->module);
140 snd_card_file_remove(card, file);
144 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
145 struct snd_ctl_elem_id *id)
148 struct snd_ctl_file *ctl;
149 struct snd_kctl_event *ev;
151 if (snd_BUG_ON(!card || !id))
153 read_lock(&card->ctl_files_rwlock);
154 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
155 card->mixer_oss_change_count++;
157 list_for_each_entry(ctl, &card->ctl_files, list) {
158 if (!ctl->subscribed)
160 spin_lock_irqsave(&ctl->read_lock, flags);
161 list_for_each_entry(ev, &ctl->events, list) {
162 if (ev->id.numid == id->numid) {
167 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
171 list_add_tail(&ev->list, &ctl->events);
173 snd_printk(KERN_ERR "No memory available to allocate event\n");
176 wake_up(&ctl->change_sleep);
177 spin_unlock_irqrestore(&ctl->read_lock, flags);
178 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
180 read_unlock(&card->ctl_files_rwlock);
183 EXPORT_SYMBOL(snd_ctl_notify);
186 * snd_ctl_new - create a control instance from the template
187 * @control: the control template
188 * @access: the default control access
190 * Allocates a new struct snd_kcontrol instance and copies the given template
191 * to the new instance. It does not copy volatile data (access).
193 * Returns the pointer of the new instance, or NULL on failure.
195 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
198 struct snd_kcontrol *kctl;
201 if (snd_BUG_ON(!control || !control->count))
204 if (control->count > MAX_CONTROL_COUNT)
207 kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
209 snd_printk(KERN_ERR "Cannot allocate control instance\n");
213 for (idx = 0; idx < kctl->count; idx++)
214 kctl->vd[idx].access = access;
219 * snd_ctl_new1 - create a control instance from the template
220 * @ncontrol: the initialization record
221 * @private_data: the private data to set
223 * Allocates a new struct snd_kcontrol instance and initialize from the given
224 * template. When the access field of ncontrol is 0, it's assumed as
225 * READWRITE access. When the count field is 0, it's assumes as one.
227 * Returns the pointer of the newly generated instance, or NULL on failure.
229 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
232 struct snd_kcontrol kctl;
235 if (snd_BUG_ON(!ncontrol || !ncontrol->info))
237 memset(&kctl, 0, sizeof(kctl));
238 kctl.id.iface = ncontrol->iface;
239 kctl.id.device = ncontrol->device;
240 kctl.id.subdevice = ncontrol->subdevice;
241 if (ncontrol->name) {
242 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
243 if (strcmp(ncontrol->name, kctl.id.name) != 0)
244 snd_printk(KERN_WARNING
245 "Control name '%s' truncated to '%s'\n",
246 ncontrol->name, kctl.id.name);
248 kctl.id.index = ncontrol->index;
249 kctl.count = ncontrol->count ? ncontrol->count : 1;
250 access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
251 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
252 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
253 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
254 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
255 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
256 kctl.info = ncontrol->info;
257 kctl.get = ncontrol->get;
258 kctl.put = ncontrol->put;
259 kctl.tlv.p = ncontrol->tlv.p;
260 kctl.private_value = ncontrol->private_value;
261 kctl.private_data = private_data;
262 return snd_ctl_new(&kctl, access);
265 EXPORT_SYMBOL(snd_ctl_new1);
268 * snd_ctl_free_one - release the control instance
269 * @kcontrol: the control instance
271 * Releases the control instance created via snd_ctl_new()
273 * Don't call this after the control was added to the card.
275 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
278 if (kcontrol->private_free)
279 kcontrol->private_free(kcontrol);
284 EXPORT_SYMBOL(snd_ctl_free_one);
286 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
289 struct snd_kcontrol *kctl;
291 /* Make sure that the ids assigned to the control do not wrap around */
292 if (card->last_numid >= UINT_MAX - count)
293 card->last_numid = 0;
295 list_for_each_entry(kctl, &card->controls, list) {
296 if (kctl->id.numid < card->last_numid + 1 + count &&
297 kctl->id.numid + kctl->count > card->last_numid + 1) {
298 card->last_numid = kctl->id.numid + kctl->count - 1;
305 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
307 unsigned int iter = 100000;
309 while (snd_ctl_remove_numid_conflict(card, count)) {
311 /* this situation is very unlikely */
312 snd_printk(KERN_ERR "unable to allocate new control numid\n");
320 * snd_ctl_add - add the control instance to the card
321 * @card: the card instance
322 * @kcontrol: the control instance to add
324 * Adds the control instance created via snd_ctl_new() or
325 * snd_ctl_new1() to the given card. Assigns also an unique
326 * numid used for fast search.
328 * Returns zero if successful, or a negative error code on failure.
330 * It frees automatically the control which cannot be added.
332 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
334 struct snd_ctl_elem_id id;
341 if (snd_BUG_ON(!card || !kcontrol->info))
344 if (id.index > UINT_MAX - kcontrol->count)
347 down_write(&card->controls_rwsem);
348 if (snd_ctl_find_id(card, &id)) {
349 up_write(&card->controls_rwsem);
350 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
359 if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
360 up_write(&card->controls_rwsem);
364 list_add_tail(&kcontrol->list, &card->controls);
365 card->controls_count += kcontrol->count;
366 kcontrol->id.numid = card->last_numid + 1;
367 card->last_numid += kcontrol->count;
368 count = kcontrol->count;
369 up_write(&card->controls_rwsem);
370 for (idx = 0; idx < count; idx++, id.index++, id.numid++)
371 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
375 snd_ctl_free_one(kcontrol);
379 EXPORT_SYMBOL(snd_ctl_add);
382 * snd_ctl_replace - replace the control instance of the card
383 * @card: the card instance
384 * @kcontrol: the control instance to replace
385 * @add_on_replace: add the control if not already added
387 * Replaces the given control. If the given control does not exist
388 * and the add_on_replace flag is set, the control is added. If the
389 * control exists, it is destroyed first.
391 * Returns zero if successful, or a negative error code on failure.
393 * It frees automatically the control which cannot be added or replaced.
395 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
398 struct snd_ctl_elem_id id;
401 struct snd_kcontrol *old;
406 if (snd_BUG_ON(!card || !kcontrol->info)) {
411 down_write(&card->controls_rwsem);
412 old = snd_ctl_find_id(card, &id);
416 up_write(&card->controls_rwsem);
420 ret = snd_ctl_remove(card, old);
422 up_write(&card->controls_rwsem);
426 if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
427 up_write(&card->controls_rwsem);
431 list_add_tail(&kcontrol->list, &card->controls);
432 card->controls_count += kcontrol->count;
433 kcontrol->id.numid = card->last_numid + 1;
434 card->last_numid += kcontrol->count;
435 count = kcontrol->count;
436 up_write(&card->controls_rwsem);
437 for (idx = 0; idx < count; idx++, id.index++, id.numid++)
438 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
442 snd_ctl_free_one(kcontrol);
445 EXPORT_SYMBOL(snd_ctl_replace);
448 * snd_ctl_remove - remove the control from the card and release it
449 * @card: the card instance
450 * @kcontrol: the control instance to remove
452 * Removes the control from the card and then releases the instance.
453 * You don't need to call snd_ctl_free_one(). You must be in
454 * the write lock - down_write(&card->controls_rwsem).
456 * Returns 0 if successful, or a negative error code on failure.
458 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
460 struct snd_ctl_elem_id id;
463 if (snd_BUG_ON(!card || !kcontrol))
465 list_del(&kcontrol->list);
466 card->controls_count -= kcontrol->count;
468 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
469 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
470 snd_ctl_free_one(kcontrol);
474 EXPORT_SYMBOL(snd_ctl_remove);
477 * snd_ctl_remove_id - remove the control of the given id and release it
478 * @card: the card instance
479 * @id: the control id to remove
481 * Finds the control instance with the given id, removes it from the
482 * card list and releases it.
484 * Returns 0 if successful, or a negative error code on failure.
486 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
488 struct snd_kcontrol *kctl;
491 down_write(&card->controls_rwsem);
492 kctl = snd_ctl_find_id(card, id);
494 up_write(&card->controls_rwsem);
497 ret = snd_ctl_remove(card, kctl);
498 up_write(&card->controls_rwsem);
502 EXPORT_SYMBOL(snd_ctl_remove_id);
505 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
506 * @file: active control handle
507 * @id: the control id to remove
509 * Finds the control instance with the given id, removes it from the
510 * card list and releases it.
512 * Returns 0 if successful, or a negative error code on failure.
514 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
515 struct snd_ctl_elem_id *id)
517 struct snd_card *card = file->card;
518 struct snd_kcontrol *kctl;
521 down_write(&card->controls_rwsem);
522 kctl = snd_ctl_find_id(card, id);
527 if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
531 for (idx = 0; idx < kctl->count; idx++)
532 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
536 ret = snd_ctl_remove(card, kctl);
539 card->user_ctl_count--;
541 up_write(&card->controls_rwsem);
546 * snd_ctl_activate_id - activate/inactivate the control of the given id
547 * @card: the card instance
548 * @id: the control id to activate/inactivate
549 * @active: non-zero to activate
551 * Finds the control instance with the given id, and activate or
552 * inactivate the control together with notification, if changed.
554 * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
556 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
559 struct snd_kcontrol *kctl;
560 struct snd_kcontrol_volatile *vd;
561 unsigned int index_offset;
564 down_write(&card->controls_rwsem);
565 kctl = snd_ctl_find_id(card, id);
570 index_offset = snd_ctl_get_ioff(kctl, &kctl->id);
571 vd = &kctl->vd[index_offset];
574 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
576 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
578 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
580 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
584 up_write(&card->controls_rwsem);
586 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
589 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
592 * snd_ctl_rename_id - replace the id of a control on the card
593 * @card: the card instance
594 * @src_id: the old id
595 * @dst_id: the new id
597 * Finds the control with the old id from the card, and replaces the
598 * id with the new one.
600 * Returns zero if successful, or a negative error code on failure.
602 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
603 struct snd_ctl_elem_id *dst_id)
605 struct snd_kcontrol *kctl;
607 down_write(&card->controls_rwsem);
608 kctl = snd_ctl_find_id(card, src_id);
610 up_write(&card->controls_rwsem);
614 kctl->id.numid = card->last_numid + 1;
615 card->last_numid += kctl->count;
616 up_write(&card->controls_rwsem);
620 EXPORT_SYMBOL(snd_ctl_rename_id);
623 * snd_ctl_find_numid - find the control instance with the given number-id
624 * @card: the card instance
625 * @numid: the number-id to search
627 * Finds the control instance with the given number-id from the card.
629 * Returns the pointer of the instance if found, or NULL if not.
631 * The caller must down card->controls_rwsem before calling this function
632 * (if the race condition can happen).
634 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
636 struct snd_kcontrol *kctl;
638 if (snd_BUG_ON(!card || !numid))
640 list_for_each_entry(kctl, &card->controls, list) {
641 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
647 EXPORT_SYMBOL(snd_ctl_find_numid);
650 * snd_ctl_find_id - find the control instance with the given id
651 * @card: the card instance
652 * @id: the id to search
654 * Finds the control instance with the given id from the card.
656 * Returns the pointer of the instance if found, or NULL if not.
658 * The caller must down card->controls_rwsem before calling this function
659 * (if the race condition can happen).
661 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
662 struct snd_ctl_elem_id *id)
664 struct snd_kcontrol *kctl;
666 if (snd_BUG_ON(!card || !id))
669 return snd_ctl_find_numid(card, id->numid);
670 list_for_each_entry(kctl, &card->controls, list) {
671 if (kctl->id.iface != id->iface)
673 if (kctl->id.device != id->device)
675 if (kctl->id.subdevice != id->subdevice)
677 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
679 if (kctl->id.index > id->index)
681 if (kctl->id.index + kctl->count <= id->index)
688 EXPORT_SYMBOL(snd_ctl_find_id);
690 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
691 unsigned int cmd, void __user *arg)
693 struct snd_ctl_card_info *info;
695 info = kzalloc(sizeof(*info), GFP_KERNEL);
698 down_read(&snd_ioctl_rwsem);
699 info->card = card->number;
700 strlcpy(info->id, card->id, sizeof(info->id));
701 strlcpy(info->driver, card->driver, sizeof(info->driver));
702 strlcpy(info->name, card->shortname, sizeof(info->name));
703 strlcpy(info->longname, card->longname, sizeof(info->longname));
704 strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
705 strlcpy(info->components, card->components, sizeof(info->components));
706 up_read(&snd_ioctl_rwsem);
707 if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
715 static int snd_ctl_elem_list(struct snd_card *card,
716 struct snd_ctl_elem_list __user *_list)
718 struct list_head *plist;
719 struct snd_ctl_elem_list list;
720 struct snd_kcontrol *kctl;
721 struct snd_ctl_elem_id *dst, *id;
722 unsigned int offset, space, jidx;
724 if (copy_from_user(&list, _list, sizeof(list)))
726 offset = list.offset;
728 /* try limit maximum space */
732 /* allocate temporary buffer for atomic operation */
733 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
736 down_read(&card->controls_rwsem);
737 list.count = card->controls_count;
738 plist = card->controls.next;
739 while (plist != &card->controls) {
742 kctl = snd_kcontrol(plist);
743 if (offset < kctl->count)
745 offset -= kctl->count;
750 while (space > 0 && plist != &card->controls) {
751 kctl = snd_kcontrol(plist);
752 for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
753 snd_ctl_build_ioff(id, kctl, jidx);
761 up_read(&card->controls_rwsem);
763 copy_to_user(list.pids, dst,
764 list.used * sizeof(struct snd_ctl_elem_id))) {
770 down_read(&card->controls_rwsem);
771 list.count = card->controls_count;
772 up_read(&card->controls_rwsem);
774 if (copy_to_user(_list, &list, sizeof(list)))
779 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
780 struct snd_ctl_elem_info *info)
782 struct snd_card *card = ctl->card;
783 struct snd_kcontrol *kctl;
784 struct snd_kcontrol_volatile *vd;
785 unsigned int index_offset;
788 down_read(&card->controls_rwsem);
789 kctl = snd_ctl_find_id(card, &info->id);
791 up_read(&card->controls_rwsem);
794 #ifdef CONFIG_SND_DEBUG
797 result = kctl->info(kctl, info);
799 snd_BUG_ON(info->access);
800 index_offset = snd_ctl_get_ioff(kctl, &info->id);
801 vd = &kctl->vd[index_offset];
802 snd_ctl_build_ioff(&info->id, kctl, index_offset);
803 info->access = vd->access;
805 info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
806 if (vd->owner == ctl)
807 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
808 info->owner = pid_vnr(vd->owner->pid);
813 up_read(&card->controls_rwsem);
817 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
818 struct snd_ctl_elem_info __user *_info)
820 struct snd_ctl_elem_info info;
823 if (copy_from_user(&info, _info, sizeof(info)))
825 snd_power_lock(ctl->card);
826 result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
828 result = snd_ctl_elem_info(ctl, &info);
829 snd_power_unlock(ctl->card);
831 if (copy_to_user(_info, &info, sizeof(info)))
836 static int snd_ctl_elem_read(struct snd_card *card,
837 struct snd_ctl_elem_value *control)
839 struct snd_kcontrol *kctl;
840 struct snd_kcontrol_volatile *vd;
841 unsigned int index_offset;
844 down_read(&card->controls_rwsem);
845 kctl = snd_ctl_find_id(card, &control->id);
849 index_offset = snd_ctl_get_ioff(kctl, &control->id);
850 vd = &kctl->vd[index_offset];
851 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
853 snd_ctl_build_ioff(&control->id, kctl, index_offset);
854 result = kctl->get(kctl, control);
858 up_read(&card->controls_rwsem);
862 static int snd_ctl_elem_read_user(struct snd_card *card,
863 struct snd_ctl_elem_value __user *_control)
865 struct snd_ctl_elem_value *control;
868 control = memdup_user(_control, sizeof(*control));
870 return PTR_ERR(control);
872 snd_power_lock(card);
873 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
875 result = snd_ctl_elem_read(card, control);
876 snd_power_unlock(card);
878 if (copy_to_user(_control, control, sizeof(*control)))
884 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
885 struct snd_ctl_elem_value *control)
887 struct snd_kcontrol *kctl;
888 struct snd_kcontrol_volatile *vd;
889 unsigned int index_offset;
892 down_read(&card->controls_rwsem);
893 kctl = snd_ctl_find_id(card, &control->id);
897 index_offset = snd_ctl_get_ioff(kctl, &control->id);
898 vd = &kctl->vd[index_offset];
899 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
901 (file && vd->owner && vd->owner != file)) {
904 snd_ctl_build_ioff(&control->id, kctl, index_offset);
905 result = kctl->put(kctl, control);
908 struct snd_ctl_elem_id id = control->id;
909 up_read(&card->controls_rwsem);
910 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
914 up_read(&card->controls_rwsem);
918 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
919 struct snd_ctl_elem_value __user *_control)
921 struct snd_ctl_elem_value *control;
922 struct snd_card *card;
925 control = memdup_user(_control, sizeof(*control));
927 return PTR_ERR(control);
930 snd_power_lock(card);
931 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
933 result = snd_ctl_elem_write(card, file, control);
934 snd_power_unlock(card);
936 if (copy_to_user(_control, control, sizeof(*control)))
942 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
943 struct snd_ctl_elem_id __user *_id)
945 struct snd_card *card = file->card;
946 struct snd_ctl_elem_id id;
947 struct snd_kcontrol *kctl;
948 struct snd_kcontrol_volatile *vd;
951 if (copy_from_user(&id, _id, sizeof(id)))
953 down_write(&card->controls_rwsem);
954 kctl = snd_ctl_find_id(card, &id);
958 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
959 if (vd->owner != NULL)
966 up_write(&card->controls_rwsem);
970 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
971 struct snd_ctl_elem_id __user *_id)
973 struct snd_card *card = file->card;
974 struct snd_ctl_elem_id id;
975 struct snd_kcontrol *kctl;
976 struct snd_kcontrol_volatile *vd;
979 if (copy_from_user(&id, _id, sizeof(id)))
981 down_write(&card->controls_rwsem);
982 kctl = snd_ctl_find_id(card, &id);
986 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
987 if (vd->owner == NULL)
989 else if (vd->owner != file)
996 up_write(&card->controls_rwsem);
1000 struct user_element {
1001 struct snd_ctl_elem_info info;
1002 struct snd_card *card;
1003 void *elem_data; /* element data */
1004 unsigned long elem_data_size; /* size of element data in bytes */
1005 void *tlv_data; /* TLV data */
1006 unsigned long tlv_data_size; /* TLV data size */
1007 void *priv_data; /* private data (like strings for enumerated type) */
1010 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1011 struct snd_ctl_elem_info *uinfo)
1013 struct user_element *ue = kcontrol->private_data;
1019 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1020 struct snd_ctl_elem_info *uinfo)
1022 struct user_element *ue = kcontrol->private_data;
1026 item = uinfo->value.enumerated.item;
1030 item = min(item, uinfo->value.enumerated.items - 1);
1031 uinfo->value.enumerated.item = item;
1033 names = ue->priv_data;
1034 for (; item > 0; --item)
1035 names += strlen(names) + 1;
1036 strcpy(uinfo->value.enumerated.name, names);
1041 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1042 struct snd_ctl_elem_value *ucontrol)
1044 struct user_element *ue = kcontrol->private_data;
1046 mutex_lock(&ue->card->user_ctl_lock);
1047 memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
1048 mutex_unlock(&ue->card->user_ctl_lock);
1052 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1053 struct snd_ctl_elem_value *ucontrol)
1056 struct user_element *ue = kcontrol->private_data;
1058 mutex_lock(&ue->card->user_ctl_lock);
1059 change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
1061 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
1062 mutex_unlock(&ue->card->user_ctl_lock);
1066 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1069 unsigned int __user *tlv)
1071 struct user_element *ue = kcontrol->private_data;
1076 if (size > 1024 * 128) /* sane value */
1079 new_data = memdup_user(tlv, size);
1080 if (IS_ERR(new_data))
1081 return PTR_ERR(new_data);
1082 mutex_lock(&ue->card->user_ctl_lock);
1083 change = ue->tlv_data_size != size;
1085 change = memcmp(ue->tlv_data, new_data, size);
1086 kfree(ue->tlv_data);
1087 ue->tlv_data = new_data;
1088 ue->tlv_data_size = size;
1089 mutex_unlock(&ue->card->user_ctl_lock);
1093 mutex_lock(&ue->card->user_ctl_lock);
1094 if (!ue->tlv_data_size || !ue->tlv_data) {
1098 if (size < ue->tlv_data_size) {
1102 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1105 mutex_unlock(&ue->card->user_ctl_lock);
1112 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1115 size_t buf_len, name_len;
1117 const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1119 if (ue->info.value.enumerated.names_length > 64 * 1024)
1122 names = memdup_user((const void __user *)user_ptrval,
1123 ue->info.value.enumerated.names_length);
1125 return PTR_ERR(names);
1127 /* check that there are enough valid names */
1128 buf_len = ue->info.value.enumerated.names_length;
1130 for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1131 name_len = strnlen(p, buf_len);
1132 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1137 buf_len -= name_len + 1;
1140 ue->priv_data = names;
1141 ue->info.value.enumerated.names_ptr = 0;
1146 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1148 struct user_element *ue = kcontrol->private_data;
1150 kfree(ue->tlv_data);
1151 kfree(ue->priv_data);
1155 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1156 struct snd_ctl_elem_info *info, int replace)
1158 struct snd_card *card = file->card;
1159 struct snd_kcontrol kctl, *_kctl;
1160 unsigned int access;
1162 struct user_element *ue;
1165 if (info->count < 1)
1167 access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
1168 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
1169 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
1170 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
1172 memset(&kctl, 0, sizeof(kctl));
1175 err = snd_ctl_remove_user_ctl(file, &info->id);
1180 if (card->user_ctl_count >= MAX_USER_CONTROLS)
1183 memcpy(&kctl.id, &info->id, sizeof(info->id));
1184 kctl.count = info->owner ? info->owner : 1;
1185 access |= SNDRV_CTL_ELEM_ACCESS_USER;
1186 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1187 kctl.info = snd_ctl_elem_user_enum_info;
1189 kctl.info = snd_ctl_elem_user_info;
1190 if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1191 kctl.get = snd_ctl_elem_user_get;
1192 if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1193 kctl.put = snd_ctl_elem_user_put;
1194 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
1195 kctl.tlv.c = snd_ctl_elem_user_tlv;
1196 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1198 switch (info->type) {
1199 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1200 case SNDRV_CTL_ELEM_TYPE_INTEGER:
1201 private_size = sizeof(long);
1202 if (info->count > 128)
1205 case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1206 private_size = sizeof(long long);
1207 if (info->count > 64)
1210 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1211 private_size = sizeof(unsigned int);
1212 if (info->count > 128 || info->value.enumerated.items == 0)
1215 case SNDRV_CTL_ELEM_TYPE_BYTES:
1216 private_size = sizeof(unsigned char);
1217 if (info->count > 512)
1220 case SNDRV_CTL_ELEM_TYPE_IEC958:
1221 private_size = sizeof(struct snd_aes_iec958);
1222 if (info->count != 1)
1228 private_size *= info->count;
1229 ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1234 ue->info.access = 0;
1235 ue->elem_data = (char *)ue + sizeof(*ue);
1236 ue->elem_data_size = private_size;
1237 if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1238 err = snd_ctl_elem_init_enum_names(ue);
1244 kctl.private_free = snd_ctl_elem_user_free;
1245 _kctl = snd_ctl_new(&kctl, access);
1246 if (_kctl == NULL) {
1247 kfree(ue->priv_data);
1251 _kctl->private_data = ue;
1252 for (idx = 0; idx < _kctl->count; idx++)
1253 _kctl->vd[idx].owner = file;
1254 err = snd_ctl_add(card, _kctl);
1258 down_write(&card->controls_rwsem);
1259 card->user_ctl_count++;
1260 up_write(&card->controls_rwsem);
1265 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1266 struct snd_ctl_elem_info __user *_info, int replace)
1268 struct snd_ctl_elem_info info;
1269 if (copy_from_user(&info, _info, sizeof(info)))
1271 return snd_ctl_elem_add(file, &info, replace);
1274 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1275 struct snd_ctl_elem_id __user *_id)
1277 struct snd_ctl_elem_id id;
1279 if (copy_from_user(&id, _id, sizeof(id)))
1281 return snd_ctl_remove_user_ctl(file, &id);
1284 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1287 if (get_user(subscribe, ptr))
1289 if (subscribe < 0) {
1290 subscribe = file->subscribed;
1291 if (put_user(subscribe, ptr))
1296 file->subscribed = 1;
1298 } else if (file->subscribed) {
1299 snd_ctl_empty_read_queue(file);
1300 file->subscribed = 0;
1305 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1306 struct snd_ctl_tlv __user *_tlv,
1309 struct snd_card *card = file->card;
1310 struct snd_ctl_tlv tlv;
1311 struct snd_kcontrol *kctl;
1312 struct snd_kcontrol_volatile *vd;
1316 if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1318 if (tlv.length < sizeof(unsigned int) * 2)
1320 down_read(&card->controls_rwsem);
1321 kctl = snd_ctl_find_numid(card, tlv.numid);
1326 if (kctl->tlv.p == NULL) {
1330 vd = &kctl->vd[tlv.numid - kctl->id.numid];
1331 if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1332 (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1333 (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1337 if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1338 if (vd->owner != NULL && vd->owner != file) {
1342 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1344 struct snd_ctl_elem_id id = kctl->id;
1345 up_read(&card->controls_rwsem);
1346 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id);
1354 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1355 if (tlv.length < len) {
1359 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1363 up_read(&card->controls_rwsem);
1367 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1369 struct snd_ctl_file *ctl;
1370 struct snd_card *card;
1371 struct snd_kctl_ioctl *p;
1372 void __user *argp = (void __user *)arg;
1373 int __user *ip = argp;
1376 ctl = file->private_data;
1378 if (snd_BUG_ON(!card))
1381 case SNDRV_CTL_IOCTL_PVERSION:
1382 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1383 case SNDRV_CTL_IOCTL_CARD_INFO:
1384 return snd_ctl_card_info(card, ctl, cmd, argp);
1385 case SNDRV_CTL_IOCTL_ELEM_LIST:
1386 return snd_ctl_elem_list(card, argp);
1387 case SNDRV_CTL_IOCTL_ELEM_INFO:
1388 return snd_ctl_elem_info_user(ctl, argp);
1389 case SNDRV_CTL_IOCTL_ELEM_READ:
1390 return snd_ctl_elem_read_user(card, argp);
1391 case SNDRV_CTL_IOCTL_ELEM_WRITE:
1392 return snd_ctl_elem_write_user(ctl, argp);
1393 case SNDRV_CTL_IOCTL_ELEM_LOCK:
1394 return snd_ctl_elem_lock(ctl, argp);
1395 case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1396 return snd_ctl_elem_unlock(ctl, argp);
1397 case SNDRV_CTL_IOCTL_ELEM_ADD:
1398 return snd_ctl_elem_add_user(ctl, argp, 0);
1399 case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1400 return snd_ctl_elem_add_user(ctl, argp, 1);
1401 case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1402 return snd_ctl_elem_remove(ctl, argp);
1403 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1404 return snd_ctl_subscribe_events(ctl, ip);
1405 case SNDRV_CTL_IOCTL_TLV_READ:
1406 return snd_ctl_tlv_ioctl(ctl, argp, 0);
1407 case SNDRV_CTL_IOCTL_TLV_WRITE:
1408 return snd_ctl_tlv_ioctl(ctl, argp, 1);
1409 case SNDRV_CTL_IOCTL_TLV_COMMAND:
1410 return snd_ctl_tlv_ioctl(ctl, argp, -1);
1411 case SNDRV_CTL_IOCTL_POWER:
1412 return -ENOPROTOOPT;
1413 case SNDRV_CTL_IOCTL_POWER_STATE:
1415 return put_user(card->power_state, ip) ? -EFAULT : 0;
1417 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1420 down_read(&snd_ioctl_rwsem);
1421 list_for_each_entry(p, &snd_control_ioctls, list) {
1422 err = p->fioctl(card, ctl, cmd, arg);
1423 if (err != -ENOIOCTLCMD) {
1424 up_read(&snd_ioctl_rwsem);
1428 up_read(&snd_ioctl_rwsem);
1429 snd_printdd("unknown ioctl = 0x%x\n", cmd);
1433 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1434 size_t count, loff_t * offset)
1436 struct snd_ctl_file *ctl;
1440 ctl = file->private_data;
1441 if (snd_BUG_ON(!ctl || !ctl->card))
1443 if (!ctl->subscribed)
1445 if (count < sizeof(struct snd_ctl_event))
1447 spin_lock_irq(&ctl->read_lock);
1448 while (count >= sizeof(struct snd_ctl_event)) {
1449 struct snd_ctl_event ev;
1450 struct snd_kctl_event *kev;
1451 while (list_empty(&ctl->events)) {
1453 if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1457 init_waitqueue_entry(&wait, current);
1458 add_wait_queue(&ctl->change_sleep, &wait);
1459 set_current_state(TASK_INTERRUPTIBLE);
1460 spin_unlock_irq(&ctl->read_lock);
1462 remove_wait_queue(&ctl->change_sleep, &wait);
1463 if (ctl->card->shutdown)
1465 if (signal_pending(current))
1466 return -ERESTARTSYS;
1467 spin_lock_irq(&ctl->read_lock);
1469 kev = snd_kctl_event(ctl->events.next);
1470 ev.type = SNDRV_CTL_EVENT_ELEM;
1471 ev.data.elem.mask = kev->mask;
1472 ev.data.elem.id = kev->id;
1473 list_del(&kev->list);
1474 spin_unlock_irq(&ctl->read_lock);
1476 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1480 spin_lock_irq(&ctl->read_lock);
1481 buffer += sizeof(struct snd_ctl_event);
1482 count -= sizeof(struct snd_ctl_event);
1483 result += sizeof(struct snd_ctl_event);
1486 spin_unlock_irq(&ctl->read_lock);
1488 return result > 0 ? result : err;
1491 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1494 struct snd_ctl_file *ctl;
1496 ctl = file->private_data;
1497 if (!ctl->subscribed)
1499 poll_wait(file, &ctl->change_sleep, wait);
1502 if (!list_empty(&ctl->events))
1503 mask |= POLLIN | POLLRDNORM;
1509 * register the device-specific control-ioctls.
1510 * called from each device manager like pcm.c, hwdep.c, etc.
1512 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1514 struct snd_kctl_ioctl *pn;
1516 pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1520 down_write(&snd_ioctl_rwsem);
1521 list_add_tail(&pn->list, lists);
1522 up_write(&snd_ioctl_rwsem);
1526 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1528 return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1531 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1533 #ifdef CONFIG_COMPAT
1534 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1536 return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1539 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1543 * de-register the device-specific control-ioctls.
1545 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1546 struct list_head *lists)
1548 struct snd_kctl_ioctl *p;
1550 if (snd_BUG_ON(!fcn))
1552 down_write(&snd_ioctl_rwsem);
1553 list_for_each_entry(p, lists, list) {
1554 if (p->fioctl == fcn) {
1556 up_write(&snd_ioctl_rwsem);
1561 up_write(&snd_ioctl_rwsem);
1566 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1568 return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1571 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1573 #ifdef CONFIG_COMPAT
1574 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1576 return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1579 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1582 static int snd_ctl_fasync(int fd, struct file * file, int on)
1584 struct snd_ctl_file *ctl;
1586 ctl = file->private_data;
1587 return fasync_helper(fd, file, on, &ctl->fasync);
1593 #ifdef CONFIG_COMPAT
1594 #include "control_compat.c"
1596 #define snd_ctl_ioctl_compat NULL
1603 static const struct file_operations snd_ctl_f_ops =
1605 .owner = THIS_MODULE,
1606 .read = snd_ctl_read,
1607 .open = snd_ctl_open,
1608 .release = snd_ctl_release,
1609 .llseek = no_llseek,
1610 .poll = snd_ctl_poll,
1611 .unlocked_ioctl = snd_ctl_ioctl,
1612 .compat_ioctl = snd_ctl_ioctl_compat,
1613 .fasync = snd_ctl_fasync,
1617 * registration of the control device
1619 static int snd_ctl_dev_register(struct snd_device *device)
1621 struct snd_card *card = device->device_data;
1625 if (snd_BUG_ON(!card))
1627 cardnum = card->number;
1628 if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1630 sprintf(name, "controlC%i", cardnum);
1631 if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1632 &snd_ctl_f_ops, card, name)) < 0)
1638 * disconnection of the control device
1640 static int snd_ctl_dev_disconnect(struct snd_device *device)
1642 struct snd_card *card = device->device_data;
1643 struct snd_ctl_file *ctl;
1646 if (snd_BUG_ON(!card))
1648 cardnum = card->number;
1649 if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1652 read_lock(&card->ctl_files_rwlock);
1653 list_for_each_entry(ctl, &card->ctl_files, list) {
1654 wake_up(&ctl->change_sleep);
1655 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1657 read_unlock(&card->ctl_files_rwlock);
1659 if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1668 static int snd_ctl_dev_free(struct snd_device *device)
1670 struct snd_card *card = device->device_data;
1671 struct snd_kcontrol *control;
1673 down_write(&card->controls_rwsem);
1674 while (!list_empty(&card->controls)) {
1675 control = snd_kcontrol(card->controls.next);
1676 snd_ctl_remove(card, control);
1678 up_write(&card->controls_rwsem);
1683 * create control core:
1684 * called from init.c
1686 int snd_ctl_create(struct snd_card *card)
1688 static struct snd_device_ops ops = {
1689 .dev_free = snd_ctl_dev_free,
1690 .dev_register = snd_ctl_dev_register,
1691 .dev_disconnect = snd_ctl_dev_disconnect,
1694 if (snd_BUG_ON(!card))
1696 return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1700 * Frequently used control callbacks/helpers
1702 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1703 struct snd_ctl_elem_info *uinfo)
1705 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1707 uinfo->value.integer.min = 0;
1708 uinfo->value.integer.max = 1;
1712 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1714 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1715 struct snd_ctl_elem_info *uinfo)
1717 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1719 uinfo->value.integer.min = 0;
1720 uinfo->value.integer.max = 1;
1724 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1727 * snd_ctl_enum_info - fills the info structure for an enumerated control
1728 * @info: the structure to be filled
1729 * @channels: the number of the control's channels; often one
1730 * @items: the number of control values; also the size of @names
1731 * @names: an array containing the names of all control values
1733 * Sets all required fields in @info to their appropriate values.
1734 * If the control's accessibility is not the default (readable and writable),
1735 * the caller has to fill @info->access.
1737 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1738 unsigned int items, const char *const names[])
1740 info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1741 info->count = channels;
1742 info->value.enumerated.items = items;
1743 if (info->value.enumerated.item >= items)
1744 info->value.enumerated.item = items - 1;
1745 strlcpy(info->value.enumerated.name,
1746 names[info->value.enumerated.item],
1747 sizeof(info->value.enumerated.name));
1750 EXPORT_SYMBOL(snd_ctl_enum_info);