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);
92 module_put(card->module);
94 snd_card_file_remove(card, file);
99 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
102 struct snd_kctl_event *cread;
104 spin_lock_irqsave(&ctl->read_lock, flags);
105 while (!list_empty(&ctl->events)) {
106 cread = snd_kctl_event(ctl->events.next);
107 list_del(&cread->list);
110 spin_unlock_irqrestore(&ctl->read_lock, flags);
113 static int snd_ctl_release(struct inode *inode, struct file *file)
116 struct snd_card *card;
117 struct snd_ctl_file *ctl;
118 struct snd_kcontrol *control;
121 ctl = file->private_data;
122 file->private_data = NULL;
124 write_lock_irqsave(&card->ctl_files_rwlock, flags);
125 list_del(&ctl->list);
126 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
127 down_write(&card->controls_rwsem);
128 list_for_each_entry(control, &card->controls, list)
129 for (idx = 0; idx < control->count; idx++)
130 if (control->vd[idx].owner == ctl)
131 control->vd[idx].owner = NULL;
132 up_write(&card->controls_rwsem);
133 snd_ctl_empty_read_queue(ctl);
136 module_put(card->module);
137 snd_card_file_remove(card, file);
141 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
142 struct snd_ctl_elem_id *id)
145 struct snd_ctl_file *ctl;
146 struct snd_kctl_event *ev;
148 if (snd_BUG_ON(!card || !id))
150 read_lock(&card->ctl_files_rwlock);
151 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
152 card->mixer_oss_change_count++;
154 list_for_each_entry(ctl, &card->ctl_files, list) {
155 if (!ctl->subscribed)
157 spin_lock_irqsave(&ctl->read_lock, flags);
158 list_for_each_entry(ev, &ctl->events, list) {
159 if (ev->id.numid == id->numid) {
164 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
168 list_add_tail(&ev->list, &ctl->events);
170 snd_printk(KERN_ERR "No memory available to allocate event\n");
173 wake_up(&ctl->change_sleep);
174 spin_unlock_irqrestore(&ctl->read_lock, flags);
175 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
177 read_unlock(&card->ctl_files_rwlock);
180 EXPORT_SYMBOL(snd_ctl_notify);
183 * snd_ctl_new - create a control instance from the template
184 * @control: the control template
185 * @access: the default control access
187 * Allocates a new struct snd_kcontrol instance and copies the given template
188 * to the new instance. It does not copy volatile data (access).
190 * Returns the pointer of the new instance, or NULL on failure.
192 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
195 struct snd_kcontrol *kctl;
198 if (snd_BUG_ON(!control || !control->count))
201 if (control->count > MAX_CONTROL_COUNT)
204 kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
206 snd_printk(KERN_ERR "Cannot allocate control instance\n");
210 for (idx = 0; idx < kctl->count; idx++)
211 kctl->vd[idx].access = access;
216 * snd_ctl_new1 - create a control instance from the template
217 * @ncontrol: the initialization record
218 * @private_data: the private data to set
220 * Allocates a new struct snd_kcontrol instance and initialize from the given
221 * template. When the access field of ncontrol is 0, it's assumed as
222 * READWRITE access. When the count field is 0, it's assumes as one.
224 * Returns the pointer of the newly generated instance, or NULL on failure.
226 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
229 struct snd_kcontrol kctl;
232 if (snd_BUG_ON(!ncontrol || !ncontrol->info))
234 memset(&kctl, 0, sizeof(kctl));
235 kctl.id.iface = ncontrol->iface;
236 kctl.id.device = ncontrol->device;
237 kctl.id.subdevice = ncontrol->subdevice;
238 if (ncontrol->name) {
239 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
240 if (strcmp(ncontrol->name, kctl.id.name) != 0)
241 snd_printk(KERN_WARNING
242 "Control name '%s' truncated to '%s'\n",
243 ncontrol->name, kctl.id.name);
245 kctl.id.index = ncontrol->index;
246 kctl.count = ncontrol->count ? ncontrol->count : 1;
247 access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
248 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
249 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
250 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
251 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
252 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
253 kctl.info = ncontrol->info;
254 kctl.get = ncontrol->get;
255 kctl.put = ncontrol->put;
256 kctl.tlv.p = ncontrol->tlv.p;
257 kctl.private_value = ncontrol->private_value;
258 kctl.private_data = private_data;
259 return snd_ctl_new(&kctl, access);
262 EXPORT_SYMBOL(snd_ctl_new1);
265 * snd_ctl_free_one - release the control instance
266 * @kcontrol: the control instance
268 * Releases the control instance created via snd_ctl_new()
270 * Don't call this after the control was added to the card.
272 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
275 if (kcontrol->private_free)
276 kcontrol->private_free(kcontrol);
281 EXPORT_SYMBOL(snd_ctl_free_one);
283 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
286 struct snd_kcontrol *kctl;
288 list_for_each_entry(kctl, &card->controls, list) {
289 if (kctl->id.numid < card->last_numid + 1 + count &&
290 kctl->id.numid + kctl->count > card->last_numid + 1) {
291 card->last_numid = kctl->id.numid + kctl->count - 1;
298 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
300 unsigned int iter = 100000;
302 while (snd_ctl_remove_numid_conflict(card, count)) {
304 /* this situation is very unlikely */
305 snd_printk(KERN_ERR "unable to allocate new control numid\n");
313 * snd_ctl_add - add the control instance to the card
314 * @card: the card instance
315 * @kcontrol: the control instance to add
317 * Adds the control instance created via snd_ctl_new() or
318 * snd_ctl_new1() to the given card. Assigns also an unique
319 * numid used for fast search.
321 * Returns zero if successful, or a negative error code on failure.
323 * It frees automatically the control which cannot be added.
325 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
327 struct snd_ctl_elem_id id;
333 if (snd_BUG_ON(!card || !kcontrol->info))
336 down_write(&card->controls_rwsem);
337 if (snd_ctl_find_id(card, &id)) {
338 up_write(&card->controls_rwsem);
339 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
348 if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
349 up_write(&card->controls_rwsem);
353 list_add_tail(&kcontrol->list, &card->controls);
354 card->controls_count += kcontrol->count;
355 kcontrol->id.numid = card->last_numid + 1;
356 card->last_numid += kcontrol->count;
357 up_write(&card->controls_rwsem);
358 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
359 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
363 snd_ctl_free_one(kcontrol);
367 EXPORT_SYMBOL(snd_ctl_add);
370 * snd_ctl_replace - replace the control instance of the card
371 * @card: the card instance
372 * @kcontrol: the control instance to replace
373 * @add_on_replace: add the control if not already added
375 * Replaces the given control. If the given control does not exist
376 * and the add_on_replace flag is set, the control is added. If the
377 * control exists, it is destroyed first.
379 * Returns zero if successful, or a negative error code on failure.
381 * It frees automatically the control which cannot be added or replaced.
383 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
386 struct snd_ctl_elem_id id;
388 struct snd_kcontrol *old;
393 if (snd_BUG_ON(!card || !kcontrol->info)) {
398 down_write(&card->controls_rwsem);
399 old = snd_ctl_find_id(card, &id);
403 up_write(&card->controls_rwsem);
407 ret = snd_ctl_remove(card, old);
409 up_write(&card->controls_rwsem);
413 if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
414 up_write(&card->controls_rwsem);
418 list_add_tail(&kcontrol->list, &card->controls);
419 card->controls_count += kcontrol->count;
420 kcontrol->id.numid = card->last_numid + 1;
421 card->last_numid += kcontrol->count;
422 up_write(&card->controls_rwsem);
423 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
424 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
428 snd_ctl_free_one(kcontrol);
431 EXPORT_SYMBOL(snd_ctl_replace);
434 * snd_ctl_remove - remove the control from the card and release it
435 * @card: the card instance
436 * @kcontrol: the control instance to remove
438 * Removes the control from the card and then releases the instance.
439 * You don't need to call snd_ctl_free_one(). You must be in
440 * the write lock - down_write(&card->controls_rwsem).
442 * Returns 0 if successful, or a negative error code on failure.
444 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
446 struct snd_ctl_elem_id id;
449 if (snd_BUG_ON(!card || !kcontrol))
451 list_del(&kcontrol->list);
452 card->controls_count -= kcontrol->count;
454 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
455 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
456 snd_ctl_free_one(kcontrol);
460 EXPORT_SYMBOL(snd_ctl_remove);
463 * snd_ctl_remove_id - remove the control of the given id and release it
464 * @card: the card instance
465 * @id: the control id to remove
467 * Finds the control instance with the given id, removes it from the
468 * card list and releases it.
470 * Returns 0 if successful, or a negative error code on failure.
472 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
474 struct snd_kcontrol *kctl;
477 down_write(&card->controls_rwsem);
478 kctl = snd_ctl_find_id(card, id);
480 up_write(&card->controls_rwsem);
483 ret = snd_ctl_remove(card, kctl);
484 up_write(&card->controls_rwsem);
488 EXPORT_SYMBOL(snd_ctl_remove_id);
491 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
492 * @file: active control handle
493 * @id: the control id to remove
495 * Finds the control instance with the given id, removes it from the
496 * card list and releases it.
498 * Returns 0 if successful, or a negative error code on failure.
500 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
501 struct snd_ctl_elem_id *id)
503 struct snd_card *card = file->card;
504 struct snd_kcontrol *kctl;
507 down_write(&card->controls_rwsem);
508 kctl = snd_ctl_find_id(card, id);
513 if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
517 for (idx = 0; idx < kctl->count; idx++)
518 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
522 ret = snd_ctl_remove(card, kctl);
525 card->user_ctl_count--;
527 up_write(&card->controls_rwsem);
532 * snd_ctl_activate_id - activate/inactivate the control of the given id
533 * @card: the card instance
534 * @id: the control id to activate/inactivate
535 * @active: non-zero to activate
537 * Finds the control instance with the given id, and activate or
538 * inactivate the control together with notification, if changed.
540 * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
542 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
545 struct snd_kcontrol *kctl;
546 struct snd_kcontrol_volatile *vd;
547 unsigned int index_offset;
550 down_write(&card->controls_rwsem);
551 kctl = snd_ctl_find_id(card, id);
556 index_offset = snd_ctl_get_ioff(kctl, &kctl->id);
557 vd = &kctl->vd[index_offset];
560 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
562 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
564 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
566 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
570 up_write(&card->controls_rwsem);
572 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
575 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
578 * snd_ctl_rename_id - replace the id of a control on the card
579 * @card: the card instance
580 * @src_id: the old id
581 * @dst_id: the new id
583 * Finds the control with the old id from the card, and replaces the
584 * id with the new one.
586 * Returns zero if successful, or a negative error code on failure.
588 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
589 struct snd_ctl_elem_id *dst_id)
591 struct snd_kcontrol *kctl;
593 down_write(&card->controls_rwsem);
594 kctl = snd_ctl_find_id(card, src_id);
596 up_write(&card->controls_rwsem);
600 kctl->id.numid = card->last_numid + 1;
601 card->last_numid += kctl->count;
602 up_write(&card->controls_rwsem);
606 EXPORT_SYMBOL(snd_ctl_rename_id);
609 * snd_ctl_find_numid - find the control instance with the given number-id
610 * @card: the card instance
611 * @numid: the number-id to search
613 * Finds the control instance with the given number-id from the card.
615 * Returns the pointer of the instance if found, or NULL if not.
617 * The caller must down card->controls_rwsem before calling this function
618 * (if the race condition can happen).
620 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
622 struct snd_kcontrol *kctl;
624 if (snd_BUG_ON(!card || !numid))
626 list_for_each_entry(kctl, &card->controls, list) {
627 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
633 EXPORT_SYMBOL(snd_ctl_find_numid);
636 * snd_ctl_find_id - find the control instance with the given id
637 * @card: the card instance
638 * @id: the id to search
640 * Finds the control instance with the given id from the card.
642 * Returns the pointer of the instance if found, or NULL if not.
644 * The caller must down card->controls_rwsem before calling this function
645 * (if the race condition can happen).
647 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
648 struct snd_ctl_elem_id *id)
650 struct snd_kcontrol *kctl;
652 if (snd_BUG_ON(!card || !id))
655 return snd_ctl_find_numid(card, id->numid);
656 list_for_each_entry(kctl, &card->controls, list) {
657 if (kctl->id.iface != id->iface)
659 if (kctl->id.device != id->device)
661 if (kctl->id.subdevice != id->subdevice)
663 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
665 if (kctl->id.index > id->index)
667 if (kctl->id.index + kctl->count <= id->index)
674 EXPORT_SYMBOL(snd_ctl_find_id);
676 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
677 unsigned int cmd, void __user *arg)
679 struct snd_ctl_card_info *info;
681 info = kzalloc(sizeof(*info), GFP_KERNEL);
684 down_read(&snd_ioctl_rwsem);
685 info->card = card->number;
686 strlcpy(info->id, card->id, sizeof(info->id));
687 strlcpy(info->driver, card->driver, sizeof(info->driver));
688 strlcpy(info->name, card->shortname, sizeof(info->name));
689 strlcpy(info->longname, card->longname, sizeof(info->longname));
690 strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
691 strlcpy(info->components, card->components, sizeof(info->components));
692 up_read(&snd_ioctl_rwsem);
693 if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
701 static int snd_ctl_elem_list(struct snd_card *card,
702 struct snd_ctl_elem_list __user *_list)
704 struct list_head *plist;
705 struct snd_ctl_elem_list list;
706 struct snd_kcontrol *kctl;
707 struct snd_ctl_elem_id *dst, *id;
708 unsigned int offset, space, jidx;
710 if (copy_from_user(&list, _list, sizeof(list)))
712 offset = list.offset;
714 /* try limit maximum space */
718 /* allocate temporary buffer for atomic operation */
719 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
722 down_read(&card->controls_rwsem);
723 list.count = card->controls_count;
724 plist = card->controls.next;
725 while (plist != &card->controls) {
728 kctl = snd_kcontrol(plist);
729 if (offset < kctl->count)
731 offset -= kctl->count;
736 while (space > 0 && plist != &card->controls) {
737 kctl = snd_kcontrol(plist);
738 for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
739 snd_ctl_build_ioff(id, kctl, jidx);
747 up_read(&card->controls_rwsem);
749 copy_to_user(list.pids, dst,
750 list.used * sizeof(struct snd_ctl_elem_id))) {
756 down_read(&card->controls_rwsem);
757 list.count = card->controls_count;
758 up_read(&card->controls_rwsem);
760 if (copy_to_user(_list, &list, sizeof(list)))
765 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
766 struct snd_ctl_elem_info *info)
768 struct snd_card *card = ctl->card;
769 struct snd_kcontrol *kctl;
770 struct snd_kcontrol_volatile *vd;
771 unsigned int index_offset;
774 down_read(&card->controls_rwsem);
775 kctl = snd_ctl_find_id(card, &info->id);
777 up_read(&card->controls_rwsem);
780 #ifdef CONFIG_SND_DEBUG
783 result = kctl->info(kctl, info);
785 snd_BUG_ON(info->access);
786 index_offset = snd_ctl_get_ioff(kctl, &info->id);
787 vd = &kctl->vd[index_offset];
788 snd_ctl_build_ioff(&info->id, kctl, index_offset);
789 info->access = vd->access;
791 info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
792 if (vd->owner == ctl)
793 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
794 info->owner = pid_vnr(vd->owner->pid);
799 up_read(&card->controls_rwsem);
803 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
804 struct snd_ctl_elem_info __user *_info)
806 struct snd_ctl_elem_info info;
809 if (copy_from_user(&info, _info, sizeof(info)))
811 snd_power_lock(ctl->card);
812 result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
814 result = snd_ctl_elem_info(ctl, &info);
815 snd_power_unlock(ctl->card);
817 if (copy_to_user(_info, &info, sizeof(info)))
822 static int snd_ctl_elem_read(struct snd_card *card,
823 struct snd_ctl_elem_value *control)
825 struct snd_kcontrol *kctl;
826 struct snd_kcontrol_volatile *vd;
827 unsigned int index_offset;
830 down_read(&card->controls_rwsem);
831 kctl = snd_ctl_find_id(card, &control->id);
835 index_offset = snd_ctl_get_ioff(kctl, &control->id);
836 vd = &kctl->vd[index_offset];
837 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
839 snd_ctl_build_ioff(&control->id, kctl, index_offset);
840 result = kctl->get(kctl, control);
844 up_read(&card->controls_rwsem);
848 static int snd_ctl_elem_read_user(struct snd_card *card,
849 struct snd_ctl_elem_value __user *_control)
851 struct snd_ctl_elem_value *control;
854 control = memdup_user(_control, sizeof(*control));
856 return PTR_ERR(control);
858 snd_power_lock(card);
859 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
861 result = snd_ctl_elem_read(card, control);
862 snd_power_unlock(card);
864 if (copy_to_user(_control, control, sizeof(*control)))
870 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
871 struct snd_ctl_elem_value *control)
873 struct snd_kcontrol *kctl;
874 struct snd_kcontrol_volatile *vd;
875 unsigned int index_offset;
878 down_read(&card->controls_rwsem);
879 kctl = snd_ctl_find_id(card, &control->id);
883 index_offset = snd_ctl_get_ioff(kctl, &control->id);
884 vd = &kctl->vd[index_offset];
885 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
887 (file && vd->owner && vd->owner != file)) {
890 snd_ctl_build_ioff(&control->id, kctl, index_offset);
891 result = kctl->put(kctl, control);
894 up_read(&card->controls_rwsem);
895 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
900 up_read(&card->controls_rwsem);
904 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
905 struct snd_ctl_elem_value __user *_control)
907 struct snd_ctl_elem_value *control;
908 struct snd_card *card;
911 control = memdup_user(_control, sizeof(*control));
913 return PTR_ERR(control);
916 snd_power_lock(card);
917 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
919 result = snd_ctl_elem_write(card, file, control);
920 snd_power_unlock(card);
922 if (copy_to_user(_control, control, sizeof(*control)))
928 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
929 struct snd_ctl_elem_id __user *_id)
931 struct snd_card *card = file->card;
932 struct snd_ctl_elem_id id;
933 struct snd_kcontrol *kctl;
934 struct snd_kcontrol_volatile *vd;
937 if (copy_from_user(&id, _id, sizeof(id)))
939 down_write(&card->controls_rwsem);
940 kctl = snd_ctl_find_id(card, &id);
944 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
945 if (vd->owner != NULL)
952 up_write(&card->controls_rwsem);
956 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
957 struct snd_ctl_elem_id __user *_id)
959 struct snd_card *card = file->card;
960 struct snd_ctl_elem_id id;
961 struct snd_kcontrol *kctl;
962 struct snd_kcontrol_volatile *vd;
965 if (copy_from_user(&id, _id, sizeof(id)))
967 down_write(&card->controls_rwsem);
968 kctl = snd_ctl_find_id(card, &id);
972 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
973 if (vd->owner == NULL)
975 else if (vd->owner != file)
982 up_write(&card->controls_rwsem);
986 struct user_element {
987 struct snd_ctl_elem_info info;
988 void *elem_data; /* element data */
989 unsigned long elem_data_size; /* size of element data in bytes */
990 void *tlv_data; /* TLV data */
991 unsigned long tlv_data_size; /* TLV data size */
992 void *priv_data; /* private data (like strings for enumerated type) */
995 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
996 struct snd_ctl_elem_info *uinfo)
998 struct user_element *ue = kcontrol->private_data;
1004 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1005 struct snd_ctl_elem_info *uinfo)
1007 struct user_element *ue = kcontrol->private_data;
1011 item = uinfo->value.enumerated.item;
1015 item = min(item, uinfo->value.enumerated.items - 1);
1016 uinfo->value.enumerated.item = item;
1018 names = ue->priv_data;
1019 for (; item > 0; --item)
1020 names += strlen(names) + 1;
1021 strcpy(uinfo->value.enumerated.name, names);
1026 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1027 struct snd_ctl_elem_value *ucontrol)
1029 struct user_element *ue = kcontrol->private_data;
1031 memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
1035 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1036 struct snd_ctl_elem_value *ucontrol)
1039 struct user_element *ue = kcontrol->private_data;
1041 change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
1043 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
1047 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1050 unsigned int __user *tlv)
1052 struct user_element *ue = kcontrol->private_data;
1057 if (size > 1024 * 128) /* sane value */
1060 new_data = memdup_user(tlv, size);
1061 if (IS_ERR(new_data))
1062 return PTR_ERR(new_data);
1063 change = ue->tlv_data_size != size;
1065 change = memcmp(ue->tlv_data, new_data, size);
1066 kfree(ue->tlv_data);
1067 ue->tlv_data = new_data;
1068 ue->tlv_data_size = size;
1070 if (! ue->tlv_data_size || ! ue->tlv_data)
1072 if (size < ue->tlv_data_size)
1074 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1080 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1083 size_t buf_len, name_len;
1085 const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1087 if (ue->info.value.enumerated.names_length > 64 * 1024)
1090 names = memdup_user((const void __user *)user_ptrval,
1091 ue->info.value.enumerated.names_length);
1093 return PTR_ERR(names);
1095 /* check that there are enough valid names */
1096 buf_len = ue->info.value.enumerated.names_length;
1098 for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1099 name_len = strnlen(p, buf_len);
1100 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1105 buf_len -= name_len + 1;
1108 ue->priv_data = names;
1109 ue->info.value.enumerated.names_ptr = 0;
1114 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1116 struct user_element *ue = kcontrol->private_data;
1118 kfree(ue->tlv_data);
1119 kfree(ue->priv_data);
1123 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1124 struct snd_ctl_elem_info *info, int replace)
1126 struct snd_card *card = file->card;
1127 struct snd_kcontrol kctl, *_kctl;
1128 unsigned int access;
1130 struct user_element *ue;
1133 if (!replace && card->user_ctl_count >= MAX_USER_CONTROLS)
1135 if (info->count < 1)
1137 access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
1138 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
1139 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
1140 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
1142 memset(&kctl, 0, sizeof(kctl));
1143 down_write(&card->controls_rwsem);
1144 _kctl = snd_ctl_find_id(card, &info->id);
1148 err = snd_ctl_remove(card, _kctl);
1155 up_write(&card->controls_rwsem);
1158 memcpy(&kctl.id, &info->id, sizeof(info->id));
1159 kctl.count = info->owner ? info->owner : 1;
1160 access |= SNDRV_CTL_ELEM_ACCESS_USER;
1161 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1162 kctl.info = snd_ctl_elem_user_enum_info;
1164 kctl.info = snd_ctl_elem_user_info;
1165 if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1166 kctl.get = snd_ctl_elem_user_get;
1167 if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1168 kctl.put = snd_ctl_elem_user_put;
1169 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
1170 kctl.tlv.c = snd_ctl_elem_user_tlv;
1171 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1173 switch (info->type) {
1174 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1175 case SNDRV_CTL_ELEM_TYPE_INTEGER:
1176 private_size = sizeof(long);
1177 if (info->count > 128)
1180 case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1181 private_size = sizeof(long long);
1182 if (info->count > 64)
1185 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1186 private_size = sizeof(unsigned int);
1187 if (info->count > 128 || info->value.enumerated.items == 0)
1190 case SNDRV_CTL_ELEM_TYPE_BYTES:
1191 private_size = sizeof(unsigned char);
1192 if (info->count > 512)
1195 case SNDRV_CTL_ELEM_TYPE_IEC958:
1196 private_size = sizeof(struct snd_aes_iec958);
1197 if (info->count != 1)
1203 private_size *= info->count;
1204 ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1208 ue->info.access = 0;
1209 ue->elem_data = (char *)ue + sizeof(*ue);
1210 ue->elem_data_size = private_size;
1211 if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1212 err = snd_ctl_elem_init_enum_names(ue);
1218 kctl.private_free = snd_ctl_elem_user_free;
1219 _kctl = snd_ctl_new(&kctl, access);
1220 if (_kctl == NULL) {
1221 kfree(ue->priv_data);
1225 _kctl->private_data = ue;
1226 for (idx = 0; idx < _kctl->count; idx++)
1227 _kctl->vd[idx].owner = file;
1228 err = snd_ctl_add(card, _kctl);
1232 down_write(&card->controls_rwsem);
1233 card->user_ctl_count++;
1234 up_write(&card->controls_rwsem);
1239 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1240 struct snd_ctl_elem_info __user *_info, int replace)
1242 struct snd_ctl_elem_info info;
1243 if (copy_from_user(&info, _info, sizeof(info)))
1245 return snd_ctl_elem_add(file, &info, replace);
1248 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1249 struct snd_ctl_elem_id __user *_id)
1251 struct snd_ctl_elem_id id;
1253 if (copy_from_user(&id, _id, sizeof(id)))
1255 return snd_ctl_remove_user_ctl(file, &id);
1258 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1261 if (get_user(subscribe, ptr))
1263 if (subscribe < 0) {
1264 subscribe = file->subscribed;
1265 if (put_user(subscribe, ptr))
1270 file->subscribed = 1;
1272 } else if (file->subscribed) {
1273 snd_ctl_empty_read_queue(file);
1274 file->subscribed = 0;
1279 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1280 struct snd_ctl_tlv __user *_tlv,
1283 struct snd_card *card = file->card;
1284 struct snd_ctl_tlv tlv;
1285 struct snd_kcontrol *kctl;
1286 struct snd_kcontrol_volatile *vd;
1290 if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1292 if (tlv.length < sizeof(unsigned int) * 2)
1294 down_read(&card->controls_rwsem);
1295 kctl = snd_ctl_find_numid(card, tlv.numid);
1300 if (kctl->tlv.p == NULL) {
1304 vd = &kctl->vd[tlv.numid - kctl->id.numid];
1305 if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1306 (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1307 (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1311 if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1312 if (vd->owner != NULL && vd->owner != file) {
1316 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1318 up_read(&card->controls_rwsem);
1319 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
1327 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1328 if (tlv.length < len) {
1332 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1336 up_read(&card->controls_rwsem);
1340 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1342 struct snd_ctl_file *ctl;
1343 struct snd_card *card;
1344 struct snd_kctl_ioctl *p;
1345 void __user *argp = (void __user *)arg;
1346 int __user *ip = argp;
1349 ctl = file->private_data;
1351 if (snd_BUG_ON(!card))
1354 case SNDRV_CTL_IOCTL_PVERSION:
1355 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1356 case SNDRV_CTL_IOCTL_CARD_INFO:
1357 return snd_ctl_card_info(card, ctl, cmd, argp);
1358 case SNDRV_CTL_IOCTL_ELEM_LIST:
1359 return snd_ctl_elem_list(card, argp);
1360 case SNDRV_CTL_IOCTL_ELEM_INFO:
1361 return snd_ctl_elem_info_user(ctl, argp);
1362 case SNDRV_CTL_IOCTL_ELEM_READ:
1363 return snd_ctl_elem_read_user(card, argp);
1364 case SNDRV_CTL_IOCTL_ELEM_WRITE:
1365 return snd_ctl_elem_write_user(ctl, argp);
1366 case SNDRV_CTL_IOCTL_ELEM_LOCK:
1367 return snd_ctl_elem_lock(ctl, argp);
1368 case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1369 return snd_ctl_elem_unlock(ctl, argp);
1370 case SNDRV_CTL_IOCTL_ELEM_ADD:
1371 return snd_ctl_elem_add_user(ctl, argp, 0);
1372 case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1373 return snd_ctl_elem_add_user(ctl, argp, 1);
1374 case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1375 return snd_ctl_elem_remove(ctl, argp);
1376 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1377 return snd_ctl_subscribe_events(ctl, ip);
1378 case SNDRV_CTL_IOCTL_TLV_READ:
1379 return snd_ctl_tlv_ioctl(ctl, argp, 0);
1380 case SNDRV_CTL_IOCTL_TLV_WRITE:
1381 return snd_ctl_tlv_ioctl(ctl, argp, 1);
1382 case SNDRV_CTL_IOCTL_TLV_COMMAND:
1383 return snd_ctl_tlv_ioctl(ctl, argp, -1);
1384 case SNDRV_CTL_IOCTL_POWER:
1385 return -ENOPROTOOPT;
1386 case SNDRV_CTL_IOCTL_POWER_STATE:
1388 return put_user(card->power_state, ip) ? -EFAULT : 0;
1390 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1393 down_read(&snd_ioctl_rwsem);
1394 list_for_each_entry(p, &snd_control_ioctls, list) {
1395 err = p->fioctl(card, ctl, cmd, arg);
1396 if (err != -ENOIOCTLCMD) {
1397 up_read(&snd_ioctl_rwsem);
1401 up_read(&snd_ioctl_rwsem);
1402 snd_printdd("unknown ioctl = 0x%x\n", cmd);
1406 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1407 size_t count, loff_t * offset)
1409 struct snd_ctl_file *ctl;
1413 ctl = file->private_data;
1414 if (snd_BUG_ON(!ctl || !ctl->card))
1416 if (!ctl->subscribed)
1418 if (count < sizeof(struct snd_ctl_event))
1420 spin_lock_irq(&ctl->read_lock);
1421 while (count >= sizeof(struct snd_ctl_event)) {
1422 struct snd_ctl_event ev;
1423 struct snd_kctl_event *kev;
1424 while (list_empty(&ctl->events)) {
1426 if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1430 init_waitqueue_entry(&wait, current);
1431 add_wait_queue(&ctl->change_sleep, &wait);
1432 set_current_state(TASK_INTERRUPTIBLE);
1433 spin_unlock_irq(&ctl->read_lock);
1435 remove_wait_queue(&ctl->change_sleep, &wait);
1436 if (signal_pending(current))
1437 return -ERESTARTSYS;
1438 spin_lock_irq(&ctl->read_lock);
1440 kev = snd_kctl_event(ctl->events.next);
1441 ev.type = SNDRV_CTL_EVENT_ELEM;
1442 ev.data.elem.mask = kev->mask;
1443 ev.data.elem.id = kev->id;
1444 list_del(&kev->list);
1445 spin_unlock_irq(&ctl->read_lock);
1447 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1451 spin_lock_irq(&ctl->read_lock);
1452 buffer += sizeof(struct snd_ctl_event);
1453 count -= sizeof(struct snd_ctl_event);
1454 result += sizeof(struct snd_ctl_event);
1457 spin_unlock_irq(&ctl->read_lock);
1459 return result > 0 ? result : err;
1462 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1465 struct snd_ctl_file *ctl;
1467 ctl = file->private_data;
1468 if (!ctl->subscribed)
1470 poll_wait(file, &ctl->change_sleep, wait);
1473 if (!list_empty(&ctl->events))
1474 mask |= POLLIN | POLLRDNORM;
1480 * register the device-specific control-ioctls.
1481 * called from each device manager like pcm.c, hwdep.c, etc.
1483 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1485 struct snd_kctl_ioctl *pn;
1487 pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1491 down_write(&snd_ioctl_rwsem);
1492 list_add_tail(&pn->list, lists);
1493 up_write(&snd_ioctl_rwsem);
1497 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1499 return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1502 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1504 #ifdef CONFIG_COMPAT
1505 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1507 return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1510 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1514 * de-register the device-specific control-ioctls.
1516 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1517 struct list_head *lists)
1519 struct snd_kctl_ioctl *p;
1521 if (snd_BUG_ON(!fcn))
1523 down_write(&snd_ioctl_rwsem);
1524 list_for_each_entry(p, lists, list) {
1525 if (p->fioctl == fcn) {
1527 up_write(&snd_ioctl_rwsem);
1532 up_write(&snd_ioctl_rwsem);
1537 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1539 return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1542 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1544 #ifdef CONFIG_COMPAT
1545 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1547 return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1550 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1553 static int snd_ctl_fasync(int fd, struct file * file, int on)
1555 struct snd_ctl_file *ctl;
1557 ctl = file->private_data;
1558 return fasync_helper(fd, file, on, &ctl->fasync);
1564 #ifdef CONFIG_COMPAT
1565 #include "control_compat.c"
1567 #define snd_ctl_ioctl_compat NULL
1574 static const struct file_operations snd_ctl_f_ops =
1576 .owner = THIS_MODULE,
1577 .read = snd_ctl_read,
1578 .open = snd_ctl_open,
1579 .release = snd_ctl_release,
1580 .llseek = no_llseek,
1581 .poll = snd_ctl_poll,
1582 .unlocked_ioctl = snd_ctl_ioctl,
1583 .compat_ioctl = snd_ctl_ioctl_compat,
1584 .fasync = snd_ctl_fasync,
1588 * registration of the control device
1590 static int snd_ctl_dev_register(struct snd_device *device)
1592 struct snd_card *card = device->device_data;
1596 if (snd_BUG_ON(!card))
1598 cardnum = card->number;
1599 if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1601 sprintf(name, "controlC%i", cardnum);
1602 if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1603 &snd_ctl_f_ops, card, name)) < 0)
1609 * disconnection of the control device
1611 static int snd_ctl_dev_disconnect(struct snd_device *device)
1613 struct snd_card *card = device->device_data;
1614 struct snd_ctl_file *ctl;
1617 if (snd_BUG_ON(!card))
1619 cardnum = card->number;
1620 if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1623 read_lock(&card->ctl_files_rwlock);
1624 list_for_each_entry(ctl, &card->ctl_files, list) {
1625 wake_up(&ctl->change_sleep);
1626 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1628 read_unlock(&card->ctl_files_rwlock);
1630 if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1639 static int snd_ctl_dev_free(struct snd_device *device)
1641 struct snd_card *card = device->device_data;
1642 struct snd_kcontrol *control;
1644 down_write(&card->controls_rwsem);
1645 while (!list_empty(&card->controls)) {
1646 control = snd_kcontrol(card->controls.next);
1647 snd_ctl_remove(card, control);
1649 up_write(&card->controls_rwsem);
1654 * create control core:
1655 * called from init.c
1657 int snd_ctl_create(struct snd_card *card)
1659 static struct snd_device_ops ops = {
1660 .dev_free = snd_ctl_dev_free,
1661 .dev_register = snd_ctl_dev_register,
1662 .dev_disconnect = snd_ctl_dev_disconnect,
1665 if (snd_BUG_ON(!card))
1667 return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1671 * Frequently used control callbacks/helpers
1673 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1674 struct snd_ctl_elem_info *uinfo)
1676 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1678 uinfo->value.integer.min = 0;
1679 uinfo->value.integer.max = 1;
1683 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1685 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1686 struct snd_ctl_elem_info *uinfo)
1688 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1690 uinfo->value.integer.min = 0;
1691 uinfo->value.integer.max = 1;
1695 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1698 * snd_ctl_enum_info - fills the info structure for an enumerated control
1699 * @info: the structure to be filled
1700 * @channels: the number of the control's channels; often one
1701 * @items: the number of control values; also the size of @names
1702 * @names: an array containing the names of all control values
1704 * Sets all required fields in @info to their appropriate values.
1705 * If the control's accessibility is not the default (readable and writable),
1706 * the caller has to fill @info->access.
1708 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1709 unsigned int items, const char *const names[])
1711 info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1712 info->count = channels;
1713 info->value.enumerated.items = items;
1714 if (info->value.enumerated.item >= items)
1715 info->value.enumerated.item = items - 1;
1716 strlcpy(info->value.enumerated.name,
1717 names[info->value.enumerated.item],
1718 sizeof(info->value.enumerated.name));
1721 EXPORT_SYMBOL(snd_ctl_enum_info);