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/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/time.h>
27 #include <sound/core.h>
28 #include <sound/minors.h>
29 #include <sound/info.h>
30 #include <sound/control.h>
32 /* max number of user-defined controls */
33 #define MAX_USER_CONTROLS 32
34 #define MAX_CONTROL_COUNT 1028
36 struct snd_kctl_ioctl {
37 struct list_head list; /* list of all ioctls */
38 snd_kctl_ioctl_func_t fioctl;
41 static DECLARE_RWSEM(snd_ioctl_rwsem);
42 static LIST_HEAD(snd_control_ioctls);
44 static LIST_HEAD(snd_control_compat_ioctls);
47 static int snd_ctl_open(struct inode *inode, struct file *file)
50 struct snd_card *card;
51 struct snd_ctl_file *ctl;
54 err = nonseekable_open(inode, file);
58 card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
63 err = snd_card_file_add(card, file);
68 if (!try_module_get(card->module)) {
72 ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
77 INIT_LIST_HEAD(&ctl->events);
78 init_waitqueue_head(&ctl->change_sleep);
79 spin_lock_init(&ctl->read_lock);
81 ctl->prefer_pcm_subdevice = -1;
82 ctl->prefer_rawmidi_subdevice = -1;
83 ctl->pid = get_pid(task_pid(current));
84 file->private_data = ctl;
85 write_lock_irqsave(&card->ctl_files_rwlock, flags);
86 list_add_tail(&ctl->list, &card->ctl_files);
87 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
91 module_put(card->module);
93 snd_card_file_remove(card, file);
98 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
101 struct snd_kctl_event *cread;
103 spin_lock_irqsave(&ctl->read_lock, flags);
104 while (!list_empty(&ctl->events)) {
105 cread = snd_kctl_event(ctl->events.next);
106 list_del(&cread->list);
109 spin_unlock_irqrestore(&ctl->read_lock, flags);
112 static int snd_ctl_release(struct inode *inode, struct file *file)
115 struct snd_card *card;
116 struct snd_ctl_file *ctl;
117 struct snd_kcontrol *control;
120 ctl = file->private_data;
121 file->private_data = NULL;
123 write_lock_irqsave(&card->ctl_files_rwlock, flags);
124 list_del(&ctl->list);
125 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
126 down_write(&card->controls_rwsem);
127 list_for_each_entry(control, &card->controls, list)
128 for (idx = 0; idx < control->count; idx++)
129 if (control->vd[idx].owner == ctl)
130 control->vd[idx].owner = NULL;
131 up_write(&card->controls_rwsem);
132 snd_ctl_empty_read_queue(ctl);
135 module_put(card->module);
136 snd_card_file_remove(card, file);
140 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
141 struct snd_ctl_elem_id *id)
144 struct snd_ctl_file *ctl;
145 struct snd_kctl_event *ev;
147 if (snd_BUG_ON(!card || !id))
149 read_lock(&card->ctl_files_rwlock);
150 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
151 card->mixer_oss_change_count++;
153 list_for_each_entry(ctl, &card->ctl_files, list) {
154 if (!ctl->subscribed)
156 spin_lock_irqsave(&ctl->read_lock, flags);
157 list_for_each_entry(ev, &ctl->events, list) {
158 if (ev->id.numid == id->numid) {
163 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
167 list_add_tail(&ev->list, &ctl->events);
169 snd_printk(KERN_ERR "No memory available to allocate event\n");
172 wake_up(&ctl->change_sleep);
173 spin_unlock_irqrestore(&ctl->read_lock, flags);
174 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
176 read_unlock(&card->ctl_files_rwlock);
179 EXPORT_SYMBOL(snd_ctl_notify);
182 * snd_ctl_new - create a control instance from the template
183 * @control: the control template
184 * @access: the default control access
186 * Allocates a new struct snd_kcontrol instance and copies the given template
187 * to the new instance. It does not copy volatile data (access).
189 * Returns the pointer of the new instance, or NULL on failure.
191 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
194 struct snd_kcontrol *kctl;
197 if (snd_BUG_ON(!control || !control->count))
200 if (control->count > MAX_CONTROL_COUNT)
203 kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
205 snd_printk(KERN_ERR "Cannot allocate control instance\n");
209 for (idx = 0; idx < kctl->count; idx++)
210 kctl->vd[idx].access = access;
215 * snd_ctl_new1 - create a control instance from the template
216 * @ncontrol: the initialization record
217 * @private_data: the private data to set
219 * Allocates a new struct snd_kcontrol instance and initialize from the given
220 * template. When the access field of ncontrol is 0, it's assumed as
221 * READWRITE access. When the count field is 0, it's assumes as one.
223 * Returns the pointer of the newly generated instance, or NULL on failure.
225 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
228 struct snd_kcontrol kctl;
231 if (snd_BUG_ON(!ncontrol || !ncontrol->info))
233 memset(&kctl, 0, sizeof(kctl));
234 kctl.id.iface = ncontrol->iface;
235 kctl.id.device = ncontrol->device;
236 kctl.id.subdevice = ncontrol->subdevice;
237 if (ncontrol->name) {
238 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
239 if (strcmp(ncontrol->name, kctl.id.name) != 0)
240 snd_printk(KERN_WARNING
241 "Control name '%s' truncated to '%s'\n",
242 ncontrol->name, kctl.id.name);
244 kctl.id.index = ncontrol->index;
245 kctl.count = ncontrol->count ? ncontrol->count : 1;
246 access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
247 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
248 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
249 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
250 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
251 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
252 kctl.info = ncontrol->info;
253 kctl.get = ncontrol->get;
254 kctl.put = ncontrol->put;
255 kctl.tlv.p = ncontrol->tlv.p;
256 kctl.private_value = ncontrol->private_value;
257 kctl.private_data = private_data;
258 return snd_ctl_new(&kctl, access);
261 EXPORT_SYMBOL(snd_ctl_new1);
264 * snd_ctl_free_one - release the control instance
265 * @kcontrol: the control instance
267 * Releases the control instance created via snd_ctl_new()
269 * Don't call this after the control was added to the card.
271 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
274 if (kcontrol->private_free)
275 kcontrol->private_free(kcontrol);
280 EXPORT_SYMBOL(snd_ctl_free_one);
282 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
285 struct snd_kcontrol *kctl;
287 list_for_each_entry(kctl, &card->controls, list) {
288 if (kctl->id.numid < card->last_numid + 1 + count &&
289 kctl->id.numid + kctl->count > card->last_numid + 1) {
290 card->last_numid = kctl->id.numid + kctl->count - 1;
297 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
299 unsigned int iter = 100000;
301 while (snd_ctl_remove_numid_conflict(card, count)) {
303 /* this situation is very unlikely */
304 snd_printk(KERN_ERR "unable to allocate new control numid\n");
312 * snd_ctl_add - add the control instance to the card
313 * @card: the card instance
314 * @kcontrol: the control instance to add
316 * Adds the control instance created via snd_ctl_new() or
317 * snd_ctl_new1() to the given card. Assigns also an unique
318 * numid used for fast search.
320 * Returns zero if successful, or a negative error code on failure.
322 * It frees automatically the control which cannot be added.
324 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
326 struct snd_ctl_elem_id id;
332 if (snd_BUG_ON(!card || !kcontrol->info))
335 down_write(&card->controls_rwsem);
336 if (snd_ctl_find_id(card, &id)) {
337 up_write(&card->controls_rwsem);
338 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
347 if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
348 up_write(&card->controls_rwsem);
352 list_add_tail(&kcontrol->list, &card->controls);
353 card->controls_count += kcontrol->count;
354 kcontrol->id.numid = card->last_numid + 1;
355 card->last_numid += kcontrol->count;
356 up_write(&card->controls_rwsem);
357 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
358 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
362 snd_ctl_free_one(kcontrol);
366 EXPORT_SYMBOL(snd_ctl_add);
369 * snd_ctl_replace - replace the control instance of the card
370 * @card: the card instance
371 * @kcontrol: the control instance to replace
372 * @add_on_replace: add the control if not already added
374 * Replaces the given control. If the given control does not exist
375 * and the add_on_replace flag is set, the control is added. If the
376 * control exists, it is destroyed first.
378 * Returns zero if successful, or a negative error code on failure.
380 * It frees automatically the control which cannot be added or replaced.
382 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
385 struct snd_ctl_elem_id id;
387 struct snd_kcontrol *old;
392 if (snd_BUG_ON(!card || !kcontrol->info)) {
397 down_write(&card->controls_rwsem);
398 old = snd_ctl_find_id(card, &id);
402 up_write(&card->controls_rwsem);
406 ret = snd_ctl_remove(card, old);
408 up_write(&card->controls_rwsem);
412 if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
413 up_write(&card->controls_rwsem);
417 list_add_tail(&kcontrol->list, &card->controls);
418 card->controls_count += kcontrol->count;
419 kcontrol->id.numid = card->last_numid + 1;
420 card->last_numid += kcontrol->count;
421 up_write(&card->controls_rwsem);
422 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
423 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
427 snd_ctl_free_one(kcontrol);
430 EXPORT_SYMBOL(snd_ctl_replace);
433 * snd_ctl_remove - remove the control from the card and release it
434 * @card: the card instance
435 * @kcontrol: the control instance to remove
437 * Removes the control from the card and then releases the instance.
438 * You don't need to call snd_ctl_free_one(). You must be in
439 * the write lock - down_write(&card->controls_rwsem).
441 * Returns 0 if successful, or a negative error code on failure.
443 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
445 struct snd_ctl_elem_id id;
448 if (snd_BUG_ON(!card || !kcontrol))
450 list_del(&kcontrol->list);
451 card->controls_count -= kcontrol->count;
453 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
454 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
455 snd_ctl_free_one(kcontrol);
459 EXPORT_SYMBOL(snd_ctl_remove);
462 * snd_ctl_remove_id - remove the control of the given id and release it
463 * @card: the card instance
464 * @id: the control id to remove
466 * Finds the control instance with the given id, removes it from the
467 * card list and releases it.
469 * Returns 0 if successful, or a negative error code on failure.
471 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
473 struct snd_kcontrol *kctl;
476 down_write(&card->controls_rwsem);
477 kctl = snd_ctl_find_id(card, id);
479 up_write(&card->controls_rwsem);
482 ret = snd_ctl_remove(card, kctl);
483 up_write(&card->controls_rwsem);
487 EXPORT_SYMBOL(snd_ctl_remove_id);
490 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
491 * @file: active control handle
492 * @id: the control id to remove
494 * Finds the control instance with the given id, removes it from the
495 * card list and releases it.
497 * Returns 0 if successful, or a negative error code on failure.
499 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
500 struct snd_ctl_elem_id *id)
502 struct snd_card *card = file->card;
503 struct snd_kcontrol *kctl;
506 down_write(&card->controls_rwsem);
507 kctl = snd_ctl_find_id(card, id);
512 if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
516 for (idx = 0; idx < kctl->count; idx++)
517 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
521 ret = snd_ctl_remove(card, kctl);
524 card->user_ctl_count--;
526 up_write(&card->controls_rwsem);
531 * snd_ctl_activate_id - activate/inactivate the control of the given id
532 * @card: the card instance
533 * @id: the control id to activate/inactivate
534 * @active: non-zero to activate
536 * Finds the control instance with the given id, and activate or
537 * inactivate the control together with notification, if changed.
539 * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
541 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
544 struct snd_kcontrol *kctl;
545 struct snd_kcontrol_volatile *vd;
546 unsigned int index_offset;
549 down_write(&card->controls_rwsem);
550 kctl = snd_ctl_find_id(card, id);
555 index_offset = snd_ctl_get_ioff(kctl, &kctl->id);
556 vd = &kctl->vd[index_offset];
559 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
561 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
563 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
565 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
569 up_write(&card->controls_rwsem);
571 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
574 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
577 * snd_ctl_rename_id - replace the id of a control on the card
578 * @card: the card instance
579 * @src_id: the old id
580 * @dst_id: the new id
582 * Finds the control with the old id from the card, and replaces the
583 * id with the new one.
585 * Returns zero if successful, or a negative error code on failure.
587 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
588 struct snd_ctl_elem_id *dst_id)
590 struct snd_kcontrol *kctl;
592 down_write(&card->controls_rwsem);
593 kctl = snd_ctl_find_id(card, src_id);
595 up_write(&card->controls_rwsem);
599 kctl->id.numid = card->last_numid + 1;
600 card->last_numid += kctl->count;
601 up_write(&card->controls_rwsem);
605 EXPORT_SYMBOL(snd_ctl_rename_id);
608 * snd_ctl_find_numid - find the control instance with the given number-id
609 * @card: the card instance
610 * @numid: the number-id to search
612 * Finds the control instance with the given number-id from the card.
614 * Returns the pointer of the instance if found, or NULL if not.
616 * The caller must down card->controls_rwsem before calling this function
617 * (if the race condition can happen).
619 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
621 struct snd_kcontrol *kctl;
623 if (snd_BUG_ON(!card || !numid))
625 list_for_each_entry(kctl, &card->controls, list) {
626 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
632 EXPORT_SYMBOL(snd_ctl_find_numid);
635 * snd_ctl_find_id - find the control instance with the given id
636 * @card: the card instance
637 * @id: the id to search
639 * Finds the control instance with the given id from the card.
641 * Returns the pointer of the instance if found, or NULL if not.
643 * The caller must down card->controls_rwsem before calling this function
644 * (if the race condition can happen).
646 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
647 struct snd_ctl_elem_id *id)
649 struct snd_kcontrol *kctl;
651 if (snd_BUG_ON(!card || !id))
654 return snd_ctl_find_numid(card, id->numid);
655 list_for_each_entry(kctl, &card->controls, list) {
656 if (kctl->id.iface != id->iface)
658 if (kctl->id.device != id->device)
660 if (kctl->id.subdevice != id->subdevice)
662 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
664 if (kctl->id.index > id->index)
666 if (kctl->id.index + kctl->count <= id->index)
673 EXPORT_SYMBOL(snd_ctl_find_id);
675 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
676 unsigned int cmd, void __user *arg)
678 struct snd_ctl_card_info *info;
680 info = kzalloc(sizeof(*info), GFP_KERNEL);
683 down_read(&snd_ioctl_rwsem);
684 info->card = card->number;
685 strlcpy(info->id, card->id, sizeof(info->id));
686 strlcpy(info->driver, card->driver, sizeof(info->driver));
687 strlcpy(info->name, card->shortname, sizeof(info->name));
688 strlcpy(info->longname, card->longname, sizeof(info->longname));
689 strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
690 strlcpy(info->components, card->components, sizeof(info->components));
691 up_read(&snd_ioctl_rwsem);
692 if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
700 static int snd_ctl_elem_list(struct snd_card *card,
701 struct snd_ctl_elem_list __user *_list)
703 struct list_head *plist;
704 struct snd_ctl_elem_list list;
705 struct snd_kcontrol *kctl;
706 struct snd_ctl_elem_id *dst, *id;
707 unsigned int offset, space, jidx;
709 if (copy_from_user(&list, _list, sizeof(list)))
711 offset = list.offset;
713 /* try limit maximum space */
717 /* allocate temporary buffer for atomic operation */
718 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
721 down_read(&card->controls_rwsem);
722 list.count = card->controls_count;
723 plist = card->controls.next;
724 while (plist != &card->controls) {
727 kctl = snd_kcontrol(plist);
728 if (offset < kctl->count)
730 offset -= kctl->count;
735 while (space > 0 && plist != &card->controls) {
736 kctl = snd_kcontrol(plist);
737 for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
738 snd_ctl_build_ioff(id, kctl, jidx);
746 up_read(&card->controls_rwsem);
748 copy_to_user(list.pids, dst,
749 list.used * sizeof(struct snd_ctl_elem_id))) {
755 down_read(&card->controls_rwsem);
756 list.count = card->controls_count;
757 up_read(&card->controls_rwsem);
759 if (copy_to_user(_list, &list, sizeof(list)))
764 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
765 struct snd_ctl_elem_info *info)
767 struct snd_card *card = ctl->card;
768 struct snd_kcontrol *kctl;
769 struct snd_kcontrol_volatile *vd;
770 unsigned int index_offset;
773 down_read(&card->controls_rwsem);
774 kctl = snd_ctl_find_id(card, &info->id);
776 up_read(&card->controls_rwsem);
779 #ifdef CONFIG_SND_DEBUG
782 result = kctl->info(kctl, info);
784 snd_BUG_ON(info->access);
785 index_offset = snd_ctl_get_ioff(kctl, &info->id);
786 vd = &kctl->vd[index_offset];
787 snd_ctl_build_ioff(&info->id, kctl, index_offset);
788 info->access = vd->access;
790 info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
791 if (vd->owner == ctl)
792 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
793 info->owner = pid_vnr(vd->owner->pid);
798 up_read(&card->controls_rwsem);
802 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
803 struct snd_ctl_elem_info __user *_info)
805 struct snd_ctl_elem_info info;
808 if (copy_from_user(&info, _info, sizeof(info)))
810 snd_power_lock(ctl->card);
811 result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
813 result = snd_ctl_elem_info(ctl, &info);
814 snd_power_unlock(ctl->card);
816 if (copy_to_user(_info, &info, sizeof(info)))
821 static int snd_ctl_elem_read(struct snd_card *card,
822 struct snd_ctl_elem_value *control)
824 struct snd_kcontrol *kctl;
825 struct snd_kcontrol_volatile *vd;
826 unsigned int index_offset;
829 down_read(&card->controls_rwsem);
830 kctl = snd_ctl_find_id(card, &control->id);
834 index_offset = snd_ctl_get_ioff(kctl, &control->id);
835 vd = &kctl->vd[index_offset];
836 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
838 snd_ctl_build_ioff(&control->id, kctl, index_offset);
839 result = kctl->get(kctl, control);
843 up_read(&card->controls_rwsem);
847 static int snd_ctl_elem_read_user(struct snd_card *card,
848 struct snd_ctl_elem_value __user *_control)
850 struct snd_ctl_elem_value *control;
853 control = memdup_user(_control, sizeof(*control));
855 return PTR_ERR(control);
857 snd_power_lock(card);
858 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
860 result = snd_ctl_elem_read(card, control);
861 snd_power_unlock(card);
863 if (copy_to_user(_control, control, sizeof(*control)))
869 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
870 struct snd_ctl_elem_value *control)
872 struct snd_kcontrol *kctl;
873 struct snd_kcontrol_volatile *vd;
874 unsigned int index_offset;
877 down_read(&card->controls_rwsem);
878 kctl = snd_ctl_find_id(card, &control->id);
882 index_offset = snd_ctl_get_ioff(kctl, &control->id);
883 vd = &kctl->vd[index_offset];
884 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
886 (file && vd->owner && vd->owner != file)) {
889 snd_ctl_build_ioff(&control->id, kctl, index_offset);
890 result = kctl->put(kctl, control);
893 up_read(&card->controls_rwsem);
894 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
899 up_read(&card->controls_rwsem);
903 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
904 struct snd_ctl_elem_value __user *_control)
906 struct snd_ctl_elem_value *control;
907 struct snd_card *card;
910 control = memdup_user(_control, sizeof(*control));
912 return PTR_ERR(control);
915 snd_power_lock(card);
916 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
918 result = snd_ctl_elem_write(card, file, control);
919 snd_power_unlock(card);
921 if (copy_to_user(_control, control, sizeof(*control)))
927 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
928 struct snd_ctl_elem_id __user *_id)
930 struct snd_card *card = file->card;
931 struct snd_ctl_elem_id id;
932 struct snd_kcontrol *kctl;
933 struct snd_kcontrol_volatile *vd;
936 if (copy_from_user(&id, _id, sizeof(id)))
938 down_write(&card->controls_rwsem);
939 kctl = snd_ctl_find_id(card, &id);
943 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
944 if (vd->owner != NULL)
951 up_write(&card->controls_rwsem);
955 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
956 struct snd_ctl_elem_id __user *_id)
958 struct snd_card *card = file->card;
959 struct snd_ctl_elem_id id;
960 struct snd_kcontrol *kctl;
961 struct snd_kcontrol_volatile *vd;
964 if (copy_from_user(&id, _id, sizeof(id)))
966 down_write(&card->controls_rwsem);
967 kctl = snd_ctl_find_id(card, &id);
971 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
972 if (vd->owner == NULL)
974 else if (vd->owner != file)
981 up_write(&card->controls_rwsem);
985 struct user_element {
986 struct snd_ctl_elem_info info;
987 void *elem_data; /* element data */
988 unsigned long elem_data_size; /* size of element data in bytes */
989 void *tlv_data; /* TLV data */
990 unsigned long tlv_data_size; /* TLV data size */
991 void *priv_data; /* private data (like strings for enumerated type) */
994 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
995 struct snd_ctl_elem_info *uinfo)
997 struct user_element *ue = kcontrol->private_data;
1003 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1004 struct snd_ctl_elem_info *uinfo)
1006 struct user_element *ue = kcontrol->private_data;
1010 item = uinfo->value.enumerated.item;
1014 item = min(item, uinfo->value.enumerated.items - 1);
1015 uinfo->value.enumerated.item = item;
1017 names = ue->priv_data;
1018 for (; item > 0; --item)
1019 names += strlen(names) + 1;
1020 strcpy(uinfo->value.enumerated.name, names);
1025 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1026 struct snd_ctl_elem_value *ucontrol)
1028 struct user_element *ue = kcontrol->private_data;
1030 memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
1034 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1035 struct snd_ctl_elem_value *ucontrol)
1038 struct user_element *ue = kcontrol->private_data;
1040 change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
1042 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
1046 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1049 unsigned int __user *tlv)
1051 struct user_element *ue = kcontrol->private_data;
1056 if (size > 1024 * 128) /* sane value */
1059 new_data = memdup_user(tlv, size);
1060 if (IS_ERR(new_data))
1061 return PTR_ERR(new_data);
1062 change = ue->tlv_data_size != size;
1064 change = memcmp(ue->tlv_data, new_data, size);
1065 kfree(ue->tlv_data);
1066 ue->tlv_data = new_data;
1067 ue->tlv_data_size = size;
1069 if (! ue->tlv_data_size || ! ue->tlv_data)
1071 if (size < ue->tlv_data_size)
1073 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1079 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1082 size_t buf_len, name_len;
1085 if (ue->info.value.enumerated.names_length > 64 * 1024)
1088 names = memdup_user(
1089 (const void __user *)ue->info.value.enumerated.names_ptr,
1090 ue->info.value.enumerated.names_length);
1092 return PTR_ERR(names);
1094 /* check that there are enough valid names */
1095 buf_len = ue->info.value.enumerated.names_length;
1097 for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1098 name_len = strnlen(p, buf_len);
1099 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1104 buf_len -= name_len + 1;
1107 ue->priv_data = names;
1108 ue->info.value.enumerated.names_ptr = 0;
1113 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1115 struct user_element *ue = kcontrol->private_data;
1117 kfree(ue->tlv_data);
1118 kfree(ue->priv_data);
1122 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1123 struct snd_ctl_elem_info *info, int replace)
1125 struct snd_card *card = file->card;
1126 struct snd_kcontrol kctl, *_kctl;
1127 unsigned int access;
1129 struct user_element *ue;
1132 if (!replace && card->user_ctl_count >= MAX_USER_CONTROLS)
1134 if (info->count < 1)
1136 access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
1137 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
1138 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
1139 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
1141 memset(&kctl, 0, sizeof(kctl));
1142 down_write(&card->controls_rwsem);
1143 _kctl = snd_ctl_find_id(card, &info->id);
1147 err = snd_ctl_remove(card, _kctl);
1154 up_write(&card->controls_rwsem);
1157 memcpy(&kctl.id, &info->id, sizeof(info->id));
1158 kctl.count = info->owner ? info->owner : 1;
1159 access |= SNDRV_CTL_ELEM_ACCESS_USER;
1160 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1161 kctl.info = snd_ctl_elem_user_enum_info;
1163 kctl.info = snd_ctl_elem_user_info;
1164 if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1165 kctl.get = snd_ctl_elem_user_get;
1166 if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1167 kctl.put = snd_ctl_elem_user_put;
1168 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
1169 kctl.tlv.c = snd_ctl_elem_user_tlv;
1170 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1172 switch (info->type) {
1173 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1174 case SNDRV_CTL_ELEM_TYPE_INTEGER:
1175 private_size = sizeof(long);
1176 if (info->count > 128)
1179 case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1180 private_size = sizeof(long long);
1181 if (info->count > 64)
1184 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1185 private_size = sizeof(unsigned int);
1186 if (info->count > 128 || info->value.enumerated.items == 0)
1189 case SNDRV_CTL_ELEM_TYPE_BYTES:
1190 private_size = sizeof(unsigned char);
1191 if (info->count > 512)
1194 case SNDRV_CTL_ELEM_TYPE_IEC958:
1195 private_size = sizeof(struct snd_aes_iec958);
1196 if (info->count != 1)
1202 private_size *= info->count;
1203 ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1207 ue->info.access = 0;
1208 ue->elem_data = (char *)ue + sizeof(*ue);
1209 ue->elem_data_size = private_size;
1210 if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1211 err = snd_ctl_elem_init_enum_names(ue);
1217 kctl.private_free = snd_ctl_elem_user_free;
1218 _kctl = snd_ctl_new(&kctl, access);
1219 if (_kctl == NULL) {
1220 kfree(ue->priv_data);
1224 _kctl->private_data = ue;
1225 for (idx = 0; idx < _kctl->count; idx++)
1226 _kctl->vd[idx].owner = file;
1227 err = snd_ctl_add(card, _kctl);
1231 down_write(&card->controls_rwsem);
1232 card->user_ctl_count++;
1233 up_write(&card->controls_rwsem);
1238 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1239 struct snd_ctl_elem_info __user *_info, int replace)
1241 struct snd_ctl_elem_info info;
1242 if (copy_from_user(&info, _info, sizeof(info)))
1244 return snd_ctl_elem_add(file, &info, replace);
1247 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1248 struct snd_ctl_elem_id __user *_id)
1250 struct snd_ctl_elem_id id;
1252 if (copy_from_user(&id, _id, sizeof(id)))
1254 return snd_ctl_remove_user_ctl(file, &id);
1257 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1260 if (get_user(subscribe, ptr))
1262 if (subscribe < 0) {
1263 subscribe = file->subscribed;
1264 if (put_user(subscribe, ptr))
1269 file->subscribed = 1;
1271 } else if (file->subscribed) {
1272 snd_ctl_empty_read_queue(file);
1273 file->subscribed = 0;
1278 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1279 struct snd_ctl_tlv __user *_tlv,
1282 struct snd_card *card = file->card;
1283 struct snd_ctl_tlv tlv;
1284 struct snd_kcontrol *kctl;
1285 struct snd_kcontrol_volatile *vd;
1289 if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1291 if (tlv.length < sizeof(unsigned int) * 2)
1293 down_read(&card->controls_rwsem);
1294 kctl = snd_ctl_find_numid(card, tlv.numid);
1299 if (kctl->tlv.p == NULL) {
1303 vd = &kctl->vd[tlv.numid - kctl->id.numid];
1304 if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1305 (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1306 (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1310 if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1311 if (vd->owner != NULL && vd->owner != file) {
1315 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1317 up_read(&card->controls_rwsem);
1318 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
1326 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1327 if (tlv.length < len) {
1331 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1335 up_read(&card->controls_rwsem);
1339 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1341 struct snd_ctl_file *ctl;
1342 struct snd_card *card;
1343 struct snd_kctl_ioctl *p;
1344 void __user *argp = (void __user *)arg;
1345 int __user *ip = argp;
1348 ctl = file->private_data;
1350 if (snd_BUG_ON(!card))
1353 case SNDRV_CTL_IOCTL_PVERSION:
1354 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1355 case SNDRV_CTL_IOCTL_CARD_INFO:
1356 return snd_ctl_card_info(card, ctl, cmd, argp);
1357 case SNDRV_CTL_IOCTL_ELEM_LIST:
1358 return snd_ctl_elem_list(card, argp);
1359 case SNDRV_CTL_IOCTL_ELEM_INFO:
1360 return snd_ctl_elem_info_user(ctl, argp);
1361 case SNDRV_CTL_IOCTL_ELEM_READ:
1362 return snd_ctl_elem_read_user(card, argp);
1363 case SNDRV_CTL_IOCTL_ELEM_WRITE:
1364 return snd_ctl_elem_write_user(ctl, argp);
1365 case SNDRV_CTL_IOCTL_ELEM_LOCK:
1366 return snd_ctl_elem_lock(ctl, argp);
1367 case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1368 return snd_ctl_elem_unlock(ctl, argp);
1369 case SNDRV_CTL_IOCTL_ELEM_ADD:
1370 return snd_ctl_elem_add_user(ctl, argp, 0);
1371 case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1372 return snd_ctl_elem_add_user(ctl, argp, 1);
1373 case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1374 return snd_ctl_elem_remove(ctl, argp);
1375 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1376 return snd_ctl_subscribe_events(ctl, ip);
1377 case SNDRV_CTL_IOCTL_TLV_READ:
1378 return snd_ctl_tlv_ioctl(ctl, argp, 0);
1379 case SNDRV_CTL_IOCTL_TLV_WRITE:
1380 return snd_ctl_tlv_ioctl(ctl, argp, 1);
1381 case SNDRV_CTL_IOCTL_TLV_COMMAND:
1382 return snd_ctl_tlv_ioctl(ctl, argp, -1);
1383 case SNDRV_CTL_IOCTL_POWER:
1384 return -ENOPROTOOPT;
1385 case SNDRV_CTL_IOCTL_POWER_STATE:
1387 return put_user(card->power_state, ip) ? -EFAULT : 0;
1389 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1392 down_read(&snd_ioctl_rwsem);
1393 list_for_each_entry(p, &snd_control_ioctls, list) {
1394 err = p->fioctl(card, ctl, cmd, arg);
1395 if (err != -ENOIOCTLCMD) {
1396 up_read(&snd_ioctl_rwsem);
1400 up_read(&snd_ioctl_rwsem);
1401 snd_printdd("unknown ioctl = 0x%x\n", cmd);
1405 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1406 size_t count, loff_t * offset)
1408 struct snd_ctl_file *ctl;
1412 ctl = file->private_data;
1413 if (snd_BUG_ON(!ctl || !ctl->card))
1415 if (!ctl->subscribed)
1417 if (count < sizeof(struct snd_ctl_event))
1419 spin_lock_irq(&ctl->read_lock);
1420 while (count >= sizeof(struct snd_ctl_event)) {
1421 struct snd_ctl_event ev;
1422 struct snd_kctl_event *kev;
1423 while (list_empty(&ctl->events)) {
1425 if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1429 init_waitqueue_entry(&wait, current);
1430 add_wait_queue(&ctl->change_sleep, &wait);
1431 set_current_state(TASK_INTERRUPTIBLE);
1432 spin_unlock_irq(&ctl->read_lock);
1434 remove_wait_queue(&ctl->change_sleep, &wait);
1435 if (signal_pending(current))
1436 return -ERESTARTSYS;
1437 spin_lock_irq(&ctl->read_lock);
1439 kev = snd_kctl_event(ctl->events.next);
1440 ev.type = SNDRV_CTL_EVENT_ELEM;
1441 ev.data.elem.mask = kev->mask;
1442 ev.data.elem.id = kev->id;
1443 list_del(&kev->list);
1444 spin_unlock_irq(&ctl->read_lock);
1446 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1450 spin_lock_irq(&ctl->read_lock);
1451 buffer += sizeof(struct snd_ctl_event);
1452 count -= sizeof(struct snd_ctl_event);
1453 result += sizeof(struct snd_ctl_event);
1456 spin_unlock_irq(&ctl->read_lock);
1458 return result > 0 ? result : err;
1461 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1464 struct snd_ctl_file *ctl;
1466 ctl = file->private_data;
1467 if (!ctl->subscribed)
1469 poll_wait(file, &ctl->change_sleep, wait);
1472 if (!list_empty(&ctl->events))
1473 mask |= POLLIN | POLLRDNORM;
1479 * register the device-specific control-ioctls.
1480 * called from each device manager like pcm.c, hwdep.c, etc.
1482 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1484 struct snd_kctl_ioctl *pn;
1486 pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1490 down_write(&snd_ioctl_rwsem);
1491 list_add_tail(&pn->list, lists);
1492 up_write(&snd_ioctl_rwsem);
1496 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1498 return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1501 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1503 #ifdef CONFIG_COMPAT
1504 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1506 return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1509 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1513 * de-register the device-specific control-ioctls.
1515 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1516 struct list_head *lists)
1518 struct snd_kctl_ioctl *p;
1520 if (snd_BUG_ON(!fcn))
1522 down_write(&snd_ioctl_rwsem);
1523 list_for_each_entry(p, lists, list) {
1524 if (p->fioctl == fcn) {
1526 up_write(&snd_ioctl_rwsem);
1531 up_write(&snd_ioctl_rwsem);
1536 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1538 return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1541 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1543 #ifdef CONFIG_COMPAT
1544 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1546 return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1549 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1552 static int snd_ctl_fasync(int fd, struct file * file, int on)
1554 struct snd_ctl_file *ctl;
1556 ctl = file->private_data;
1557 return fasync_helper(fd, file, on, &ctl->fasync);
1563 #ifdef CONFIG_COMPAT
1564 #include "control_compat.c"
1566 #define snd_ctl_ioctl_compat NULL
1573 static const struct file_operations snd_ctl_f_ops =
1575 .owner = THIS_MODULE,
1576 .read = snd_ctl_read,
1577 .open = snd_ctl_open,
1578 .release = snd_ctl_release,
1579 .llseek = no_llseek,
1580 .poll = snd_ctl_poll,
1581 .unlocked_ioctl = snd_ctl_ioctl,
1582 .compat_ioctl = snd_ctl_ioctl_compat,
1583 .fasync = snd_ctl_fasync,
1587 * registration of the control device
1589 static int snd_ctl_dev_register(struct snd_device *device)
1591 struct snd_card *card = device->device_data;
1595 if (snd_BUG_ON(!card))
1597 cardnum = card->number;
1598 if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1600 sprintf(name, "controlC%i", cardnum);
1601 if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1602 &snd_ctl_f_ops, card, name)) < 0)
1608 * disconnection of the control device
1610 static int snd_ctl_dev_disconnect(struct snd_device *device)
1612 struct snd_card *card = device->device_data;
1613 struct snd_ctl_file *ctl;
1616 if (snd_BUG_ON(!card))
1618 cardnum = card->number;
1619 if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1622 read_lock(&card->ctl_files_rwlock);
1623 list_for_each_entry(ctl, &card->ctl_files, list) {
1624 wake_up(&ctl->change_sleep);
1625 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1627 read_unlock(&card->ctl_files_rwlock);
1629 if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1638 static int snd_ctl_dev_free(struct snd_device *device)
1640 struct snd_card *card = device->device_data;
1641 struct snd_kcontrol *control;
1643 down_write(&card->controls_rwsem);
1644 while (!list_empty(&card->controls)) {
1645 control = snd_kcontrol(card->controls.next);
1646 snd_ctl_remove(card, control);
1648 up_write(&card->controls_rwsem);
1653 * create control core:
1654 * called from init.c
1656 int snd_ctl_create(struct snd_card *card)
1658 static struct snd_device_ops ops = {
1659 .dev_free = snd_ctl_dev_free,
1660 .dev_register = snd_ctl_dev_register,
1661 .dev_disconnect = snd_ctl_dev_disconnect,
1664 if (snd_BUG_ON(!card))
1666 return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1670 * Frequently used control callbacks/helpers
1672 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1673 struct snd_ctl_elem_info *uinfo)
1675 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1677 uinfo->value.integer.min = 0;
1678 uinfo->value.integer.max = 1;
1682 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1684 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1685 struct snd_ctl_elem_info *uinfo)
1687 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1689 uinfo->value.integer.min = 0;
1690 uinfo->value.integer.max = 1;
1694 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1697 * snd_ctl_enum_info - fills the info structure for an enumerated control
1698 * @info: the structure to be filled
1699 * @channels: the number of the control's channels; often one
1700 * @items: the number of control values; also the size of @names
1701 * @names: an array containing the names of all control values
1703 * Sets all required fields in @info to their appropriate values.
1704 * If the control's accessibility is not the default (readable and writable),
1705 * the caller has to fill @info->access.
1707 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1708 unsigned int items, const char *const names[])
1710 info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1711 info->count = channels;
1712 info->value.enumerated.items = items;
1713 if (info->value.enumerated.item >= items)
1714 info->value.enumerated.item = items - 1;
1715 strlcpy(info->value.enumerated.name,
1716 names[info->value.enumerated.item],
1717 sizeof(info->value.enumerated.name));
1720 EXPORT_SYMBOL(snd_ctl_enum_info);