diff options
Diffstat (limited to 'sound/core/control.c')
| -rw-r--r-- | sound/core/control.c | 382 |
1 files changed, 311 insertions, 71 deletions
diff --git a/sound/core/control.c b/sound/core/control.c index 45a818002d9..f0b0e14497a 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -21,6 +21,7 @@ #include <linux/threads.h> #include <linux/interrupt.h> +#include <linux/module.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/time.h> @@ -85,6 +86,7 @@ static int snd_ctl_open(struct inode *inode, struct file *file) write_lock_irqsave(&card->ctl_files_rwlock, flags); list_add_tail(&ctl->list, &card->ctl_files); write_unlock_irqrestore(&card->ctl_files_rwlock, flags); + snd_card_unref(card); return 0; __error: @@ -92,6 +94,8 @@ static int snd_ctl_open(struct inode *inode, struct file *file) __error2: snd_card_file_remove(card, file); __error1: + if (card) + snd_card_unref(card); return err; } @@ -147,7 +151,7 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask, if (snd_BUG_ON(!card || !id)) return; read_lock(&card->ctl_files_rwlock); -#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE) +#if IS_ENABLED(CONFIG_SND_MIXER_OSS) card->mixer_oss_change_count++; #endif list_for_each_entry(ctl, &card->ctl_files, list) { @@ -166,7 +170,7 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask, ev->mask = mask; list_add_tail(&ev->list, &ctl->events); } else { - snd_printk(KERN_ERR "No memory available to allocate event\n"); + dev_err(card->dev, "No memory available to allocate event\n"); } _found: wake_up(&ctl->change_sleep); @@ -186,7 +190,7 @@ EXPORT_SYMBOL(snd_ctl_notify); * Allocates a new struct snd_kcontrol instance and copies the given template * to the new instance. It does not copy volatile data (access). * - * Returns the pointer of the new instance, or NULL on failure. + * Return: The pointer of the new instance, or %NULL on failure. */ static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, unsigned int access) @@ -202,7 +206,7 @@ static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL); if (kctl == NULL) { - snd_printk(KERN_ERR "Cannot allocate control instance\n"); + pr_err("ALSA: Cannot allocate control instance\n"); return NULL; } *kctl = *control; @@ -220,7 +224,7 @@ static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, * template. When the access field of ncontrol is 0, it's assumed as * READWRITE access. When the count field is 0, it's assumes as one. * - * Returns the pointer of the newly generated instance, or NULL on failure. + * Return: The pointer of the newly generated instance, or %NULL on failure. */ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol, void *private_data) @@ -237,14 +241,14 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol, if (ncontrol->name) { strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name)); if (strcmp(ncontrol->name, kctl.id.name) != 0) - snd_printk(KERN_WARNING - "Control name '%s' truncated to '%s'\n", - ncontrol->name, kctl.id.name); + pr_warn("ALSA: Control name '%s' truncated to '%s'\n", + ncontrol->name, kctl.id.name); } kctl.id.index = ncontrol->index; kctl.count = ncontrol->count ? ncontrol->count : 1; access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE : (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE| + SNDRV_CTL_ELEM_ACCESS_VOLATILE| SNDRV_CTL_ELEM_ACCESS_INACTIVE| SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE| SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND| @@ -279,33 +283,35 @@ void snd_ctl_free_one(struct snd_kcontrol *kcontrol) EXPORT_SYMBOL(snd_ctl_free_one); -static unsigned int snd_ctl_hole_check(struct snd_card *card, - unsigned int count) +static bool snd_ctl_remove_numid_conflict(struct snd_card *card, + unsigned int count) { struct snd_kcontrol *kctl; + /* Make sure that the ids assigned to the control do not wrap around */ + if (card->last_numid >= UINT_MAX - count) + card->last_numid = 0; + list_for_each_entry(kctl, &card->controls, list) { - if ((kctl->id.numid <= card->last_numid && - kctl->id.numid + kctl->count > card->last_numid) || - (kctl->id.numid <= card->last_numid + count - 1 && - kctl->id.numid + kctl->count > card->last_numid + count - 1)) - return card->last_numid = kctl->id.numid + kctl->count - 1; + if (kctl->id.numid < card->last_numid + 1 + count && + kctl->id.numid + kctl->count > card->last_numid + 1) { + card->last_numid = kctl->id.numid + kctl->count - 1; + return true; + } } - return card->last_numid; + return false; } static int snd_ctl_find_hole(struct snd_card *card, unsigned int count) { - unsigned int last_numid, iter = 100000; + unsigned int iter = 100000; - last_numid = card->last_numid; - while (last_numid != snd_ctl_hole_check(card, count)) { + while (snd_ctl_remove_numid_conflict(card, count)) { if (--iter == 0) { /* this situation is very unlikely */ - snd_printk(KERN_ERR "unable to allocate new control numid\n"); + dev_err(card->dev, "unable to allocate new control numid\n"); return -ENOMEM; } - last_numid = card->last_numid; } return 0; } @@ -319,14 +325,16 @@ static int snd_ctl_find_hole(struct snd_card *card, unsigned int count) * snd_ctl_new1() to the given card. Assigns also an unique * numid used for fast search. * - * Returns zero if successful, or a negative error code on failure. - * * It frees automatically the control which cannot be added. + * + * Return: Zero if successful, or a negative error code on failure. + * */ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) { struct snd_ctl_elem_id id; unsigned int idx; + unsigned int count; int err = -EINVAL; if (! kcontrol) @@ -334,10 +342,13 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) if (snd_BUG_ON(!card || !kcontrol->info)) goto error; id = kcontrol->id; + if (id.index > UINT_MAX - kcontrol->count) + goto error; + down_write(&card->controls_rwsem); if (snd_ctl_find_id(card, &id)) { up_write(&card->controls_rwsem); - snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n", + dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n", id.iface, id.device, id.subdevice, @@ -355,8 +366,9 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) card->controls_count += kcontrol->count; kcontrol->id.numid = card->last_numid + 1; card->last_numid += kcontrol->count; + count = kcontrol->count; up_write(&card->controls_rwsem); - for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++) + for (idx = 0; idx < count; idx++, id.index++, id.numid++) snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id); return 0; @@ -368,6 +380,72 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) EXPORT_SYMBOL(snd_ctl_add); /** + * snd_ctl_replace - replace the control instance of the card + * @card: the card instance + * @kcontrol: the control instance to replace + * @add_on_replace: add the control if not already added + * + * Replaces the given control. If the given control does not exist + * and the add_on_replace flag is set, the control is added. If the + * control exists, it is destroyed first. + * + * It frees automatically the control which cannot be added or replaced. + * + * Return: Zero if successful, or a negative error code on failure. + */ +int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, + bool add_on_replace) +{ + struct snd_ctl_elem_id id; + unsigned int count; + unsigned int idx; + struct snd_kcontrol *old; + int ret; + + if (!kcontrol) + return -EINVAL; + if (snd_BUG_ON(!card || !kcontrol->info)) { + ret = -EINVAL; + goto error; + } + id = kcontrol->id; + down_write(&card->controls_rwsem); + old = snd_ctl_find_id(card, &id); + if (!old) { + if (add_on_replace) + goto add; + up_write(&card->controls_rwsem); + ret = -EINVAL; + goto error; + } + ret = snd_ctl_remove(card, old); + if (ret < 0) { + up_write(&card->controls_rwsem); + goto error; + } +add: + if (snd_ctl_find_hole(card, kcontrol->count) < 0) { + up_write(&card->controls_rwsem); + ret = -ENOMEM; + goto error; + } + list_add_tail(&kcontrol->list, &card->controls); + card->controls_count += kcontrol->count; + kcontrol->id.numid = card->last_numid + 1; + card->last_numid += kcontrol->count; + count = kcontrol->count; + up_write(&card->controls_rwsem); + for (idx = 0; idx < count; idx++, id.index++, id.numid++) + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id); + return 0; + +error: + snd_ctl_free_one(kcontrol); + return ret; +} +EXPORT_SYMBOL(snd_ctl_replace); + +/** * snd_ctl_remove - remove the control from the card and release it * @card: the card instance * @kcontrol: the control instance to remove @@ -375,8 +453,8 @@ EXPORT_SYMBOL(snd_ctl_add); * Removes the control from the card and then releases the instance. * You don't need to call snd_ctl_free_one(). You must be in * the write lock - down_write(&card->controls_rwsem). - * - * Returns 0 if successful, or a negative error code on failure. + * + * Return: 0 if successful, or a negative error code on failure. */ int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol) { @@ -403,8 +481,8 @@ EXPORT_SYMBOL(snd_ctl_remove); * * Finds the control instance with the given id, removes it from the * card list and releases it. - * - * Returns 0 if successful, or a negative error code on failure. + * + * Return: 0 if successful, or a negative error code on failure. */ int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id) { @@ -431,8 +509,8 @@ EXPORT_SYMBOL(snd_ctl_remove_id); * * Finds the control instance with the given id, removes it from the * card list and releases it. - * - * Returns 0 if successful, or a negative error code on failure. + * + * Return: 0 if successful, or a negative error code on failure. */ static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file, struct snd_ctl_elem_id *id) @@ -466,6 +544,52 @@ error: } /** + * snd_ctl_activate_id - activate/inactivate the control of the given id + * @card: the card instance + * @id: the control id to activate/inactivate + * @active: non-zero to activate + * + * Finds the control instance with the given id, and activate or + * inactivate the control together with notification, if changed. + * + * Return: 0 if unchanged, 1 if changed, or a negative error code on failure. + */ +int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id, + int active) +{ + struct snd_kcontrol *kctl; + struct snd_kcontrol_volatile *vd; + unsigned int index_offset; + int ret; + + down_write(&card->controls_rwsem); + kctl = snd_ctl_find_id(card, id); + if (kctl == NULL) { + ret = -ENOENT; + goto unlock; + } + index_offset = snd_ctl_get_ioff(kctl, &kctl->id); + vd = &kctl->vd[index_offset]; + ret = 0; + if (active) { + if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)) + goto unlock; + vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE; + } else { + if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE) + goto unlock; + vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE; + } + ret = 1; + unlock: + up_write(&card->controls_rwsem); + if (ret > 0) + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id); + return ret; +} +EXPORT_SYMBOL_GPL(snd_ctl_activate_id); + +/** * snd_ctl_rename_id - replace the id of a control on the card * @card: the card instance * @src_id: the old id @@ -474,7 +598,7 @@ error: * Finds the control with the old id from the card, and replaces the * id with the new one. * - * Returns zero if successful, or a negative error code on failure. + * Return: Zero if successful, or a negative error code on failure. */ int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id) @@ -503,10 +627,11 @@ EXPORT_SYMBOL(snd_ctl_rename_id); * * Finds the control instance with the given number-id from the card. * - * Returns the pointer of the instance if found, or NULL if not. - * * The caller must down card->controls_rwsem before calling this function * (if the race condition can happen). + * + * Return: The pointer of the instance if found, or %NULL if not. + * */ struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid) { @@ -530,10 +655,11 @@ EXPORT_SYMBOL(snd_ctl_find_numid); * * Finds the control instance with the given id from the card. * - * Returns the pointer of the instance if found, or NULL if not. - * * The caller must down card->controls_rwsem before calling this function * (if the race condition can happen). + * + * Return: The pointer of the instance if found, or %NULL if not. + * */ struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card, struct snd_ctl_elem_id *id) @@ -596,13 +722,12 @@ static int snd_ctl_elem_list(struct snd_card *card, struct snd_ctl_elem_list list; struct snd_kcontrol *kctl; struct snd_ctl_elem_id *dst, *id; - unsigned int offset, space, first, jidx; + unsigned int offset, space, jidx; if (copy_from_user(&list, _list, sizeof(list))) return -EFAULT; offset = list.offset; space = list.space; - first = 0; /* try limit maximum space */ if (space > 16384) return -ENOMEM; @@ -783,9 +908,9 @@ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file, result = kctl->put(kctl, control); } if (result > 0) { + struct snd_ctl_elem_id id = control->id; up_read(&card->controls_rwsem); - snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, - &control->id); + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id); return 0; } } @@ -877,12 +1002,12 @@ static int snd_ctl_elem_unlock(struct snd_ctl_file *file, struct user_element { struct snd_ctl_elem_info info; + struct snd_card *card; void *elem_data; /* element data */ unsigned long elem_data_size; /* size of element data in bytes */ void *tlv_data; /* TLV data */ unsigned long tlv_data_size; /* TLV data size */ void *priv_data; /* private data (like strings for enumerated type) */ - unsigned long priv_data_size; /* size of private data in bytes */ }; static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol, @@ -894,12 +1019,36 @@ static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol, return 0; } +static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_info *uinfo) +{ + struct user_element *ue = kcontrol->private_data; + const char *names; + unsigned int item; + + item = uinfo->value.enumerated.item; + + *uinfo = ue->info; + + item = min(item, uinfo->value.enumerated.items - 1); + uinfo->value.enumerated.item = item; + + names = ue->priv_data; + for (; item > 0; --item) + names += strlen(names) + 1; + strcpy(uinfo->value.enumerated.name, names); + + return 0; +} + static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol) { struct user_element *ue = kcontrol->private_data; + mutex_lock(&ue->card->user_ctl_lock); memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size); + mutex_unlock(&ue->card->user_ctl_lock); return 0; } @@ -908,10 +1057,12 @@ static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol, { int change; struct user_element *ue = kcontrol->private_data; - + + mutex_lock(&ue->card->user_ctl_lock); change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0; if (change) memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size); + mutex_unlock(&ue->card->user_ctl_lock); return change; } @@ -931,28 +1082,76 @@ static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol, new_data = memdup_user(tlv, size); if (IS_ERR(new_data)) return PTR_ERR(new_data); + mutex_lock(&ue->card->user_ctl_lock); change = ue->tlv_data_size != size; if (!change) change = memcmp(ue->tlv_data, new_data, size); kfree(ue->tlv_data); ue->tlv_data = new_data; ue->tlv_data_size = size; + mutex_unlock(&ue->card->user_ctl_lock); } else { - if (! ue->tlv_data_size || ! ue->tlv_data) - return -ENXIO; - if (size < ue->tlv_data_size) - return -ENOSPC; + int ret = 0; + + mutex_lock(&ue->card->user_ctl_lock); + if (!ue->tlv_data_size || !ue->tlv_data) { + ret = -ENXIO; + goto err_unlock; + } + if (size < ue->tlv_data_size) { + ret = -ENOSPC; + goto err_unlock; + } if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size)) - return -EFAULT; + ret = -EFAULT; +err_unlock: + mutex_unlock(&ue->card->user_ctl_lock); + if (ret) + return ret; } return change; } +static int snd_ctl_elem_init_enum_names(struct user_element *ue) +{ + char *names, *p; + size_t buf_len, name_len; + unsigned int i; + const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr; + + if (ue->info.value.enumerated.names_length > 64 * 1024) + return -EINVAL; + + names = memdup_user((const void __user *)user_ptrval, + ue->info.value.enumerated.names_length); + if (IS_ERR(names)) + return PTR_ERR(names); + + /* check that there are enough valid names */ + buf_len = ue->info.value.enumerated.names_length; + p = names; + for (i = 0; i < ue->info.value.enumerated.items; ++i) { + name_len = strnlen(p, buf_len); + if (name_len == 0 || name_len >= 64 || name_len == buf_len) { + kfree(names); + return -EINVAL; + } + p += name_len + 1; + buf_len -= name_len + 1; + } + + ue->priv_data = names; + ue->info.value.enumerated.names_ptr = 0; + + return 0; +} + static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol) { struct user_element *ue = kcontrol->private_data; - if (ue->tlv_data) - kfree(ue->tlv_data); + + kfree(ue->tlv_data); + kfree(ue->priv_data); kfree(ue); } @@ -965,9 +1164,7 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, long private_size; struct user_element *ue; int idx, err; - - if (card->user_ctl_count >= MAX_USER_CONTROLS) - return -ENOMEM; + if (info->count < 1) return -EINVAL; access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE : @@ -976,25 +1173,23 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)); info->id.numid = 0; memset(&kctl, 0, sizeof(kctl)); - down_write(&card->controls_rwsem); - _kctl = snd_ctl_find_id(card, &info->id); - err = 0; - if (_kctl) { - if (replace) - err = snd_ctl_remove(card, _kctl); - else - err = -EBUSY; - } else { - if (replace) - err = -ENOENT; + + if (replace) { + err = snd_ctl_remove_user_ctl(file, &info->id); + if (err) + return err; } - up_write(&card->controls_rwsem); - if (err < 0) - return err; + + if (card->user_ctl_count >= MAX_USER_CONTROLS) + return -ENOMEM; + memcpy(&kctl.id, &info->id, sizeof(info->id)); kctl.count = info->owner ? info->owner : 1; access |= SNDRV_CTL_ELEM_ACCESS_USER; - kctl.info = snd_ctl_elem_user_info; + if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) + kctl.info = snd_ctl_elem_user_enum_info; + else + kctl.info = snd_ctl_elem_user_info; if (access & SNDRV_CTL_ELEM_ACCESS_READ) kctl.get = snd_ctl_elem_user_get; if (access & SNDRV_CTL_ELEM_ACCESS_WRITE) @@ -1015,6 +1210,11 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, if (info->count > 64) return -EINVAL; break; + case SNDRV_CTL_ELEM_TYPE_ENUMERATED: + private_size = sizeof(unsigned int); + if (info->count > 128 || info->value.enumerated.items == 0) + return -EINVAL; + break; case SNDRV_CTL_ELEM_TYPE_BYTES: private_size = sizeof(unsigned char); if (info->count > 512) @@ -1032,13 +1232,22 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file, ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL); if (ue == NULL) return -ENOMEM; + ue->card = card; ue->info = *info; ue->info.access = 0; ue->elem_data = (char *)ue + sizeof(*ue); ue->elem_data_size = private_size; + if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) { + err = snd_ctl_elem_init_enum_names(ue); + if (err < 0) { + kfree(ue); + return err; + } + } kctl.private_free = snd_ctl_elem_user_free; _kctl = snd_ctl_new(&kctl, access); if (_kctl == NULL) { + kfree(ue->priv_data); kfree(ue); return -ENOMEM; } @@ -1133,10 +1342,11 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file, err = -EPERM; goto __kctl_end; } - err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv); + err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv); if (err > 0) { + struct snd_ctl_elem_id id = kctl->id; up_read(&card->controls_rwsem); - snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id); + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id); return 0; } } else { @@ -1219,7 +1429,7 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg } } up_read(&snd_ioctl_rwsem); - snd_printdd("unknown ioctl = 0x%x\n", cmd); + dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd); return -ENOTTY; } @@ -1253,6 +1463,8 @@ static ssize_t snd_ctl_read(struct file *file, char __user *buffer, spin_unlock_irq(&ctl->read_lock); schedule(); remove_wait_queue(&ctl->change_sleep, &wait); + if (ctl->card->shutdown) + return -ENODEV; if (signal_pending(current)) return -ERESTARTSYS; spin_lock_irq(&ctl->read_lock); @@ -1488,7 +1700,7 @@ int snd_ctl_create(struct snd_card *card) } /* - * Frequently used control callbacks + * Frequently used control callbacks/helpers */ int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo) @@ -1513,3 +1725,31 @@ int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol, } EXPORT_SYMBOL(snd_ctl_boolean_stereo_info); + +/** + * snd_ctl_enum_info - fills the info structure for an enumerated control + * @info: the structure to be filled + * @channels: the number of the control's channels; often one + * @items: the number of control values; also the size of @names + * @names: an array containing the names of all control values + * + * Sets all required fields in @info to their appropriate values. + * If the control's accessibility is not the default (readable and writable), + * the caller has to fill @info->access. + * + * Return: Zero. + */ +int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels, + unsigned int items, const char *const names[]) +{ + info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED; + info->count = channels; + info->value.enumerated.items = items; + if (info->value.enumerated.item >= items) + info->value.enumerated.item = items - 1; + strlcpy(info->value.enumerated.name, + names[info->value.enumerated.item], + sizeof(info->value.enumerated.name)); + return 0; +} +EXPORT_SYMBOL(snd_ctl_enum_info); |