1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Routines for driver control interface
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
7 #include <linux/threads.h>
8 #include <linux/interrupt.h>
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/slab.h>
12 #include <linux/vmalloc.h>
13 #include <linux/time.h>
15 #include <linux/math64.h>
16 #include <linux/sched/signal.h>
17 #include <sound/core.h>
18 #include <sound/minors.h>
19 #include <sound/info.h>
20 #include <sound/control.h>
22 // Max allocation size for user controls.
23 static int max_user_ctl_alloc_size
= 8 * 1024 * 1024;
24 module_param_named(max_user_ctl_alloc_size
, max_user_ctl_alloc_size
, int, 0444);
25 MODULE_PARM_DESC(max_user_ctl_alloc_size
, "Max allocation size for user controls");
27 #define MAX_CONTROL_COUNT 1028
29 struct snd_kctl_ioctl
{
30 struct list_head list
; /* list of all ioctls */
31 snd_kctl_ioctl_func_t fioctl
;
34 static DECLARE_RWSEM(snd_ioctl_rwsem
);
35 static DECLARE_RWSEM(snd_ctl_layer_rwsem
);
36 static LIST_HEAD(snd_control_ioctls
);
38 static LIST_HEAD(snd_control_compat_ioctls
);
40 static struct snd_ctl_layer_ops
*snd_ctl_layer
;
42 static int snd_ctl_open(struct inode
*inode
, struct file
*file
)
45 struct snd_card
*card
;
46 struct snd_ctl_file
*ctl
;
49 err
= stream_open(inode
, file
);
53 card
= snd_lookup_minor_data(iminor(inode
), SNDRV_DEVICE_TYPE_CONTROL
);
58 err
= snd_card_file_add(card
, file
);
63 if (!try_module_get(card
->module
)) {
67 ctl
= kzalloc(sizeof(*ctl
), GFP_KERNEL
);
72 INIT_LIST_HEAD(&ctl
->events
);
73 init_waitqueue_head(&ctl
->change_sleep
);
74 spin_lock_init(&ctl
->read_lock
);
76 for (i
= 0; i
< SND_CTL_SUBDEV_ITEMS
; i
++)
77 ctl
->preferred_subdevice
[i
] = -1;
78 ctl
->pid
= get_pid(task_pid(current
));
79 file
->private_data
= ctl
;
80 write_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
81 list_add_tail(&ctl
->list
, &card
->ctl_files
);
82 write_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
87 module_put(card
->module
);
89 snd_card_file_remove(card
, file
);
96 static void snd_ctl_empty_read_queue(struct snd_ctl_file
* ctl
)
99 struct snd_kctl_event
*cread
;
101 spin_lock_irqsave(&ctl
->read_lock
, flags
);
102 while (!list_empty(&ctl
->events
)) {
103 cread
= snd_kctl_event(ctl
->events
.next
);
104 list_del(&cread
->list
);
107 spin_unlock_irqrestore(&ctl
->read_lock
, flags
);
110 static int snd_ctl_release(struct inode
*inode
, struct file
*file
)
113 struct snd_card
*card
;
114 struct snd_ctl_file
*ctl
;
115 struct snd_kcontrol
*control
;
118 ctl
= file
->private_data
;
119 file
->private_data
= NULL
;
121 write_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
122 list_del(&ctl
->list
);
123 write_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
124 down_write(&card
->controls_rwsem
);
125 list_for_each_entry(control
, &card
->controls
, list
)
126 for (idx
= 0; idx
< control
->count
; idx
++)
127 if (control
->vd
[idx
].owner
== ctl
)
128 control
->vd
[idx
].owner
= NULL
;
129 up_write(&card
->controls_rwsem
);
130 snd_ctl_empty_read_queue(ctl
);
133 module_put(card
->module
);
134 snd_card_file_remove(card
, file
);
139 * snd_ctl_notify - Send notification to user-space for a control change
140 * @card: the card to send notification
141 * @mask: the event mask, SNDRV_CTL_EVENT_*
142 * @id: the ctl element id to send notification
144 * This function adds an event record with the given id and mask, appends
145 * to the list and wakes up the user-space for notification. This can be
146 * called in the atomic context.
148 void snd_ctl_notify(struct snd_card
*card
, unsigned int mask
,
149 struct snd_ctl_elem_id
*id
)
152 struct snd_ctl_file
*ctl
;
153 struct snd_kctl_event
*ev
;
155 if (snd_BUG_ON(!card
|| !id
))
159 read_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
160 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
161 card
->mixer_oss_change_count
++;
163 list_for_each_entry(ctl
, &card
->ctl_files
, list
) {
164 if (!ctl
->subscribed
)
166 spin_lock(&ctl
->read_lock
);
167 list_for_each_entry(ev
, &ctl
->events
, list
) {
168 if (ev
->id
.numid
== id
->numid
) {
173 ev
= kzalloc(sizeof(*ev
), GFP_ATOMIC
);
177 list_add_tail(&ev
->list
, &ctl
->events
);
179 dev_err(card
->dev
, "No memory available to allocate event\n");
182 wake_up(&ctl
->change_sleep
);
183 spin_unlock(&ctl
->read_lock
);
184 kill_fasync(&ctl
->fasync
, SIGIO
, POLL_IN
);
186 read_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
188 EXPORT_SYMBOL(snd_ctl_notify
);
191 * snd_ctl_notify_one - Send notification to user-space for a control change
192 * @card: the card to send notification
193 * @mask: the event mask, SNDRV_CTL_EVENT_*
194 * @kctl: the pointer with the control instance
195 * @ioff: the additional offset to the control index
197 * This function calls snd_ctl_notify() and does additional jobs
198 * like LED state changes.
200 void snd_ctl_notify_one(struct snd_card
*card
, unsigned int mask
,
201 struct snd_kcontrol
*kctl
, unsigned int ioff
)
203 struct snd_ctl_elem_id id
= kctl
->id
;
204 struct snd_ctl_layer_ops
*lops
;
208 snd_ctl_notify(card
, mask
, &id
);
209 down_read(&snd_ctl_layer_rwsem
);
210 for (lops
= snd_ctl_layer
; lops
; lops
= lops
->next
)
211 lops
->lnotify(card
, mask
, kctl
, ioff
);
212 up_read(&snd_ctl_layer_rwsem
);
214 EXPORT_SYMBOL(snd_ctl_notify_one
);
217 * snd_ctl_new - create a new control instance with some elements
218 * @kctl: the pointer to store new control instance
219 * @count: the number of elements in this control
220 * @access: the default access flags for elements in this control
221 * @file: given when locking these elements
223 * Allocates a memory object for a new control instance. The instance has
224 * elements as many as the given number (@count). Each element has given
225 * access permissions (@access). Each element is locked when @file is given.
227 * Return: 0 on success, error code on failure
229 static int snd_ctl_new(struct snd_kcontrol
**kctl
, unsigned int count
,
230 unsigned int access
, struct snd_ctl_file
*file
)
234 if (count
== 0 || count
> MAX_CONTROL_COUNT
)
237 *kctl
= kzalloc(struct_size(*kctl
, vd
, count
), GFP_KERNEL
);
241 for (idx
= 0; idx
< count
; idx
++) {
242 (*kctl
)->vd
[idx
].access
= access
;
243 (*kctl
)->vd
[idx
].owner
= file
;
245 (*kctl
)->count
= count
;
251 * snd_ctl_new1 - create a control instance from the template
252 * @ncontrol: the initialization record
253 * @private_data: the private data to set
255 * Allocates a new struct snd_kcontrol instance and initialize from the given
256 * template. When the access field of ncontrol is 0, it's assumed as
257 * READWRITE access. When the count field is 0, it's assumes as one.
259 * Return: The pointer of the newly generated instance, or %NULL on failure.
261 struct snd_kcontrol
*snd_ctl_new1(const struct snd_kcontrol_new
*ncontrol
,
264 struct snd_kcontrol
*kctl
;
269 if (snd_BUG_ON(!ncontrol
|| !ncontrol
->info
))
272 count
= ncontrol
->count
;
276 access
= ncontrol
->access
;
278 access
= SNDRV_CTL_ELEM_ACCESS_READWRITE
;
279 access
&= (SNDRV_CTL_ELEM_ACCESS_READWRITE
|
280 SNDRV_CTL_ELEM_ACCESS_VOLATILE
|
281 SNDRV_CTL_ELEM_ACCESS_INACTIVE
|
282 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE
|
283 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND
|
284 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK
|
285 SNDRV_CTL_ELEM_ACCESS_LED_MASK
|
286 SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK
);
288 err
= snd_ctl_new(&kctl
, count
, access
, NULL
);
292 /* The 'numid' member is decided when calling snd_ctl_add(). */
293 kctl
->id
.iface
= ncontrol
->iface
;
294 kctl
->id
.device
= ncontrol
->device
;
295 kctl
->id
.subdevice
= ncontrol
->subdevice
;
296 if (ncontrol
->name
) {
297 strscpy(kctl
->id
.name
, ncontrol
->name
, sizeof(kctl
->id
.name
));
298 if (strcmp(ncontrol
->name
, kctl
->id
.name
) != 0)
299 pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
300 ncontrol
->name
, kctl
->id
.name
);
302 kctl
->id
.index
= ncontrol
->index
;
304 kctl
->info
= ncontrol
->info
;
305 kctl
->get
= ncontrol
->get
;
306 kctl
->put
= ncontrol
->put
;
307 kctl
->tlv
.p
= ncontrol
->tlv
.p
;
309 kctl
->private_value
= ncontrol
->private_value
;
310 kctl
->private_data
= private_data
;
314 EXPORT_SYMBOL(snd_ctl_new1
);
317 * snd_ctl_free_one - release the control instance
318 * @kcontrol: the control instance
320 * Releases the control instance created via snd_ctl_new()
322 * Don't call this after the control was added to the card.
324 void snd_ctl_free_one(struct snd_kcontrol
*kcontrol
)
327 if (kcontrol
->private_free
)
328 kcontrol
->private_free(kcontrol
);
332 EXPORT_SYMBOL(snd_ctl_free_one
);
334 static bool snd_ctl_remove_numid_conflict(struct snd_card
*card
,
337 struct snd_kcontrol
*kctl
;
339 /* Make sure that the ids assigned to the control do not wrap around */
340 if (card
->last_numid
>= UINT_MAX
- count
)
341 card
->last_numid
= 0;
343 list_for_each_entry(kctl
, &card
->controls
, list
) {
344 if (kctl
->id
.numid
< card
->last_numid
+ 1 + count
&&
345 kctl
->id
.numid
+ kctl
->count
> card
->last_numid
+ 1) {
346 card
->last_numid
= kctl
->id
.numid
+ kctl
->count
- 1;
353 static int snd_ctl_find_hole(struct snd_card
*card
, unsigned int count
)
355 unsigned int iter
= 100000;
357 while (snd_ctl_remove_numid_conflict(card
, count
)) {
359 /* this situation is very unlikely */
360 dev_err(card
->dev
, "unable to allocate new control numid\n");
367 enum snd_ctl_add_mode
{
368 CTL_ADD_EXCLUSIVE
, CTL_REPLACE
, CTL_ADD_ON_REPLACE
,
371 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
372 static int __snd_ctl_add_replace(struct snd_card
*card
,
373 struct snd_kcontrol
*kcontrol
,
374 enum snd_ctl_add_mode mode
)
376 struct snd_ctl_elem_id id
;
378 struct snd_kcontrol
*old
;
382 if (id
.index
> UINT_MAX
- kcontrol
->count
)
385 old
= snd_ctl_find_id(card
, &id
);
387 if (mode
== CTL_REPLACE
)
390 if (mode
== CTL_ADD_EXCLUSIVE
) {
392 "control %i:%i:%i:%s:%i is already present\n",
393 id
.iface
, id
.device
, id
.subdevice
, id
.name
,
398 err
= snd_ctl_remove(card
, old
);
403 if (snd_ctl_find_hole(card
, kcontrol
->count
) < 0)
406 list_add_tail(&kcontrol
->list
, &card
->controls
);
407 card
->controls_count
+= kcontrol
->count
;
408 kcontrol
->id
.numid
= card
->last_numid
+ 1;
409 card
->last_numid
+= kcontrol
->count
;
411 for (idx
= 0; idx
< kcontrol
->count
; idx
++)
412 snd_ctl_notify_one(card
, SNDRV_CTL_EVENT_MASK_ADD
, kcontrol
, idx
);
417 static int snd_ctl_add_replace(struct snd_card
*card
,
418 struct snd_kcontrol
*kcontrol
,
419 enum snd_ctl_add_mode mode
)
425 if (snd_BUG_ON(!card
|| !kcontrol
->info
))
428 down_write(&card
->controls_rwsem
);
429 err
= __snd_ctl_add_replace(card
, kcontrol
, mode
);
430 up_write(&card
->controls_rwsem
);
436 snd_ctl_free_one(kcontrol
);
441 * snd_ctl_add - add the control instance to the card
442 * @card: the card instance
443 * @kcontrol: the control instance to add
445 * Adds the control instance created via snd_ctl_new() or
446 * snd_ctl_new1() to the given card. Assigns also an unique
447 * numid used for fast search.
449 * It frees automatically the control which cannot be added.
451 * Return: Zero if successful, or a negative error code on failure.
454 int snd_ctl_add(struct snd_card
*card
, struct snd_kcontrol
*kcontrol
)
456 return snd_ctl_add_replace(card
, kcontrol
, CTL_ADD_EXCLUSIVE
);
458 EXPORT_SYMBOL(snd_ctl_add
);
461 * snd_ctl_replace - replace the control instance of the card
462 * @card: the card instance
463 * @kcontrol: the control instance to replace
464 * @add_on_replace: add the control if not already added
466 * Replaces the given control. If the given control does not exist
467 * and the add_on_replace flag is set, the control is added. If the
468 * control exists, it is destroyed first.
470 * It frees automatically the control which cannot be added or replaced.
472 * Return: Zero if successful, or a negative error code on failure.
474 int snd_ctl_replace(struct snd_card
*card
, struct snd_kcontrol
*kcontrol
,
477 return snd_ctl_add_replace(card
, kcontrol
,
478 add_on_replace
? CTL_ADD_ON_REPLACE
: CTL_REPLACE
);
480 EXPORT_SYMBOL(snd_ctl_replace
);
483 * snd_ctl_remove - remove the control from the card and release it
484 * @card: the card instance
485 * @kcontrol: the control instance to remove
487 * Removes the control from the card and then releases the instance.
488 * You don't need to call snd_ctl_free_one(). You must be in
489 * the write lock - down_write(&card->controls_rwsem).
491 * Return: 0 if successful, or a negative error code on failure.
493 int snd_ctl_remove(struct snd_card
*card
, struct snd_kcontrol
*kcontrol
)
497 if (snd_BUG_ON(!card
|| !kcontrol
))
499 list_del(&kcontrol
->list
);
500 card
->controls_count
-= kcontrol
->count
;
501 for (idx
= 0; idx
< kcontrol
->count
; idx
++)
502 snd_ctl_notify_one(card
, SNDRV_CTL_EVENT_MASK_REMOVE
, kcontrol
, idx
);
503 snd_ctl_free_one(kcontrol
);
506 EXPORT_SYMBOL(snd_ctl_remove
);
509 * snd_ctl_remove_id - remove the control of the given id and release it
510 * @card: the card instance
511 * @id: the control id to remove
513 * Finds the control instance with the given id, removes it from the
514 * card list and releases it.
516 * Return: 0 if successful, or a negative error code on failure.
518 int snd_ctl_remove_id(struct snd_card
*card
, struct snd_ctl_elem_id
*id
)
520 struct snd_kcontrol
*kctl
;
523 down_write(&card
->controls_rwsem
);
524 kctl
= snd_ctl_find_id(card
, id
);
526 up_write(&card
->controls_rwsem
);
529 ret
= snd_ctl_remove(card
, kctl
);
530 up_write(&card
->controls_rwsem
);
533 EXPORT_SYMBOL(snd_ctl_remove_id
);
536 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
537 * @file: active control handle
538 * @id: the control id to remove
540 * Finds the control instance with the given id, removes it from the
541 * card list and releases it.
543 * Return: 0 if successful, or a negative error code on failure.
545 static int snd_ctl_remove_user_ctl(struct snd_ctl_file
* file
,
546 struct snd_ctl_elem_id
*id
)
548 struct snd_card
*card
= file
->card
;
549 struct snd_kcontrol
*kctl
;
552 down_write(&card
->controls_rwsem
);
553 kctl
= snd_ctl_find_id(card
, id
);
558 if (!(kctl
->vd
[0].access
& SNDRV_CTL_ELEM_ACCESS_USER
)) {
562 for (idx
= 0; idx
< kctl
->count
; idx
++)
563 if (kctl
->vd
[idx
].owner
!= NULL
&& kctl
->vd
[idx
].owner
!= file
) {
567 ret
= snd_ctl_remove(card
, kctl
);
569 up_write(&card
->controls_rwsem
);
574 * snd_ctl_activate_id - activate/inactivate the control of the given id
575 * @card: the card instance
576 * @id: the control id to activate/inactivate
577 * @active: non-zero to activate
579 * Finds the control instance with the given id, and activate or
580 * inactivate the control together with notification, if changed.
581 * The given ID data is filled with full information.
583 * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
585 int snd_ctl_activate_id(struct snd_card
*card
, struct snd_ctl_elem_id
*id
,
588 struct snd_kcontrol
*kctl
;
589 struct snd_kcontrol_volatile
*vd
;
590 unsigned int index_offset
;
593 down_write(&card
->controls_rwsem
);
594 kctl
= snd_ctl_find_id(card
, id
);
599 index_offset
= snd_ctl_get_ioff(kctl
, id
);
600 vd
= &kctl
->vd
[index_offset
];
603 if (!(vd
->access
& SNDRV_CTL_ELEM_ACCESS_INACTIVE
))
605 vd
->access
&= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE
;
607 if (vd
->access
& SNDRV_CTL_ELEM_ACCESS_INACTIVE
)
609 vd
->access
|= SNDRV_CTL_ELEM_ACCESS_INACTIVE
;
611 snd_ctl_build_ioff(id
, kctl
, index_offset
);
612 downgrade_write(&card
->controls_rwsem
);
613 snd_ctl_notify_one(card
, SNDRV_CTL_EVENT_MASK_INFO
, kctl
, index_offset
);
614 up_read(&card
->controls_rwsem
);
618 up_write(&card
->controls_rwsem
);
621 EXPORT_SYMBOL_GPL(snd_ctl_activate_id
);
624 * snd_ctl_rename_id - replace the id of a control on the card
625 * @card: the card instance
626 * @src_id: the old id
627 * @dst_id: the new id
629 * Finds the control with the old id from the card, and replaces the
630 * id with the new one.
632 * Return: Zero if successful, or a negative error code on failure.
634 int snd_ctl_rename_id(struct snd_card
*card
, struct snd_ctl_elem_id
*src_id
,
635 struct snd_ctl_elem_id
*dst_id
)
637 struct snd_kcontrol
*kctl
;
639 down_write(&card
->controls_rwsem
);
640 kctl
= snd_ctl_find_id(card
, src_id
);
642 up_write(&card
->controls_rwsem
);
646 kctl
->id
.numid
= card
->last_numid
+ 1;
647 card
->last_numid
+= kctl
->count
;
648 up_write(&card
->controls_rwsem
);
651 EXPORT_SYMBOL(snd_ctl_rename_id
);
654 * snd_ctl_find_numid - find the control instance with the given number-id
655 * @card: the card instance
656 * @numid: the number-id to search
658 * Finds the control instance with the given number-id from the card.
660 * The caller must down card->controls_rwsem before calling this function
661 * (if the race condition can happen).
663 * Return: The pointer of the instance if found, or %NULL if not.
666 struct snd_kcontrol
*snd_ctl_find_numid(struct snd_card
*card
, unsigned int numid
)
668 struct snd_kcontrol
*kctl
;
670 if (snd_BUG_ON(!card
|| !numid
))
672 list_for_each_entry(kctl
, &card
->controls
, list
) {
673 if (kctl
->id
.numid
<= numid
&& kctl
->id
.numid
+ kctl
->count
> numid
)
678 EXPORT_SYMBOL(snd_ctl_find_numid
);
681 * snd_ctl_find_id - find the control instance with the given id
682 * @card: the card instance
683 * @id: the id to search
685 * Finds the control instance with the given id from the card.
687 * The caller must down card->controls_rwsem before calling this function
688 * (if the race condition can happen).
690 * Return: The pointer of the instance if found, or %NULL if not.
693 struct snd_kcontrol
*snd_ctl_find_id(struct snd_card
*card
,
694 struct snd_ctl_elem_id
*id
)
696 struct snd_kcontrol
*kctl
;
698 if (snd_BUG_ON(!card
|| !id
))
701 return snd_ctl_find_numid(card
, id
->numid
);
702 list_for_each_entry(kctl
, &card
->controls
, list
) {
703 if (kctl
->id
.iface
!= id
->iface
)
705 if (kctl
->id
.device
!= id
->device
)
707 if (kctl
->id
.subdevice
!= id
->subdevice
)
709 if (strncmp(kctl
->id
.name
, id
->name
, sizeof(kctl
->id
.name
)))
711 if (kctl
->id
.index
> id
->index
)
713 if (kctl
->id
.index
+ kctl
->count
<= id
->index
)
719 EXPORT_SYMBOL(snd_ctl_find_id
);
721 static int snd_ctl_card_info(struct snd_card
*card
, struct snd_ctl_file
* ctl
,
722 unsigned int cmd
, void __user
*arg
)
724 struct snd_ctl_card_info
*info
;
726 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
729 down_read(&snd_ioctl_rwsem
);
730 info
->card
= card
->number
;
731 strscpy(info
->id
, card
->id
, sizeof(info
->id
));
732 strscpy(info
->driver
, card
->driver
, sizeof(info
->driver
));
733 strscpy(info
->name
, card
->shortname
, sizeof(info
->name
));
734 strscpy(info
->longname
, card
->longname
, sizeof(info
->longname
));
735 strscpy(info
->mixername
, card
->mixername
, sizeof(info
->mixername
));
736 strscpy(info
->components
, card
->components
, sizeof(info
->components
));
737 up_read(&snd_ioctl_rwsem
);
738 if (copy_to_user(arg
, info
, sizeof(struct snd_ctl_card_info
))) {
746 static int snd_ctl_elem_list(struct snd_card
*card
,
747 struct snd_ctl_elem_list
*list
)
749 struct snd_kcontrol
*kctl
;
750 struct snd_ctl_elem_id id
;
751 unsigned int offset
, space
, jidx
;
754 offset
= list
->offset
;
757 down_read(&card
->controls_rwsem
);
758 list
->count
= card
->controls_count
;
761 list_for_each_entry(kctl
, &card
->controls
, list
) {
762 if (offset
>= kctl
->count
) {
763 offset
-= kctl
->count
;
766 for (jidx
= offset
; jidx
< kctl
->count
; jidx
++) {
767 snd_ctl_build_ioff(&id
, kctl
, jidx
);
768 if (copy_to_user(list
->pids
+ list
->used
, &id
,
781 up_read(&card
->controls_rwsem
);
785 static int snd_ctl_elem_list_user(struct snd_card
*card
,
786 struct snd_ctl_elem_list __user
*_list
)
788 struct snd_ctl_elem_list list
;
791 if (copy_from_user(&list
, _list
, sizeof(list
)))
793 err
= snd_ctl_elem_list(card
, &list
);
796 if (copy_to_user(_list
, &list
, sizeof(list
)))
802 /* Check whether the given kctl info is valid */
803 static int snd_ctl_check_elem_info(struct snd_card
*card
,
804 const struct snd_ctl_elem_info
*info
)
806 static const unsigned int max_value_counts
[] = {
807 [SNDRV_CTL_ELEM_TYPE_BOOLEAN
] = 128,
808 [SNDRV_CTL_ELEM_TYPE_INTEGER
] = 128,
809 [SNDRV_CTL_ELEM_TYPE_ENUMERATED
] = 128,
810 [SNDRV_CTL_ELEM_TYPE_BYTES
] = 512,
811 [SNDRV_CTL_ELEM_TYPE_IEC958
] = 1,
812 [SNDRV_CTL_ELEM_TYPE_INTEGER64
] = 64,
815 if (info
->type
< SNDRV_CTL_ELEM_TYPE_BOOLEAN
||
816 info
->type
> SNDRV_CTL_ELEM_TYPE_INTEGER64
) {
819 "control %i:%i:%i:%s:%i: invalid type %d\n",
820 info
->id
.iface
, info
->id
.device
,
821 info
->id
.subdevice
, info
->id
.name
,
822 info
->id
.index
, info
->type
);
825 if (info
->type
== SNDRV_CTL_ELEM_TYPE_ENUMERATED
&&
826 info
->value
.enumerated
.items
== 0) {
829 "control %i:%i:%i:%s:%i: zero enum items\n",
830 info
->id
.iface
, info
->id
.device
,
831 info
->id
.subdevice
, info
->id
.name
,
835 if (info
->count
> max_value_counts
[info
->type
]) {
838 "control %i:%i:%i:%s:%i: invalid count %d\n",
839 info
->id
.iface
, info
->id
.device
,
840 info
->id
.subdevice
, info
->id
.name
,
841 info
->id
.index
, info
->count
);
848 /* The capacity of struct snd_ctl_elem_value.value.*/
849 static const unsigned int value_sizes
[] = {
850 [SNDRV_CTL_ELEM_TYPE_BOOLEAN
] = sizeof(long),
851 [SNDRV_CTL_ELEM_TYPE_INTEGER
] = sizeof(long),
852 [SNDRV_CTL_ELEM_TYPE_ENUMERATED
] = sizeof(unsigned int),
853 [SNDRV_CTL_ELEM_TYPE_BYTES
] = sizeof(unsigned char),
854 [SNDRV_CTL_ELEM_TYPE_IEC958
] = sizeof(struct snd_aes_iec958
),
855 [SNDRV_CTL_ELEM_TYPE_INTEGER64
] = sizeof(long long),
858 #ifdef CONFIG_SND_CTL_VALIDATION
859 /* fill the remaining snd_ctl_elem_value data with the given pattern */
860 static void fill_remaining_elem_value(struct snd_ctl_elem_value
*control
,
861 struct snd_ctl_elem_info
*info
,
864 size_t offset
= value_sizes
[info
->type
] * info
->count
;
866 offset
= DIV_ROUND_UP(offset
, sizeof(u32
));
867 memset32((u32
*)control
->value
.bytes
.data
+ offset
, pattern
,
868 sizeof(control
->value
) / sizeof(u32
) - offset
);
871 /* check whether the given integer ctl value is valid */
872 static int sanity_check_int_value(struct snd_card
*card
,
873 const struct snd_ctl_elem_value
*control
,
874 const struct snd_ctl_elem_info
*info
,
877 long long lval
, lmin
, lmax
, lstep
;
880 switch (info
->type
) {
882 case SNDRV_CTL_ELEM_TYPE_BOOLEAN
:
883 lval
= control
->value
.integer
.value
[i
];
888 case SNDRV_CTL_ELEM_TYPE_INTEGER
:
889 lval
= control
->value
.integer
.value
[i
];
890 lmin
= info
->value
.integer
.min
;
891 lmax
= info
->value
.integer
.max
;
892 lstep
= info
->value
.integer
.step
;
894 case SNDRV_CTL_ELEM_TYPE_INTEGER64
:
895 lval
= control
->value
.integer64
.value
[i
];
896 lmin
= info
->value
.integer64
.min
;
897 lmax
= info
->value
.integer64
.max
;
898 lstep
= info
->value
.integer64
.step
;
900 case SNDRV_CTL_ELEM_TYPE_ENUMERATED
:
901 lval
= control
->value
.enumerated
.item
[i
];
903 lmax
= info
->value
.enumerated
.items
- 1;
908 if (lval
< lmin
|| lval
> lmax
) {
910 "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
911 control
->id
.iface
, control
->id
.device
,
912 control
->id
.subdevice
, control
->id
.name
,
913 control
->id
.index
, lval
, lmin
, lmax
, i
);
917 div64_u64_rem(lval
, lstep
, &rem
);
920 "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
921 control
->id
.iface
, control
->id
.device
,
922 control
->id
.subdevice
, control
->id
.name
,
923 control
->id
.index
, lval
, lstep
, i
);
931 /* perform sanity checks to the given snd_ctl_elem_value object */
932 static int sanity_check_elem_value(struct snd_card
*card
,
933 const struct snd_ctl_elem_value
*control
,
934 const struct snd_ctl_elem_info
*info
,
941 switch (info
->type
) {
942 case SNDRV_CTL_ELEM_TYPE_BOOLEAN
:
943 case SNDRV_CTL_ELEM_TYPE_INTEGER
:
944 case SNDRV_CTL_ELEM_TYPE_INTEGER64
:
945 case SNDRV_CTL_ELEM_TYPE_ENUMERATED
:
946 for (i
= 0; i
< info
->count
; i
++) {
947 ret
= sanity_check_int_value(card
, control
, info
, i
);
956 /* check whether the remaining area kept untouched */
957 offset
= value_sizes
[info
->type
] * info
->count
;
958 offset
= DIV_ROUND_UP(offset
, sizeof(u32
));
959 p
= (u32
*)control
->value
.bytes
.data
+ offset
;
960 for (; offset
< sizeof(control
->value
) / sizeof(u32
); offset
++, p
++) {
965 *p
= 0; /* clear the checked area */
971 static inline void fill_remaining_elem_value(struct snd_ctl_elem_value
*control
,
972 struct snd_ctl_elem_info
*info
,
977 static inline int sanity_check_elem_value(struct snd_card
*card
,
978 struct snd_ctl_elem_value
*control
,
979 struct snd_ctl_elem_info
*info
,
986 static int __snd_ctl_elem_info(struct snd_card
*card
,
987 struct snd_kcontrol
*kctl
,
988 struct snd_ctl_elem_info
*info
,
989 struct snd_ctl_file
*ctl
)
991 struct snd_kcontrol_volatile
*vd
;
992 unsigned int index_offset
;
995 #ifdef CONFIG_SND_DEBUG
998 result
= snd_power_ref_and_wait(card
);
1000 result
= kctl
->info(kctl
, info
);
1001 snd_power_unref(card
);
1003 snd_BUG_ON(info
->access
);
1004 index_offset
= snd_ctl_get_ioff(kctl
, &info
->id
);
1005 vd
= &kctl
->vd
[index_offset
];
1006 snd_ctl_build_ioff(&info
->id
, kctl
, index_offset
);
1007 info
->access
= vd
->access
;
1009 info
->access
|= SNDRV_CTL_ELEM_ACCESS_LOCK
;
1010 if (vd
->owner
== ctl
)
1011 info
->access
|= SNDRV_CTL_ELEM_ACCESS_OWNER
;
1012 info
->owner
= pid_vnr(vd
->owner
->pid
);
1016 if (!snd_ctl_skip_validation(info
) &&
1017 snd_ctl_check_elem_info(card
, info
) < 0)
1023 static int snd_ctl_elem_info(struct snd_ctl_file
*ctl
,
1024 struct snd_ctl_elem_info
*info
)
1026 struct snd_card
*card
= ctl
->card
;
1027 struct snd_kcontrol
*kctl
;
1030 down_read(&card
->controls_rwsem
);
1031 kctl
= snd_ctl_find_id(card
, &info
->id
);
1035 result
= __snd_ctl_elem_info(card
, kctl
, info
, ctl
);
1036 up_read(&card
->controls_rwsem
);
1040 static int snd_ctl_elem_info_user(struct snd_ctl_file
*ctl
,
1041 struct snd_ctl_elem_info __user
*_info
)
1043 struct snd_ctl_elem_info info
;
1046 if (copy_from_user(&info
, _info
, sizeof(info
)))
1048 result
= snd_ctl_elem_info(ctl
, &info
);
1051 /* drop internal access flags */
1052 info
.access
&= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK
|
1053 SNDRV_CTL_ELEM_ACCESS_LED_MASK
);
1054 if (copy_to_user(_info
, &info
, sizeof(info
)))
1059 static int snd_ctl_elem_read(struct snd_card
*card
,
1060 struct snd_ctl_elem_value
*control
)
1062 struct snd_kcontrol
*kctl
;
1063 struct snd_kcontrol_volatile
*vd
;
1064 unsigned int index_offset
;
1065 struct snd_ctl_elem_info info
;
1066 const u32 pattern
= 0xdeadbeef;
1069 kctl
= snd_ctl_find_id(card
, &control
->id
);
1073 index_offset
= snd_ctl_get_ioff(kctl
, &control
->id
);
1074 vd
= &kctl
->vd
[index_offset
];
1075 if (!(vd
->access
& SNDRV_CTL_ELEM_ACCESS_READ
) || kctl
->get
== NULL
)
1078 snd_ctl_build_ioff(&control
->id
, kctl
, index_offset
);
1080 #ifdef CONFIG_SND_CTL_VALIDATION
1081 /* info is needed only for validation */
1082 memset(&info
, 0, sizeof(info
));
1083 info
.id
= control
->id
;
1084 ret
= __snd_ctl_elem_info(card
, kctl
, &info
, NULL
);
1089 if (!snd_ctl_skip_validation(&info
))
1090 fill_remaining_elem_value(control
, &info
, pattern
);
1091 ret
= snd_power_ref_and_wait(card
);
1093 ret
= kctl
->get(kctl
, control
);
1094 snd_power_unref(card
);
1097 if (!snd_ctl_skip_validation(&info
) &&
1098 sanity_check_elem_value(card
, control
, &info
, pattern
) < 0) {
1100 "control %i:%i:%i:%s:%i: access overflow\n",
1101 control
->id
.iface
, control
->id
.device
,
1102 control
->id
.subdevice
, control
->id
.name
,
1109 static int snd_ctl_elem_read_user(struct snd_card
*card
,
1110 struct snd_ctl_elem_value __user
*_control
)
1112 struct snd_ctl_elem_value
*control
;
1115 control
= memdup_user(_control
, sizeof(*control
));
1116 if (IS_ERR(control
))
1117 return PTR_ERR(control
);
1119 down_read(&card
->controls_rwsem
);
1120 result
= snd_ctl_elem_read(card
, control
);
1121 up_read(&card
->controls_rwsem
);
1125 if (copy_to_user(_control
, control
, sizeof(*control
)))
1132 static int snd_ctl_elem_write(struct snd_card
*card
, struct snd_ctl_file
*file
,
1133 struct snd_ctl_elem_value
*control
)
1135 struct snd_kcontrol
*kctl
;
1136 struct snd_kcontrol_volatile
*vd
;
1137 unsigned int index_offset
;
1140 down_write(&card
->controls_rwsem
);
1141 kctl
= snd_ctl_find_id(card
, &control
->id
);
1143 up_write(&card
->controls_rwsem
);
1147 index_offset
= snd_ctl_get_ioff(kctl
, &control
->id
);
1148 vd
= &kctl
->vd
[index_offset
];
1149 if (!(vd
->access
& SNDRV_CTL_ELEM_ACCESS_WRITE
) || kctl
->put
== NULL
||
1150 (file
&& vd
->owner
&& vd
->owner
!= file
)) {
1151 up_write(&card
->controls_rwsem
);
1155 snd_ctl_build_ioff(&control
->id
, kctl
, index_offset
);
1156 result
= snd_power_ref_and_wait(card
);
1158 result
= kctl
->put(kctl
, control
);
1159 snd_power_unref(card
);
1161 up_write(&card
->controls_rwsem
);
1166 downgrade_write(&card
->controls_rwsem
);
1167 snd_ctl_notify_one(card
, SNDRV_CTL_EVENT_MASK_VALUE
, kctl
, index_offset
);
1168 up_read(&card
->controls_rwsem
);
1170 up_write(&card
->controls_rwsem
);
1176 static int snd_ctl_elem_write_user(struct snd_ctl_file
*file
,
1177 struct snd_ctl_elem_value __user
*_control
)
1179 struct snd_ctl_elem_value
*control
;
1180 struct snd_card
*card
;
1183 control
= memdup_user(_control
, sizeof(*control
));
1184 if (IS_ERR(control
))
1185 return PTR_ERR(control
);
1188 result
= snd_ctl_elem_write(card
, file
, control
);
1192 if (copy_to_user(_control
, control
, sizeof(*control
)))
1199 static int snd_ctl_elem_lock(struct snd_ctl_file
*file
,
1200 struct snd_ctl_elem_id __user
*_id
)
1202 struct snd_card
*card
= file
->card
;
1203 struct snd_ctl_elem_id id
;
1204 struct snd_kcontrol
*kctl
;
1205 struct snd_kcontrol_volatile
*vd
;
1208 if (copy_from_user(&id
, _id
, sizeof(id
)))
1210 down_write(&card
->controls_rwsem
);
1211 kctl
= snd_ctl_find_id(card
, &id
);
1215 vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, &id
)];
1216 if (vd
->owner
!= NULL
)
1223 up_write(&card
->controls_rwsem
);
1227 static int snd_ctl_elem_unlock(struct snd_ctl_file
*file
,
1228 struct snd_ctl_elem_id __user
*_id
)
1230 struct snd_card
*card
= file
->card
;
1231 struct snd_ctl_elem_id id
;
1232 struct snd_kcontrol
*kctl
;
1233 struct snd_kcontrol_volatile
*vd
;
1236 if (copy_from_user(&id
, _id
, sizeof(id
)))
1238 down_write(&card
->controls_rwsem
);
1239 kctl
= snd_ctl_find_id(card
, &id
);
1243 vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, &id
)];
1244 if (vd
->owner
== NULL
)
1246 else if (vd
->owner
!= file
)
1253 up_write(&card
->controls_rwsem
);
1257 struct user_element
{
1258 struct snd_ctl_elem_info info
;
1259 struct snd_card
*card
;
1260 char *elem_data
; /* element data */
1261 unsigned long elem_data_size
; /* size of element data in bytes */
1262 void *tlv_data
; /* TLV data */
1263 unsigned long tlv_data_size
; /* TLV data size */
1264 void *priv_data
; /* private data (like strings for enumerated type) */
1267 // check whether the addition (in bytes) of user ctl element may overflow the limit.
1268 static bool check_user_elem_overflow(struct snd_card
*card
, ssize_t add
)
1270 return (ssize_t
)card
->user_ctl_alloc_size
+ add
> max_user_ctl_alloc_size
;
1273 static int snd_ctl_elem_user_info(struct snd_kcontrol
*kcontrol
,
1274 struct snd_ctl_elem_info
*uinfo
)
1276 struct user_element
*ue
= kcontrol
->private_data
;
1277 unsigned int offset
;
1279 offset
= snd_ctl_get_ioff(kcontrol
, &uinfo
->id
);
1281 snd_ctl_build_ioff(&uinfo
->id
, kcontrol
, offset
);
1286 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol
*kcontrol
,
1287 struct snd_ctl_elem_info
*uinfo
)
1289 struct user_element
*ue
= kcontrol
->private_data
;
1292 unsigned int offset
;
1294 item
= uinfo
->value
.enumerated
.item
;
1296 offset
= snd_ctl_get_ioff(kcontrol
, &uinfo
->id
);
1298 snd_ctl_build_ioff(&uinfo
->id
, kcontrol
, offset
);
1300 item
= min(item
, uinfo
->value
.enumerated
.items
- 1);
1301 uinfo
->value
.enumerated
.item
= item
;
1303 names
= ue
->priv_data
;
1304 for (; item
> 0; --item
)
1305 names
+= strlen(names
) + 1;
1306 strcpy(uinfo
->value
.enumerated
.name
, names
);
1311 static int snd_ctl_elem_user_get(struct snd_kcontrol
*kcontrol
,
1312 struct snd_ctl_elem_value
*ucontrol
)
1314 struct user_element
*ue
= kcontrol
->private_data
;
1315 unsigned int size
= ue
->elem_data_size
;
1316 char *src
= ue
->elem_data
+
1317 snd_ctl_get_ioff(kcontrol
, &ucontrol
->id
) * size
;
1319 memcpy(&ucontrol
->value
, src
, size
);
1323 static int snd_ctl_elem_user_put(struct snd_kcontrol
*kcontrol
,
1324 struct snd_ctl_elem_value
*ucontrol
)
1327 struct user_element
*ue
= kcontrol
->private_data
;
1328 unsigned int size
= ue
->elem_data_size
;
1329 char *dst
= ue
->elem_data
+
1330 snd_ctl_get_ioff(kcontrol
, &ucontrol
->id
) * size
;
1332 change
= memcmp(&ucontrol
->value
, dst
, size
) != 0;
1334 memcpy(dst
, &ucontrol
->value
, size
);
1338 /* called in controls_rwsem write lock */
1339 static int replace_user_tlv(struct snd_kcontrol
*kctl
, unsigned int __user
*buf
,
1342 struct user_element
*ue
= kctl
->private_data
;
1343 unsigned int *container
;
1344 unsigned int mask
= 0;
1348 if (size
> 1024 * 128) /* sane value */
1351 // does the TLV size change cause overflow?
1352 if (check_user_elem_overflow(ue
->card
, (ssize_t
)(size
- ue
->tlv_data_size
)))
1355 container
= vmemdup_user(buf
, size
);
1356 if (IS_ERR(container
))
1357 return PTR_ERR(container
);
1359 change
= ue
->tlv_data_size
!= size
;
1361 change
= memcmp(ue
->tlv_data
, container
, size
) != 0;
1367 if (ue
->tlv_data
== NULL
) {
1368 /* Now TLV data is available. */
1369 for (i
= 0; i
< kctl
->count
; ++i
)
1370 kctl
->vd
[i
].access
|= SNDRV_CTL_ELEM_ACCESS_TLV_READ
;
1371 mask
= SNDRV_CTL_EVENT_MASK_INFO
;
1373 ue
->card
->user_ctl_alloc_size
-= ue
->tlv_data_size
;
1374 ue
->tlv_data_size
= 0;
1375 kvfree(ue
->tlv_data
);
1378 ue
->tlv_data
= container
;
1379 ue
->tlv_data_size
= size
;
1380 // decremented at private_free.
1381 ue
->card
->user_ctl_alloc_size
+= size
;
1383 mask
|= SNDRV_CTL_EVENT_MASK_TLV
;
1384 for (i
= 0; i
< kctl
->count
; ++i
)
1385 snd_ctl_notify_one(ue
->card
, mask
, kctl
, i
);
1390 static int read_user_tlv(struct snd_kcontrol
*kctl
, unsigned int __user
*buf
,
1393 struct user_element
*ue
= kctl
->private_data
;
1395 if (ue
->tlv_data_size
== 0 || ue
->tlv_data
== NULL
)
1398 if (size
< ue
->tlv_data_size
)
1401 if (copy_to_user(buf
, ue
->tlv_data
, ue
->tlv_data_size
))
1407 static int snd_ctl_elem_user_tlv(struct snd_kcontrol
*kctl
, int op_flag
,
1408 unsigned int size
, unsigned int __user
*buf
)
1410 if (op_flag
== SNDRV_CTL_TLV_OP_WRITE
)
1411 return replace_user_tlv(kctl
, buf
, size
);
1413 return read_user_tlv(kctl
, buf
, size
);
1416 /* called in controls_rwsem write lock */
1417 static int snd_ctl_elem_init_enum_names(struct user_element
*ue
)
1420 size_t buf_len
, name_len
;
1422 const uintptr_t user_ptrval
= ue
->info
.value
.enumerated
.names_ptr
;
1424 buf_len
= ue
->info
.value
.enumerated
.names_length
;
1425 if (buf_len
> 64 * 1024)
1428 if (check_user_elem_overflow(ue
->card
, buf_len
))
1430 names
= vmemdup_user((const void __user
*)user_ptrval
, buf_len
);
1432 return PTR_ERR(names
);
1434 /* check that there are enough valid names */
1436 for (i
= 0; i
< ue
->info
.value
.enumerated
.items
; ++i
) {
1437 name_len
= strnlen(p
, buf_len
);
1438 if (name_len
== 0 || name_len
>= 64 || name_len
== buf_len
) {
1443 buf_len
-= name_len
+ 1;
1446 ue
->priv_data
= names
;
1447 ue
->info
.value
.enumerated
.names_ptr
= 0;
1448 // increment the allocation size; decremented again at private_free.
1449 ue
->card
->user_ctl_alloc_size
+= ue
->info
.value
.enumerated
.names_length
;
1454 static size_t compute_user_elem_size(size_t size
, unsigned int count
)
1456 return sizeof(struct user_element
) + size
* count
;
1459 static void snd_ctl_elem_user_free(struct snd_kcontrol
*kcontrol
)
1461 struct user_element
*ue
= kcontrol
->private_data
;
1463 // decrement the allocation size.
1464 ue
->card
->user_ctl_alloc_size
-= compute_user_elem_size(ue
->elem_data_size
, kcontrol
->count
);
1465 ue
->card
->user_ctl_alloc_size
-= ue
->tlv_data_size
;
1467 ue
->card
->user_ctl_alloc_size
-= ue
->info
.value
.enumerated
.names_length
;
1469 kvfree(ue
->tlv_data
);
1470 kvfree(ue
->priv_data
);
1474 static int snd_ctl_elem_add(struct snd_ctl_file
*file
,
1475 struct snd_ctl_elem_info
*info
, int replace
)
1477 struct snd_card
*card
= file
->card
;
1478 struct snd_kcontrol
*kctl
;
1480 unsigned int access
;
1483 struct user_element
*ue
;
1484 unsigned int offset
;
1487 if (!*info
->id
.name
)
1489 if (strnlen(info
->id
.name
, sizeof(info
->id
.name
)) >= sizeof(info
->id
.name
))
1492 /* Delete a control to replace them if needed. */
1495 err
= snd_ctl_remove_user_ctl(file
, &info
->id
);
1500 /* Check the number of elements for this userspace control. */
1501 count
= info
->owner
;
1505 /* Arrange access permissions if needed. */
1506 access
= info
->access
;
1508 access
= SNDRV_CTL_ELEM_ACCESS_READWRITE
;
1509 access
&= (SNDRV_CTL_ELEM_ACCESS_READWRITE
|
1510 SNDRV_CTL_ELEM_ACCESS_INACTIVE
|
1511 SNDRV_CTL_ELEM_ACCESS_TLV_WRITE
);
1513 /* In initial state, nothing is available as TLV container. */
1514 if (access
& SNDRV_CTL_ELEM_ACCESS_TLV_WRITE
)
1515 access
|= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK
;
1516 access
|= SNDRV_CTL_ELEM_ACCESS_USER
;
1519 * Check information and calculate the size of data specific to
1520 * this userspace control.
1522 /* pass NULL to card for suppressing error messages */
1523 err
= snd_ctl_check_elem_info(NULL
, info
);
1526 /* user-space control doesn't allow zero-size data */
1527 if (info
->count
< 1)
1529 private_size
= value_sizes
[info
->type
] * info
->count
;
1530 alloc_size
= compute_user_elem_size(private_size
, count
);
1532 down_write(&card
->controls_rwsem
);
1533 if (check_user_elem_overflow(card
, alloc_size
)) {
1539 * Keep memory object for this userspace control. After passing this
1540 * code block, the instance should be freed by snd_ctl_free_one().
1542 * Note that these elements in this control are locked.
1544 err
= snd_ctl_new(&kctl
, count
, access
, file
);
1547 memcpy(&kctl
->id
, &info
->id
, sizeof(kctl
->id
));
1548 ue
= kzalloc(alloc_size
, GFP_KERNEL
);
1554 kctl
->private_data
= ue
;
1555 kctl
->private_free
= snd_ctl_elem_user_free
;
1557 // increment the allocated size; decremented again at private_free.
1558 card
->user_ctl_alloc_size
+= alloc_size
;
1560 /* Set private data for this userspace control. */
1563 ue
->info
.access
= 0;
1564 ue
->elem_data
= (char *)ue
+ sizeof(*ue
);
1565 ue
->elem_data_size
= private_size
;
1566 if (ue
->info
.type
== SNDRV_CTL_ELEM_TYPE_ENUMERATED
) {
1567 err
= snd_ctl_elem_init_enum_names(ue
);
1569 snd_ctl_free_one(kctl
);
1574 /* Set callback functions. */
1575 if (info
->type
== SNDRV_CTL_ELEM_TYPE_ENUMERATED
)
1576 kctl
->info
= snd_ctl_elem_user_enum_info
;
1578 kctl
->info
= snd_ctl_elem_user_info
;
1579 if (access
& SNDRV_CTL_ELEM_ACCESS_READ
)
1580 kctl
->get
= snd_ctl_elem_user_get
;
1581 if (access
& SNDRV_CTL_ELEM_ACCESS_WRITE
)
1582 kctl
->put
= snd_ctl_elem_user_put
;
1583 if (access
& SNDRV_CTL_ELEM_ACCESS_TLV_WRITE
)
1584 kctl
->tlv
.c
= snd_ctl_elem_user_tlv
;
1586 /* This function manage to free the instance on failure. */
1587 err
= __snd_ctl_add_replace(card
, kctl
, CTL_ADD_EXCLUSIVE
);
1589 snd_ctl_free_one(kctl
);
1592 offset
= snd_ctl_get_ioff(kctl
, &info
->id
);
1593 snd_ctl_build_ioff(&info
->id
, kctl
, offset
);
1595 * Here we cannot fill any field for the number of elements added by
1596 * this operation because there're no specific fields. The usage of
1597 * 'owner' field for this purpose may cause any bugs to userspace
1598 * applications because the field originally means PID of a process
1599 * which locks the element.
1602 up_write(&card
->controls_rwsem
);
1606 static int snd_ctl_elem_add_user(struct snd_ctl_file
*file
,
1607 struct snd_ctl_elem_info __user
*_info
, int replace
)
1609 struct snd_ctl_elem_info info
;
1612 if (copy_from_user(&info
, _info
, sizeof(info
)))
1614 err
= snd_ctl_elem_add(file
, &info
, replace
);
1617 if (copy_to_user(_info
, &info
, sizeof(info
))) {
1618 snd_ctl_remove_user_ctl(file
, &info
.id
);
1625 static int snd_ctl_elem_remove(struct snd_ctl_file
*file
,
1626 struct snd_ctl_elem_id __user
*_id
)
1628 struct snd_ctl_elem_id id
;
1630 if (copy_from_user(&id
, _id
, sizeof(id
)))
1632 return snd_ctl_remove_user_ctl(file
, &id
);
1635 static int snd_ctl_subscribe_events(struct snd_ctl_file
*file
, int __user
*ptr
)
1638 if (get_user(subscribe
, ptr
))
1640 if (subscribe
< 0) {
1641 subscribe
= file
->subscribed
;
1642 if (put_user(subscribe
, ptr
))
1647 file
->subscribed
= 1;
1649 } else if (file
->subscribed
) {
1650 snd_ctl_empty_read_queue(file
);
1651 file
->subscribed
= 0;
1656 static int call_tlv_handler(struct snd_ctl_file
*file
, int op_flag
,
1657 struct snd_kcontrol
*kctl
,
1658 struct snd_ctl_elem_id
*id
,
1659 unsigned int __user
*buf
, unsigned int size
)
1661 static const struct {
1665 {SNDRV_CTL_TLV_OP_READ
, SNDRV_CTL_ELEM_ACCESS_TLV_READ
},
1666 {SNDRV_CTL_TLV_OP_WRITE
, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE
},
1667 {SNDRV_CTL_TLV_OP_CMD
, SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND
},
1669 struct snd_kcontrol_volatile
*vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, id
)];
1672 /* Check support of the request for this element. */
1673 for (i
= 0; i
< ARRAY_SIZE(pairs
); ++i
) {
1674 if (op_flag
== pairs
[i
].op
&& (vd
->access
& pairs
[i
].perm
))
1677 if (i
== ARRAY_SIZE(pairs
))
1680 if (kctl
->tlv
.c
== NULL
)
1683 /* Write and command operations are not allowed for locked element. */
1684 if (op_flag
!= SNDRV_CTL_TLV_OP_READ
&&
1685 vd
->owner
!= NULL
&& vd
->owner
!= file
)
1688 ret
= snd_power_ref_and_wait(file
->card
);
1690 ret
= kctl
->tlv
.c(kctl
, op_flag
, size
, buf
);
1691 snd_power_unref(file
->card
);
1695 static int read_tlv_buf(struct snd_kcontrol
*kctl
, struct snd_ctl_elem_id
*id
,
1696 unsigned int __user
*buf
, unsigned int size
)
1698 struct snd_kcontrol_volatile
*vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, id
)];
1701 if (!(vd
->access
& SNDRV_CTL_ELEM_ACCESS_TLV_READ
))
1704 if (kctl
->tlv
.p
== NULL
)
1707 len
= sizeof(unsigned int) * 2 + kctl
->tlv
.p
[1];
1711 if (copy_to_user(buf
, kctl
->tlv
.p
, len
))
1717 static int snd_ctl_tlv_ioctl(struct snd_ctl_file
*file
,
1718 struct snd_ctl_tlv __user
*buf
,
1721 struct snd_ctl_tlv header
;
1722 unsigned int __user
*container
;
1723 unsigned int container_size
;
1724 struct snd_kcontrol
*kctl
;
1725 struct snd_ctl_elem_id id
;
1726 struct snd_kcontrol_volatile
*vd
;
1728 if (copy_from_user(&header
, buf
, sizeof(header
)))
1731 /* In design of control core, numerical ID starts at 1. */
1732 if (header
.numid
== 0)
1735 /* At least, container should include type and length fields. */
1736 if (header
.length
< sizeof(unsigned int) * 2)
1738 container_size
= header
.length
;
1739 container
= buf
->tlv
;
1741 kctl
= snd_ctl_find_numid(file
->card
, header
.numid
);
1745 /* Calculate index of the element in this set. */
1747 snd_ctl_build_ioff(&id
, kctl
, header
.numid
- id
.numid
);
1748 vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, &id
)];
1750 if (vd
->access
& SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK
) {
1751 return call_tlv_handler(file
, op_flag
, kctl
, &id
, container
,
1754 if (op_flag
== SNDRV_CTL_TLV_OP_READ
) {
1755 return read_tlv_buf(kctl
, &id
, container
,
1760 /* Not supported. */
1764 static long snd_ctl_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1766 struct snd_ctl_file
*ctl
;
1767 struct snd_card
*card
;
1768 struct snd_kctl_ioctl
*p
;
1769 void __user
*argp
= (void __user
*)arg
;
1770 int __user
*ip
= argp
;
1773 ctl
= file
->private_data
;
1775 if (snd_BUG_ON(!card
))
1778 case SNDRV_CTL_IOCTL_PVERSION
:
1779 return put_user(SNDRV_CTL_VERSION
, ip
) ? -EFAULT
: 0;
1780 case SNDRV_CTL_IOCTL_CARD_INFO
:
1781 return snd_ctl_card_info(card
, ctl
, cmd
, argp
);
1782 case SNDRV_CTL_IOCTL_ELEM_LIST
:
1783 return snd_ctl_elem_list_user(card
, argp
);
1784 case SNDRV_CTL_IOCTL_ELEM_INFO
:
1785 return snd_ctl_elem_info_user(ctl
, argp
);
1786 case SNDRV_CTL_IOCTL_ELEM_READ
:
1787 return snd_ctl_elem_read_user(card
, argp
);
1788 case SNDRV_CTL_IOCTL_ELEM_WRITE
:
1789 return snd_ctl_elem_write_user(ctl
, argp
);
1790 case SNDRV_CTL_IOCTL_ELEM_LOCK
:
1791 return snd_ctl_elem_lock(ctl
, argp
);
1792 case SNDRV_CTL_IOCTL_ELEM_UNLOCK
:
1793 return snd_ctl_elem_unlock(ctl
, argp
);
1794 case SNDRV_CTL_IOCTL_ELEM_ADD
:
1795 return snd_ctl_elem_add_user(ctl
, argp
, 0);
1796 case SNDRV_CTL_IOCTL_ELEM_REPLACE
:
1797 return snd_ctl_elem_add_user(ctl
, argp
, 1);
1798 case SNDRV_CTL_IOCTL_ELEM_REMOVE
:
1799 return snd_ctl_elem_remove(ctl
, argp
);
1800 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS
:
1801 return snd_ctl_subscribe_events(ctl
, ip
);
1802 case SNDRV_CTL_IOCTL_TLV_READ
:
1803 down_read(&ctl
->card
->controls_rwsem
);
1804 err
= snd_ctl_tlv_ioctl(ctl
, argp
, SNDRV_CTL_TLV_OP_READ
);
1805 up_read(&ctl
->card
->controls_rwsem
);
1807 case SNDRV_CTL_IOCTL_TLV_WRITE
:
1808 down_write(&ctl
->card
->controls_rwsem
);
1809 err
= snd_ctl_tlv_ioctl(ctl
, argp
, SNDRV_CTL_TLV_OP_WRITE
);
1810 up_write(&ctl
->card
->controls_rwsem
);
1812 case SNDRV_CTL_IOCTL_TLV_COMMAND
:
1813 down_write(&ctl
->card
->controls_rwsem
);
1814 err
= snd_ctl_tlv_ioctl(ctl
, argp
, SNDRV_CTL_TLV_OP_CMD
);
1815 up_write(&ctl
->card
->controls_rwsem
);
1817 case SNDRV_CTL_IOCTL_POWER
:
1818 return -ENOPROTOOPT
;
1819 case SNDRV_CTL_IOCTL_POWER_STATE
:
1820 return put_user(SNDRV_CTL_POWER_D0
, ip
) ? -EFAULT
: 0;
1822 down_read(&snd_ioctl_rwsem
);
1823 list_for_each_entry(p
, &snd_control_ioctls
, list
) {
1824 err
= p
->fioctl(card
, ctl
, cmd
, arg
);
1825 if (err
!= -ENOIOCTLCMD
) {
1826 up_read(&snd_ioctl_rwsem
);
1830 up_read(&snd_ioctl_rwsem
);
1831 dev_dbg(card
->dev
, "unknown ioctl = 0x%x\n", cmd
);
1835 static ssize_t
snd_ctl_read(struct file
*file
, char __user
*buffer
,
1836 size_t count
, loff_t
* offset
)
1838 struct snd_ctl_file
*ctl
;
1842 ctl
= file
->private_data
;
1843 if (snd_BUG_ON(!ctl
|| !ctl
->card
))
1845 if (!ctl
->subscribed
)
1847 if (count
< sizeof(struct snd_ctl_event
))
1849 spin_lock_irq(&ctl
->read_lock
);
1850 while (count
>= sizeof(struct snd_ctl_event
)) {
1851 struct snd_ctl_event ev
;
1852 struct snd_kctl_event
*kev
;
1853 while (list_empty(&ctl
->events
)) {
1854 wait_queue_entry_t wait
;
1855 if ((file
->f_flags
& O_NONBLOCK
) != 0 || result
> 0) {
1859 init_waitqueue_entry(&wait
, current
);
1860 add_wait_queue(&ctl
->change_sleep
, &wait
);
1861 set_current_state(TASK_INTERRUPTIBLE
);
1862 spin_unlock_irq(&ctl
->read_lock
);
1864 remove_wait_queue(&ctl
->change_sleep
, &wait
);
1865 if (ctl
->card
->shutdown
)
1867 if (signal_pending(current
))
1868 return -ERESTARTSYS
;
1869 spin_lock_irq(&ctl
->read_lock
);
1871 kev
= snd_kctl_event(ctl
->events
.next
);
1872 ev
.type
= SNDRV_CTL_EVENT_ELEM
;
1873 ev
.data
.elem
.mask
= kev
->mask
;
1874 ev
.data
.elem
.id
= kev
->id
;
1875 list_del(&kev
->list
);
1876 spin_unlock_irq(&ctl
->read_lock
);
1878 if (copy_to_user(buffer
, &ev
, sizeof(struct snd_ctl_event
))) {
1882 spin_lock_irq(&ctl
->read_lock
);
1883 buffer
+= sizeof(struct snd_ctl_event
);
1884 count
-= sizeof(struct snd_ctl_event
);
1885 result
+= sizeof(struct snd_ctl_event
);
1888 spin_unlock_irq(&ctl
->read_lock
);
1890 return result
> 0 ? result
: err
;
1893 static __poll_t
snd_ctl_poll(struct file
*file
, poll_table
* wait
)
1896 struct snd_ctl_file
*ctl
;
1898 ctl
= file
->private_data
;
1899 if (!ctl
->subscribed
)
1901 poll_wait(file
, &ctl
->change_sleep
, wait
);
1904 if (!list_empty(&ctl
->events
))
1905 mask
|= EPOLLIN
| EPOLLRDNORM
;
1911 * register the device-specific control-ioctls.
1912 * called from each device manager like pcm.c, hwdep.c, etc.
1914 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn
, struct list_head
*lists
)
1916 struct snd_kctl_ioctl
*pn
;
1918 pn
= kzalloc(sizeof(struct snd_kctl_ioctl
), GFP_KERNEL
);
1922 down_write(&snd_ioctl_rwsem
);
1923 list_add_tail(&pn
->list
, lists
);
1924 up_write(&snd_ioctl_rwsem
);
1929 * snd_ctl_register_ioctl - register the device-specific control-ioctls
1930 * @fcn: ioctl callback function
1932 * called from each device manager like pcm.c, hwdep.c, etc.
1934 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn
)
1936 return _snd_ctl_register_ioctl(fcn
, &snd_control_ioctls
);
1938 EXPORT_SYMBOL(snd_ctl_register_ioctl
);
1940 #ifdef CONFIG_COMPAT
1942 * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1944 * @fcn: ioctl callback function
1946 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn
)
1948 return _snd_ctl_register_ioctl(fcn
, &snd_control_compat_ioctls
);
1950 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat
);
1954 * de-register the device-specific control-ioctls.
1956 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn
,
1957 struct list_head
*lists
)
1959 struct snd_kctl_ioctl
*p
;
1961 if (snd_BUG_ON(!fcn
))
1963 down_write(&snd_ioctl_rwsem
);
1964 list_for_each_entry(p
, lists
, list
) {
1965 if (p
->fioctl
== fcn
) {
1967 up_write(&snd_ioctl_rwsem
);
1972 up_write(&snd_ioctl_rwsem
);
1978 * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1979 * @fcn: ioctl callback function to unregister
1981 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn
)
1983 return _snd_ctl_unregister_ioctl(fcn
, &snd_control_ioctls
);
1985 EXPORT_SYMBOL(snd_ctl_unregister_ioctl
);
1987 #ifdef CONFIG_COMPAT
1989 * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
1990 * 32bit control-ioctls
1991 * @fcn: ioctl callback function to unregister
1993 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn
)
1995 return _snd_ctl_unregister_ioctl(fcn
, &snd_control_compat_ioctls
);
1997 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat
);
2000 static int snd_ctl_fasync(int fd
, struct file
* file
, int on
)
2002 struct snd_ctl_file
*ctl
;
2004 ctl
= file
->private_data
;
2005 return fasync_helper(fd
, file
, on
, &ctl
->fasync
);
2008 /* return the preferred subdevice number if already assigned;
2009 * otherwise return -1
2011 int snd_ctl_get_preferred_subdevice(struct snd_card
*card
, int type
)
2013 struct snd_ctl_file
*kctl
;
2015 unsigned long flags
;
2017 read_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
2018 list_for_each_entry(kctl
, &card
->ctl_files
, list
) {
2019 if (kctl
->pid
== task_pid(current
)) {
2020 subdevice
= kctl
->preferred_subdevice
[type
];
2021 if (subdevice
!= -1)
2025 read_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
2028 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice
);
2033 #ifdef CONFIG_COMPAT
2034 #include "control_compat.c"
2036 #define snd_ctl_ioctl_compat NULL
2040 * control layers (audio LED etc.)
2044 * snd_ctl_request_layer - request to use the layer
2045 * @module_name: Name of the kernel module (NULL == build-in)
2047 * Return an error code when the module cannot be loaded.
2049 int snd_ctl_request_layer(const char *module_name
)
2051 struct snd_ctl_layer_ops
*lops
;
2053 if (module_name
== NULL
)
2055 down_read(&snd_ctl_layer_rwsem
);
2056 for (lops
= snd_ctl_layer
; lops
; lops
= lops
->next
)
2057 if (strcmp(lops
->module_name
, module_name
) == 0)
2059 up_read(&snd_ctl_layer_rwsem
);
2062 return request_module(module_name
);
2064 EXPORT_SYMBOL_GPL(snd_ctl_request_layer
);
2067 * snd_ctl_register_layer - register new control layer
2068 * @lops: operation structure
2070 * The new layer can track all control elements and do additional
2071 * operations on top (like audio LED handling).
2073 void snd_ctl_register_layer(struct snd_ctl_layer_ops
*lops
)
2075 struct snd_card
*card
;
2078 down_write(&snd_ctl_layer_rwsem
);
2079 lops
->next
= snd_ctl_layer
;
2080 snd_ctl_layer
= lops
;
2081 up_write(&snd_ctl_layer_rwsem
);
2082 for (card_number
= 0; card_number
< SNDRV_CARDS
; card_number
++) {
2083 card
= snd_card_ref(card_number
);
2085 down_read(&card
->controls_rwsem
);
2086 lops
->lregister(card
);
2087 up_read(&card
->controls_rwsem
);
2088 snd_card_unref(card
);
2092 EXPORT_SYMBOL_GPL(snd_ctl_register_layer
);
2095 * snd_ctl_disconnect_layer - disconnect control layer
2096 * @lops: operation structure
2098 * It is expected that the information about tracked cards
2099 * is freed before this call (the disconnect callback is
2102 void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops
*lops
)
2104 struct snd_ctl_layer_ops
*lops2
, *prev_lops2
;
2106 down_write(&snd_ctl_layer_rwsem
);
2107 for (lops2
= snd_ctl_layer
, prev_lops2
= NULL
; lops2
; lops2
= lops2
->next
) {
2108 if (lops2
== lops
) {
2110 snd_ctl_layer
= lops
->next
;
2112 prev_lops2
->next
= lops
->next
;
2117 up_write(&snd_ctl_layer_rwsem
);
2119 EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer
);
2125 static const struct file_operations snd_ctl_f_ops
=
2127 .owner
= THIS_MODULE
,
2128 .read
= snd_ctl_read
,
2129 .open
= snd_ctl_open
,
2130 .release
= snd_ctl_release
,
2131 .llseek
= no_llseek
,
2132 .poll
= snd_ctl_poll
,
2133 .unlocked_ioctl
= snd_ctl_ioctl
,
2134 .compat_ioctl
= snd_ctl_ioctl_compat
,
2135 .fasync
= snd_ctl_fasync
,
2139 * registration of the control device
2141 static int snd_ctl_dev_register(struct snd_device
*device
)
2143 struct snd_card
*card
= device
->device_data
;
2144 struct snd_ctl_layer_ops
*lops
;
2147 err
= snd_register_device(SNDRV_DEVICE_TYPE_CONTROL
, card
, -1,
2148 &snd_ctl_f_ops
, card
, &card
->ctl_dev
);
2151 down_read(&card
->controls_rwsem
);
2152 down_read(&snd_ctl_layer_rwsem
);
2153 for (lops
= snd_ctl_layer
; lops
; lops
= lops
->next
)
2154 lops
->lregister(card
);
2155 up_read(&snd_ctl_layer_rwsem
);
2156 up_read(&card
->controls_rwsem
);
2161 * disconnection of the control device
2163 static int snd_ctl_dev_disconnect(struct snd_device
*device
)
2165 struct snd_card
*card
= device
->device_data
;
2166 struct snd_ctl_file
*ctl
;
2167 struct snd_ctl_layer_ops
*lops
;
2168 unsigned long flags
;
2170 read_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
2171 list_for_each_entry(ctl
, &card
->ctl_files
, list
) {
2172 wake_up(&ctl
->change_sleep
);
2173 kill_fasync(&ctl
->fasync
, SIGIO
, POLL_ERR
);
2175 read_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
2177 down_read(&card
->controls_rwsem
);
2178 down_read(&snd_ctl_layer_rwsem
);
2179 for (lops
= snd_ctl_layer
; lops
; lops
= lops
->next
)
2180 lops
->ldisconnect(card
);
2181 up_read(&snd_ctl_layer_rwsem
);
2182 up_read(&card
->controls_rwsem
);
2184 return snd_unregister_device(&card
->ctl_dev
);
2190 static int snd_ctl_dev_free(struct snd_device
*device
)
2192 struct snd_card
*card
= device
->device_data
;
2193 struct snd_kcontrol
*control
;
2195 down_write(&card
->controls_rwsem
);
2196 while (!list_empty(&card
->controls
)) {
2197 control
= snd_kcontrol(card
->controls
.next
);
2198 snd_ctl_remove(card
, control
);
2200 up_write(&card
->controls_rwsem
);
2201 put_device(&card
->ctl_dev
);
2206 * create control core:
2207 * called from init.c
2209 int snd_ctl_create(struct snd_card
*card
)
2211 static const struct snd_device_ops ops
= {
2212 .dev_free
= snd_ctl_dev_free
,
2213 .dev_register
= snd_ctl_dev_register
,
2214 .dev_disconnect
= snd_ctl_dev_disconnect
,
2218 if (snd_BUG_ON(!card
))
2220 if (snd_BUG_ON(card
->number
< 0 || card
->number
>= SNDRV_CARDS
))
2223 snd_device_initialize(&card
->ctl_dev
, card
);
2224 dev_set_name(&card
->ctl_dev
, "controlC%d", card
->number
);
2226 err
= snd_device_new(card
, SNDRV_DEV_CONTROL
, card
, &ops
);
2228 put_device(&card
->ctl_dev
);
2233 * Frequently used control callbacks/helpers
2237 * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2238 * callback with a mono channel
2239 * @kcontrol: the kcontrol instance
2240 * @uinfo: info to store
2242 * This is a function that can be used as info callback for a standard
2243 * boolean control with a single mono channel.
2245 int snd_ctl_boolean_mono_info(struct snd_kcontrol
*kcontrol
,
2246 struct snd_ctl_elem_info
*uinfo
)
2248 uinfo
->type
= SNDRV_CTL_ELEM_TYPE_BOOLEAN
;
2250 uinfo
->value
.integer
.min
= 0;
2251 uinfo
->value
.integer
.max
= 1;
2254 EXPORT_SYMBOL(snd_ctl_boolean_mono_info
);
2257 * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2258 * callback with stereo two channels
2259 * @kcontrol: the kcontrol instance
2260 * @uinfo: info to store
2262 * This is a function that can be used as info callback for a standard
2263 * boolean control with stereo two channels.
2265 int snd_ctl_boolean_stereo_info(struct snd_kcontrol
*kcontrol
,
2266 struct snd_ctl_elem_info
*uinfo
)
2268 uinfo
->type
= SNDRV_CTL_ELEM_TYPE_BOOLEAN
;
2270 uinfo
->value
.integer
.min
= 0;
2271 uinfo
->value
.integer
.max
= 1;
2274 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info
);
2277 * snd_ctl_enum_info - fills the info structure for an enumerated control
2278 * @info: the structure to be filled
2279 * @channels: the number of the control's channels; often one
2280 * @items: the number of control values; also the size of @names
2281 * @names: an array containing the names of all control values
2283 * Sets all required fields in @info to their appropriate values.
2284 * If the control's accessibility is not the default (readable and writable),
2285 * the caller has to fill @info->access.
2289 int snd_ctl_enum_info(struct snd_ctl_elem_info
*info
, unsigned int channels
,
2290 unsigned int items
, const char *const names
[])
2292 info
->type
= SNDRV_CTL_ELEM_TYPE_ENUMERATED
;
2293 info
->count
= channels
;
2294 info
->value
.enumerated
.items
= items
;
2297 if (info
->value
.enumerated
.item
>= items
)
2298 info
->value
.enumerated
.item
= items
- 1;
2299 WARN(strlen(names
[info
->value
.enumerated
.item
]) >= sizeof(info
->value
.enumerated
.name
),
2300 "ALSA: too long item name '%s'\n",
2301 names
[info
->value
.enumerated
.item
]);
2302 strscpy(info
->value
.enumerated
.name
,
2303 names
[info
->value
.enumerated
.item
],
2304 sizeof(info
->value
.enumerated
.name
));
2307 EXPORT_SYMBOL(snd_ctl_enum_info
);