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Commit 66b5b972 authored by Dimitris Papastamos's avatar Dimitris Papastamos Committed by Takashi Iwai
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ALSA: Add snd_ctl_replace() to dynamically replace a control 



Add a function to dynamically replace a given control.  If the
control does not already exist, a third parameter is used to determine
whether to actually add that control.  This is useful in cases where
downloadable firmware at runtime can add or replace existing controls.
A separate patch needs to be made to allow ALSA Mixer to render the
replaced controls on the fly.

Signed-off-by: default avatarDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 1872f589

include/sound/control.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -113,6 +113,7 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new * kcontrolnew, v 
void snd_ctl_free_one(struct snd_kcontrol * kcontrol);

void snd_ctl_free_one(struct snd_kcontrol * kcontrol);

int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol);

int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol);

int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);

int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);

int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, bool add_on_replace);

int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);

int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);

int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);

int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);

int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,

int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,

sound/core/control.c

+64 −0
Original line number Original line Diff line number Diff line
@@ -365,6 +365,70 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) 




EXPORT_SYMBOL(snd_ctl_add);

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.

 *

 * Returns zero if successful, or a negative error code on failure.

 *

 * It frees automatically the control which cannot be added or replaced.

 */

int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,

		    bool add_on_replace)

{

	struct snd_ctl_elem_id id;

	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;

	up_write(&card->controls_rwsem);

	for (idx = 0; idx < kcontrol->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

 * snd_ctl_remove - remove the control from the card and release it

 * @card: the card instance

 * @card: the card instance