Commit 306f3f78 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: control: Keep the previous numid at snd_ctl_rename_id() 



We don't need to change the numid at each time snd_ctl_rename_id() is
called, as the control element size itself doesn't change.  Let's keep
the previous numid value.

Along with it, add a note about calling this function only in the
card init phase.

Reviewed-by: default avatarJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230606094035.14808-1-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent ebcbfd84

sound/core/control.c

+10 −2
Original line number Diff line number Diff line
@@ -730,12 +730,20 @@ EXPORT_SYMBOL_GPL(snd_ctl_activate_id); 
 * Finds the control with the old id from the card, and replaces the

 * id with the new one.

 *

 * The function tries to keep the already assigned numid while replacing

 * the rest.

 *

 * Note that this function should be used only in the card initialization

 * phase.  Calling after the card instantiation may cause issues with

 * user-space expecting persistent numids.

 *

 * 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)

{

	struct snd_kcontrol *kctl;

	int saved_numid;



	down_write(&card->controls_rwsem);

	kctl = snd_ctl_find_id(card, src_id);
@@ -743,10 +751,10 @@ int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id, 
		up_write(&card->controls_rwsem);

		return -ENOENT;

	}

	saved_numid = kctl->id.numid;

	remove_hash_entries(card, kctl);

	kctl->id = *dst_id;

	kctl->id.numid = card->last_numid + 1;

	card->last_numid += kctl->count;

	kctl->id.numid = saved_numid;

	add_hash_entries(card, kctl);

	up_write(&card->controls_rwsem);

	return 0;