diff options
Diffstat (limited to 'sound/core/control.c')
| -rw-r--r-- | sound/core/control.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/sound/core/control.c b/sound/core/control.c index 9ce00ed20fba..db51e4e64984 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -466,6 +466,52 @@ 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. + * + * Returns 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 |