snd_hda_find_mixer_ctl
kctl = snd_hda_find_mixer_ctl(codec, "IEC958 Playback Switch");
!snd_hda_find_mixer_ctl(codec, "Master Playback Volume")) {
!snd_hda_find_mixer_ctl(codec, "Master Playback Switch")) {
kctl = snd_hda_find_mixer_ctl(codec, "Master Playback Volume");
kctl = snd_hda_find_mixer_ctl(codec, oldname);
EXPORT_SYMBOL_GPL(snd_hda_find_mixer_ctl);
struct snd_kcontrol *snd_hda_find_mixer_ctl(struct hda_codec *codec,