AC_VERB_GET_CONV
AC_VERB_GET_CONV, 0);
AC_VERB_GET_CONV, 0);
oldval = snd_hda_codec_read(codec, nid, 0, AC_VERB_GET_CONV, 0);
int conv = snd_hda_codec_read(codec, nid, 0, AC_VERB_GET_CONV, 0);
case AC_VERB_GET_CONV: /* managed in PCM code */