name
tlv
Creates a virtual matster control with the given name string. Returns the created control element, or NULL for errors (ENOMEM).
After creating a vmaster element, you can add the slave controls via snd_ctl_add_slave or snd_ctl_add_slave_uncached.
The optional argument tlv can be used to specify the TLV information for dB scale of the master control. It should be a single element with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.