AD1848_LINE_CHANNEL
(void) ad1848_set_channel_gain(sc, AD1848_LINE_CHANNEL, &vol_mid);
ad1848_mute_channel(sc, AD1848_LINE_CHANNEL,
{GUSMAX_LINE_IN_LVL, AD1848_KIND_LVL, AD1848_LINE_CHANNEL},
{GUSMAX_LINE_IN_MUTE, AD1848_KIND_MUTE, AD1848_LINE_CHANNEL},