It worked correctly for AUX_OUT register, but if you plug out the headphone you can't change the volume of the speakers anymore(with AC97 Mixer) since you replace the Master Volume register with Headphone(Aux Out) register during init. I just wanted to sync the values of both registers with one Slider, which controls both volumes. In OSS it syncs both registers for all AC97 audio cards IIRC. Therefore I did the change in multi_audio in 2nd patch in order sync them, like in windows. In 3rd patch I let it behaved like ALSA mixer which assigns two volume controls for each register, which i don't suggest,but better than not be able to adjust the both volumes. In Short my aim was: One Volume slider that updates both MASTER_OUT_VOLUME and AUX_OUT_VOLUME registers with the same values. Sorry for my english, Hope it helps. Bye, Hüseyin