HelenOS sources

hda_set_amp_gain_mute  278 uspace/drv/audio/hdaudio/codec.c 	rc = hda_set_amp_gain_mute(codec, aw, 0xb000 + offset);
hda_set_amp_gain_mute  314 uspace/drv/audio/hdaudio/codec.c 		rc = hda_set_amp_gain_mute(codec, aw, 0x7000 + (i << 8) + offset);
HelenOS homepage, sources at GitHub