AC97_MASTER_VOLUME_REGISTER
WR(AC97_MASTER_VOLUME_REGISTER, 0x20);
if ((RD(AC97_MASTER_VOLUME_REGISTER) & 0x1f) == 0x1f) {
ac_stereo_set(ctrl, value, AC97_MASTER_VOLUME_REGISTER);
ac_wr(ac, AC97_MASTER_VOLUME_REGISTER, 0);