ac97_reg_update_bits
ac97_reg_update_bits(dev, AC97_PAGING, 0xf, 0);
ac97_reg_update_bits(dev, AC97_EXTENDED_STAT_CTRL, 1, 1); // enable variable rate audio
ac97_reg_update_bits(dev, AC97_CENTER_LFE_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_SURR_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_MASTER_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_AUX_OUT_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_MONO_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_PCM_OUT_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_CD_VOLUME, 0x8000, 0x8000);
ac97_reg_update_bits(dev, AC97_LINE_IN_VOLUME, 0x8000, 0x8000);
if (ac97_reg_update_bits(dev, AC97_EXTENDED_STAT_CTRL, 0x0002, 0x0002)) {
ac97_reg_update_bits(dev, AC97_EXTENDED_STAT_CTRL, 0x0002, 0x0000);
ac97_reg_update_bits(dev, AC97_ALC650_CLOCK_SOURCE, 0x400, 0x400);
ac97_reg_update_bits(dev, AC97_PAGING, 0xf, 0);
ac97_reg_update_bits(dev, AC97_ALC650_MISC_CONTROL, 0x800, 0x800);
ac97_reg_update_bits(dev, AC97_PAGING, 0xf, 0);
bool ac97_reg_update_bits(ac97_dev *dev, uint8 reg, uint16 mask,