SOUND_MIXER_OGAIN
type = SOUND_MIXER_OGAIN;
#define SOUND_MIXER_READ_OGAIN MIXER_READ(SOUND_MIXER_OGAIN)
#define SOUND_MIXER_WRITE_OGAIN MIXER_WRITE(SOUND_MIXER_OGAIN)
#define SOUND_MASK_OGAIN (1 << SOUND_MIXER_OGAIN)