SOUND_MIXER_NONE 799 include/linux/soundcard.h #define SOUND_MIXER_ENHANCE SOUND_MIXER_NONE SOUND_MIXER_NONE 800 include/linux/soundcard.h #define SOUND_MIXER_MUTE SOUND_MIXER_NONE SOUND_MIXER_NONE 801 include/linux/soundcard.h #define SOUND_MIXER_LOUD SOUND_MIXER_NONE SOUND_MIXER_NONE 2131 sound/oss/ad1848.c if (n == SOUND_MIXER_NONE)