Android ALSA Porting

출처 : http://www.aesop.or.kr/?document_srl=71231#9

1. 공식사이트에서 다운로드 받아서 하는 방법
- ALSA interface does not recognized in original android source. So need to fix up followings,
- Apply alsa library , audio interface

git clone git://android.git.kernel.org/platform/external/alsa-lib.git
==> copy alsa-lib directory to external directory (cp -a)

git clone git://android.git.kernel.org/platform/hardware/alsa_sound.git
==> copy alsa_sound directory to hardware directory (cp -a)

- Modify file "build/target/board/generic/BoardConfig.mk"
BOARD_USES_GENERIC_AUDIO := false
BOARD_USES_ALSA_AUDIO := true

2. system/core/init/devices.c의 permmission 조정

struct perms_ {
    char *name;
    mode_t perm;
    unsigned int uid;
    unsigned int gid;
    unsigned short prefix;
};
static struct perms_ devperms[] = {
 ...
    { "/dev/snd/",          0660,   AID_ROOT,       AID_AUDIO,      1 },   // 다음과 같은 세 줄을 추가한다.
    { "/dev/snd/dsp",       0660,   AID_ROOT,       AID_AUDIO,      0 },
    { "/dev/snd/mixer",     0660,   AID_ROOT,       AID_AUDIO,      0 },
    { NULL, 0, 0, 0, 0 },
};

3. make 하시면 됩니다.