망고210 보드를 사용하고 있습니다.

1. ALSA library와 Android Audio HAL부분에 대해서 보고 있는데 아래의 내용에 대한 원인을 알고 계시는 분 있나요?

2. /system/etc/asound.conf 파일은 어떻게 설정 되는 것인가요?

어플에서 Speaker 볼륨을 조절하기 위해서 AudioFlinger를 조절하기 위해서 setMasterVolume을 사용을 하려고 합니다. AudioSystem 서비스에서 setStreamVolume -> setMasterVolume으로 조절을 하였습니다.

HAL부분(./external/libaudio/AudioHardwareALSA.cpp)에 있는 setMasterVolume()에서 alsa-api를 사용하지 못합니다.

----------------------------------------------------------------------------

status_t ALSAMixer::setMasterVolume(float volume)
{
    mixer_info_t *info = mixerMasterProp[SND_PCM_STREAM_PLAYBACK].mInfo;
    if (!info || !info->elem) return INVALID_OPERATION;

    long minVol = info->min;
    long maxVol = info->max;

    // Make sure volume is between bounds.
    long vol = minVol + volume * (maxVol - minVol);
    if (vol > maxVol) vol = maxVol;
    if (vol < minVol) vol = minVol;

    info->volume = vol;
    snd_mixer_selem_set_playback_volume_all (info->elem, vol);

    return NO_ERROR;
}

----------------------------------------------------------------------------

원인을 알수가 없어서 아래 부분의 PCM->Playback으로 변경을 하여 alsa-api를 사용할 수 있습니다.

static alsa_properties_t
mixerMasterProp[SND_PCM_STREAM_LAST+1] = {
    { ROUTE_ALL, "alsa.mixer.playback.master",  "PCM",     NULL},
    { ROUTE_ALL, "alsa.mixer.capture.master",   "Capture", NULL}
};

아래 log는 PCM으로 설정된 경우 입니다.

D/AudioHardwareALSA( 2000): Mixer: element name: 'Headphone'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Playback'
D/AudioHardwareALSA( 2000): Mixer: element name: '3D'
D/AudioHardwareALSA( 2000): Mixer: element name: 'ALC Attack'
D/AudioHardwareALSA( 2000): Mixer: element name: 'ALC Decay'
D/AudioHardwareALSA( 2000): Mixer: element name: 'ALC Hold Time'
D/AudioHardwareALSA( 2000): Mixer: element name: 'ALC Max Gain'
D/AudioHardwareALSA( 2000): Mixer: element name: 'ALC Min Gain'
D/AudioHardwareALSA( 2000): Mixer: element name: 'ALC Target'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Left Output Mixer Boost Bypass'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Left Output Mixer LINPUT3'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Noise Gate Threshold'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Right Output Mixer Boost Bypass'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Right Output Mixer RINPUT3'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Speaker'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Speaker AC'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Speaker DC'
D/AudioHardwareALSA( 2000): Mixer: master 'PCM' not found.
D/AudioHardwareALSA( 2000): Mixer: route 'Earpiece' not found.
D/AudioHardwareALSA( 2000): Mixer: route 'Speaker' found.
D/AudioHardwareALSA( 2000): Mixer: route 'Bluetooth' not found.
D/AudioHardwareALSA( 2000): Mixer: route 'Headphone' found.
D/AudioHardwareALSA( 2000): Mixer: route 'Bluetooth A2DP' not found.
D/AudioHardwareALSA( 2000): Mixer: element name: 'Playback'
D/AudioHardwareALSA( 2000): Mixer: element name: 'Capture'
D/AudioHardwareALSA( 2000): Mixer: master 'Capture' found.
D/AudioHardwareALSA( 2000): Mixer: route 'Capture' found.
D/AudioHardwareALSA( 2000): Mixer: route '' not found.
D/AudioHardwareALSA( 2000): Mixer: route 'Bluetooth Capture' not found.
D/AudioHardwareALSA( 2000): Mixer: route 'Capture' found.
D/AudioHardwareALSA( 2000): Mixer: route 'Bluetooth A2DP Capture' not found.
D/AudioHardwareALSA( 2000): mixer initialized.
D/AudioHardwareInterface( 2000): setMode(NORMAL)