RK3128 Android7.1 usb和speak同时播放媒体

主要是Engine.cpp里的getDeviceForStrategyInt方法

frameworks/av/services/audiopolicy/enginedefault/src/Engine.cpp

case STRATEGY_MEDIA: {
        uint32_t device2 = AUDIO_DEVICE_NONE;
        if (strategy != STRATEGY_SONIFICATION) {
            // no sonification on remote submix (e.g. WFD)
            if (availableOutputDevices.getDevice(AUDIO_DEVICE_OUT_REMOTE_SUBMIX,
                                                 String8("0")) != 0) {
                device2 = availableOutputDevices.types() & AUDIO_DEVICE_OUT_REMOTE_SUBMIX;
            }
        }
        if (isInCall() && (strategy == STRATEGY_MEDIA)) {
            device = getDeviceForStrategyInt(
                    STRATEGY_PHONE, availableOutputDevices, availableInputDevices, outputs);
            break;
        }
        if ((device2 == AUDIO_DEVICE_NONE) &&
                (mForceUse[AUDIO_POLICY_FORCE_FOR_MEDIA] != AUDIO_POLICY_FORCE_NO_BT_A2DP) &&
                (outputs.getA2dpOutput() != 0)) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP;
            if (device2 == AUDIO_DEVICE_NONE) {
                device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES;
            }
            if (device2 == AUDIO_DEVICE_NONE) {
                device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER;
            }
        }
        if ((device2 == AUDIO_DEVICE_NONE) &&
            (mForceUse[AUDIO_POLICY_FORCE_FOR_MEDIA] == AUDIO_POLICY_FORCE_SPEAKER)) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_SPEAKER;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_WIRED_HEADPHONE;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_LINE;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_WIRED_HEADSET;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_USB_ACCESSORY;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_USB_DEVICE;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET;
        }
        if ((device2 == AUDIO_DEVICE_NONE) && (strategy != STRATEGY_SONIFICATION)) {
            // no sonification on aux digital (e.g. HDMI)
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_AUX_DIGITAL;
        }
        if ((device2 == AUDIO_DEVICE_NONE) &&
                (mForceUse[AUDIO_POLICY_FORCE_FOR_DOCK] == AUDIO_POLICY_FORCE_ANALOG_DOCK)) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET;
        }
        if (device2 == AUDIO_DEVICE_NONE) {
            device2 = availableOutputDevicesType & AUDIO_DEVICE_OUT_SPEAKER;
        }
        int device3 = AUDIO_DEVICE_NONE;
        if (strategy == STRATEGY_MEDIA) {
            // ARC, SPDIF and AUX_LINE can co-exist with others.
#ifdef BOX_STRATEGY
            device3 = availableOutputDevicesType & AUDIO_DEVICE_OUT_HDMI;
#else
            device3 = availableOutputDevicesType & AUDIO_DEVICE_OUT_HDMI_ARC;
#endif
            device3 |= (availableOutputDevicesType & AUDIO_DEVICE_OUT_SPDIF);
            device3 |= (availableOutputDevicesType & AUDIO_DEVICE_OUT_AUX_LINE);
        }

        device2 |= device3;
        // device is DEVICE_OUT_SPEAKER if we come from case STRATEGY_SONIFICATION or
        // STRATEGY_ENFORCED_AUDIBLE, AUDIO_DEVICE_NONE otherwise
        device |= device2;

        // If hdmi system audio mode is on, remove speaker out of output list.
        if ((strategy == STRATEGY_MEDIA) &&
            (mForceUse[AUDIO_POLICY_FORCE_FOR_HDMI_SYSTEM_AUDIO] ==
                AUDIO_POLICY_FORCE_HDMI_SYSTEM_AUDIO_ENFORCED)) {
            device &= ~AUDIO_DEVICE_OUT_SPEAKER;
        }
        } break;

    default:
        ALOGW("getDeviceForStrategy() unknown strategy: %d", strategy);
        break;
    }

#ifdef BOX_STRATEGY
    if ((device & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP)
        || (device & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES)
        || (device & AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER)
	|| (device & AUDIO_DEVICE_OUT_USB_DEVICE)) {
        device &= ~AUDIO_DEVICE_OUT_SPDIF;
        device &= ~AUDIO_DEVICE_OUT_HDMI;
        device &= ~AUDIO_DEVICE_OUT_SPEAKER;
    }
#endif
    if (device == AUDIO_DEVICE_NONE) {
        ALOGV("getDeviceForStrategy() no device found for strategy %d", strategy);
        device = mApmObserver->getDefaultOutputDevice()->type();
        ALOGE_IF(device == AUDIO_DEVICE_NONE,
                 "getDeviceForStrategy() no default device defined");
    }

    char value[PROPERTY_VALUE_MAX];
    property_get("media.audio.device_policy", value, "");
    if (strstr(value, "hdmi")) {
        ALOGD("set audio policy to hdmi, availableOutputDevicesType : 0x%x", availableOutputDevicesType);
        if (availableOutputDevicesType & AUDIO_DEVICE_OUT_HDMI) {
            ALOGD("set audio policy to hdmi succeed");
            device = AUDIO_DEVICE_OUT_HDMI;
        }
    } else if (strstr(value, "usb")) {
        ALOGD("set audio policy to usb, availableOutputDevicesType : 0x%x", availableOutputDevicesType);
        if (availableOutputDevicesType & AUDIO_DEVICE_OUT_USB_DEVICE) {
            ALOGD("set audio policy to usb succeed");
            device = AUDIO_DEVICE_OUT_USB_DEVICE;
        }
    }

    //我这里是强制判断只要是媒体且有usb的情况下，加上speak
    if (strategy == STRATEGY_MEDIA && device == AUDIO_DEVICE_OUT_USB_DEVICE) {
        device |= AUDIO_DEVICE_OUT_SPEAKER;
    }

    ALOGVV("getDeviceForStrategy() strategy %d, device %x", strategy, device);
    return device;
}