咸鱼买了个骁龙8155车机，这个蓝牙a2dp默认是从机，然后我root之后，设置一下属性，把从机关了。
persist.service.bt.hfp.client=0
persist.service.bt.a2dp.sink=0
然后可以连接耳机了，但是不出声，adb抓取日志如下。
02-16 00:11:39.049 638 3890 E bt_a2dp_hw: start_audio_datapath: Try opening data socket
02-16 00:11:39.049 638 3890 E bt_a2dp_hw: ts_error_log: [a2dp_out_write] ts 1608995831, diff 02109724, val 3584 7168
02-16 00:11:39.059 638 3890 E bt_a2dp_hw: a2dp_ctrl_receive: a2dp_ctrl_receive: ret=1, error(Try again)
02-16 00:11:39.059 638 3890 E bt_a2dp_hw: a2dp_ctrl_receive: a2dp_ctrl_receive: ret=2, error(Try again)
02-16 00:11:41.198 638 3890 E bt_a2dp_hw: a2dp_ctrl_receive: a2dp_ctrl_receive: ret=1, error(Try again)
日志不断循环这几行，死活不播放，看到638是audioserver发出的，不知道啥问题，求大佬指点，谢谢。
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现在折腾成这样了
10-22 13:36:53.919 592 2355 D audio_hw_primary: out_standby: exit
10-22 13:36:53.923 592 2355 D audio_hw_primary: start_output_stream: enter: stream(0xb4240000)usecase(1: low-latency-playback) devices(0x80)
10-22 13:36:53.924 592 2355 E audio_hw_primary: start_output_stream: A2DP profile is not ready, return error
10-22 13:36:53.974 592 2355 D audio_hw_primary: out_standby: enter: stream (0xb4240000) usecase(1: low-latency-playback)
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