Dear All.
I am now testing audio part of RK3399-Android 8.1 using Sound Recorder App.

After I changed rt5651_config.h and rt5651.c to route bst3 input since my custom board uses IN3P as headset microphone.
My configuration is below for rt5651_config.h

const struct config_control rt5651_main_mic_capture_controls[] = {
{
.ctl_name = "RECMIXL BST3 Switch",
.int_val = {on},
},
{
.ctl_name = "RECMIXR BST3 Switch",
.int_val = {on},
},
{
.ctl_name = "Stereo1 ADC L1 Mux",
.str_val = "ADC",
},
{
.ctl_name = "Stereo1 ADC R1 Mux",
.str_val = "ADC",
},
{
.ctl_name = "Stereo1 ADC MIXL ADC1 Switch",
.int_val = {on},
},
{
.ctl_name = "Stereo1 ADC MIXR ADC1 Switch",
.int_val = {on},
},
{
.ctl_name = "IN3 Boost",
.int_val = {1},
},
{
.ctl_name = "ADC Capture Switch",
.int_val = {on, on},
},
{
.ctl_name = "ADC Capture Volume",
.int_val = {47, 47},
},

And I put a line below into rt5651.c, static const struct snd_kcontrol_new rt5651_snd_controls[] = {
SOC_SINGLE_TLV("IN3 Boost", RT5651_IN3,
RT5651_BST_SFT1, 8, 0, bst_tlv),

My problem observed is that the sound gauge shows bouncing after 8 seconds of recording start.
I could not figure out what makes this problem even though I checked kernel configuration according to the events.

Does anyone suggest a point to debug? The problem is not shown after disable internal MIC-bst2 via rt5651_config as above.

Thanks in advance.
Regards, JK Cha