Hello, finally (sorry for the delay), I have managed to get some log when trying to make a call through the car bluetooth handsfree, following these steps:
1. logcat -c -b all
2. dialing a call through handsfree - the dial tone sounds relatively normally, once the other side answers, there is just loud digital noise (on both ends)
3. logcat -b -all
- the resulting log iscopy-pasted below:
--------- beginning of events
01-16 16:58:38.921 6957 6957 I auditd : type=1400 audit(0.0:593): avc: granted { execute } for comm="bash" name="logcat" dev="mmcblk0p24" ino=399711 scontext=u:r:untrusted_app_27:s0:c173,c256,c512,c768 tcontext=u

bject_r:app_data_file:s0:c173,c256,c512,c768 tclass=file app=com.termux
01-16 16:58:38.921 6957 6957 I auditd : type=1300 audit(0.0:593): arch=c00000b7 syscall=48 success=yes exit=0 a0=ffffff9c a1=775be07800 a2=1 a3=0 items=0 ppid=6796 auid=4294967295 uid=10173 gid=10173 euid=10173 suid=10173 fsuid=10173 egid=10173 sgid=10173 fsgid=10173 tty=pts0 ses=4294967295 comm="bash" exe="/data/data/com.termux/files/usr/bin/bash" subj=u:r:untrusted_app_27:s0:c173,c256,c512,c768 key=(null) app=com.termux
01-16 16:58:38.921 6957 6957 I auditd : type=1400 audit(0.0:594): avc: granted { execute } for comm="bash" name="logcat" dev="mmcblk0p24" ino=399711 scontext=u:r:untrusted_app_27:s0:c173,c256,c512,c768 tcontext=u

bject_r:app_data_file:s0:c173,c256,c512,c768 tclass=file app=com.termux
01-16 16:59:08.872 6745 6745 I am_on_top_resumed_lost_called: [0,com.termux.app.TermuxActivity,topStateChangedWhenResumed]
01-16 16:59:08.881 6745 6745 I am_on_paused_called: [0,com.termux.app.TermuxActivity,performPause]
01-16 16:59:09.471 6745 6745 I am_on_stop_called: [0,com.termux.app.TermuxActivity,STOP_ACTIVITY_ITEM]
--------- beginning of main
01-16 17:01:21.225 6745 6792 D BufferPoolAccessor: bufferpool2 0x7ac2038e20 : 0(0 size) total buffers - 0(0 size) used buffers - 2/9 (recycle/alloc) - 7/24 (fetch/transfer)
01-16 17:01:21.225 6745 6792 D BufferPoolAccessor: Destruction - bufferpool2 0x7ac2038e20 cached: 0/0M, 0/0% in use; allocs: 9, 22% recycled; transfers: 24, 71% unfetced
01-16 17:01:41.613 6745 6745 I am_on_restart_called: [0,com.termux.app.TermuxActivity,performRestartActivity]
01-16 17:01:41.621 6745 6745 I am_on_start_called: [0,com.termux.app.TermuxActivity,handleStartActivity]
01-16 17:01:41.624 6745 6745 I am_on_resume_called: [0,com.termux.app.TermuxActivity,RESUME_ACTIVITY]
01-16 17:01:41.625 6745 6745 I am_on_top_resumed_gained_called: [0,com.termux.app.TermuxActivity,topWhenResuming]
01-16 17:01:41.636 6745 6768 D mali_winsys: EGLint new_window_surface(egl_winsys_display *, void *, EGLSurface, EGLConfig, egl_winsys_surface **, EGLBoolean) returns 0x3000, [720x1280]-format:1
01-16 17:01:41.641 6745 7891 D CCodec : allocate(c2.android.vorbis.decoder)
01-16 17:01:41.645 6745 7891 I CCodec : Created component [c2.android.vorbis.decoder]
01-16 17:01:41.645 6745 7891 D CCodecConfig: read media type: audio/vorbis
01-16 17:01:41.651 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: algo.buffers.max-count.values
01-16 17:01:41.652 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: output.subscribed-indices.values
01-16 17:01:41.652 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: input.buffers.allocator-ids.values
01-16 17:01:41.652 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: output.buffers.allocator-ids.values
01-16 17:01:41.652 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: algo.buffers.allocator-ids.values
01-16 17:01:41.652 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: output.buffers.pool-ids.values
01-16 17:01:41.652 6745 7891 D ReflectedParamUpdater: extent() != 1 for single value type: algo.buffers.pool-ids.values
01-16 17:01:41.656 6745 7891 I CCodecConfig: query failed after returning 7 values (BAD_INDEX)
01-16 17:01:41.656 6745 7891 D CCodecConfig: c2 config diff is Dict {
01-16 17:01:41.656 6745 7891 D CCodecConfig: c2::u32 coded.bitrate.value = 64000
01-16 17:01:41.656 6745 7891 D CCodecConfig: c2::u32 input.buffers.max-size.value = 32768
01-16 17:01:41.656 6745 7891 D CCodecConfig: c2::u32 input.delay.value = 0
01-16 17:01:41.656 6745 7891 D CCodecConfig: string input.media-type.value = "audio/vorbis"
01-16 17:01:41.656 6745 7891 D CCodecConfig: string output.media-type.value = "audio/raw"
01-16 17:01:41.656 6745 7891 D CCodecConfig: c2::u32 raw.channel-count.value = 1
01-16 17:01:41.656 6745 7891 D CCodecConfig: c2::u32 raw.sample-rate.value = 48000
01-16 17:01:41.656 6745 7891 D CCodecConfig: }
01-16 17:01:41.657 6745 7891 D CCodecConfig: no c2 equivalents for durationUs
01-16 17:01:41.657 6745 7891 D CCodecConfig: no c2 equivalents for csd-1
01-16 17:01:41.657 6745 7891 D CCodecConfig: no c2 equivalents for track-id
01-16 17:01:41.657 6745 7891 D CCodecConfig: no c2 equivalents for channel-mask
01-16 17:01:41.658 6745 7891 D CCodecConfig: c2 config diff is c2::u32 raw.sample-rate.value = 44100
01-16 17:01:41.659 6745 7891 W Codec2Client: query -- param skipped: index = 1107298332.
01-16 17:01:41.659 6745 7891 D CCodec : setup formats input: AMessage(what = 0x00000000) = {
01-16 17:01:41.659 6745 7891 D CCodec : int32_t channel-count = 1
01-16 17:01:41.659 6745 7891 D CCodec : int32_t max-input-size = 32768
01-16 17:01:41.659 6745 7891 D CCodec : string mime = "audio/vorbis"
01-16 17:01:41.659 6745 7891 D CCodec : int32_t sample-rate = 44100
01-16 17:01:41.659 6745 7891 D CCodec : } and output: AMessage(what = 0x00000000) = {
01-16 17:01:41.659 6745 7891 D CCodec : int32_t channel-count = 1
01-16 17:01:41.659 6745 7891 D CCodec : string mime = "audio/raw"
01-16 17:01:41.659 6745 7891 D CCodec : int32_t sample-rate = 44100
01-16 17:01:41.659 6745 7891 D CCodec : int32_t channel-mask = 1
01-16 17:01:41.659 6745 7891 D CCodec : }
01-16 17:01:41.660 6745 7891 W Codec2Client: query -- param skipped: index = 1342179345.
01-16 17:01:41.660 6745 7891 W Codec2Client: query -- param skipped: index = 2415921170.
01-16 17:01:41.663 6745 7891 D CCodecBufferChannel: [c2.android.vorbis.decoder#739] Created input block pool with allocatorID 16 => poolID 18 - OK (0)
01-16 17:01:41.667 6745 7891 I CCodecBufferChannel: [c2.android.vorbis.decoder#739] Created output block pool with allocatorID 16 => poolID 32 - OK
01-16 17:01:41.669 6745 7891 D CCodecBufferChannel: [c2.android.vorbis.decoder#739] Configured output block pool ids 32 => OK
01-16 17:01:43.961 7895 7895 I auditd : type=1400 audit(0.0:813): avc: granted { execute } for comm="bash" name="logcat" dev="mmcblk0p24" ino=399711 scontext=u:r:untrusted_app_27:s0:c173,c256,c512,c768 tcontext=u

bject_r:app_data_file:s0:c173,c256,c512,c768 tclass=file app=com.termux
01-16 17:01:43.961 7895 7895 W bash : type=1400 audit(0.0:813): avc: granted { execute } for name="logcat" dev="mmcblk0p24" ino=399711 scontext=u:r:untrusted_app_27:s0:c173,c256,c512,c768 tcontext=u

bject_r:app_data_file:s0:c173,c256,c512,c768 tclass=file app=com.termux
01-16 17:01:43.961 7895 7895 I auditd : type=1300 audit(0.0:813): arch=c00000b7 syscall=48 success=yes exit=0 a0=ffffff9c a1=775be07770 a2=1 a3=0 items=0 ppid=6796 auid=4294967295 uid=10173 gid=10173 euid=10173 suid=10173 fsuid=10173 egid=10173 sgid=10173 fsgid=10173 tty=pts0 ses=4294967295 comm="bash" exe="/data/data/com.termux/files/usr/bin/bash" subj=u:r:untrusted_app_27:s0:c173,c256,c512,c768 key=(null) app=com.termux
01-16 17:01:43.961 7895 7895 W bash : type=1300 audit(0.0:813): arch=c00000b7 syscall=48 success=yes exit=0 a0=ffffff9c a1=775be07770 a2=1 a3=0 items=0 ppid=6796 auid=4294967295 uid=10173 gid=10173 euid=10173 suid=10173 fsuid=10173 egid=10173 sgid=10173 fsgid=10173 tty=pts0 ses=4294967295 exe="/data/data/com.termux/files/usr/bin/bash" subj=u:r:untrusted_app_27:s0:c173,c256,c512,c768 key=(null) app=com.termux
01-16 17:01:43.961 7895 7895 I auditd : type=1400 audit(0.0:814): avc: granted { execute } for comm="bash" name="logcat" dev="mmcblk0p24" ino=399711 scontext=u:r:untrusted_app_27:s0:c173,c256,c512,c768 tcontext=u

bject_r:app_data_file:s0:c173,c256,c512,c768 tclass=file app=com.termux
01-16 17:01:43.961 7895 7895 W bash : type=1400 audit(0.0:814): avc: granted { execute } for name="logcat" dev="mmcblk0p24" ino=399711 scontext=u:r:untrusted_app_27:s0:c173,c256,c512,c768 tcontext=u

bject_r:app_data_file:s0:c173,c256,c512,c768 tclass=file app=com.termux
- I hope this can help to identify the problem source. Of course, please let me know if I can supply any additional information, conduct some more test(s), ....