We have two similar values in enum gsm0503_amr_dtx_frames:
* AFS_SID_UPDATE - precursor of SID UPDATE,
* AFS_SID_UPDATE_CN - the actual SID UPDATE.
The former is internally used by libosmocoding to mark the current
frame as a precursor of the actual SID UPDATE frame - the later.
+---+---+---+---+---+---+---+---+
| _ | _ | _ | _ | a | b | c | d | AFS_SID_UPDATE
+---+---+---+---+---+---+---+---+
| a | b | c | d | _ | _ | _ | _ | AFS_SID_UPDATE_CN
+---+---+---+---+---+---+---+---+
^
|
| We're here.
Do not treat the precursor frames as a SUB frames, as they contain
no information (rc=-1) and usually have *expected* BER ~50%. This
fixes unexpected RXQUAL-SUB > 0 in the Uplink measurements during DTX.
Change-Id: I46f32bbbcb6284615d05b8703945c5ca4da55b92
Related: SYS#5853
Vadim Yanitskiy
1f9fbd8816