[LAD] issue with AD1989A codec and alsamixer

Hi all, I am working on a system which includes a connexant AD1989A HDA codec connected to a ATOM processor. I have four microphones connected to the B and C ports of this codec. If I change one of the 3 capture gains present in the alsamixer (Capture, Capture 1 or Capture 3), I can't have any more signal on the B and C ports It seems to be due to the fact that ALSA breaks (for example for the Capture gain) the link between the ADC selector 0 and ADC_0 widgets of the codec, what can be easily seen with codecgraph. Have you ever had this kind of problem? Do you know how can I resolve it ? Many thanks for your asnwers and best regards Vincent