ICHD_MIC2
return snd_intel8x0_pcm_open(substream, &chip->ichd[ICHD_MIC2]);
chip->ichd[ICHD_MIC2].substream = NULL;
.ac97_idx = ICHD_MIC2,
chip->ichd[ICHD_MIC2].pcm = &pbus->pcms[5];