for (i = 0; i < AUTO_PIN_LAST; i++) {
                hda_nid_t nid = cfg->input_pins[i];
                if (nid) {
-                       unsigned int pinctl = AC_PINCTL_IN_EN;
+                       unsigned int pinctl = snd_hda_codec_read(codec, nid,
+                               0, AC_VERB_GET_PIN_WIDGET_CONTROL, 0);
+                       /* if PINCTL already set then skip */
+                       if (pinctl & AC_PINCAP_IN)
+                               continue;
+                       pinctl = AC_PINCTL_IN_EN;
                        if (i == AUTO_PIN_MIC || i == AUTO_PIN_FRONT_MIC)
                                pinctl |= stac92xx_get_vref(codec, nid);
                        stac92xx_auto_set_pinctl(codec, nid, pinctl);
        switch (spec->board_config) {
        case STAC_HP_M4:
                spec->num_dmics = 0;
-               spec->num_smuxes = 1;
+               spec->num_smuxes = 0;
                spec->num_dmuxes = 0;
 
                /* enable internal microphone */
-               snd_hda_codec_write_cache(codec, 0x0e, 0,
-                       AC_VERB_SET_PIN_WIDGET_CONTROL, PIN_VREF80);
+               stac92xx_set_config_reg(codec, 0x0e, 0x01813040);
+               stac92xx_auto_set_pinctl(codec, 0x0e,
+                       AC_PINCTL_IN_EN | AC_PINCTL_VREF_80);
                break;
        default:
                spec->num_dmics = STAC92HD71BXX_NUM_DMICS;