diff --git a/hal/audio_extn/audio_extn.h b/hal/audio_extn/audio_extn.h
index 12fe04d..2ca76fa 100644
--- a/hal/audio_extn/audio_extn.h
+++ b/hal/audio_extn/audio_extn.h
@@ -107,7 +107,6 @@
 #define audio_extn_sound_trigger_init(adev)                            (0)
 #define audio_extn_sound_trigger_deinit(adev)                          (0)
 #define audio_extn_sound_trigger_update_device_status(snd_dev, event)  (0)
-#define audio_extn_sound_trigger_update_stream_status(uc_info, event)  (0)
 #define audio_extn_sound_trigger_set_parameters(adev, parms)           (0)
 #define audio_extn_sound_trigger_check_and_get_session(in)             (0)
 #define audio_extn_sound_trigger_stop_lab(in)                          (0)
@@ -127,8 +126,6 @@
 void audio_extn_sound_trigger_deinit(struct audio_device *adev);
 void audio_extn_sound_trigger_update_device_status(snd_device_t snd_device,
                                      st_event_type_t event);
-void audio_extn_sound_trigger_update_stream_status(struct audio_usecase *uc_info,
-                                     st_event_type_t event);
 void audio_extn_sound_trigger_set_parameters(struct audio_device *adev,
                                              struct str_parms *parms);
 void audio_extn_sound_trigger_check_and_get_session(struct stream_in *in);
diff --git a/hal/audio_extn/soundtrigger.c b/hal/audio_extn/soundtrigger.c
index c11e747..111f9a2 100644
--- a/hal/audio_extn/soundtrigger.c
+++ b/hal/audio_extn/soundtrigger.c
@@ -28,121 +28,17 @@
 #include "audio_extn.h"
 #include "platform.h"
 #include "platform_api.h"
-
-/*-------------------- Begin: AHAL-STHAL Interface ---------------------------*/
-/*
- * Maintain the proprietary interface between AHAL and STHAL locally to avoid
- * the compilation dependency of interface header file from STHAL.
- */
-
-#define MAKE_HAL_VERSION(maj, min) ((((maj) & 0xff) << 8) | ((min) & 0xff))
-#define MAJOR_VERSION(ver) (((ver) & 0xff00) >> 8)
-#define MINOR_VERSION(ver) ((ver) & 0x00ff)
-
-/* Proprietary interface version used for compatibility with STHAL */
-#define STHAL_PROP_API_VERSION_1_0 MAKE_HAL_VERSION(1, 0)
-#define STHAL_PROP_API_CURRENT_VERSION STHAL_PROP_API_VERSION_1_0
-
-#define ST_EVENT_CONFIG_MAX_STR_VALUE 32
-
-typedef enum {
-    ST_EVENT_SESSION_REGISTER,
-    ST_EVENT_SESSION_DEREGISTER
-} sound_trigger_event_type_t;
-
-typedef enum {
-    AUDIO_EVENT_CAPTURE_DEVICE_INACTIVE,
-    AUDIO_EVENT_CAPTURE_DEVICE_ACTIVE,
-    AUDIO_EVENT_PLAYBACK_STREAM_INACTIVE,
-    AUDIO_EVENT_PLAYBACK_STREAM_ACTIVE,
-    AUDIO_EVENT_STOP_LAB,
-    AUDIO_EVENT_SSR,
-    AUDIO_EVENT_NUM_ST_SESSIONS,
-    AUDIO_EVENT_READ_SAMPLES,
-    AUDIO_EVENT_DEVICE_CONNECT,
-    AUDIO_EVENT_DEVICE_DISCONNECT,
-    AUDIO_EVENT_SVA_EXEC_MODE,
-    AUDIO_EVENT_SVA_EXEC_MODE_STATUS,
-    AUDIO_EVENT_CAPTURE_STREAM_INACTIVE,
-    AUDIO_EVENT_CAPTURE_STREAM_ACTIVE,
-} audio_event_type_t;
-
-typedef enum {
-    USECASE_TYPE_PCM_PLAYBACK,
-    USECASE_TYPE_PCM_CAPTURE,
-    USECASE_TYPE_VOICE_CALL,
-    USECASE_TYPE_VOIP_CALL,
-} audio_stream_usecase_type_t;
-
-typedef enum {
-    SND_CARD_STATUS_OFFLINE,
-    SND_CARD_STATUS_ONLINE,
-    CPE_STATUS_OFFLINE,
-    CPE_STATUS_ONLINE
-} ssr_event_status_t;
-
-struct sound_trigger_session_info {
-    void* p_ses; /* opaque pointer to st_session obj */
-    int capture_handle;
-    struct pcm *pcm;
-    struct pcm_config config;
-};
-
-struct audio_read_samples_info {
-    struct sound_trigger_session_info *ses_info;
-    void *buf;
-    size_t num_bytes;
-};
-
-struct audio_hal_usecase {
-    audio_stream_usecase_type_t type;
-};
-
-struct sound_trigger_event_info {
-    struct sound_trigger_session_info st_ses;
-};
-
-struct audio_event_info {
-    union {
-        ssr_event_status_t status;
-        int value;
-        struct sound_trigger_session_info ses_info;
-        struct audio_read_samples_info aud_info;
-        char str_value[ST_EVENT_CONFIG_MAX_STR_VALUE];
-        struct audio_hal_usecase usecase;
-    }u;
-};
-
-/* STHAL callback which is called by AHAL */
-typedef int (*sound_trigger_hw_call_back_t)(audio_event_type_t,
-                                  struct audio_event_info*);
-
-/*---------------- End: AHAL-STHAL Interface ----------------------------------*/
+#include "sound_trigger_prop_intf.h"
 
 #define XSTR(x) STR(x)
 #define STR(x) #x
 
-#define DLSYM(handle, ptr, symbol, err)                                   \
-do {                                                                      \
-    ptr = dlsym(handle, #symbol);                                         \
-    if (ptr == NULL) {                                                    \
-        ALOGE("%s: dlsym %s failed . %s", __func__, #symbol, dlerror());  \
-        err = -ENODEV;                                                    \
-    }                                                                     \
-} while(0)
-
 #ifdef __LP64__
-#define SOUND_TRIGGER_LIBRARY_PATH "/vendor/lib64/hw/sound_trigger.primary.%s.so"
+#define SOUND_TRIGGER_LIBRARY_PATH "/system/vendor/lib64/hw/sound_trigger.primary.%s.so"
 #else
-#define SOUND_TRIGGER_LIBRARY_PATH "/vendor/lib/hw/sound_trigger.primary.%s.so"
+#define SOUND_TRIGGER_LIBRARY_PATH "/system/vendor/lib/hw/sound_trigger.primary.%s.so"
 #endif
 
-/*
- * Current proprietary API version used by AHAL. Queried by STHAL
- * for compatibility check with AHAL
- */
-const unsigned int sthal_prop_api_version = STHAL_PROP_API_CURRENT_VERSION;
-
 struct sound_trigger_info  {
     struct sound_trigger_session_info st_ses;
     bool lab_stopped;
@@ -155,7 +51,6 @@
     sound_trigger_hw_call_back_t st_callback;
     struct listnode st_ses_list;
     pthread_mutex_t lock;
-    unsigned int sthal_prop_api_version;
 };
 
 static struct sound_trigger_audio_device *st_dev;
@@ -165,7 +60,7 @@
 {
     struct sound_trigger_info  *st_ses_info = NULL;
     struct listnode *node;
-    ALOGV("%s: list empty %d capture_handle %d", __func__,
+    ALOGV("%s: list %d capture_handle %d", __func__,
            list_empty(&st_dev->st_ses_list), capture_handle);
     list_for_each(node, &st_dev->st_ses_list) {
         st_ses_info = node_to_item(node, struct sound_trigger_info , list);
@@ -175,37 +70,6 @@
     return NULL;
 }
 
-static int populate_usecase(struct audio_hal_usecase *usecase,
-                       struct audio_usecase *uc_info)
-{
-    int status  = 0;
-
-    switch (uc_info->type) {
-    case PCM_PLAYBACK:
-        if (uc_info->id == USECASE_AUDIO_PLAYBACK_VOIP)
-            usecase->type = USECASE_TYPE_VOIP_CALL;
-        else
-            usecase->type = USECASE_TYPE_PCM_PLAYBACK;
-        break;
-
-    case PCM_CAPTURE:
-        if (uc_info->id == USECASE_AUDIO_RECORD_VOIP)
-            usecase->type = USECASE_TYPE_VOIP_CALL;
-        else
-            usecase->type = USECASE_TYPE_PCM_CAPTURE;
-        break;
-
-    case VOICE_CALL:
-        usecase->type = USECASE_TYPE_VOICE_CALL;
-        break;
-
-    default:
-        ALOGE("%s: unsupported usecase type %d", __func__, uc_info->type);
-        status = -EINVAL;
-    }
-    return status;
-}
-
 static void stdev_snd_mon_cb(void * stream __unused, struct str_parms * parms)
 {
     if (!parms)
@@ -216,7 +80,7 @@
 }
 
 int audio_hw_call_back(sound_trigger_event_type_t event,
-                       struct sound_trigger_event_info* config)
+                       sound_trigger_event_info_t* config)
 {
     int status = 0;
     struct sound_trigger_info  *st_ses_info;
@@ -274,7 +138,7 @@
 {
     int ret = -1;
     struct sound_trigger_info  *st_info = NULL;
-    struct audio_event_info event;
+    audio_event_info_t event;
 
     if (!st_dev)
        return ret;
@@ -310,10 +174,11 @@
 
 void audio_extn_sound_trigger_stop_lab(struct stream_in *in)
 {
+    int status = 0;
     struct sound_trigger_info  *st_ses_info = NULL;
-    struct audio_event_info event;
+    audio_event_info_t event;
 
-    if (!st_dev || !in || !in->is_st_session_active)
+    if (!st_dev || !in)
        return;
 
     pthread_mutex_lock(&st_dev->lock);
@@ -323,10 +188,8 @@
         event.u.ses_info = st_ses_info->st_ses;
         ALOGV("%s: AUDIO_EVENT_STOP_LAB pcm %p", __func__, st_ses_info->st_ses.pcm);
         st_dev->st_callback(AUDIO_EVENT_STOP_LAB, &event);
-        in->is_st_session_active = false;
     }
 }
-
 void audio_extn_sound_trigger_check_and_get_session(struct stream_in *in)
 {
     struct sound_trigger_info  *st_ses_info = NULL;
@@ -362,9 +225,6 @@
     if (!st_dev)
        return;
 
-    if (st_dev->sthal_prop_api_version >= STHAL_PROP_API_VERSION_1_0)
-        return;
-
     if (snd_device >= SND_DEVICE_OUT_BEGIN &&
         snd_device < SND_DEVICE_OUT_END) {
         device_type = PCM_PLAYBACK;
@@ -396,52 +256,10 @@
     }/*Events for output device, if required can be placed here in else*/
 }
 
-void audio_extn_sound_trigger_update_stream_status(struct audio_usecase *uc_info,
-                                     st_event_type_t event)
-{
-    bool raise_event = false;
-    struct audio_event_info ev_info;
-    audio_event_type_t ev;
-
-    if (!st_dev)
-       return;
-
-    if (st_dev->sthal_prop_api_version < STHAL_PROP_API_VERSION_1_0)
-        return;
-
-    if (uc_info == NULL) {
-        ALOGE("%s: null usecase", __func__);
-        return;
-    }
-
-    bool valid_type =
-            (uc_info->type == PCM_PLAYBACK &&
-             platform_snd_device_has_speaker(uc_info->out_snd_device)) ||
-            (uc_info->type == PCM_CAPTURE) ||
-            (uc_info->type == VOICE_CALL);
-
-    if (valid_type && platform_sound_trigger_usecase_needs_event(uc_info->id)) {
-        ALOGV("%s: uc_id %d of type %d for Event %d, with Raise=%d",
-              __func__, uc_info->id, uc_info->type, event, raise_event);
-        if (uc_info->type == PCM_CAPTURE) {
-            ev = (event == ST_EVENT_STREAM_BUSY) ? AUDIO_EVENT_CAPTURE_STREAM_ACTIVE :
-                                                   AUDIO_EVENT_CAPTURE_STREAM_INACTIVE;
-        } else {
-            ev = (event == ST_EVENT_STREAM_BUSY) ? AUDIO_EVENT_PLAYBACK_STREAM_ACTIVE :
-                                                   AUDIO_EVENT_PLAYBACK_STREAM_INACTIVE;
-        }
-        if (!populate_usecase(&ev_info.u.usecase, uc_info)) {
-            ALOGI("%s: send event %d: usecase id %d, type %d",
-                  __func__, ev, uc_info->id, uc_info->type);
-            st_dev->st_callback(ev, &ev_info);
-        }
-    }
-}
-
 void audio_extn_sound_trigger_set_parameters(struct audio_device *adev __unused,
                                struct str_parms *params)
 {
-    struct audio_event_info event;
+    audio_event_info_t event;
     char value[32];
     int ret, val;
 
@@ -490,7 +308,7 @@
 {
     int status = 0;
     char sound_trigger_lib[100];
-    void *sthal_prop_api_version;
+    void *lib_handle;
 
     ALOGV("%s: Enter", __func__);
 
@@ -508,33 +326,20 @@
     st_dev->lib_handle = dlopen(sound_trigger_lib, RTLD_NOW);
 
     if (st_dev->lib_handle == NULL) {
-        ALOGE("%s: error %s", __func__, dlerror());
-        status = -ENODEV;
+        ALOGE("%s: DLOPEN failed for %s. error = %s", __func__, sound_trigger_lib,
+                dlerror());
+        status = -EINVAL;
         goto cleanup;
     }
     ALOGV("%s: DLOPEN successful for %s", __func__, sound_trigger_lib);
 
-    DLSYM(st_dev->lib_handle, st_dev->st_callback, sound_trigger_hw_call_back,
-          status);
-    if (status)
-        goto cleanup;
+    st_dev->st_callback = (sound_trigger_hw_call_back_t)
+              dlsym(st_dev->lib_handle, "sound_trigger_hw_call_back");
 
-    DLSYM(st_dev->lib_handle, sthal_prop_api_version,
-          sthal_prop_api_version, status);
-    if (status) {
-        st_dev->sthal_prop_api_version = 0;
-        status  = 0; /* passthru for backward compability */
-    } else {
-        st_dev->sthal_prop_api_version = *(int*)sthal_prop_api_version;
-        if (MAJOR_VERSION(st_dev->sthal_prop_api_version) !=
-            MAJOR_VERSION(STHAL_PROP_API_CURRENT_VERSION)) {
-            ALOGE("%s: Incompatible API versions ahal:0x%x != sthal:0x%x",
-                  __func__, STHAL_PROP_API_CURRENT_VERSION,
-                  st_dev->sthal_prop_api_version);
-            goto cleanup;
-        }
-        ALOGD("%s: sthal is using proprietary API version 0x%04x", __func__,
-              st_dev->sthal_prop_api_version);
+    if (st_dev->st_callback == NULL) {
+       ALOGE("%s: ERROR. dlsym Error:%s sound_trigger_hw_call_back", __func__,
+               dlerror());
+       goto cleanup;
     }
 
     st_dev->adev = adev;
@@ -549,6 +354,7 @@
     free(st_dev);
     st_dev = NULL;
     return status;
+
 }
 
 void audio_extn_sound_trigger_deinit(struct audio_device *adev)
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index f586865..f2dec25 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -563,11 +563,11 @@
         snd_device = usecase->in_snd_device;
     else
         snd_device = usecase->out_snd_device;
+
     audio_extn_utils_send_app_type_cfg(adev, usecase);
     audio_extn_utils_send_audio_calibration(adev, usecase);
     strcpy(mixer_path, use_case_table[usecase->id]);
     platform_add_backend_name(adev->platform, mixer_path, snd_device);
-    audio_extn_sound_trigger_update_stream_status(usecase, ST_EVENT_STREAM_BUSY);
     ALOGD("%s: usecase(%d) apply and update mixer path: %s", __func__,  usecase->id, mixer_path);
     audio_route_apply_and_update_path(adev->audio_route, mixer_path);
 
@@ -593,7 +593,6 @@
     platform_add_backend_name(adev->platform, mixer_path, snd_device);
     ALOGD("%s: usecase(%d) reset and update mixer path: %s", __func__, usecase->id, mixer_path);
     audio_route_reset_and_update_path(adev->audio_route, mixer_path);
-    audio_extn_sound_trigger_update_stream_status(usecase, ST_EVENT_STREAM_FREE);
 
     ALOGV("%s: exit", __func__);
     return 0;
diff --git a/hal/msm8916/platform.c b/hal/msm8916/platform.c
index 66803bc..af48c03 100644
--- a/hal/msm8916/platform.c
+++ b/hal/msm8916/platform.c
@@ -2457,12 +2457,3 @@
 {
     return -ENOSYS;
 }
-
-bool platform_sound_trigger_usecase_needs_event(audio_usecase_t uc_id __unused)
-{
-    return false;
-}
-
-bool platform_snd_device_has_speaker(snd_device_t dev __unused) {
-    return false;
-}
diff --git a/hal/msm8960/platform.c b/hal/msm8960/platform.c
index 580f230..d123646 100644
--- a/hal/msm8960/platform.c
+++ b/hal/msm8960/platform.c
@@ -1326,12 +1326,3 @@
 {
     return -ENOSYS;
 }
-
-bool platform_sound_trigger_usecase_needs_event(audio_usecase_t uc_id __unused)
-{
-    return false;
-}
-
-bool platform_snd_device_has_speaker(snd_device_t dev __unused) {
-    return false;
-}
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index 92f534f..44107bd 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -4159,49 +4159,3 @@
     return -1;
 #endif
 }
-
-bool platform_sound_trigger_usecase_needs_event(audio_usecase_t uc_id)
-{
-    bool needs_event = false;
-
-    switch (uc_id) {
-    /* concurrent capture usecases which needs event */
-    case USECASE_AUDIO_RECORD:
-    case USECASE_AUDIO_RECORD_LOW_LATENCY:
-    case USECASE_AUDIO_RECORD_MMAP:
-    case USECASE_AUDIO_RECORD_HIFI:
-    case USECASE_AUDIO_RECORD_VOIP:
-    case USECASE_VOICEMMODE1_CALL:
-    case USECASE_VOICEMMODE2_CALL:
-    /* concurrent playback usecases that needs event */
-    case USECASE_AUDIO_PLAYBACK_DEEP_BUFFER:
-    case USECASE_AUDIO_PLAYBACK_OFFLOAD:
-        needs_event = true;
-        break;
-    default:
-        ALOGV("%s:usecase_id[%d] no need to raise event.", __func__, uc_id);
-    }
-    return needs_event;
-}
-
-bool platform_snd_device_has_speaker(snd_device_t dev) {
-    int num_devs = 2;
-    snd_device_t split_devs[2] = {SND_DEVICE_NONE, SND_DEVICE_NONE};
-    if (platform_can_split_snd_device(dev, &num_devs, split_devs) == 0) {
-        return platform_snd_device_has_speaker(split_devs[0]) ||
-                platform_snd_device_has_speaker(split_devs[1]);
-    }
-
-    switch (dev) {
-        case SND_DEVICE_OUT_SPEAKER:
-        case SND_DEVICE_OUT_SPEAKER_SAFE:
-        case SND_DEVICE_OUT_SPEAKER_REVERSE:
-        case SND_DEVICE_OUT_SPEAKER_PROTECTED:
-        case SND_DEVICE_OUT_VOICE_SPEAKER_PROTECTED:
-        case SND_DEVICE_OUT_VOICE_SPEAKER_HFP:
-            return true;
-        default:
-            break;
-    }
-    return false;
-}
diff --git a/hal/platform_api.h b/hal/platform_api.h
index be1c653..e7c26e7 100644
--- a/hal/platform_api.h
+++ b/hal/platform_api.h
@@ -104,8 +104,6 @@
 int platform_set_snd_device_backend(snd_device_t snd_device, const char * backend,
                                     const char * hw_interface);
 
-bool platform_sound_trigger_usecase_needs_event(audio_usecase_t uc_id);
-
 /* From platform_info.c */
 int platform_info_init(const char *filename, void *);
 
@@ -150,6 +148,4 @@
                           bool enable, char * str);
 int platform_get_mmap_data_fd(void *platform, int dev, int dir,
                               int *fd, uint32_t *size);
-bool platform_sound_trigger_usecase_needs_event(audio_usecase_t uc_id);
-bool platform_snd_device_has_speaker(snd_device_t dev);
 #endif // AUDIO_PLATFORM_API_H