diff --git a/dlls/wineoss.drv/mmdevdrv.c b/dlls/wineoss.drv/mmdevdrv.c
index cc9d22d21d0..80bac1d9ceb 100644
--- a/dlls/wineoss.drv/mmdevdrv.c
+++ b/dlls/wineoss.drv/mmdevdrv.c
@@ -1349,37 +1349,15 @@ static HRESULT WINAPI AudioCaptureClient_ReleaseBuffer(
         IAudioCaptureClient *iface, UINT32 done)
 {
     ACImpl *This = impl_from_IAudioCaptureClient(iface);
-    struct oss_stream *stream = This->stream;
+    struct release_capture_buffer_params params;
 
     TRACE("(%p)->(%u)\n", This, done);
 
-    oss_lock(stream);
+    params.stream = This->stream;
+    params.done = done;
+    OSS_CALL(release_capture_buffer, &params);
 
-    if(!done){
-        stream->getbuf_last = 0;
-        oss_unlock(stream);
-        return S_OK;
-    }
-
-    if(!stream->getbuf_last){
-        oss_unlock(stream);
-        return AUDCLNT_E_OUT_OF_ORDER;
-    }
-
-    if(stream->getbuf_last != done){
-        oss_unlock(stream);
-        return AUDCLNT_E_INVALID_SIZE;
-    }
-
-    stream->written_frames += done;
-    stream->held_frames -= done;
-    stream->lcl_offs_frames += done;
-    stream->lcl_offs_frames %= stream->bufsize_frames;
-    stream->getbuf_last = 0;
-
-    oss_unlock(stream);
-
-    return S_OK;
+    return params.result;
 }
 
 static HRESULT WINAPI AudioCaptureClient_GetNextPacketSize(
diff --git a/dlls/wineoss.drv/oss.c b/dlls/wineoss.drv/oss.c
index 2e811f9b424..f1994295618 100644
--- a/dlls/wineoss.drv/oss.c
+++ b/dlls/wineoss.drv/oss.c
@@ -1048,6 +1048,34 @@ static NTSTATUS get_capture_buffer(void *args)
     return oss_unlock_result(stream, &params->result, *frames ? S_OK : AUDCLNT_S_BUFFER_EMPTY);
 }
 
+static NTSTATUS release_capture_buffer(void *args)
+{
+    struct release_capture_buffer_params *params = args;
+    struct oss_stream *stream = params->stream;
+    UINT32 done = params->done;
+
+    oss_lock(stream);
+
+    if(!done){
+        stream->getbuf_last = 0;
+        return oss_unlock_result(stream, &params->result, S_OK);
+    }
+
+    if(!stream->getbuf_last)
+        return oss_unlock_result(stream, &params->result, AUDCLNT_E_OUT_OF_ORDER);
+
+    if(stream->getbuf_last != done)
+        return oss_unlock_result(stream, &params->result, AUDCLNT_E_INVALID_SIZE);
+
+    stream->written_frames += done;
+    stream->held_frames -= done;
+    stream->lcl_offs_frames += done;
+    stream->lcl_offs_frames %= stream->bufsize_frames;
+    stream->getbuf_last = 0;
+
+    return oss_unlock_result(stream, &params->result, S_OK);
+}
+
 static NTSTATUS is_format_supported(void *args)
 {
     struct is_format_supported_params *params = args;
@@ -1248,6 +1276,7 @@ unixlib_entry_t __wine_unix_call_funcs[] =
     get_render_buffer,
     release_render_buffer,
     get_capture_buffer,
+    release_capture_buffer,
     is_format_supported,
     get_mix_format,
     get_buffer_size,
diff --git a/dlls/wineoss.drv/unixlib.h b/dlls/wineoss.drv/unixlib.h
index ca6d1d69de3..2f0884b9ac5 100644
--- a/dlls/wineoss.drv/unixlib.h
+++ b/dlls/wineoss.drv/unixlib.h
@@ -140,6 +140,13 @@ struct get_capture_buffer_params
     UINT64 *qpcpos;
 };
 
+struct release_capture_buffer_params
+{
+    struct oss_stream *stream;
+    UINT32 done;
+    HRESULT result;
+};
+
 struct is_format_supported_params
 {
     const char *device;
@@ -199,6 +206,7 @@ enum oss_funcs
     oss_get_render_buffer,
     oss_release_render_buffer,
     oss_get_capture_buffer,
+    oss_release_capture_buffer,
     oss_is_format_supported,
     oss_get_mix_format,
     oss_get_buffer_size,