+ * @brief Creates a new window on the given display.
+ * @param[in] output A output object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A created window object
+ * @since 2.0.0
+ */
+tdm_hwc_window *
+tdm_output_hwc_create_window(tdm_output *output, tdm_error *error);
+
+/**
+ * @brief Creates a new video window on the given output.
+ * @param[in] output A output object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A created window object
+ * @since 2.0.0
+ */
+tdm_hwc_window *
+tdm_output_hwc_create_video_window(tdm_output *output, tdm_error *error);
+
+/**
+ * @brief Destroys the given window.
+ * @param[in] output A output object
+ * @param[in] window the pointer of the window to destroy
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_destroy_window(tdm_output *output, tdm_hwc_window *hwc_window);
+
+/**
+ * @brief Set the client(relative to the TDM) target buffer
+ * @details Sets the buffer which will receive the output of client composition.
+ * Window marked as TDM_COMPOSITION_CLIENT or TDM_COMPOSITION_DEVICE_CANDIDATE
+ * will be composited into this buffer prior to the call to tdm_output_commit(),
+ * and windows not marked as TDM_COMPOSITION_CLIENT and
+ * TDM_COMPOSITION_DEVICE_CANDIDATE should be composited with this buffer by the
+ * device.
+ *
+ * The buffer handle provided may be null if no windows are being composited by
+ * the client. This must not result in an error (unless an invalid display
+ * handle is also provided).
+ *
+ * The damage parameter describes a buffer damage region as defined in the
+ * description of tdm_hwc_window_set_buffer_damage().
+ *
+ * List of composited hwc_windows (hwc_windows which buffers are presented on #target_buffer)
+ * should be passed along with #target_buffer to allow tdm to make the smooth transition
+ * from a DEVICE type to a CLIENT type.
+ *
+ * Should be called before tdm_output_commit() if any of the layers are marked as
+ * TDM_COMPOSITION_CLIENT or TDM_COMPOSITION_DEVICE_CANDIDATE. If no layers are
+ * so marked, then it is not necessary to call this function. It is not necessary
+ * to call tdm_output_hwc_validate() after changing the target through this function.
+ * @param[in] output A output object
+ * @param[in] target_buffer The new target buffer
+ * @param[in] damage The buffer damage region
+ * @param[in] composited_wnds The array of composited hwc_wnds
+ * @param[in] num_wnds The size of #composited_wnds array
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_set_client_target_buffer(tdm_output *output, tbm_surface_h target_buffer, tdm_hwc_region damage);
+
+/**
+ * @brief Unset the client(relative to the TDM) target buffer
+ * @details TODO
+ * @param[in] output A output object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_unset_client_target_buffer(tdm_output *output);
+
+/**
+ * @brief Commit changes for a target_window
+ * @details After all change of a window object are applied, a user commit handler
+ * will be called.
+ * @param[in] hwc_window A window object
+ * @param[in] func A user commit handler
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+tdm_error
+tdm_output_hwc_commit_client_target_buffer(tdm_output *output, tdm_output_hwc_target_buffer_commit_handler func, void *user_data);
+
+/**
+ * @brief Validate the output
+ * @details Instructs the device to inspect all of the layer state and
+ * determine if there are any composition type changes necessary before
+ * presenting the output. Permitted changes are described in the definition
+ * of tdm_hwc_window_composition_t above.
+ * @param[in] output A output object
+ * @param[out] num_types The number of composition type changes required by
+ * the device; if greater than 0, the client must either set and validate new
+ * types, or call tdm_output_hwc_accept_changes() to accept the changes returned by
+ * tdm_output_hwc_get_changed_composition_types(); must be the same as the number of
+ * changes returned by tdm_output_hwc_get_changed_composition_types (see the
+ * declaration of that function for more information); pointer will be non-NULL
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_validate(tdm_output *output, tdm_hwc_window **composited_wnds, uint32_t num_wnds,
+ uint32_t *num_types);
+
+/**
+ * @brief Set the 'need to validate' handler for the 'output'
+ *
+ * @details During backend's work it may need to ask for the revalidation
+ * (make client (E20) do tdm_output_hwc_validate() again), so a 'hndl' will
+ * be called as such need happen. Only one handler per output is supported.
+ *
+ * @param[in] output The output object a hndl is going to be registered for.
+ * @param[in] hndl The handler which will be called on the 'need to validate' event.
+ *
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_set_need_validate_handler(tdm_output *output,
+ tdm_output_need_validate_handler hndl);
+
+/**
+ * @brief Get changed composition types
+ * @details Retrieves the windows for which the device requires a different
+ * composition type than had been set prior to the last call to tdm_output_hwc_validate().
+ * The client will either update its state with these types and call
+ * tdm_output_hwc_accept_changes, or will set new types and attempt to validate the
+ * display again.
+ * windows and types may be NULL to retrieve the number of elements which
+ * will be returned. The number of elements returned must be the same as the
+ * value returned in num_types from the last call to tdm_output_hwc_validate().
+ * @param[in] output A output object
+ * @param[out] num_elements If windows or types were NULL, the number of layers
+ * and types which would have been returned; if both were non-NULL, the
+ * number of elements returned in layers and types, which must not exceed
+ * the value stored in num_elements prior to the call; pointer will be
+ * non-NULL
+ * @param[in] output A output object
+ * @param[out] windows An array of windows
+ * @param[out] composition_types An array of composition types, each corresponding
+ * to an element of windows
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_get_changed_composition_types(tdm_output *output,uint32_t *num_elements,
+ tdm_hwc_window **hwc_window,
+ tdm_hwc_window_composition *composition_types);
+
+/**
+ * @brief Accepts the changes required by the device
+ * @details Accepts the changes required by the device from the previous
+ * tdm_output_hwc_validate() call (which may be queried using
+ * tdm_output_get_chaged_composition_types()) and revalidates the display. This
+ * function is equivalent to requesting the changed types from
+ * tdm_output_get_chaged_composition_types(), setting those types on the
+ * corresponding windows, and then calling tdm_output_hwc_validate again.
+ * After this call it must be valid to present this display. Calling this after
+ * tdm_output_hwc_validate() returns 0 changes must succeed with TDM_ERROR_NONE, but
+ * should have no other effect.
+ * @param[in] output A output object
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @since 2.0.0
+ */
+tdm_error
+tdm_output_hwc_accept_changes(tdm_output *output);
+
+/**
+ * @brief Get a target buffer queue
+ * @details Buffers from target buffer queue will receive the output of
+ * client composition. Window marked as TDM_COMPOSITION_CLIENT or
+ * TDM_COMPOSITION_DEVICE_CANDIDATE will be composited into this buffers
+ * prior to the call to tdm_output_commit().
+ * @param[in] output A output object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A buffer queue
+ * @since 2.0.0
+ */
+tbm_surface_queue_h
+tdm_output_hwc_get_target_buffer_queue(tdm_output *output, tdm_error *error);
+
+/**
+ * @brief Get the supported format array for video hwc windows of a output object.
+ * @param[in] output A output object
+ * @param[out] formats The available format array
+ * @param[out] count The count of formats
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+tdm_error
+tdm_output_hwc_get_video_supported_formats(tdm_layer *layer, const tbm_format **formats,
+ int *count);
+
+/**
+ * @brief Get a output object of a layer object
+ * @param[in] layer A layer object
+ * @param[out] error #TDM_ERROR_NONE if success. Otherwise, error value.
+ * @return A TDM output object if success. Otherwise, NULL.
+ */
+tdm_output*
+tdm_layer_get_output(tdm_layer *layer, tdm_error *error);
+
+/**