hwc: modify the doxygen of tdm_hwc_window_composition

Change-Id: Ie27771f551f9885ed2168d7a05ad717acba20c18

diff --git a/include/tdm_types.h b/include/tdm_types.h
index 86ad6e7..b87fc18 100644 (file)
--- a/include/tdm_types.h
+++ b/include/tdm_types.h
@@ -161,47 +161,52 @@ typedef struct _tdm_info_capture {
  */
 typedef enum {
 
-       /** Set by the client for an invisible window. The value by default.
+       /** The composition type for an invisible window. The value by default.
         *
-        * The device ignores windows of this type.
+        * The backend ignores windows of this type.
         */
        TDM_COMPOSITION_NONE = 0,
 
-       /** The client will composite this window into the client target window
+       /** The compostion type for an window to be compsoited by the client.
         *
-        * User can choose this type for window to avoid a hardware composition for
-        * this window.
+        * When the client sets this composition type,
+        * the backend MUST NOT modify this composition type into other types.
         *
-        * The device must not request any composition type changes for windows of
-        * this type.
+        * When the backend changes TDM_COMPOSITION_DEVICE or TDM_COMPOSITION_CURSOR
+        * to this composition type at the time of tdm_hwc_validate and
+        * tdm_hwc_get_changed_composition_types,
+        * the client has to composite this window with gl or other drawing operations.
         */
        TDM_COMPOSITION_CLIENT = 1,
 
-       /** Set by the HWC after tdm_hwc_validate().
+       /** The compostion type for an window to be set to the hw overlay.
         *
-        * The device will handle the composition of this window through a hardware
-        * overlay or other similar means.
-        *
-        * Upon tdm_hwc_validate(), the device may request a change from this type to
-        * TDM_COMPOSITION_CLIENT or TDM_COMPOSITION_DEVICE_CANDIDATE. */
+        * The client sets this composition type to the visible windows before requesting
+        * the tdm_hwc_validate.
+        * Nomally, the backend leave it if the backend sets the window to the hw overlay.
+        * If the backend does not set the window to the hw overlay at the time of
+        * tdm_hwc_validate, the backend changes the composition type of the window into
+        * TDM_COMPOSITION_CLIENT.
+        */
        TDM_COMPOSITION_DEVICE = 3,
 
-       /** Similar to DEVICE, but the position of this layer may also be set
-        * asynchronously through layer_set_cursor_position. If this functionality is not
-        * supported on a layer that the client sets to TDM_COMPOSITION_CURSOR, the
-        * device must request that the composition type of that layer is changed to
-        * TDM_COMPOSITION_CLIENT upon the next call to tdm_hwc_validate().
+       /** The compostion type for an window to be set to the cursor hw overlay.
         *
-        * Upon tdm_hwc_validate(), the device may request a change from this type to
-        * either TDM_COMPOSITION_DEVICE or TDM_COMPOSITION_CLIENT. Changing to
-        * TDM_COMPOSITION_DEVICE will prevent the use of layer_set_cursor_position but
-        * still permit the device to composite the layer. */
+        * The client sets this composition type to the cursor window before requesting
+        * the tdm_hwc_validate.
+        * If the backend does not support the cursor hw overlay, the backend can change
+        * the comopsition type into the TDM_COMPOSITION_CLIENT.
+        */
        TDM_COMPOSITION_CURSOR = 4,
 
-       /** This type is for the VIDEO window which can be set to the reserved hw overlay
-        *  which is assigned by the device.
+       /** The compostion type for an window to be set to the video hw overlay.
         *
-        * Normally, this VIDEO window displays under the primary hw overlayer of the output. */
+        * The client sets this composition type to the video window before requesting
+        * the tdm_hwc_validate.
+        * If the backend does not support the video hw overlay, the backend can change
+        * the comopsition type into the TDM_COMPOSITION_CLIENT.
+        * Normally, this VIDEO window displays under the primary hw overlayer of the output.
+        */
        TDM_COMPOSITION_VIDEO = 5,
 } tdm_hwc_window_composition;