compositor: don't release the front buffer after page flip

On repaint, wlsc_output_repaint will replace output->scanout_buffer with
the new front buffer and then output->present() will cause this buffer
to be displayed. When wlsc_output_finish_frame is called, the
compositor will send a release buffer event for output->scanout_buffer
which is actually the front buffer now.

This patch changes this code to release the previous scanout_buffer
instead of the front buffer on wlsc_output_finish_frame.

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>

diff --git a/compositor/compositor.c b/compositor/compositor.c
index c59163c..17b347e 100644 (file)
--- a/compositor/compositor.c
+++ b/compositor/compositor.c
@@ -227,6 +227,21 @@ output_handle_scanout_buffer_destroy(struct wl_listener *listener,
                output->scanout_buffer = NULL;
 }
 
+static void
+output_handle_old_scanout_buffer_destroy(struct wl_listener *listener,
+                                        struct wl_resource *resource,
+                                        uint32_t time)
+{
+       struct wlsc_output *output =
+               container_of(listener, struct wlsc_output,
+                            old_scanout_buffer_destroy_listener);
+       struct wl_buffer *buffer = (struct wl_buffer *) resource;
+
+       if (output->old_scanout_buffer == buffer)
+               output->old_scanout_buffer = NULL;
+}
+
+
 WL_EXPORT struct wlsc_surface *
 wlsc_surface_create(struct wlsc_compositor *compositor,
                    int32_t x, int32_t y, int32_t width, int32_t height)
@@ -846,9 +861,16 @@ setup_scanout_surface(struct wlsc_output *output, struct wlsc_surface *es)
            output->prepare_scanout_surface(output, es) != 0)
                return 0;
 
+       output->old_scanout_buffer = output->scanout_buffer;
        output->scanout_buffer = es->buffer;
        output->scanout_buffer->busy_count++;
 
+       if (output->old_scanout_buffer) {
+               wl_list_remove(&output->old_scanout_buffer_destroy_listener.link);
+               wl_list_insert(output->old_scanout_buffer->resource.destroy_listener_list.prev,
+                              &output->old_scanout_buffer_destroy_listener.link);
+       }
+
        wl_list_remove(&output->scanout_buffer_destroy_listener.link);
        wl_list_insert(output->scanout_buffer->resource.destroy_listener_list.prev,
                       &output->scanout_buffer_destroy_listener.link);
@@ -968,8 +990,8 @@ idle_repaint(void *data)
 WL_EXPORT void
 wlsc_output_finish_frame(struct wlsc_output *output, int msecs)
 {
-       wlsc_buffer_post_release(output->scanout_buffer);
-       output->scanout_buffer = NULL;
+       wlsc_buffer_post_release(output->old_scanout_buffer);
+       output->old_scanout_buffer = NULL;
        output->repaint_scheduled = 0;
 
        if (output->repaint_needed)
@@ -1920,6 +1942,11 @@ wlsc_output_init(struct wlsc_output *output, struct wlsc_compositor *c,
        output->scanout_buffer_destroy_listener.func =
                output_handle_scanout_buffer_destroy;
        wl_list_init(&output->scanout_buffer_destroy_listener.link);
+
+       output->old_scanout_buffer_destroy_listener.func =
+               output_handle_old_scanout_buffer_destroy;
+       wl_list_init(&output->old_scanout_buffer_destroy_listener.link);
+
        wl_list_init(&output->frame_callback_list);
 
        output->resource.object.interface = &wl_output_interface;

diff --git a/compositor/compositor.h b/compositor/compositor.h
index 35aaf55..d63017c 100644 (file)
--- a/compositor/compositor.h
+++ b/compositor/compositor.h
@@ -85,6 +85,8 @@ struct wlsc_output {
        struct wl_list mode_list;
        struct wl_buffer *scanout_buffer;
        struct wl_listener scanout_buffer_destroy_listener;
+       struct wl_buffer *old_scanout_buffer;
+       struct wl_listener old_scanout_buffer_destroy_listener;
 
        int (*prepare_render)(struct wlsc_output *output);
        int (*present)(struct wlsc_output *output);