[PATCH v2 weston 2/7] compositor: do not flush shm buffer on destroy

[Kristian Høgsberg]

On Tue, Dec 04, 2012 at 03:58:11PM +0200, Pekka Paalanen wrote:
> The protocol does not require us to flush_damage() on wl_buffer
> destruction. In fact, by the time the server receives this request, the
> client may have already clobbered the buffer's storage, so we could be
> reading undefined data. Instead, just forget about the buffer. The
> protocol already says, that a client must not destroy a buffer that is
> being read by the server, or the window contents become undefined.
> 
> The practical reason for this change is that the following commit can
> consolidate wl_buffer destruction listener handlers.

Yeah, I think that's fine.  Before surface.commit, the semantics were
that you could destroy a buffer right after attach, and the server
would reference or copy the underlying pixels.  But requiring the
buffer to be valid until the release event is more well-defined.

Kristian

> Signed-off-by: Pekka Paalanen <ppaalanen at gmail.com>
> ---
>  src/compositor.c |    3 ---
>  1 files changed, 0 insertions(+), 3 deletions(-)
> 
> diff --git a/src/compositor.c b/src/compositor.c
> index 88a37f7..d80d929 100644
> --- a/src/compositor.c
> +++ b/src/compositor.c
> @@ -187,9 +187,6 @@ surface_handle_buffer_destroy(struct wl_listener *listener, void *data)
>  		container_of(listener, struct weston_surface, 
>  			     buffer_destroy_listener);
>  
> -	if (es->buffer && wl_buffer_is_shm(es->buffer))
> -		es->compositor->renderer->flush_damage(es);
> -
>  	es->buffer = NULL;
>  }
>  
> -- 
> 1.7.8.6
>