compositor: add early wl_buffer.release

A client can reliably avoid allocating a second buffer per surface, if
the compositor sends the wl_buffer.release event before the frame
callback. To enable clients' single-buffering, release the wl_buffer
early if possible. Otherwise clients will double-buffer.

Releasing early is not possible, if the backend needs the buffer for
migrating a surface to or from a non-primary weston_plane. In that case,
a new buffer must arrive, before the old can be released. Backends will
indicate this by setting weston_surface:keep_buffer to 1 in
assign_planes().

A proper buffer reference in the backends would be better than the
keep_buffer flag, but that would require a per-surface backend private.

The rpi and DRM backends are updated to set keep_buffer, other backends
do not support planes, so do not have to set it.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
Pekka Paalanen 12 years ago committed by Kristian Høgsberg
parent fb003d3457
commit ccfeae2ad7
  1. 10
      src/compositor-drm.c
  2. 3
      src/compositor-rpi.c
  3. 14
      src/compositor.c
  4. 1
      src/compositor.h

@ -805,6 +805,16 @@ drm_assign_planes(struct weston_output *output)
pixman_region32_init(&overlap);
primary = &c->base.primary_plane;
wl_list_for_each_safe(es, next, &c->base.surface_list, link) {
/* test whether this buffer can ever go into a plane:
* non-shm, or small enough to be a cursor
*/
if ((es->buffer_ref.buffer &&
!wl_buffer_is_shm(es->buffer_ref.buffer)) ||
(es->geometry.width <= 64 && es->geometry.height <= 64))
es->keep_buffer = 1;
else
es->keep_buffer = 0;
pixman_region32_init(&surface_overlap);
pixman_region32_intersect(&surface_overlap, &overlap,
&es->transform.boundingbox);

@ -798,6 +798,9 @@ rpi_output_assign_planes(struct weston_output *base)
pixman_region32_init(&overlap);
wl_list_for_each(surface, &compositor->base.surface_list, link) {
/* always, since all buffers are shm on rpi */
surface->keep_buffer = 1;
pixman_region32_init(&surface_overlap);
pixman_region32_intersect(&surface_overlap, &overlap,
&surface->transform.boundingbox);

@ -1084,9 +1084,21 @@ weston_output_repaint(struct weston_output *output, uint32_t msecs)
pixman_region32_fini(&ec->primary_plane.opaque);
pixman_region32_init(&ec->primary_plane.opaque);
wl_list_for_each(es, &ec->surface_list, link)
wl_list_for_each(es, &ec->surface_list, link) {
surface_accumulate_damage(es, &opaque);
/* Both the renderer and the backend have seen the buffer
* by now. If renderer needs the buffer, it has its own
* reference set. If the backend wants to keep the buffer
* around for migrating the surface into a non-primary plane
* later, keep_buffer is true. Otherwise, drop the core
* reference now, and allow early buffer release. This enables
* clients to use single-buffering.
*/
if (!es->keep_buffer)
weston_buffer_reference(&es->buffer_ref, NULL);
}
pixman_region32_fini(&opaque);
pixman_region32_init(&output_damage);

@ -444,6 +444,7 @@ struct weston_surface {
struct weston_buffer_reference buffer_ref;
uint32_t buffer_transform;
int keep_buffer; /* bool for backends to prevent early release */
/* All the pending state, that wl_surface.commit will apply. */
struct {

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