Introduce support for the zwp_linux_explicit_synchronization_unstable_v1
protocol with an implementation of the zwp_linux_explicit_synchronization_v1
interface.
Explicit synchronization provides a more versatile notification
mechanism for buffer readiness and availability, and can be used to
improve efficiency by integrating with related functionality in display
and graphics APIs.
In addition, the per-commit nature of the release events provided by
this protocol potentially offers a solution to a deficiency of the
wl_buffer.release event (see
https://gitlab.freedesktop.org/wayland/wayland/issues/46).
Support for this protocol depends on the capabilities of the backend, so
we don't register it by default but provide a function which each
backend will need to call. In this commit only the headless backend when
using the noop renderer supports this to enable testing.
Note that the zwp_surface_synchronization_v1 interface, which contains
the core functionality of the protocol, is not implemented in this
commit. Support for it will be added in future commits.
Changes in v7:
- Added some information in the commit message about the benefits of
the explicit sync protocol.
Changes in v6:
- Fall back to advertising minor version 1 of the explicit sync protocol,
although we support minor version 2 features, until the new
wayland-protocols version is released.
Changes in v5:
- Meson support.
- Advertise minor version 2 of the explicit sync protocol.
Changes in v4:
- Enable explicit sync support in the headless backend for all
renderers.
Changes in v3:
- Use wl_resource_get_version() instead of hardcoding version 1.
- Use updated protocol interface names.
- Use correct format specifier for resource id.
- Change test name to 'linux-explicit-synchronization.weston'
(s/_/-/g).
Changes in v2:
- Move implementation to separate file so protocol can be registered
on demand by backends.
- Register protocol in headless+noop backend for testing purposes.
Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
