From 3e897faa29d13bef6f9af31d4f2e89a526e60f4c Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Wed, 26 May 2021 12:07:17 +0200 Subject: [PATCH] protocol: allow immediate wl_buffer.destroy if not re-used Allow wl_buffer objects to be destroyed without having to wait for wl_buffer.release if the underlying storage isn't going to be re-used. The main motivation for this is to avoid glitches when a client is torn down. When a client disconnects, all of its objects are destroyed in arbitrary order. However some compositors will still need to access the destroyed buffer's underlying storage afterwards, e.g. for visual effects (fade-out) or for atomic layout updates (wait for other clients to commit a new buffer before hiding the buffer). It's still incorrect for clients to destroy a wl_buffer and mutate the underlying storage without waiting for wl_buffer.release. Signed-off-by: Simon Ser Closes: https://gitlab.freedesktop.org/wayland/wayland/-/issues/185 --- protocol/wayland.xml | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/protocol/wayland.xml b/protocol/wayland.xml index acb85fd..ef65714 100644 --- a/protocol/wayland.xml +++ b/protocol/wayland.xml @@ -1435,9 +1435,12 @@ from the same backing storage or use wp_linux_buffer_release. Destroying the wl_buffer after wl_buffer.release does not change - the surface contents. However, if the client destroys the - wl_buffer before receiving the wl_buffer.release event, the surface - contents become undefined immediately. + the surface contents. Destroying the wl_buffer before wl_buffer.release + is allowed as long as the underlying buffer storage isn't re-used (this + can happen e.g. on client process termination). However, if the client + destroys the wl_buffer before receiving the wl_buffer.release event and + mutates the underlying buffer storage, the surface contents become + undefined immediately. If wl_surface.attach is sent with a NULL wl_buffer, the following wl_surface.commit will remove the surface content. -- 2.7.4