[PATCH wayland-protocols v2] Add zwp_linux_explicit_synchronization_v1

Alexandros Frantzis alexandros.frantzis at collabora.com
Tue Oct 9 15:11:22 UTC 2018


Signed-off-by: Alexandros Frantzis <alexandros.frantzis at collabora.com>
---

patch v1 here: https://patchwork.freedesktop.org/patch/177866/
Changes since patch v1:
  - Add NO_SURFACE error for zwp_surface_synchronization_v1 requests.
  - Remove restriction to destroy a zwp_surface_synchronization_v1 object
    after the associated wl_surface is destroyed.
  - Clarify which buffer the acquire fence is associated with.
  - Clarify that exactly one event, either a fenced_release or a
    immediate_release, will be emitted for each commit.

 Makefile.am                                   |   1 +
 .../linux-explicit-synchronization/README     |   6 +
 ...x-explicit-synchronization-unstable-v1.xml | 222 ++++++++++++++++++
 3 files changed, 229 insertions(+)
 create mode 100644 unstable/linux-explicit-synchronization/README
 create mode 100644 unstable/linux-explicit-synchronization/linux-explicit-synchronization-unstable-v1.xml

diff --git a/Makefile.am b/Makefile.am
index 6394e26..7dfbb9e 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,6 +21,7 @@ unstable_protocols =								\
 	unstable/xdg-output/xdg-output-unstable-v1.xml				\
 	unstable/input-timestamps/input-timestamps-unstable-v1.xml	\
 	unstable/xdg-decoration/xdg-decoration-unstable-v1.xml	\
+	unstable/linux-explicit-synchronization/linux-explicit-synchronization-unstable-v1.xml \
 	$(NULL)
 
 stable_protocols =								\
diff --git a/unstable/linux-explicit-synchronization/README b/unstable/linux-explicit-synchronization/README
new file mode 100644
index 0000000..f13b404
--- /dev/null
+++ b/unstable/linux-explicit-synchronization/README
@@ -0,0 +1,6 @@
+Linux explicit synchronization (dma-fence) protocol
+
+Maintainers:
+David Reveman <reveman at chromium.org>
+Daniel Stone <daniels at collabora.com>
+Alexandros Frantzis <alexandros.frantzis at collabora.com>
diff --git a/unstable/linux-explicit-synchronization/linux-explicit-synchronization-unstable-v1.xml b/unstable/linux-explicit-synchronization/linux-explicit-synchronization-unstable-v1.xml
new file mode 100644
index 0000000..11ef3f0
--- /dev/null
+++ b/unstable/linux-explicit-synchronization/linux-explicit-synchronization-unstable-v1.xml
@@ -0,0 +1,222 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="zwp_linux_explicit_synchronization_unstable_v1">
+
+  <copyright>
+    Copyright 2016 The Chromium Authors.
+    Copyright 2017 Intel Corporation
+    Copyright 2018 Collabora, Ltd
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice (including the next
+    paragraph) shall be included in all copies or substantial portions of the
+    Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+  </copyright>
+
+  <interface name="zwp_linux_explicit_synchronization_v1" version="1">
+    <description summary="protocol for providing explicit synchronization">
+      This global is a factory interface, allowing clients to request
+      explicit synchronization for buffers on a per-surface basis.
+
+      See zwp_surface_synchronization_v1 for more information.
+
+      This interface is derived from Chromium's
+      zcr_linux_explicit_synchronization_v1.
+
+      Warning! The protocol described in this file is experimental and
+      backward incompatible changes may be made. Backward compatible changes
+      may be added together with the corresponding interface version bump.
+      Backward incompatible changes are done by bumping the version number in
+      the protocol and interface names and resetting the interface version.
+      Once the protocol is to be declared stable, the 'z' prefix and the
+      version number in the protocol and interface names are removed and the
+      interface version number is reset.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy explicit synchronization factory object">
+        Destroy this explicit synchronization factory object. Other objects,
+        including zwp_surface_synchronization_v1 objects created by this
+        factory, shall not be affected by this request.
+      </description>
+    </request>
+
+    <enum name="error">
+      <entry name="synchronization_exists" value="0"
+             summary="the surface already has a synchronization object associated"/>
+    </enum>
+
+    <request name="get_synchronization">
+      <description summary="extend surface interface for explicit synchronization">
+        Instantiate an interface extension for the given wl_surface to
+        provide explicit synchronization.
+
+        If the given wl_surface already has an explicit synchronization object
+        associated, the synchronization_exists protocol error is raised.
+      </description>
+
+      <arg name="id" type="new_id" interface="zwp_surface_synchronization_v1"
+           summary="the new synchronization interface id"/>
+      <arg name="surface" type="object" interface="wl_surface"
+           summary="the surface"/>
+    </request>
+  </interface>
+
+  <interface name="zwp_surface_synchronization_v1" version="1">
+    <description summary="per-surface explicit synchronization support">
+      This object implements per-surface explicit synchronization.
+
+      Explicit synchronization refers to co-ordination of pipelined
+      operations performed on buffers. Most GPU clients will schedule
+      an asynchronous operation to render to the buffer, then immediately
+      send the buffer to the compositor to be attached to a surface.
+      Ensuring that the rendering operation is complete before the
+      compositor displays the buffer is an implementation detail handled
+      by either the kernel or userspace graphics driver. This is referred
+      to as 'implicit synchronization'.
+
+      By contrast, explicit synchronization takes dma_fence objects as a
+      marker of when the asynchronous operations are complete. The fence
+      provided by the client will be waited on before the compositor
+      accesses the buffer. Conversely, in place of wl_buffer.release
+      events, the Wayland server will inform the client when the buffer
+      can be destructively accessed through a zwp_buffer_release_v1
+      object.
+
+      This interface cannot be instantiated multiple times for a single
+      surface, and as such should only be used by the component which
+      performs the wl_surface.attach request. Whenever control of
+      buffer attachments is released, the releasing component should
+      ensure it destroys the zwp_surface_synchronization_v1 object.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy synchronization object">
+        Destroy this explicit synchronization object.
+
+        Any fence set with set_acquire_fence in this commit cycle will
+        be invalidated in the server.
+
+        zwp_buffer_release_v1 objects created by this object are not affected
+        by this request.
+      </description>
+    </request>
+
+    <enum name="error">
+      <entry name="invalid_fence" value="0"
+             summary="the fence specified by the client could not be imported"/>
+      <entry name="duplicate_fence" value="1"
+             summary="multiple fences added for a single surface commit"/>
+      <entry name="duplicate_release" value="2"
+             summary="multiple releases added for a single surface commit"/>
+      <entry name="no_surface" value="3"
+             summary="the associated wl_surface was destroyed"/>
+    </enum>
+
+    <request name="set_acquire_fence">
+      <description summary="set the acquire fence">
+        Set the acquire fence that must be signaled before the compositor
+        may sample from the buffer attached with wl_buffer_attach. The fence
+        is a dma_fence kernel object.
+
+        The acquire fence is double-buffered state, and will be applied on the
+        next wl_surface.commit request for the associated surface. Thus, it
+        applies only to the buffer that is attached to the surface at commit
+        time.
+
+        If the fence could not be imported, an INVALID_FENCE error is signaled
+        to the client.
+
+        If a fence has already been attached during the same commit cycle,
+        a DUPLICATE_FENCE error is signaled to the client.
+
+        If the associated wl_surface was destroyed, a NO_SURFACE error
+        is signaled to the client.
+      </description>
+      <arg name="fd" type="fd" summary="acquire fence fd"/>
+    </request>
+
+    <request name="get_release">
+      <description summary="release fence for last-attached buffer">
+        Create a listener for the release of the buffer attached by the
+        client with wl_buffer.attach. See zwp_buffer_release_v1
+        documentation for more information.
+
+        The release object is double-buffered state, and will be applied
+        on the next wl_surface.commit request for the associated surface.
+
+        If a zwp_buffer_release_v1 object has already been requested for
+        the surface in the same commit cycle, a DUPLICATE_RELEASE error
+        is signaled to the client.
+
+        If the associated wl_surface was destroyed, a NO_SURFACE error
+        is signaled to the client.
+      </description>
+
+      <arg name="release" type="new_id" interface="zwp_buffer_release_v1"
+           summary="new zwp_buffer_release_v1 object"/>
+    </request>
+  </interface>
+
+  <interface name="zwp_buffer_release_v1" version="1">
+    <description summary="buffer release explicit synchronization">
+      This object is instantiated in response to a
+      zwp_surface_synchronization_v1 request.
+
+      It provides an alternative to wl_buffer.release events, providing
+      a unique release from a single wl_surface.commit request. The release
+      event also supports explicit synchronization, providing a fence FD
+      where relevant for the client to synchronize against before reusing
+      the buffer.
+
+      Exactly one event, either a fenced_release or an immediate_release,
+      will be emitted for each wl_surface.commit request.
+
+      This event does not replace wl_buffer.release events; servers are still
+      required to send those events.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy buffer release synchronization object">
+        Destroy this buffer release explicit synchronization object. The object
+        may be destroyed at any time.
+      </description>
+    </request>
+
+    <event name="fenced_release">
+      <description summary="release buffer with fence">
+        Sent when the compositor has finalised its usage of the associated
+        buffer, providing a dma_fence which will be signaled when all
+        operations by the compositor on that buffer have finished.
+
+        Clients must not perform any destructive operations (e.g. clearing or
+        rendering) on the buffer until that fence has passed. They may,
+        however, destroy the wl_buffer object.
+      </description>
+      <arg name="fence" type="fd" summary="fence for last operation on buffer"/>
+    </event>
+
+    <event name="immediate_release">
+      <description summary="release buffer immediately">
+        Sent when the compositor has finalised its usage of the associated
+        buffer, and either performed no operations using it, or has a
+        guarantee that all its operations have finished and no more external
+        effects will be observed from these operations.
+      </description>
+    </event>
+  </interface>
+
+</protocol>
-- 
2.19.1



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