83 lines
3.9 KiB
XML
83 lines
3.9 KiB
XML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
<protocol name="weston_direct_display">
|
||
|
|
||
|
<copyright>
|
||
|
Copyright © 2019 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="weston_direct_display_v1" version="1">
|
||
|
<description summary="weston direct display">
|
||
|
Weston extension to instruct the compositor to avoid any import
|
||
|
of the dmabuf created by 'linux-dmabuf' protocol other than the display
|
||
|
controller.
|
||
|
|
||
|
Compositors are already going to use direct scan-out as much as possible but
|
||
|
there's no assurance that while doing so, they won't first import the dmabuf
|
||
|
in to the GPU. This extension assures the client that the compositor will
|
||
|
never attempt to import in to the GPU and pass it directly to the display
|
||
|
controller.
|
||
|
|
||
|
Clients can make use of this extension to pass the dmabuf buffer to the
|
||
|
display controller, potentially increasing the performance and lowering the
|
||
|
bandwidth usage.
|
||
|
|
||
|
Lastly, clients can make use of this extension in tandem with content-protection
|
||
|
one thus avoiding any GPU interaction and providing a secure-content path.
|
||
|
Also, in some cases, the memory where dmabuf are allocated are in specially
|
||
|
crafted memory zone which would be seen as an illegal memory access when the
|
||
|
GPU will attempt to read it.
|
||
|
|
||
|
WARNING: This interface by design might break screenshoting functionality
|
||
|
as compositing might be involved while doing that. Also, do note, that in
|
||
|
case the dmabufer provided can't be imported by KMS, the client connection
|
||
|
will be terminated.
|
||
|
|
||
|
WARNING: This extension requires 'linux-dmabuf' protocol and
|
||
|
'zwp_linux_buffer_params_v1' be already created by 'zwp_linux_buffer_v1'.
|
||
|
</description>
|
||
|
|
||
|
<request name="enable">
|
||
|
<description summary="forward buffer to display controller">
|
||
|
This request tells the compositor not to import the dmabuf to the GPU
|
||
|
in order to bypass it entirely, such that the buffer will be directly
|
||
|
scanned-out by the display controller. If HW is not capable/or there
|
||
|
aren't any available resources to directly scan-out the buffer, a
|
||
|
placeholder should be installed in-place by the compositor. The
|
||
|
compositor may perform checks on the dmabuf and refuse to create a
|
||
|
wl_buffer if the dmabuf seems unusable for being used directly.
|
||
|
|
||
|
Assumes that 'zwp_linux_buffer_params_v1' was already created
|
||
|
by 'zwp_linux_dmabuf_v1_create_params'.
|
||
|
</description>
|
||
|
<arg name="dmabuf" type="object" interface="zwp_linux_buffer_params_v1"
|
||
|
summary="enable direct-display for dmabuf buffer"/>
|
||
|
</request>
|
||
|
|
||
|
<request name="destroy" type="destructor">
|
||
|
<description summary="destroy factory object">
|
||
|
Destroys the factory object, but does not affect any other objects.
|
||
|
</description>
|
||
|
</request>
|
||
|
</interface>
|
||
|
|
||
|
</protocol>
|