Hi guys,
As most of you already know, we've been lately working on adding Wayland
support to our drivers by using EGLStreams and friends.
As part of that effort, I've been working through the feedback I got
from you last time.
In order to address one of Daniel Stone's concerns about modifying
current EGL_WL_bind_wayland_display extension and adding buffer queries
to fetch the stream file descriptor, and create compositor endpoint out
of it, we've put together this new EGL_WL_wayland_eglstream extension
that will make things a bit different, and won't require any
modification to the current extensions.
I'd really appreciate getting feedback from you.
Please, find attached the latest draft of EGL_WL_wayland_eglstream.
Note that it requires the not-yet published EGL_NV_stream_attrib
extension, which draft can be found here:
https://github.com/aritger/eglstreams-kms-example/blob/master/proposed-extensions/EGL_NV_stream_attrib.txt
Thanks,
--
Miguel
Name
WL_wayland_eglstream
Name Strings
EGL_WL_wayland_eglstream
Contributors
Miguel A. Vico
Adam Cheney
Contact
Miguel A. Vico, NVIDIA Corporation (mvicomoya 'at' nvidia.com)
Status
Draft
Version
3 - April 29, 2015
Number
TBD
Extension Type
Display extension
Dependencies
Requires EGL_KHR_stream
Requires EGL_NV_stream_attrib
Requires EGL_WL_bind_wayland_display
This extension is written against the wording of the EGL 1.5
specification, but may be used with older versions that support
EGLAttribKHR.
Overview
This extension provides means for a Wayland compositor to create
the consumer endpoint of an EGLStream from a wl_resource. The EGL
implementation must provide one or more interfaces in the Wayland
protocol to allow Wayland clients to create wl_resource objects
that represent an EGLStream.
IP Status
No known IP issues.
New Procedures and Functions
None
New Tokens
Accepted in the <attrib_list> parameter of eglCreateStreamAttribNV:
EGL_WAYLAND_EGLSTREAM_WL 0x334B
Add to the EGL_WL_bind_wayland_display extension specification after
the section describing how to create EGLImage objects from a wl_buffer:
A wl_resource can be bound to an EGLStream in the compositor. A
pointer to wl_resource must be passed as EGL_WAYLAND_EGLSTREAM_WL
attribute in <attrib_list> of eglCreateStreamAttribNV. In case of
success, eglCreateStreamAttribNV will return an EGLStream handle
associated to the given wl_resource, which can be used by the
compositor to attach a consumer and start acquiring frames from the
wayland client (producer). Otherwise, EGL_NO_STREAM_KHR will be
returned and an EGL error will be generated.
Add a new entry to table "Table 3.10.4.4 EGLStream Attributes" of the
EGL_KHR_stream extension specification:
Attribute Read/Write Type Section
-------------------------- ---------- ------ --------
EGL_WAYLAND_EGLSTREAM_WL wo *wl_resource 3.10.4.x
Add a new subsection 3.10.4.x at the end of section "3.10.4 EGLStream
Attributes" of the EGL_KHR_stream extension specification:
3.10.4.x EGL_WAYLAND_EGLSTREAM_WL Attribute
This attribute is only accepted by eglCreateStreamAttribNV. It
allows a wayland compositor to create a consumer endpoint EGLStream
instance from a given wl_resource. The valid value for this
attribute is a pointer to a wl_resource.
Add to the list of failures of eglCreateStreamAttribNV in the
EGL_NV_stream_attrib extension specification:
- EGL_BAD_MATCH is generated if <attrib_list> contains multiple
EGL_WAYLAND_EGLSTREAM_WL attributes.
- EGL_BAD_ACCESS is generated if <attrib_list> contains an
EGL_WAYLAND_EGLSTREAM_WL attribute and the corresponding
wl_resource pointer is NULL or does not represent a valid
EGLStream.
- EGL_BAD_ACCESS is generated if <attrib_list> contains an
EGL_WAYLAND_EGLSTREAM_WL attribute and one or more producer-side
specific attributes.
- EGL_BAD_STREAM_KHR is generated if <attrib_list> contains an
EGL_WAYLAND_EGLSTREAM_WL attribute and the corresponding
wl_resource pointer represents a previously created EGLStream.
Issues
None
Revision History:
#3 (April 29th, 2016) Miguel A. Vico
- Extending the list of failures of eglCreateStreamAttribNV.
#2 (April 19th, 2016) Miguel A. Vico
- Assign enumeration value for EGL_WAYLAND_EGLSTREAM_WL.
#1 (April 18th, 2016) Miguel A. Vico
- Initial draft, adding a new attribute for
eglCreateStreamAttribNV function defined in
EGL_NV_stream_attrib.
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