If there is a pending frame, the RenderLoop will delay all schedule
repaint requests to the next vblank event. This means that the render
loop needs to be notified when a frame has been presented or failed.
At the moment, the RenderLoop is notified only about successfully
presented frames. If some frame fails, no repaints will be scheduled
on that output.
In order to make frame scheduling robust, the RenderLoop has to be
notified if a frame has failed.
The compositing timing algorithm assumes that glXSwapBuffers() and
eglSwapBuffers() block. While this was true long time ago with NVIDIA
drivers, nowadays, it's not the case. The NVIDIA driver queues
several buffers in advance and if the application runs out of them,
it will block. With Mesa driver, swapping buffer was never blocking.
This change makes the render backends swap buffers right after ending
a compositing cycle. This may potentially block, but it shouldn't be
an issue with modern drivers. In case it gets proven, we can move
glXSwapBuffers() and eglSwapBuffers() in a separate thread.
Note that this change breaks the compositing timing algorithm, but
it's already sort of broken with Mesa drivers.
Currently, the OpenGLBackend and the QPainterBackend have hooks to
indicate the start and the end of compositing cycle, but in both cases,
the hooks have different names. This change fixes that inconsistency.
In order to allow per screen rendering, we need the Compositor to be
able to drive rendering on each screen. Currently, it's not possible
because Scene::paint() paints all screen.
With this change, the Compositor will be able to ask the Scene to paint
only a screen with the specific id.
Currently, every time compositing is restarted, both the gbm and the egl
streams backend will re-obtain the EGLDisplay object.
This is wrong because the core assumption is that the EGL display doesn't
change once it has been obtained.
Uses a setter and clear method pattern rather than having the code
repeated.
Instead of keeping a QPointer, now we are a QObject and we get notified
about destruction intention directly, so we can clear the pointer when
necessary.
The main advantage of SPDX license identifiers over the traditional
license headers is that it's more difficult to overlook inappropriate
licenses for kwin, for example GPL 3. We also don't have to copy a
lot of boilerplate text.
In order to create this change, I ran licensedigger -r -c from the
toplevel source directory.
Summary:
Selecting not to vsync does not make sense for an X11 compositor. In the end
we want clients to be able to present async if they want to but the compositor
is supposed to send swaps with vsync to the XServer in order to not generate
tearing artifacts.
There was also a detection logic which did some questionable things in case
vsync was not available. I don't think this is necessary at all since we can
just always run a timer to present with or without vsync.
Test Plan: kwin_x11 tested on i915.
Reviewers: #kwin, zzag
Subscribers: zzag, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D23511
Summary:
This is the initial implementation of a DRM backend based on the EGLDevice,
EGLOutput, and EGLStream extensions, supporting NVIDIA graphics hardware using
their proprietary driver. The new backend will be used if the environment
variable KWIN_DRM_USE_EGL_STREAMS is set. On initialization, it will attempt to
create an EGLDevice based on the DRM device currently in use and create
EGLOutputs and EGLStreams for any attached displays. These are used to control
presentation of the final composited frame. Additionally, it will register the
wl_eglstream_controller Wayland interface so that native EGL windows created by
clients can be attached to an EGLStream allowing buffer contents to be shared
with the compositor as a GL texture.
At this time there are two known bugs in the NVIDIA driver's EGL implementation
affecting desktop functionality. The first can result in tooltip windows drawn
by plasmashell to contain incorrect contents. The second prevents KWayland from
being able to query the format of EGLStream-backed buffers which interferes
with the blur effect. Fixes for both of these are currently in development and
should appear in an upcoming NVIDIA driver release.
Additionally, hardware cursors are currently not supported with this backend.
Enabling them causes the desktop to intermittently hang for several seconds.
This is also likely a bug in the NVIDIA DRM-KMS implementation but the root
cause is still under investigation.
Test Plan:
On a system with an NVIDIA graphics card running a recent release of their
proprietary driver
* Ensure the nvidia_drm kernel module is loaded with the option "modeset=1"
("# cat /sys/module/nvidia_drm/parameters/modeset" should print "Y")
* Ensure EGL external platform support is installed
https://github.com/NVIDIA/eglexternalplatform
* Ensure KWin was build with the CMake option
KWIN_BUILD_EGL_STREAM_BACKEND=ON (this is the default)
* Start a plasma wayland session with the environment variable
KWIN_DRM_USE_EGL_STREAMS set
* Ensure output from KWin OpenGL initialization indicates the NVIDIA EGL
driver is in use (as opposed to Mesa / llvmpipe).
* Desktop should be fully functional and perform smoothly.
Reviewers: #kwin, romangg, davidedmundson
Reviewed By: #kwin, romangg, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18570
