Right now we rely entirely on implicit sync for synchronizing
access to GPU buffers. Implicit sync works by setting
synchronization points on the buffer in writers, and letting
readers wait on these sync points before accessing the buffer.
With OpenGL, sync points are created using functions such as
eglSwapBuffers or glFlush. If none of these special functions
are called, no sync point will be created and readers will
potentially access a buffer that hasn't finished rendering yet.
In the context of wlroots, OpenGL is the writer and the backend
(KMS or parent Wayland/X11 session) is the reader. After we're
done rendering a frame, and before passing that frame to the
backend, we need to call glFlush.
glFlush is called when the buffer is detached from the renderer.
This is a task done by output_clear_back_buffer. So let's call
this function before invoking the impl->commit hook, instead of
calling it after.
All of this is maybe a little tricky to get right with the
current renderer_bind_buffer API. The new
wlr_renderer_begin_with_buffer API is much better, because glFlush
is called on wlr_renderer_end, so it's more intuitive.
Closes: https://github.com/swaywm/wlroots/issues/3020
Everything needs to go through the unified wlr_buffer interface
now.
If necessary, there are two ways support for
EGL_WL_bind_wayland_display could be restored by compositors:
- Either by using GBM to convert back EGL Wayland buffers to
DMA-BUFs, then wrap the DMA-BUF into a wlr_buffer.
- Or by wrapping the EGL Wayland buffer into a special wlr_buffer
that doesn't implement any wlr_buffer_impl hook, and special-case
that buffer type in the renderer.
This allows renderers to choose between implementing the old
wlr_renderer_impl.texture_from_wl_drm hook, or opt for the new
wlr_drm stub. The stub has the advantage of not requiring any
special support code: stubbed wl_drm buffers look exactly like
DMA-BUFs from linux-dmabuf-unstable-v1.
This will allow us to remove all of our EGL wl_drm support code
and remove some weird stuff we need just for wl_drm support. In
particular, wl_drm buffers coming from the EGL implementation
can't easily be wrapped into a wlr_buffer properly.
The previous fix tried to side-step cursor->pending_fb completely.
However that messes up our buffer locking mechanism.
Instead, stop clearing the pending cursor FB on a failed commit. The
pending cursor FB will remain for the next commit.
Fixes: 6c3d080e25 ("backend/drm: populate cursor plane's current_fb")
This reverts commit 6c3d080e25.
Populating wlr_drm_plane.current_fb messes up the buffer's locking.
The previous buffer is released while it's still being displayed
on-screen.
The mailing list has never been used.
I think listing the deprecated functions in the release notes is
enough. I'd rather not add the burden of maintaining a separate
communication medium.
We were bumping the pending sequence number after emitting the
commit event, so commit handlers were seeing inconsistent state
where current.seq == pending.seq. This prevents commit handlers
from immediately locking the pending state.
Fix this by bumping the pending sequence number before firing the
commit event.
Custom backends and renderers need to implement
wlr_backend_impl.get_buffer_caps and
wlr_renderer_impl.get_render_buffer_caps. They can't if enum
wlr_buffer_cap isn't made public.
We never create an EGL context with the platform set to something
other than EGL_PLATFORM_GBM_KHR. Let's simplify wlr_egl_create by
taking a DRM FD instead of a (platform, remote_display) tuple.
This hides the internal details of creating an EGL context for a
specific device. This will allow us to transparently use the device
platform [1] when the time comes.
[1]: https://github.com/swaywm/wlroots/pull/2671
There are still many situations where the buffer scale is not
divisible by scale. The fix will require a tad more work, so
let's just log the client error for now and continue handling
the surface commit as usual.
Closes: https://github.com/swaywm/sway/issues/6352
New warnings can be hard to notice in CI, since CI will just pass in
that case. Meson sometimes uses warnings for important mistakes, e.g.
invalid option.
Let's turn warnings into errors so that we can spot these more easily.
The wlr_egl functions are mostly used internally by the GLES2
renderer. Let's reduce our API surface a bit by hiding them. If
there are good use-cases for one of these, we can always make them
public again.
The functions mutating the current EGL context are not made private
because e.g. Wayfire uses them.
