f606a4424a
The existing comment tells us this is necessary:
> there may be drawing between the last damage event and the
> XDamageSubtract() that needs to be flushed as well.
But the commit message for 551101c65cda also tells us that
synchronization is necessary before-update. Assuming both are correct
then it needs to be done in both places.
I did try optimizing out the second sync to only do it if damage
arrived during the update, but that doesn't seem to be the issue.
The damage event is arriving before the update starts and it's some
secondary changes within the damage region running late that need
flushing. So this means the client is reporting damage more frequently
than the frame rate and we're ignoring the secondary damage reports
for efficiency (XDamageReportBoundingBox), which is still a good thing.
Fixes: 551101c65cda ("compositor-x11: Move synchronization to before-update")
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2880
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3590>
Mutter
Mutter is a Wayland display server and X11 window manager and compositor library.
When used as a Wayland display server, it runs on top of KMS and libinput. It implements the compositor side of the Wayland core protocol as well as various protocol extensions. It also has functionality related to running X11 applications using Xwayland.
When used on top of Xorg it acts as a X11 window manager and compositing manager.
It contains functionality related to, among other things, window management, window compositing, focus tracking, workspace management, keybindings and monitor configuration.
Internally it uses a fork of Cogl, a hardware acceleration abstraction library used to simplify usage of OpenGL pipelines, as well as a fork of Clutter, a scene graph and user interface toolkit.
Mutter is used by, for example, GNOME Shell, the GNOME core user interface, and by Gala, elementary OS's window manager. It can also be run standalone, using the command "mutter", but just running plain mutter is only intended for debugging purposes.
Contributing
To contribute, open merge requests at https://gitlab.gnome.org/GNOME/mutter.
It can be useful to first look at the GNOME Handbook and the documentation and API references below first.
Documentation
- Coding style and conventions
- Git conventions
- Code overview
- Building and Running
- Debugging
- Monitor configuration
API Reference
- Meta: https://mutter.gnome.org/meta/
- Clutter: https://mutter.gnome.org/clutter/
- Cally: https://mutter.gnome.org/cally/
- Cogl: https://mutter.gnome.org/cogl/
- CoglPango: https://mutter.gnome.org/cogl-pango/
- Mtk: https://mutter.gnome.org/mtk/
License
Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.