My KWIN fork where I work on features like per-output virtual desktops
56cd5f5557
Summary: QtQuick windows created by KWin currently use the default swap interval of 1, meaning buffer swaps will block until vblank. However, this results in a problematic interaction on hybrid graphics systems running the proprietary NVIDIA driver. VSync on such setups relies on a system called "PRIME synchronization", where the xf86-video-modesetting driver controlling the display will signal the NVIDIA driver when vblank has occurred. The issue is that it will only do so if there has been damage to the screen. So, when KWin creates a QtQuick window, compositing will stop waiting on the window to render, therefore no damage to the screen will occur. But this means that no vblank notifications will be delivered to the NVIDIA driver, so the glXSwapBuffers call by the QtQuick window will block perpetually. The end result is a freeze of the desktop. To get around this, we can simply disable vsync for QtQuick windows by setting the swap interval for the default QSurfaceFormat to 0. Since they are redirected, this shouldn't cause any tearing. BUG: 406180 FIXED-IN: 5.16.2 Test Plan: Using the proprietary NVIDIA driver on a hybrid graphics system, with PRIME synchronization enabled (see https://devtalk.nvidia.com/default/topic/957814/linux/prime-and-prime-synchronization/), perform any action causing a QtQuick window to be created by KWin, for example, triggering the application switcher dialogue with alt + tab. Ensure the desktop does not temporarily freeze. Note, this required a Qt build that includes commit https://code.qt.io/cgit/qt/qtbase.git/commit/?id=0c1831178540462da31fd7a4b6d2e446bc84498b resolving a bug that prevented the changing the swap interval. Reviewers: #kwin, davidedmundson, zzag Reviewed By: #kwin, davidedmundson, zzag Subscribers: zzag, romangg, alexeymin, kwin Tags: #kwin Differential Revision: https://phabricator.kde.org/D21808 |
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| autotests | ||
| cmake/modules | ||
| colorcorrection | ||
| data | ||
| decorations | ||
| doc | ||
| effects | ||
| helpers | ||
| kcmkwin | ||
| kconf_update | ||
| libinput | ||
| libkwineffects | ||
| platformsupport | ||
| plugins | ||
| qml | ||
| scripting | ||
| scripts | ||
| tabbox | ||
| tests | ||
| xwl | ||
| .arcconfig | ||
| .arclint | ||
| abstract_client.cpp | ||
| abstract_client.h | ||
| abstract_opengl_context_attribute_builder.cpp | ||
| abstract_opengl_context_attribute_builder.h | ||
| abstract_output.cpp | ||
| abstract_output.h | ||
| abstract_wayland_output.cpp | ||
| abstract_wayland_output.h | ||
| activation.cpp | ||
| activities.cpp | ||
| activities.h | ||
| appmenu.cpp | ||
| appmenu.h | ||
| atoms.cpp | ||
| atoms.h | ||
| client.cpp | ||
| client.h | ||
| client_machine.cpp | ||
| client_machine.h | ||
| CMakeLists.txt | ||
| composite.cpp | ||
| composite.h | ||
| config-kwin.h.cmake | ||
| COPYING | ||
| cursor.cpp | ||
| cursor.h | ||
| dbusinterface.cpp | ||
| dbusinterface.h | ||
| debug_console.cpp | ||
| debug_console.h | ||
| debug_console.ui | ||
| deleted.cpp | ||
| deleted.h | ||
| effectloader.cpp | ||
| effectloader.h | ||
| effects.cpp | ||
| effects.h | ||
| egl_context_attribute_builder.cpp | ||
| egl_context_attribute_builder.h | ||
| events.cpp | ||
| fixqopengl.h | ||
| focuschain.cpp | ||
| focuschain.h | ||
| geometry.cpp | ||
| geometrytip.cpp | ||
| geometrytip.h | ||
| gestures.cpp | ||
| gestures.h | ||
| globalshortcuts.cpp | ||
| globalshortcuts.h | ||
| group.cpp | ||
| group.h | ||
| HACKING.md | ||
| idle_inhibition.cpp | ||
| idle_inhibition.h | ||
| input.cpp | ||
| input.h | ||
| input_event.cpp | ||
| input_event.h | ||
| input_event_spy.cpp | ||
| input_event_spy.h | ||
| internal_client.cpp | ||
| internal_client.h | ||
| keyboard_input.cpp | ||
| keyboard_input.h | ||
| keyboard_layout.cpp | ||
| keyboard_layout.h | ||
| keyboard_layout_switching.cpp | ||
| keyboard_layout_switching.h | ||
| keyboard_repeat.cpp | ||
| keyboard_repeat.h | ||
| killwindow.cpp | ||
| killwindow.h | ||
| kwin.kcfg | ||
| kwin.notifyrc | ||
| kwinbindings.cpp | ||
| KWinDBusInterfaceConfig.cmake.in | ||
| layers.cpp | ||
| logind.cpp | ||
| logind.h | ||
| main.cpp | ||
| main.h | ||
| main_wayland.cpp | ||
| main_wayland.h | ||
| main_x11.cpp | ||
| main_x11.h | ||
| Mainpage.dox | ||
| manage.cpp | ||
| Messages.sh | ||
| modifier_only_shortcuts.cpp | ||
| modifier_only_shortcuts.h | ||
| moving_client_x11_filter.cpp | ||
| moving_client_x11_filter.h | ||
| netinfo.cpp | ||
| netinfo.h | ||
| onscreennotification.cpp | ||
| onscreennotification.h | ||
| options.cpp | ||
| options.h | ||
| org.kde.kappmenu.xml | ||
| org.kde.kwin.ColorCorrect.xml | ||
| org.kde.kwin.Compositing.xml | ||
| org.kde.kwin.Effects.xml | ||
| org.kde.kwin.OrientationSensor.xml | ||
| org.kde.KWin.VirtualDesktopManager.xml | ||
| org.kde.KWin.xml | ||
| orientation_sensor.cpp | ||
| orientation_sensor.h | ||
| osd.cpp | ||
| osd.h | ||
| outline.cpp | ||
| outline.h | ||
| outputscreens.cpp | ||
| outputscreens.h | ||
| overlaywindow.cpp | ||
| overlaywindow.h | ||
| placement.cpp | ||
| placement.h | ||
| platform.cpp | ||
| platform.h | ||
| pointer_input.cpp | ||
| pointer_input.h | ||
| popup_input_filter.cpp | ||
| popup_input_filter.h | ||
| README.md | ||
| rootinfo_filter.cpp | ||
| rootinfo_filter.h | ||
| rules.cpp | ||
| rules.h | ||
| scene.cpp | ||
| scene.h | ||
| screenedge.cpp | ||
| screenedge.h | ||
| screenlockerwatcher.cpp | ||
| screenlockerwatcher.h | ||
| screens.cpp | ||
| screens.h | ||
| settings.kcfgc | ||
| shadow.cpp | ||
| shadow.h | ||
| shell_client.cpp | ||
| shell_client.h | ||
| shortcutdialog.ui | ||
| sm.cpp | ||
| sm.h | ||
| tabgroup.cpp | ||
| tabgroup.h | ||
| tabletmodemanager.cpp | ||
| tabletmodemanager.h | ||
| TESTING.md | ||
| thumbnailitem.cpp | ||
| thumbnailitem.h | ||
| toplevel.cpp | ||
| toplevel.h | ||
| touch_hide_cursor_spy.cpp | ||
| touch_hide_cursor_spy.h | ||
| touch_input.cpp | ||
| touch_input.h | ||
| udev.cpp | ||
| udev.h | ||
| unmanaged.cpp | ||
| unmanaged.h | ||
| useractions.cpp | ||
| useractions.h | ||
| utils.cpp | ||
| utils.h | ||
| virtual_terminal.cpp | ||
| virtual_terminal.h | ||
| virtualdesktops.cpp | ||
| virtualdesktops.h | ||
| virtualdesktopsdbustypes.cpp | ||
| virtualdesktopsdbustypes.h | ||
| virtualkeyboard.cpp | ||
| virtualkeyboard.h | ||
| virtualkeyboard_dbus.cpp | ||
| virtualkeyboard_dbus.h | ||
| was_user_interaction_x11_filter.cpp | ||
| was_user_interaction_x11_filter.h | ||
| wayland_cursor_theme.cpp | ||
| wayland_cursor_theme.h | ||
| wayland_server.cpp | ||
| wayland_server.h | ||
| window_property_notify_x11_filter.cpp | ||
| window_property_notify_x11_filter.h | ||
| workspace.cpp | ||
| workspace.h | ||
| x11eventfilter.cpp | ||
| x11eventfilter.h | ||
| xcbutils.cpp | ||
| xcbutils.h | ||
| xkb.cpp | ||
| xkb.h | ||
| xkb_qt_mapping.h | ||
KWin
KWin is an easy to use, but flexible, composited Window Manager for Xorg windowing systems (Wayland, X11) on Linux. Its primary usage is in conjunction with a Desktop Shell (e.g. KDE Plasma Desktop). KWin is designed to go out of the way; users should not notice that they use a window manager at all. Nevertheless KWin provides a steep learning curve for advanced features, which are available, if they do not conflict with the primary mission. KWin does not have a dedicated targeted user group, but follows the targeted user group of the Desktop Shell using KWin as it's window manager.
KWin is not...
- a standalone window manager (c.f. openbox, i3) and does not provide any functionality belonging to a Desktop Shell.
- a replacement for window managers designed for use with a specific Desktop Shell (e.g. GNOME Shell)
- a minimalistic window manager
- designed for use without compositing or for X11 network transparency, though both are possible.
Contacting KWin development team
- mailing list: kwin@kde.org
- IRC: #kwin on freenode
Support
Application Developer
If you are an application developer having questions regarding windowing systems (either X11 or Wayland) please do not hesitate to contact us. Preferable through our mailing list. Ideally subscribe to the mailing list, so that your mail doesn't get stuck in the moderation queue.
End user
Please contact the support channels of your Linux distribution for user support. The KWin development team does not provide end user support.
Reporting bugs
Please use KDE's bugtracker and report for product KWin.
Developing on KWin
Please refer to hacking documentation for how to build and start KWin. Further information about KWin's test suite can be found in TESTING.md.
Guidelines for new features
A new Feature can only be added to KWin if:
- it does not violate the primary missions as stated at the start of this document
- it does not introduce instabilities
- it is maintained, that is bugs are fixed in a timely manner (second next minor release) if it is not a corner case.
- it works together with all existing features
- it supports both single and multi screen (xrandr)
- it adds a significant advantage
- it is feature complete, that is supports at least all useful features from competitive implementations
- it is not a special case for a small user group
- it does not increase code complexity significantly
- it does not affect KWin's license (GPLv2+)
All new added features are under probation, that is if any of the non-functional requirements as listed above do not hold true in the next two feature releases, the added feature will be removed again.
The same non functional requirements hold true for any kind of plugins (effects, scripts, etc.). It is suggested to use scripted plugins and distribute them separately.