e86ae36088
The current implementation for DMA-Buf sharing on kwin is slightly broken. When a client connects to the kwin screencast's stream, it supplies a `SPA_PARAM_EnumFormat` list, containing entries for every supported format, and the drm modifier list for that format (for dmabuf sharing). Usually, the `SPA_FORMAT_VIDEO_modifier` property from the consumer has the `SPA_POD_PROP_FLAG_DONT_FIXATE` flag set. Kwin then receives the full choice list, and gets to pick a relevant modifier. In situations where the DONT_FIXATE flag is missing, pipewire chooses an arbitrary match between the consumer and kwin. In that case, kwin currently assumes DRM_FORMAT_MOD_INVALID is to be used no matter what, which goes against the comment right above it within the screencaststream.cpp file. Even worse, if DRM_FORMAT_MOD_INVALID is not supported by the consumer, this also causes the param_changed callback to freak out, as one of the conditions to update the stream params is `!receivedModifiers.contains(m_dmabufParams->modifier`. Since m_dmabufParams->modifier contains DRM_FORMAT_MOD_INVALID, which is not among the modifiers kwin receives, the params are changed continuously and no buffer sharing can happen. -- I'd be happy to supply code to reproduce what I attempted to describe above if needed. I'm not aware of any program currently affected, but I found this out when messing around myself. Relevant docs are here : <https://docs.pipewire.org/page_dma_buf.html> > If the SPA_PARAM_Format contains a modifier key, without the flag SPA_POD_PROP_FLAG_DONT_FIXATE, it should only contain one value in the SPA_CHOICE_Enum. In this case announce the SPA_PARAM_Buffers accordingly to the selected format and modifier. |
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| autotests | ||
| cmake/modules | ||
| data | ||
| doc | ||
| examples | ||
| kconf_update | ||
| LICENSES | ||
| po | ||
| src | ||
| tests | ||
| .clang-format | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .kde-ci.yml | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| KWinDBusInterfaceConfig.cmake.in | ||
| logo.png | ||
| Mainpage.dox | ||
| plasma-kwin_wayland.service.in | ||
| plasma-kwin_x11.service.in | ||
| README.md | ||
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.
Contributing to KWin
Please refer to the contributing document for everything you need to know to get started contributing to KWin.
Contacting KWin development team
- mailing list: kwin@kde.org
- IRC: #kde-kwin on irc.libera.chat
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.
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.