Return to

Looking Glass Beta 4 Release Candidate 2

After many months of hard work from our team, I am pleased to announce Beta 4 Release Candidate 2 which brings with it a huge number of improvements.

If you like this project and find it useful and would like to help out you can support this project directly by using the following platforms.



  • Added coloring to the client’s terminal output for warnings/errors, etc.
  • default minimizeOnFocusLoss to off
  • Stopped the windows event code from generating false events.
  • Improved the windows event handling reducing CPU usage considerably.
  • Improved NvFBC performance by boosting the kernel thread priority as is done for DXGI.
  • Documentation improvements.


  • SDL has been deprecated and is no longer needed to build the client
  • Help overlay for EGL when the escapeKey is held
  • Allow FPS display to be toggled at runtime with escapeKey+D
  • added win:autoScreensaver which automatically disables screensaver when requested by applications in the guest
  • VM->Host DMABUF support - Kernel Module — Looking Glass B4-rc2 documentation
  • asynchronous Wayland clipboard transfers
  • Release all keys when the client loses focus and prevent stuck keys when navigating away with window manager shortcuts. The old behavior can be restored with input:releaseKeysOnFocusLoss=no
  • Wayland feature parity with X11, scaling support, and improved compatibility
  • add an option to build with libdecor (-DENABLE_LIBDECOR=ON) for showing window decoration on GNOME Wayland
  • open log from taskbar notification icon is re-added with better security
  • improve cursor interactions with overlapping windows
  • documentation is now generated using sphynx and is now available as part of the CI builds on the website.
  • Fixed issue with large clipboard transfers failing
  • DXGI is now the default capture interface, NvFBC is still available but must be selected via the host configuration file.
  • DXGI CPU usage improved with smarter sleep timing in the frame thread
  • Fix issue with parsing configuration files saved in UTF8 format (Windows)
  • Client framebuffer copy performance improvements
  • EGL fixed issue with textures getting overwritten during drawing
  • OpenGL flickering issue fixed when not using a compositor
  • Old/incorrect cursor shape on initial client connection fixed.

Looking forward to upgrade in the next days! Some time back you mentioned that some companies, like cloud or datacenter companies, had contact with you about LookingGlass. Did anything come from it, are they maybe willing to give you some sponsorship for the development? While I am willing to make donations to people for helpful software I would love to see some institutions with more money making a commitment, also!

1 Like

Unfortunately no, nothing has come from any of this. We have though noticed that Intel has forked and is working on a version of LG that seems to focus on the Android VM stuff they are doing, so fingers crossed that they see the value in supporting this project.


Off topic question, but does Looking Glass support Freesync if the host GPU does? I want to switch to Linux with a VM for games, but I don’t want to leave behind 165Hz VRR.

Sorry but I don’t have any freesync hardware I can use to implement this on, in theory it’s possible but I can’t say for certain.

I don’t grok compositing in Linux yet, but if LG is presenting frames like any other program then what are the chances that “it just works”? Or would you need to explicitly add support for VRR?

Either way, thanks for pushing things forward.

From what I understand a few minor changes need to be made to LG to support this, but without some clear documentation on what’s required and the hardware to verify the changes are working I am not inclined to just blindly add it.

Edit: That said, if someone else has the hardware to verify and makes a PR to incorporate this, it will be accepted. From what I understand the swap interval just needs to be set to -1 instead of 0 or 1, but some logic will be needed to verify that the user’s hardware supports it and this setting is valid for them.

1 Like