hax11 is a hackbrary to Hook and Augment X11 protocol calls.

I initially created hax11 to work around poor MST support in Linux GPU drivers; however, its use outgrew its initial purpose. hax11 was initially based on kislotniq’s simple dell4khack library, however it no longer shares any code with its ancestor, and now uses a different approach (intercepting the X11 socket connection instead of library calls).

hax11 attempts to fix game and full-screen application issues on Linux, such as:

  • starting on the wrong monitor
  • spanning too many monitors
  • spanning one half of a tiled (MST) monitor (such as some 4K/5K/8K monitors)
  • refusing to allow selecting a desired resolution

It can also work around some common annoyances:

  • exclusively grabbing the mouse or keyboard
  • forcefully pausing the game when the window loses focus
  • not restricting the mouse cursor to its window/monitor
  • messing with the X PRIMARY selection

More information on the project’s GitHub page.

Note: this article is back-dated, and was originally written on 2018-11-06.