Assertion Failed: X context is not using direct rendering (vis 0xxxx). Unfasten your seatbelt...
We have a few problems in the Steam Linux client that we're trying to pin down but we need more specific configuration information than we're getting in order to diagnose them. We're looking for a handful of volunteers hitting these problems that are willing to send us detailed configuration information. If you're hitting one of these issues reproducibly, you are familiar with the Linux shell and GitHub and you can upload configuration information please reply to this.
Issues that you might have seen in shell output from the client:
1. Assert( Assertion Failed: !"Fatal Error: VGUI_Setup failed" ):Main.cpp:1939
2. Assert( Assertion Failed: X context is not using direct rendering (vis 0xxxx). Unfasten your seatbelt... ):surface_linux.cpp:1667
3. Assert( Assertion Failed: Could not open connection to X ):updateui_xwin.cpp:482