diff -ur client_generic.orig/DisplayOutput/OpenGL/glx.cpp client_generic/DisplayOutput/OpenGL/glx.cpp --- client_generic.orig/DisplayOutput/OpenGL/glx.cpp 2018-07-14 23:10:29.000000000 +0200 +++ client_generic/DisplayOutput/OpenGL/glx.cpp 2019-01-20 19:08:12.055142844 +0100 @@ -466,13 +466,15 @@ { m_VSync = !m_VSync; - if( GLEE_GLX_SGI_swap_control ) - { - if( m_VSync ) - glXSwapIntervalSGI(1); - else - glXSwapIntervalSGI(2); - } + // broken when extension not available + + //if( GLEE_GLX_SGI_swap_control ) + //{ + //if( m_VSync ) + //glXSwapIntervalSGI(1); + //else + //glXSwapIntervalSGI(2); + //} } /*