> The only workaround is [...] to only use fullscreen DRI video applications > (OpenGL or libva decoders) that use SwapBuffers. Yes, works perfectly while only one screen is connected. That means, this definition of "fullscreen" is "the whole framebuffer", and not "the content of one display"? This would in some way explain why tearing can not be reliably prevented while more than one screen is active. Thanks for the explanations! Greets, Kiste