On Sat, 31 Mar 2012 19:52:09 +0200, Oliver Seitz <info at vtnd.de> wrote: [snip] > If, however, two screens are next to or on top of each other, playing > video on one of the screens can show some tearing. It is not always seen > with normal video, a special test pattern is helpful. Also, it does only > tear in one out of ten tries, you can hit pause again and again, sooner > or later the tearing will appear, and disappear again after the next > pause/unpause cycle. While the tearing is there, it stays at about the > same height of the video until the next pause/unpause cycle. Most times > it is seen in the top third of the video. It does not matter if the > video is fullscreen or not. > > Is it likely that this is a bug, or am I doing something wrong? Video tearing in windows is a known issue on SandyBridge as they removed the commands to perform vsync'ed updates and hid the logic behind a baffling sequence of registers that we have not yet got working. The only workaround is to force pageflipping (ie exchange the whole scanout for each frame) either by using a compositing WM (and hoping for the best) or to only use fullscreen DRI video applications (OpenGL or libva decoders) that use SwapBuffers. -Chris -- Chris Wilson, Intel Open Source Technology Centre
