This happens all the time. Vs gets messed up and nothing gets drawn, and the test passes. This is always a huge source of wasted time for me. I'd be highly in favor of having a way to pre clear... Perhaps via cmdline option so that only people actively working on driver dev incur the extra cost. <div class="gmail_quote">On Jun 8, 2015 1:01 PM, "Marek Olšák" <<a href="mailto:maraeo@gmail.com">maraeo@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I recently ran into this. A tessellation test passed when it shouldn't. That was pretty weird. The driver or hw was dropping draw calls for some reason, yet most of the time the test passed. The solution: <a href="http://cgit.freedesktop.org/piglit/commit/?id=98c92d7bb2b80954912d9f8004e7810e7d21ff20" target="_blank">http://cgit.freedesktop.org/piglit/commit/?id=98c92d7bb2b80954912d9f8004e7810e7d21ff20</a> Marek On Sun, Jun 7, 2015 at 10:29 PM, Dave Airlie <<a href="mailto:airlied@gmail.com">airlied@gmail.com</a>> wrote: > On 7 June 2015 at 12:11, Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> wrote: >> Hi all, >> >> This patch series ports all vpfp-generic tests to shader_runner, >> and then deletes vpfp-generic. >> >> A bit of history: >> - vpfp-generic was introduced by Nicolai Hähnle in 2009, as a generic >> ARB_vertex|fragment_program test runner. >> - shader_runner was introduced by Ian Romanick in 2010, as a generic >> GLSL shader runner. >> - shader_runner gained ARB program support in 2011 (courtesy of Eric Anholt). >> >> At this point, vpfp-generic is fairly redundant - shader_runner can do >> everything we need, and is much more widespread (12000+ tests). I've >> been meaning to delete it for a few years, but never got around to it. >> >> One difference is that the new tests don't glClear() before drawing. Since >> they draw the entire window, it's pretty unnecessary, and just makes the >> tests harder to debug. Many shader_runner tests don't bother clearing. > > This is actually annoying feature, esp if all tests use the same color > for success, > > because we render one test, it passes, we render another test, it > doesn't draw anything > but it has gotten the back buffer from the previous tests, and it > magically passes. > > This happens a lot more often on GPUs with VRAM. > > Dave. > _______________________________________________ > Piglit mailing list > <a href="mailto:Piglit@lists.freedesktop.org">Piglit@lists.freedesktop.org</a> > <a href="http://lists.freedesktop.org/mailman/listinfo/piglit" target="_blank">http://lists.freedesktop.org/mailman/listinfo/piglit</a> _______________________________________________ Piglit mailing list <a href="mailto:Piglit@lists.freedesktop.org">Piglit@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/piglit" target="_blank">http://lists.freedesktop.org/mailman/listinfo/piglit</a> </blockquote></div>