<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [BDW, BSW] arb_shader_image_load_store.execution.basic-imagestore-from-uniform intermittent" href="https://bugs.freedesktop.org/show_bug.cgi?id=91611#c1">Comment # 1</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [BDW, BSW] arb_shader_image_load_store.execution.basic-imagestore-from-uniform intermittent" href="https://bugs.freedesktop.org/show_bug.cgi?id=91611">bug 91611</a> from <a class="email" href="mailto:currojerez@riseup.net" title="Francisco Jerez <currojerez@riseup.net>"> Francisco Jerez</a> <pre>I've been looking into this today and I don't think that this test could actually be causing the failure you've seen, it's pretty much trivial, most likely it was run concurrently with some other test that hung the GPU causing it to misrender (can you confirm if there was a GPU hang message in your kernel logs when the failure occurred?). I've managed to reproduce an intermittent hang on BDW by running piglit in a loop, but it comes from the spec@arb_shader_image_load_store@host-mem-barrier Indirect/RaW subtest. It seems rather difficult to reproduce, it often takes dozens of runs until the first failure occurs, which is why it didn't catch my eye until now. It looks like the hang is caused by some interaction between context switches with the hardware UAV coherency function on the VS stage, which leads the VS to stall indefinitely for some reason I don't fully understand yet. The attached hack should sidestep the issue.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>