<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [BAT][GDG] Failed assertion: gtt[1024*i] == ~i in igt@prime_vgem@basic-gtt" href="https://bugs.freedesktop.org/show_bug.cgi?id=102577#c6">Comment # 6</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [BAT][GDG] Failed assertion: gtt[1024*i] == ~i in igt@prime_vgem@basic-gtt" href="https://bugs.freedesktop.org/show_bug.cgi?id=102577">bug 102577</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>(In reply to Martin Peres from <a href="show_bug.cgi?id=102577#c5">comment #5</a>) > (In reply to Chris Wilson from <a href="show_bug.cgi?id=102577#c4">comment #4</a>) > > For a similar issue within the kernel (i.e. not this test but others): > > commit c5ba5b24657e473b1c64b0a614b168a635a2c935 > > Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> > > Date: Thu Sep 7 19:45:20 2017 +0100 > > > > drm/i915: Apply the GTT write flush for all !llc machines > > > > We also see the delayed GTT write issue on i915g/i915gm, so let's > > presume that it is a universal problem for all !llc machines, and that we > > just haven't yet noticed on g33, gen4 and gen5 machines. > > This does not seem to be sufficient... It's for the same issue but inside the kernel (should show up in the pwrite tests, some reloc tests). Here userspace is able to expose the coherency issue using two mmaps that are expected to coherent, there's no kernel intervention in the test; there's an equivalent test in gem_mmap_gtt to show how the same issue can be detected during pure i915 mmappings. It is theorectically possible to prevent it, we would have to trap every fault and do exclusive domain management. We would have to intercept all contending mmaps -- challenging.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>