<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Xorg segfault on cpu which does not support PAT" href="https://bugs.freedesktop.org/show_bug.cgi?id=110774#c2">Comment # 2</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Xorg segfault on cpu which does not support PAT" href="https://bugs.freedesktop.org/show_bug.cgi?id=110774">bug 110774</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>If you want the full detection method, static bool test_has_wc_mmap(struct kgem *kgem) { struct local_i915_gem_mmap2 wc; bool ret; if (DBG_NO_WC_MMAP) return false; /* XXX See <a class="bz_bug_link bz_status_CLOSED bz_closed" title="CLOSED FIXED - [gen3 4.0] mmap(wc) batch incoherence" href="show_bug.cgi?id=90841">https://bugs.freedesktop.org/show_bug.cgi?id=90841</a> */ if (kgem->gen < 033) return false; if (gem_param(kgem, LOCAL_I915_PARAM_MMAP_VERSION) < 1) return false; VG_CLEAR(wc); wc.handle = gem_create(kgem->fd, 1); wc.offset = 0; wc.size = 4096; wc.flags = I915_MMAP_WC; ret = do_ioctl(kgem->fd, LOCAL_IOCTL_I915_GEM_MMAP_v2, &wc) == 0; gem_close(kgem->fd, wc.handle); return ret; } The parameter just said which version of the struct was supported; you were then meant to query which flags were supported by trial-and-error. At this point, I would just refuse to run unless WC mmaps were available.</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> </ul> </body> </html>