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            <b><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - [snb] Freeze with SMP support (stuck on render ring)"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=80913#c4">Comment # 4</a>
              on <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - [snb] Freeze with SMP support (stuck on render ring)"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=80913">bug 80913</a>
              from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
        <pre>Something to test:

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c
b/drivers/gpu/drm/i915/i915_gem_gtt.c
index ed4376e..d05d1b6 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -991,14 +991,17 @@ static void gen6_ppgtt_insert_entries(struct
i915_address_space *vm,
                                       cache_level, true, flags);

                if (++act_pte == I915_PPGTT_PT_ENTRIES) {
+                       drm_clflush_virt_range(pd_vaddr, PAGE_SIZE);
                        kunmap_atomic(pt_vaddr);
                        pt_vaddr = NULL;
                        act_pt++;
                        act_pte = 0;
                }
        }
-       if (pt_vaddr)
+       if (pt_vaddr) {
+               drm_clflush_virt_range(pd_vaddr, PAGE_SIZE);
                kunmap_atomic(pt_vaddr);
+       }
 }</pre>
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