[Bug 88191] [PNV Bisected]igt/gem_exec_big fails

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=88191

--- Comment #4 from Chris Wilson <chris at chris-wilson.co.uk> ---
My hypothesis is that we need a mb() to serialise updating the GTT and
accessing the PTE via the CPU.

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c
b/drivers/gpu/drm/i915/i915_gem
index bdfd44c..c8932b3 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1444,6 +1444,7 @@ static int i915_ggtt_bind_vma(struct i915_vma *vma,

        BUG_ON(!i915_is_ggtt(vma->vm));
        intel_gtt_insert_sg_entries(vma->obj->pages, entry, flags);
+       wmb();
        vma->bound = GLOBAL_BIND;
        vma->vm->dirty = true;

is sufficient, but intel_gtt_insert_sg_entries() already ends with a readl()!

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20150108/0bdde361/attachment.html>