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            <b><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - WARNING: CPU: 1 PID: 1961 at drivers/gpu/drm/i915/intel_sprite.c:58 intel_pipe_update_start"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=78114#c2">Comment # 2</a>
              on <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - WARNING: CPU: 1 PID: 1961 at drivers/gpu/drm/i915/intel_sprite.c:58 intel_pipe_update_start"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=78114">bug 78114</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>Could it be as simple as

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 36bdbdfbedb0..160b4b5eb125 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -476,8 +476,11 @@ static int i915_drm_freeze(struct drm_device *dev)
                 * for _thaw.
                 */
                mutex_lock(&dev->mode_config.mutex);
-               list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+               list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                       mutex_lock(&crtc->mutex);
                        dev_priv->display.crtc_disable(crtc);
+                       mutex_unlock(&crtc->mutex);
+               }
                mutex_unlock(&dev->mode_config.mutex);

                intel_modeset_suspend_hw(dev);

?</pre>
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