drm/i915: ILK + VT-d workaround

Idle the GPU before doing any unmaps. We know if VT-d is in use through
an exported variable from iommu code.

This should avoid a known HW issue.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/include/drm/intel-gtt.h b/include/drm/intel-gtt.h
index 9e343c0..b174620 100644
--- a/include/drm/intel-gtt.h
+++ b/include/drm/intel-gtt.h
@@ -13,6 +13,8 @@
 	unsigned int gtt_mappable_entries;
 	/* Whether i915 needs to use the dmar apis or not. */
 	unsigned int needs_dmar : 1;
+	/* Whether we idle the gpu before mapping/unmapping */
+	unsigned int do_idle_maps : 1;
 } *intel_gtt_get(void);
 
 void intel_gtt_chipset_flush(void);