drm/i915/bdw: Always use MMIO flips with Execlists

The normal flip function places things in the ring in the legacy
way, so we either fix that or force MMIO flips always as we do in
this patch.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch. Fucking again.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -9536,6 +9536,8 @@ static bool use_mmio_flip(struct intel_engine_cs *ring,
 		return false;
 	else if (i915.use_mmio_flip > 0)
 		return true;
+	else if (i915.enable_execlists)
+		return true;
 	else
 		return ring != obj->ring;
 }

drivers/gpu/drm/i915/intel_lrc.c

@@ -85,7 +85,8 @@ int intel_sanitize_enable_execlists(struct drm_device *dev, int enable_execlists
 	if (enable_execlists == 0)
 		return 0;
 
-	if (HAS_LOGICAL_RING_CONTEXTS(dev) && USES_PPGTT(dev))
+	if (HAS_LOGICAL_RING_CONTEXTS(dev) && USES_PPGTT(dev) &&
+	    i915.use_mmio_flip >= 0)
 		return 1;
 
 	return 0;