drm/i915: Double check we didn't miss an unclaimed register access

Currently, if the user has enabled mmio-debug around each register
access, we presume that we have then checked them all. However, it is
still possible through omission (raw register access) or external
interaction that the unclaimed access was not highlighted.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180904111732.24266-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_uncore.c

@@ -2283,15 +2283,16 @@ bool intel_uncore_unclaimed_mmio(struct drm_i915_private *dev_priv)
 bool
 intel_uncore_arm_unclaimed_mmio_detection(struct drm_i915_private *dev_priv)
 {
-	if (unlikely(i915_modparams.mmio_debug ||
-		     dev_priv->uncore.unclaimed_mmio_check <= 0))
+	if (unlikely(dev_priv->uncore.unclaimed_mmio_check <= 0))
 		return false;
 
 	if (unlikely(intel_uncore_unclaimed_mmio(dev_priv))) {
+		if (!i915_modparams.mmio_debug) {
 			DRM_DEBUG("Unclaimed register detected, "
 				  "enabling oneshot unclaimed register reporting. "
 				  "Please use i915.mmio_debug=N for more information.\n");
 			i915_modparams.mmio_debug++;
+		}
 		dev_priv->uncore.unclaimed_mmio_check--;
 		return true;
 	}