drm/i915: Tune down rpm wakelock debug checks

They're causing massive amounts of dmesg noise and hence CI noise all
over the place. Enabling them for a bit was good enough to refresh our
task list of what's still needed to enable rpm by default.

To make sure we're not forgetting to make this noisy again add a FIXME
comment.

Fixes: da5827c366 ("drm/i915: add assert_rpm_wakelock_held helper")
Cc: Imre Deak <imre.deak@intel.com>
Cc: drm-intel-fixes@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1452012847-4737-1-git-send-email-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
(cherry picked from commit becd9ca2de)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_drv.h

@@ -1442,8 +1442,10 @@ static inline void
 assert_rpm_wakelock_held(struct drm_i915_private *dev_priv)
 {
 	assert_rpm_device_not_suspended(dev_priv);
-	WARN_ONCE(!atomic_read(&dev_priv->pm.wakeref_count),
-		  "RPM wakelock ref not held during HW access");
+	/* FIXME: Needs to be converted back to WARN_ONCE, but currently causes
+	 * too much noise. */
+	if (!atomic_read(&dev_priv->pm.wakeref_count))
+		DRM_DEBUG_DRIVER("RPM wakelock ref not held during HW access");
 }
 
 static inline int