From: Takashi Iwai <tiwai@suse.de>
Subject: drm/i915: suppress spurious !wm_changed warning
Patch-mainline: Never, SLE12-SP2 / openSUSE-42.2 only
References: bsc#1006267

The infamous !wm_changed kernel warning appears on many Skylake
systems although it's known to be mostly harmless.  The warning itself
got fixed (removed) in 4.8.x upstream, but it's no trivial change for
4.4.x.  So for the time being, it's better to just paper over this
warning and stop annoying users.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/intel_pm.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3598,7 +3598,8 @@ static void skl_update_other_pipe_wm(str
 		 * because it was really needed, so we expect the WM values to
 		 * be different.
 		 */
-		WARN_ON(!wm_changed);
+		if (!wm_changed)
+			DRM_DEBUG_DRIVER("inconsistent wm_changed\n");
 
 		skl_compute_wm_results(dev, &params, &pipe_wm, r, intel_crtc);
 		r->dirty[intel_crtc->pipe] = true;
