drm/i915: Do not add all planes when checking scalers on glk+

We cannot switch between HQ and normal mode on GLK+, so only
add planes on platforms where it makes sense.

We could probably restrict it even more to only add when scaler
users toggles between 1 and 2, but lets just leave it for now.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190920114235.22411-9-maarten.lankhorst@linux.intel.comReviewed-by: Matt Roper <matthew.d.roper@intel.com>

drivers/gpu/drm/i915/display/intel_atomic.c

@@ -373,6 +373,15 @@ int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
 			 */
 			if (!plane) {
 				struct drm_plane_state *state;
+
+				/*
+				 * GLK+ scalers don't have a HQ mode so it
+				 * isn't necessary to change between HQ and dyn mode
+				 * on those platforms.
+				 */
+				if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
+					continue;
+
 				plane = drm_plane_from_index(&dev_priv->drm, i);
 				state = drm_atomic_get_plane_state(drm_state, plane);
 				if (IS_ERR(state)) {