drm/i915/gen9+: Program watermarks as a separate step during evasion, v3.

The watermark updates for SKL style watermarks are no longer done
in the plane callbacks, but are now called in a separate watermark
update function that's called during the same vblank evasion,
before the plane updates.

This also gets rid of the global skl_results, which was required for
keeping track of the current atomic commit.

Changes since v1:
- Move line unwrap to correct patch. (Lyude)
- Make sure we don't regress ILK watermarks. (Matt)
- Rephrase commit message. (Matt)
Changes since v2:
- Fix disable watermark check to use the correct way to determine single
  step watermark support.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lyude <cpaul@redhat.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1478609742-13603-3-git-send-email-maarten.lankhorst@linux.intel.com
[mlankhorst: Small whitespace fix in skl_initial_wm]
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7a5812e..5d53a08 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4202,19 +4202,29 @@ static void skl_atomic_update_crtc_wm(struct intel_atomic_state *state,
 	struct intel_crtc *crtc = to_intel_crtc(cstate->base.crtc);
 	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
 	struct skl_pipe_wm *pipe_wm = &cstate->wm.skl.optimal;
+	const struct skl_ddb_allocation *ddb = &state->wm_results.ddb;
 	enum pipe pipe = crtc->pipe;
+	int plane;
+
+	if (!(state->wm_results.dirty_pipes & drm_crtc_mask(&crtc->base)))
+		return;
 
 	I915_WRITE(PIPE_WM_LINETIME(pipe), pipe_wm->linetime);
+
+	for_each_universal_plane(dev_priv, pipe, plane)
+		skl_write_plane_wm(crtc, &pipe_wm->planes[plane], ddb, plane);
+
+	skl_write_cursor_wm(crtc, &pipe_wm->planes[PLANE_CURSOR], ddb);
 }
 
-static void skl_update_wm(struct intel_crtc *intel_crtc)
+static void skl_initial_wm(struct intel_atomic_state *state,
+			   struct intel_crtc_state *cstate)
 {
+	struct intel_crtc *intel_crtc = to_intel_crtc(cstate->base.crtc);
 	struct drm_device *dev = intel_crtc->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
-	struct skl_wm_values *results = &dev_priv->wm.skl_results;
+	struct skl_wm_values *results = &state->wm_results;
 	struct skl_wm_values *hw_vals = &dev_priv->wm.skl_hw;
-	struct intel_crtc_state *cstate = to_intel_crtc_state(intel_crtc->base.state);
-	struct skl_pipe_wm *pipe_wm = &cstate->wm.skl.optimal;
 	enum pipe pipe = intel_crtc->pipe;
 
 	if ((results->dirty_pipes & drm_crtc_mask(&intel_crtc->base)) == 0)
@@ -4222,22 +4232,8 @@ static void skl_update_wm(struct intel_crtc *intel_crtc)
 
 	mutex_lock(&dev_priv->wm.wm_mutex);
 
-	/*
-	 * If this pipe isn't active already, we're going to be enabling it
-	 * very soon. Since it's safe to update a pipe's ddb allocation while
-	 * the pipe's shut off, just do so here. Already active pipes will have
-	 * their watermarks updated once we update their planes.
-	 */
-	if (intel_crtc->base.state->active_changed) {
-		int plane;
-
-		for_each_universal_plane(dev_priv, pipe, plane)
-			skl_write_plane_wm(intel_crtc, &pipe_wm->planes[plane],
-					   &results->ddb, plane);
-
-		skl_write_cursor_wm(intel_crtc, &pipe_wm->planes[PLANE_CURSOR],
-				    &results->ddb);
-	}
+	if (cstate->base.active_changed)
+		skl_atomic_update_crtc_wm(state, cstate);
 
 	skl_copy_wm_for_pipe(hw_vals, results, pipe);
 
@@ -7706,7 +7702,7 @@ void intel_init_pm(struct drm_i915_private *dev_priv)
 	/* For FIFO watermark updates */
 	if (INTEL_GEN(dev_priv) >= 9) {
 		skl_setup_wm_latency(dev_priv);
-		dev_priv->display.update_wm = skl_update_wm;
+		dev_priv->display.initial_watermarks = skl_initial_wm;
 		dev_priv->display.atomic_update_watermarks = skl_atomic_update_crtc_wm;
 		dev_priv->display.compute_global_watermarks = skl_compute_wm;
 	} else if (HAS_PCH_SPLIT(dev_priv)) {