drm/i915: Nuke intel_atomic_crtc_state_for_each_plane_state() from skl+ wm code

intel_atomic_crtc_state_for_each_plane_state() peeks at the
plane's current state without holding the plane's mutex, trusting
that the crtc's mutex will protect it. In practice that does work
since our planes can't move between pipes, but it sets a bad
example. intel_atomic_crtc_state_for_each_plane_state() also
relies on crtc_state.uapi.plane_mask which may be full of lies
when it comes to the bigjoiner stuff, so soon we can't use it as
is anyway. So best to just get rid of it entirely. Which we can
easily do by switching to the g4x/vlv "raw" watermark approach.

Later on we should even be able to move the "raw" watermark
computation into the normal .plane_check() code, leaving only
the merging/clamping of the final watermarks to the later
stages. But that will require adjusting the ilk+ wm code
similarly as well.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201106173042.7534-3-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -755,6 +755,8 @@ struct intel_crtc_wm_state {
 		} ilk;
 
 		struct {
+			/* "raw" watermarks */
+			struct skl_pipe_wm raw;
 			/* gen9+ only needs 1-step wm programming */
 			struct skl_pipe_wm optimal;
 			struct skl_ddb_entry ddb;

drivers/gpu/drm/i915/intel_pm.c

@@ -5480,7 +5480,7 @@ static int skl_build_plane_wm_single(struct intel_crtc_state *crtc_state,
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct skl_plane_wm *wm = &crtc_state->wm.skl.optimal.planes[plane_id];
+	struct skl_plane_wm *wm = &crtc_state->wm.skl.raw.planes[plane_id];
 	struct skl_wm_params wm_params;
 	int ret;
 
@@ -5503,7 +5503,7 @@ static int skl_build_plane_wm_uv(struct intel_crtc_state *crtc_state,
 				 const struct intel_plane_state *plane_state,
 				 enum plane_id plane_id)
 {
-	struct skl_plane_wm *wm = &crtc_state->wm.skl.optimal.planes[plane_id];
+	struct skl_plane_wm *wm = &crtc_state->wm.skl.raw.planes[plane_id];
 	struct skl_wm_params wm_params;
 	int ret;
 
@@ -5524,10 +5524,13 @@ static int skl_build_plane_wm(struct intel_crtc_state *crtc_state,
 			      const struct intel_plane_state *plane_state)
 {
 	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
-	const struct drm_framebuffer *fb = plane_state->hw.fb;
 	enum plane_id plane_id = plane->id;
+	struct skl_plane_wm *wm = &crtc_state->wm.skl.raw.planes[plane_id];
+	const struct drm_framebuffer *fb = plane_state->hw.fb;
 	int ret;
 
+	memset(wm, 0, sizeof(*wm));
+
 	if (!intel_wm_plane_visible(crtc_state, plane_state))
 		return 0;
 
@@ -5549,10 +5552,14 @@ static int skl_build_plane_wm(struct intel_crtc_state *crtc_state,
 static int icl_build_plane_wm(struct intel_crtc_state *crtc_state,
 			      const struct intel_plane_state *plane_state)
 {
-	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
-	enum plane_id plane_id = to_intel_plane(plane_state->uapi.plane)->id;
+	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
+	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
+	enum plane_id plane_id = plane->id;
+	struct skl_plane_wm *wm = &crtc_state->wm.skl.raw.planes[plane_id];
 	int ret;
 
+	memset(wm, 0, sizeof(*wm));
+
 	/* Watermarks calculated in master */
 	if (plane_state->planar_slave)
 		return 0;
@@ -5591,19 +5598,18 @@ static int skl_build_pipe_wm(struct intel_atomic_state *state,
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	struct intel_crtc_state *crtc_state =
 		intel_atomic_get_new_crtc_state(state, crtc);
-	struct skl_pipe_wm *pipe_wm = &crtc_state->wm.skl.optimal;
-	struct intel_plane *plane;
 	const struct intel_plane_state *plane_state;
-	int ret;
-
-	/*
-	 * We'll only calculate watermarks for planes that are actually
-	 * enabled, so make sure all other planes are set as disabled.
-	 */
-	memset(pipe_wm->planes, 0, sizeof(pipe_wm->planes));
+	struct intel_plane *plane;
+	int ret, i;
 
-	intel_atomic_crtc_state_for_each_plane_state(plane, plane_state,
-						     crtc_state) {
+	for_each_new_intel_plane_in_state(state, plane, plane_state, i) {
+		/*
+		 * FIXME should perhaps check {old,new}_plane_crtc->hw.crtc
+		 * instead but we don't populate that correctly for NV12 Y
+		 * planes so for now hack this.
+		 */
+		if (plane->pipe != crtc->pipe)
+			continue;
 
 		if (INTEL_GEN(dev_priv) >= 11)
 			ret = icl_build_plane_wm(crtc_state, plane_state);
@@ -5613,6 +5619,8 @@ static int skl_build_pipe_wm(struct intel_atomic_state *state,
 			return ret;
 	}
 
+	crtc_state->wm.skl.optimal = crtc_state->wm.skl.raw;
+
 	return 0;
 }
 
@@ -6273,6 +6281,7 @@ void skl_wm_get_hw_state(struct drm_i915_private *dev_priv)
 		crtc_state = to_intel_crtc_state(crtc->base.state);
 
 		skl_pipe_wm_get_hw_state(crtc, &crtc_state->wm.skl.optimal);
+		crtc_state->wm.skl.raw = crtc_state->wm.skl.optimal;
 	}
 
 	if (dev_priv->active_pipes) {