drm/i915: Introduce crtc_state->update_planes bitmask

Keep track which planes need updating during the commit. For now
we set the bit for any plane that was or will be visible (including
icl+ nv12 slave planes). In the future I'll have need to update
invisible planes as well, for skl plane ddbs and for pre-skl pipe
gamma/csc control (which lives in the primary plane control register).

v2: Pimp the commit message to mention icl+ nv12 slave planes (Matt)
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181127163742.30215-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_atomic.c

@@ -184,6 +184,7 @@ intel_crtc_duplicate_state(struct drm_crtc *crtc)
 	crtc_state->fifo_changed = false;
 	crtc_state->wm.need_postvbl_update = false;
 	crtc_state->fb_bits = 0;
+	crtc_state->update_planes = 0;
 
 	return &crtc_state->base;
 }

drivers/gpu/drm/i915/intel_atomic_plane.c

@@ -139,6 +139,9 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
 	if (state->visible && state->fb->format->format == DRM_FORMAT_NV12)
 		crtc_state->nv12_planes |= BIT(intel_plane->id);
 
+	if (state->visible || old_plane_state->base.visible)
+		crtc_state->update_planes |= BIT(intel_plane->id);
+
 	return intel_plane_atomic_calc_changes(old_crtc_state,
 					       &crtc_state->base,
 					       old_plane_state,
@@ -173,14 +176,11 @@ void intel_update_planes_on_crtc(struct intel_atomic_state *old_state,
 				 struct intel_crtc_state *old_crtc_state,
 				 struct intel_crtc_state *new_crtc_state)
 {
+	u32 update_mask = new_crtc_state->update_planes;
 	struct intel_plane_state *new_plane_state;
 	struct intel_plane *plane;
-	u32 update_mask;
 	int i;
 
-	update_mask = old_crtc_state->active_planes;
-	update_mask |= new_crtc_state->active_planes;
-
 	for_each_new_intel_plane_in_state(old_state, plane, new_plane_state, i) {
 		if (crtc->pipe != plane->pipe ||
 		    !(update_mask & BIT(plane->id)))

drivers/gpu/drm/i915/intel_display.c

@@ -10839,8 +10839,10 @@ static int icl_check_nv12_planes(struct intel_crtc_state *crtc_state)
 			continue;
 
 		plane_state->linked_plane = NULL;
-		if (plane_state->slave && !plane_state->base.visible)
+		if (plane_state->slave && !plane_state->base.visible) {
 			crtc_state->active_planes &= ~BIT(plane->id);
+			crtc_state->update_planes |= BIT(plane->id);
+		}
 
 		plane_state->slave = false;
 	}
@@ -10881,6 +10883,7 @@ static int icl_check_nv12_planes(struct intel_crtc_state *crtc_state)
 		linked_state->slave = true;
 		linked_state->linked_plane = plane;
 		crtc_state->active_planes |= BIT(linked->id);
+		crtc_state->update_planes |= BIT(linked->id);
 		DRM_DEBUG_KMS("Using %s as Y plane for %s\n", linked->base.name, plane->base.name);
 	}
 

drivers/gpu/drm/i915/intel_drv.h

@@ -926,6 +926,9 @@ struct intel_crtc_state {
 	u8 active_planes;
 	u8 nv12_planes;
 
+	/* bitmask of planes that will be updated during the commit */
+	u8 update_planes;
+
 	/* HDMI scrambling status */
 	bool hdmi_scrambling;