drm/i915/fbc: handle dirty rect coords for the first frame

During enabling FBC, for the very first frame, the prepare dirty
rect routine wouldnt have executed as at that time the plane
reference in the fbc_state would be NULL. So this could make
driver program some invalid entries as the damage area. Though
fbc hw ignores the dirty rect values programmed for the first
frame after enabling FBC, driver must ensure that valid dirty
rect coords are programmed. So ensure that for the first frame
correct dirty rect coords are updated to the HW.

Signed-off-by: Vinod Govindapillai <[e-mail]>
Reviewed-by: Ville Syrjälä <[e-mail]>
Signed-off-by: Mika Kahola <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

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

···
 
 	intel_atomic_prepare_plane_clear_colors(state);
 
-	intel_fbc_prepare_dirty_rect(state);
+	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i)
+		intel_fbc_prepare_dirty_rect(state, crtc);
 
 	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i)
 		intel_atomic_dsb_finish(state, crtc);

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

···
 }
 
 static void
-intel_fbc_dirty_rect_update(struct intel_dsb *dsb, struct intel_fbc *fbc)
+intel_fbc_invalidate_dirty_rect(struct intel_fbc *fbc)
+{
+	lockdep_assert_held(&fbc->lock);
+
+	fbc->state.dirty_rect = DRM_RECT_INIT(0, 0, 0, 0);
+}
+
+static void
+intel_fbc_program_dirty_rect(struct intel_dsb *dsb, struct intel_fbc *fbc,
+			     const struct drm_rect *fbc_dirty_rect)
 {
 	struct intel_display *display = fbc->display;
-	const struct drm_rect *fbc_dirty_rect = &fbc->state.dirty_rect;
 
-	lockdep_assert_held(&fbc->lock);
+	drm_WARN_ON(display->drm, fbc_dirty_rect->y2 == 0);
 
 	intel_de_write_dsb(display, dsb, XE3_FBC_DIRTY_RECT(fbc->id),
 			   FBC_DIRTY_RECT_START_LINE(fbc_dirty_rect->y1) |
 			   FBC_DIRTY_RECT_END_LINE(fbc_dirty_rect->y2 - 1));
+}
+
+static void
+intel_fbc_dirty_rect_update(struct intel_dsb *dsb, struct intel_fbc *fbc)
+{
+	const struct drm_rect *fbc_dirty_rect = &fbc->state.dirty_rect;
+
+	lockdep_assert_held(&fbc->lock);
+
+	if (!drm_rect_visible(fbc_dirty_rect))
+		return;
+
+	intel_fbc_program_dirty_rect(dsb, fbc, fbc_dirty_rect);
 }
 
 void
···
 }
 
 static void
-__intel_fbc_prepare_dirty_rect(const struct intel_plane_state *plane_state)
+intel_fbc_hw_intialize_dirty_rect(struct intel_fbc *fbc,
+				  const struct intel_plane_state *plane_state)
 {
-	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
-	struct intel_fbc *fbc = plane->fbc;
-	struct drm_rect *fbc_dirty_rect = &fbc->state.dirty_rect;
-	int width = drm_rect_width(&plane_state->uapi.src) >> 16;
-	const struct drm_rect *damage = &plane_state->damage;
-	int y_offset = plane_state->view.color_plane[0].y;
+	struct drm_rect src;
 
-	lockdep_assert_held(&fbc->lock);
+	/*
+	 * Initializing the FBC HW with the whole plane area as the dirty rect.
+	 * This is to ensure that we have valid coords be written to the
+	 * HW as dirty rect.
+	 */
+	drm_rect_fp_to_int(&src, &plane_state->uapi.src);
 
-	if (drm_rect_visible(damage))
-		*fbc_dirty_rect = *damage;
-	else
-		/* dirty rect must cover at least one line */
-		*fbc_dirty_rect = DRM_RECT_INIT(0, y_offset, width, 1);
-}
-
-void
-intel_fbc_prepare_dirty_rect(struct intel_atomic_state *state)
-{
-	struct intel_display *display = to_intel_display(state);
-	struct intel_plane_state *plane_state;
-	struct intel_plane *plane;
-	int i;
-
-	if (!HAS_FBC_DIRTY_RECT(display))
-		return;
-
-	for_each_new_intel_plane_in_state(state, plane, plane_state, i) {
-		struct intel_fbc *fbc = plane->fbc;
-
-		if (!fbc)
-			continue;
-
-		mutex_lock(&fbc->lock);
-
-		if (fbc->state.plane == plane)
-			__intel_fbc_prepare_dirty_rect(plane_state);
-
-		mutex_unlock(&fbc->lock);
-	}
+	intel_fbc_program_dirty_rect(NULL, fbc, &src);
 }
 
 static void intel_fbc_update_state(struct intel_atomic_state *state,
···
 	return !plane_state->no_fbc_reason &&
 		intel_fbc_is_fence_ok(plane_state) &&
 		intel_fbc_is_cfb_ok(plane_state);
+}
+
+static void
+__intel_fbc_prepare_dirty_rect(const struct intel_plane_state *plane_state,
+			       const struct intel_crtc_state *crtc_state)
+{
+	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
+	struct intel_fbc *fbc = plane->fbc;
+	struct drm_rect *fbc_dirty_rect = &fbc->state.dirty_rect;
+	int width = drm_rect_width(&plane_state->uapi.src) >> 16;
+	const struct drm_rect *damage = &plane_state->damage;
+	int y_offset = plane_state->view.color_plane[0].y;
+
+	lockdep_assert_held(&fbc->lock);
+
+	if (intel_crtc_needs_modeset(crtc_state) ||
+	    !intel_fbc_is_ok(plane_state)) {
+		intel_fbc_invalidate_dirty_rect(fbc);
+		return;
+	}
+
+	if (drm_rect_visible(damage))
+		*fbc_dirty_rect = *damage;
+	else
+		/* dirty rect must cover at least one line */
+		*fbc_dirty_rect = DRM_RECT_INIT(0, y_offset, width, 1);
+}
+
+void
+intel_fbc_prepare_dirty_rect(struct intel_atomic_state *state,
+			     struct intel_crtc *crtc)
+{
+	struct intel_display *display = to_intel_display(state);
+	const struct intel_crtc_state *crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+	struct intel_plane_state *plane_state;
+	struct intel_plane *plane;
+	int i;
+
+	if (!HAS_FBC_DIRTY_RECT(display))
+		return;
+
+	for_each_new_intel_plane_in_state(state, plane, plane_state, i) {
+		struct intel_fbc *fbc = plane->fbc;
+
+		if (!fbc || plane->pipe != crtc->pipe)
+			continue;
+
+		mutex_lock(&fbc->lock);
+
+		if (fbc->state.plane == plane)
+			__intel_fbc_prepare_dirty_rect(plane_state,
+						       crtc_state);
+
+		mutex_unlock(&fbc->lock);
+	}
 }
 
 static int intel_fbc_check_plane(struct intel_atomic_state *state,
···
 	drm_dbg_kms(display->drm, "Disabling FBC on [PLANE:%d:%s]\n",
 		    plane->base.base.id, plane->base.name);
 
+	intel_fbc_invalidate_dirty_rect(fbc);
+
 	__intel_fbc_cleanup_cfb(fbc);
 
 	fbc->state.plane = NULL;
···
 	fbc->no_fbc_reason = "FBC enabled but not active yet\n";
 
 	intel_fbc_update_state(state, crtc, plane);
+
+	if (HAS_FBC_DIRTY_RECT(display))
+		intel_fbc_hw_intialize_dirty_rect(fbc, plane_state);
 
 	intel_fbc_program_workarounds(fbc);
 	intel_fbc_program_cfb(fbc);

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

···
 void intel_fbc_reset_underrun(struct intel_display *display);
 void intel_fbc_crtc_debugfs_add(struct intel_crtc *crtc);
 void intel_fbc_debugfs_register(struct intel_display *display);
-void intel_fbc_prepare_dirty_rect(struct intel_atomic_state *state);
+void intel_fbc_prepare_dirty_rect(struct intel_atomic_state *state,
+				  struct intel_crtc *crtc);
 void intel_fbc_dirty_rect_update_noarm(struct intel_dsb *dsb,
 				       struct intel_plane *plane);