drm/atomic: Loosen FB atomic checks

Loosen the requirements for atomic and legacy commit so that, in cases
where pixel_source != FB, the commit can still go through.

This includes adding framebuffer NULL checks in other areas to account for
FB being NULL when non-FB pixel sources are enabled.

To disable a plane, the pixel_source must be NONE or the FB must be NULL
if pixel_source == FB.

Signed-off-by: Jessica Zhang <[e-mail]>
Reviewed-by: Dmitry Baryshkov <[e-mail]>
Signed-off-by: Dmitry Baryshkov <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_atomic.c

···
 {
 	struct drm_plane *plane = new_plane_state->plane;
 	struct drm_crtc *crtc = new_plane_state->crtc;
-	const struct drm_framebuffer *fb = new_plane_state->fb;
 	int ret;
 
-	/* either *both* CRTC and FB must be set, or neither */
-	if (crtc && !fb) {
-		drm_dbg_atomic(plane->dev, "[PLANE:%d:%s] CRTC set but no FB\n",
+	/* either *both* CRTC and pixel source must be set, or neither */
+	if (crtc && !drm_plane_has_visible_data(new_plane_state)) {
+		drm_dbg_atomic(plane->dev, "[PLANE:%d:%s] CRTC set but no visible data\n",
 			       plane->base.id, plane->name);
 		return -EINVAL;
-	} else if (fb && !crtc) {
-		drm_dbg_atomic(plane->dev, "[PLANE:%d:%s] FB set but no CRTC\n",
-			       plane->base.id, plane->name);
+	} else if (drm_plane_has_visible_data(new_plane_state) && !crtc) {
+		drm_dbg_atomic(plane->dev, "[PLANE:%d:%s] Source %d has visible data but no CRTC\n",
+			       plane->base.id, plane->name, new_plane_state->pixel_source);
 		return -EINVAL;
 	}
 
···
 	}
 
 
-	ret = drm_atomic_plane_check_fb(new_plane_state);
-	if (ret)
-		return ret;
+	if (new_plane_state->pixel_source == DRM_PLANE_PIXEL_SOURCE_FB && new_plane_state->fb) {
+		ret = drm_atomic_plane_check_fb(new_plane_state);
+		if (ret)
+			return ret;
+	}
 
 	if (plane_switching_crtc(old_plane_state, new_plane_state)) {
 		drm_dbg_atomic(plane->dev,

drivers/gpu/drm/drm_atomic_helper.c

···
 					bool can_position,
 					bool can_update_disabled)
 {
-	struct drm_framebuffer *fb = plane_state->fb;
 	struct drm_rect *src = &plane_state->src;
 	struct drm_rect *dst = &plane_state->dst;
 	unsigned int rotation = plane_state->rotation;
···
 	*src = drm_plane_state_src(plane_state);
 	*dst = drm_plane_state_dest(plane_state);
 
-	if (!fb) {
+	if (!drm_plane_has_visible_data(plane_state)) {
 		plane_state->visible = false;
 		return 0;
 	}
···
 		return -EINVAL;
 	}
 
-	drm_rect_rotate(src, fb->width << 16, fb->height << 16, rotation);
+	/* Check that selected pixel source is valid */
+	if (plane_state->pixel_source == DRM_PLANE_PIXEL_SOURCE_FB && plane_state->fb) {
+		struct drm_framebuffer *fb = plane_state->fb;
+		drm_rect_rotate(src, fb->width << 16, fb->height << 16, rotation);
 
-	/* Check scaling */
-	hscale = drm_rect_calc_hscale(src, dst, min_scale, max_scale);
-	vscale = drm_rect_calc_vscale(src, dst, min_scale, max_scale);
-	if (hscale < 0 || vscale < 0) {
-		drm_dbg_kms(plane_state->plane->dev,
-			    "Invalid scaling of plane\n");
-		drm_rect_debug_print("src: ", &plane_state->src, true);
-		drm_rect_debug_print("dst: ", &plane_state->dst, false);
-		return -ERANGE;
+		/* Check scaling */
+		hscale = drm_rect_calc_hscale(src, dst, min_scale, max_scale);
+		vscale = drm_rect_calc_vscale(src, dst, min_scale, max_scale);
+
+		if (hscale < 0 || vscale < 0) {
+			drm_dbg_kms(plane_state->plane->dev,
+					"Invalid scaling of plane\n");
+			drm_rect_debug_print("src: ", &plane_state->src, true);
+			drm_rect_debug_print("dst: ", &plane_state->dst, false);
+			return -ERANGE;
+		}
+
+		if (crtc_state->enable)
+			drm_mode_get_hv_timing(&crtc_state->mode, &clip.x2, &clip.y2);
+
+		plane_state->visible = drm_rect_clip_scaled(src, dst, &clip);
+		drm_rect_rotate_inv(src, fb->width << 16, fb->height << 16, rotation);
+	} else if (drm_plane_solid_fill_enabled(plane_state)) {
+		plane_state->visible = true;
 	}
-
-	if (crtc_state->enable)
-		drm_mode_get_hv_timing(&crtc_state->mode, &clip.x2, &clip.y2);
-
-	plane_state->visible = drm_rect_clip_scaled(src, dst, &clip);
-
-	drm_rect_rotate_inv(src, fb->width << 16, fb->height << 16, rotation);
 
 	if (!plane_state->visible)
 		/*

include/drm/drm_atomic_helper.h

···
 	 * Anything else should be considered a bug in the atomic core, so we
 	 * gently warn about it.
 	 */
-	WARN_ON((new_plane_state->crtc == NULL && new_plane_state->fb != NULL) ||
-		(new_plane_state->crtc != NULL && new_plane_state->fb == NULL));
+	WARN_ON((new_plane_state->crtc == NULL && drm_plane_has_visible_data(new_plane_state)) ||
+		(new_plane_state->crtc != NULL && !drm_plane_has_visible_data(new_plane_state)));
 
 	return old_plane_state->crtc && !new_plane_state->crtc;
 }

include/drm/drm_plane.h

···
 #define drm_for_each_plane(plane, dev) \
 	list_for_each_entry(plane, &(dev)->mode_config.plane_list, head)
 
+/**
+ * drm_plane_solid_fill_enabled - Check if solid fill is enabled on plane
+ * @state: plane state
+ *
+ * Returns:
+ * Whether the plane has been assigned a solid_fill_blob
+ */
+static inline bool drm_plane_solid_fill_enabled(struct drm_plane_state *state)
+{
+	if (!state)
+		return false;
+	return state->pixel_source == DRM_PLANE_PIXEL_SOURCE_SOLID_FILL && state->solid_fill_blob;
+}
+
+static inline bool drm_plane_has_visible_data(const struct drm_plane_state *state)
+{
+	switch (state->pixel_source) {
+	case DRM_PLANE_PIXEL_SOURCE_NONE:
+		return false;
+	case DRM_PLANE_PIXEL_SOURCE_SOLID_FILL:
+		return state->solid_fill_blob != NULL;
+	case DRM_PLANE_PIXEL_SOURCE_FB:
+	default:
+		WARN_ON(state->pixel_source != DRM_PLANE_PIXEL_SOURCE_FB);
+	}
+
+	return state->fb != NULL;
+}
+
 bool drm_any_plane_has_format(struct drm_device *dev,
 			      u32 format, u64 modifier);