backend/drm: make wlr_drm_plane.{pending,queued,current}_fb pointers

This will be useful once we start re-using wlr_drm_fb.

backend/drm/atomic.c

@@ -134,7 +134,7 @@ static void set_plane_props(struct atomic *atom, struct wlr_drm_backend *drm,
 	uint32_t id = plane->id;
 	const union wlr_drm_plane_props *props = &plane->props;
 	struct wlr_drm_fb *fb = plane_get_next_fb(plane);
-	if (!fb->id) {
+	if (fb == NULL) {
 		wlr_log(WLR_ERROR, "Failed to acquire FB");
 		goto error;
 	}

backend/drm/drm.c

@@ -324,9 +324,9 @@ static bool drm_connector_attach_render(struct wlr_output *output,
 static void drm_plane_set_committed(struct wlr_drm_plane *plane) {
 	drm_fb_move(&plane->queued_fb, &plane->pending_fb);
 
-	struct wlr_buffer *queued = plane->queued_fb.wlr_buf;
+	if (plane->queued_fb && plane->queued_fb->wlr_buf) {
-	if (queued != NULL) {
+		wlr_swapchain_set_buffer_submitted(plane->surf.swapchain,
-		wlr_swapchain_set_buffer_submitted(plane->surf.swapchain, queued);
+			plane->queued_fb->wlr_buf);
 	}
 }
 
@@ -366,7 +366,7 @@ static bool drm_crtc_page_flip(struct wlr_drm_connector *conn) {
 	}
 
 	assert(crtc->pending.active);
-	assert(plane_get_next_fb(crtc->primary)->bo);
+	assert(plane_get_next_fb(crtc->primary));
 	if (!drm_crtc_commit(conn, DRM_MODE_PAGE_FLIP_EVENT)) {
 		return false;
 	}
@@ -638,11 +638,11 @@ static bool drm_connector_export_dmabuf(struct wlr_output *output,
 		return false;
 	}
 
-	struct wlr_drm_fb *fb = &crtc->primary->queued_fb;
+	struct wlr_drm_fb *fb = crtc->primary->queued_fb;
-	if (fb->wlr_buf == NULL) {
+	if (fb == NULL) {
-		fb = &crtc->primary->current_fb;
+		fb = crtc->primary->current_fb;
 	}
-	if (fb->wlr_buf == NULL) {
+	if (fb == NULL) {
 		return false;
 	}
 
@@ -657,13 +657,13 @@ static bool drm_connector_export_dmabuf(struct wlr_output *output,
 }
 
 struct wlr_drm_fb *plane_get_next_fb(struct wlr_drm_plane *plane) {
-	if (plane->pending_fb.bo) {
+	if (plane->pending_fb) {
-		return &plane->pending_fb;
+		return plane->pending_fb;
 	}
-	if (plane->queued_fb.bo) {
+	if (plane->queued_fb) {
-		return &plane->queued_fb;
+		return plane->queued_fb;
 	}
-	return &plane->current_fb;
+	return plane->current_fb;
 }
 
 static bool drm_connector_pageflip_renderer(struct wlr_drm_connector *conn) {
@@ -676,7 +676,7 @@ static bool drm_connector_pageflip_renderer(struct wlr_drm_connector *conn) {
 
 	// drm_crtc_page_flip expects a FB to be available
 	struct wlr_drm_plane *plane = crtc->primary;
-	if (!plane_get_next_fb(plane)->bo) {
+	if (!plane_get_next_fb(plane)) {
 		if (!drm_surface_render_black_frame(&plane->surf)) {
 			return false;
 		}
@@ -1466,10 +1466,10 @@ static void page_flip_handler(int fd, unsigned seq,
 	}
 
 	struct wlr_drm_plane *plane = conn->crtc->primary;
-	if (plane->queued_fb.bo) {
+	if (plane->queued_fb) {
 		drm_fb_move(&plane->current_fb, &plane->queued_fb);
 	}
-	if (conn->crtc->cursor && conn->crtc->cursor->queued_fb.bo) {
+	if (conn->crtc->cursor && conn->crtc->cursor->queued_fb) {
 		drm_fb_move(&conn->crtc->cursor->current_fb,
 			&conn->crtc->cursor->queued_fb);
 	}
@@ -1480,8 +1480,8 @@ static void page_flip_handler(int fd, unsigned seq,
 	 * data between the GPUs, even if we were using the direct scanout
 	 * interface.
 	 */
-	if (!drm->parent && plane->current_fb.wlr_buf &&
+	if (!drm->parent && plane->current_fb->wlr_buf &&
-			wlr_client_buffer_get(plane->current_fb.wlr_buf)) {
+			wlr_client_buffer_get(plane->current_fb->wlr_buf)) {
 		present_flags |= WLR_OUTPUT_PRESENT_ZERO_COPY;
 	}
 

backend/drm/legacy.c

@@ -17,7 +17,7 @@ static bool legacy_crtc_commit(struct wlr_drm_backend *drm,
 	uint32_t fb_id = 0;
 	if (crtc->pending.active) {
 		struct wlr_drm_fb *fb = plane_get_next_fb(crtc->primary);
-		if (!fb->id) {
+		if (fb == NULL) {
 			wlr_log(WLR_ERROR, "%s: failed to acquire primary FB",
 				conn->output.name);
 			return false;
@@ -76,7 +76,7 @@ static bool legacy_crtc_commit(struct wlr_drm_backend *drm,
 
 	if (cursor != NULL && drm_connector_is_cursor_visible(conn)) {
 		struct wlr_drm_fb *cursor_fb = plane_get_next_fb(cursor);
-		if (!cursor_fb->bo) {
+		if (cursor_fb == NULL) {
 			wlr_drm_conn_log(conn, WLR_DEBUG, "Failed to acquire cursor FB");
 			return false;
 		}

backend/drm/renderer.c

@@ -291,12 +291,13 @@ bool drm_plane_init_surface(struct wlr_drm_plane *plane,
 	return ok;
 }
 
-void drm_fb_clear(struct wlr_drm_fb *fb) {
+void drm_fb_clear(struct wlr_drm_fb **fb_ptr) {
-	if (!fb->bo) {
+	if (*fb_ptr == NULL) {
-		assert(!fb->wlr_buf);
 		return;
 	}
 
+	struct wlr_drm_fb *fb = *fb_ptr;
+
 	struct gbm_device *gbm = gbm_bo_get_device(fb->bo);
 	if (drmModeRmFB(gbm_device_get_fd(gbm), fb->id) != 0) {
 		wlr_log(WLR_ERROR, "drmModeRmFB failed");
@@ -305,11 +306,12 @@ void drm_fb_clear(struct wlr_drm_fb *fb) {
 	gbm_bo_destroy(fb->bo);
 	wlr_buffer_unlock(fb->wlr_buf);
 	wlr_buffer_unlock(fb->mgpu_wlr_buf);
+	free(fb);
 
-	memset(fb, 0, sizeof(*fb));
+	*fb_ptr = NULL;
 }
 
-bool drm_fb_lock_surface(struct wlr_drm_fb *fb, struct wlr_drm_backend *drm,
+bool drm_fb_lock_surface(struct wlr_drm_fb **fb_ptr, struct wlr_drm_backend *drm,
 		struct wlr_drm_surface *surf, struct wlr_drm_surface *mgpu) {
 	assert(surf->back_buffer != NULL);
 
@@ -319,7 +321,7 @@ bool drm_fb_lock_surface(struct wlr_drm_fb *fb, struct wlr_drm_backend *drm,
 	// making another context current.
 	drm_surface_unset_current(surf);
 
-	bool ok = drm_fb_import(fb, drm, buffer, mgpu, NULL);
+	bool ok = drm_fb_import(fb_ptr, drm, buffer, mgpu, NULL);
 	wlr_buffer_unlock(buffer);
 	return ok;
 }
@@ -361,10 +363,13 @@ static struct gbm_bo *get_bo_for_dmabuf(struct gbm_device *gbm,
 	}
 }
 
-bool drm_fb_import(struct wlr_drm_fb *fb, struct wlr_drm_backend *drm,
+bool drm_fb_import(struct wlr_drm_fb **fb_ptr, struct wlr_drm_backend *drm,
 		struct wlr_buffer *buf, struct wlr_drm_surface *mgpu,
 		struct wlr_drm_format_set *set) {
-	drm_fb_clear(fb);
+	struct wlr_drm_fb *fb = calloc(1, sizeof(*fb));
+	if (!fb) {
+		return false;
+	}
 
 	fb->wlr_buf = wlr_buffer_lock(buf);
 
@@ -410,6 +415,8 @@ bool drm_fb_import(struct wlr_drm_fb *fb, struct wlr_drm_backend *drm,
 		goto error_get_fb_for_bo;
 	}
 
+	drm_fb_move(fb_ptr, &fb);
+
 	return true;
 
 error_get_fb_for_bo:
@@ -418,15 +425,14 @@ error_get_dmabuf:
 	wlr_buffer_unlock(fb->mgpu_wlr_buf);
 error_mgpu_wlr_buf:
 	wlr_buffer_unlock(fb->wlr_buf);
-	memset(fb, 0, sizeof(*fb));
+	free(fb);
 	return false;
 }
 
-void drm_fb_move(struct wlr_drm_fb *new, struct wlr_drm_fb *old) {
+void drm_fb_move(struct wlr_drm_fb **new, struct wlr_drm_fb **old) {
 	drm_fb_clear(new);
-
 	*new = *old;
-	memset(old, 0, sizeof(*old));
+	*old = NULL;
 }
 
 bool drm_surface_render_black_frame(struct wlr_drm_surface *surf) {

include/backend/drm/drm.h

@@ -24,11 +24,11 @@ struct wlr_drm_plane {
 	struct wlr_drm_surface mgpu_surf;
 
 	/* Buffer to be submitted to the kernel on the next page-flip */
-	struct wlr_drm_fb pending_fb;
+	struct wlr_drm_fb *pending_fb;
 	/* Buffer submitted to the kernel, will be presented on next vblank */
-	struct wlr_drm_fb queued_fb;
+	struct wlr_drm_fb *queued_fb;
 	/* Buffer currently displayed on screen */
-	struct wlr_drm_fb current_fb;
+	struct wlr_drm_fb *current_fb;
 
 	struct wlr_drm_format_set formats;
 

include/backend/drm/renderer.h

@@ -45,14 +45,14 @@ void finish_drm_renderer(struct wlr_drm_renderer *renderer);
 bool drm_surface_make_current(struct wlr_drm_surface *surf, int *buffer_age);
 void drm_surface_unset_current(struct wlr_drm_surface *surf);
 
-void drm_fb_clear(struct wlr_drm_fb *fb);
+bool drm_fb_lock_surface(struct wlr_drm_fb **fb, struct wlr_drm_backend *drm,
-bool drm_fb_lock_surface(struct wlr_drm_fb *fb, struct wlr_drm_backend *drm,
 		struct wlr_drm_surface *surf, struct wlr_drm_surface *mgpu);
-bool drm_fb_import(struct wlr_drm_fb *fb, struct wlr_drm_backend *drm,
+bool drm_fb_import(struct wlr_drm_fb **fb, struct wlr_drm_backend *drm,
 		struct wlr_buffer *buf, struct wlr_drm_surface *mgpu,
 		struct wlr_drm_format_set *set);
 
-void drm_fb_move(struct wlr_drm_fb *new, struct wlr_drm_fb *old);
+void drm_fb_clear(struct wlr_drm_fb **fb);
+void drm_fb_move(struct wlr_drm_fb **new, struct wlr_drm_fb **old);
 
 bool drm_surface_render_black_frame(struct wlr_drm_surface *surf);