From 43df0bd565d532d3f11024c8f3ab8f628b9a485e Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Thu, 21 Oct 2021 15:23:20 +0200
Subject: [PATCH] render/timeline: add wlr_render_timeline_transfer

---
 include/wlr/render/timeline.h |  7 +++++++
 render/timeline.c             | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/wlr/render/timeline.h b/include/wlr/render/timeline.h
index dc799c8d7..3e4b6bc3f 100644
--- a/include/wlr/render/timeline.h
+++ b/include/wlr/render/timeline.h
@@ -39,6 +39,13 @@ struct wlr_render_timeline *wlr_render_timeline_import(int drm_fd,
  * Destroy a synchronization timeline.
  */
 void wlr_render_timeline_destroy(struct wlr_render_timeline *timeline);
+/**
+ * Transfer a point from a timeline to another.
+ *
+ * Both timelines must have been created with the same DRM FD.
+ */
+bool wlr_render_timeline_transfer(struct wlr_render_timeline *dst,
+	uint64_t dst_point, struct wlr_render_timeline *src, uint64_t src_point);
 /**
  * Export a timeline point as a sync_file FD.
  *
diff --git a/render/timeline.c b/render/timeline.c
index df98b5325..4cae1f749 100644
--- a/render/timeline.c
+++ b/render/timeline.c
@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <linux/dma-buf.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -48,6 +49,19 @@ void wlr_render_timeline_destroy(struct wlr_render_timeline *timeline) {
 	free(timeline);
 }
 
+bool wlr_render_timeline_transfer(struct wlr_render_timeline *dst,
+		uint64_t dst_point, struct wlr_render_timeline *src, uint64_t src_point) {
+	assert(dst->drm_fd == src->drm_fd);
+
+	if (drmSyncobjTransfer(dst->drm_fd, dst->handle, dst_point,
+			src->handle, src_point, 0) != 0) {
+		wlr_log_errno(WLR_ERROR, "drmSyncobjTransfer failed");
+		return false;
+	}
+
+	return true;
+}
+
 int wlr_render_timeline_export_sync_file(struct wlr_render_timeline *timeline,
 		uint64_t src_point) {
 	int sync_file_fd = -1;