Merge branch 'dmabuf-waiter' into 'master'

Add wlr_compositor_dmabuf_waiter

See merge request wlroots/wlroots!5329

include/wlr/render/drm_syncobj.h

@@ -97,11 +97,7 @@ bool wlr_drm_syncobj_timeline_signal(struct wlr_drm_syncobj_timeline *timeline,
 /**
  * Asynchronously wait for a timeline point.
  *
- * Flags can be:
- *
- * - 0 to wait for the point to be signalled
- * - DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE to only wait for a fence to
- *   materialize
+ * See wlr_drm_syncobj_timeline_eventfd for available flags.
  *
  * A callback must be provided that will be invoked when the waiter has finished.
  */
@@ -112,6 +108,20 @@ bool wlr_drm_syncobj_timeline_waiter_init(struct wlr_drm_syncobj_timeline_waiter
  * Cancel a timeline waiter.
  */
 void wlr_drm_syncobj_timeline_waiter_finish(struct wlr_drm_syncobj_timeline_waiter *waiter);
+/**
+ * Create an eventfd that becomes readable when a timeline point is ready.
+ *
+ * Flags can be:
+ *
+ * - 0 to wait for the point to be signaled
+ * - DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE to only wait for a fence to
+ *   materialize
+ *
+ * The returned FD is owned by the caller and must be closed when no longer
+ * needed.
+ */
+int wlr_drm_syncobj_timeline_eventfd(struct wlr_drm_syncobj_timeline *timeline,
+	uint64_t point, uint32_t flags);
 /**
  * Export a timeline point as a sync_file FD.
  *

include/wlr/types/wlr_linux_dmabuf_v1.h

@@ -16,6 +16,7 @@
 #include <wlr/render/dmabuf.h>
 #include <wlr/render/drm_format_set.h>
 
+struct wlr_compositor;
 struct wlr_surface;
 
 struct wlr_dmabuf_v1_buffer {
@@ -134,4 +135,51 @@ struct wlr_linux_dmabuf_feedback_v1_init_options {
 bool wlr_linux_dmabuf_feedback_v1_init_with_options(struct wlr_linux_dmabuf_feedback_v1 *feedback,
 	const struct wlr_linux_dmabuf_feedback_v1_init_options *options);
 
+enum wlr_surface_dmabuf_waiter_mode {
+	WLR_SURFACE_DMABUF_WAITER_MODE_AVAILABLE,
+	WLR_SURFACE_DMABUF_WAITER_MODE_COMPLETE,
+};
+
+/**
+ * A helper to wait for client buffers to be ready.
+ *
+ * When attached to a surface, this helper will delay commits until the
+ * relevant GPU fences are materialized or work has completed, depending on
+ * mode. When set to WLR_SURFACE_DMABUF_WAITER_MODE_COMPLETE, this means that
+ * wlr_surface.events.commit will only fire when the GPU buffers attached to
+ * that commit are ready to be read.
+ */
+struct wlr_surface_dmabuf_waiter {
+	struct wlr_surface *surface;
+	enum wlr_surface_dmabuf_waiter_mode mode;
+
+	struct {
+		struct wl_list commits; // wlr_surface_dmabuf_waiter_commit.link
+		struct wl_listener client_commit;
+	} WLR_PRIVATE;
+};
+
+/**
+ * Initialize a buffer waiter for a surface.
+ *
+ * Callers must call wlr_surface_dmabuf_waiter_finish() to unregister the waiter.
+ */
+void wlr_surface_dmabuf_waiter_init(struct wlr_surface_dmabuf_waiter *waiter,
+	struct wlr_surface *surface, enum wlr_surface_dmabuf_waiter_mode mode);
+
+/**
+ * Clean up a buffer waiter.
+ *
+ * Any pending commit waiting on GPU work to complete will be applied
+ * immediately.
+ */
+void wlr_surface_dmabuf_waiter_finish(struct wlr_surface_dmabuf_waiter *waiter);
+
+/**
+ * Initialize a compositor-wide buffer waiter, which will listen for new
+ * surfaces and attach buffer waiters to them.
+ */
+void wlr_compositor_dmabuf_waiter_create(struct wlr_compositor *compositor,
+	enum wlr_surface_dmabuf_waiter_mode mode);
+
 #endif

include/wlr/types/wlr_linux_drm_syncobj_v1.h

@@ -43,6 +43,10 @@ struct wlr_linux_drm_syncobj_manager_v1 {
  * The compositor must be prepared to handle fences coming from clients and to
  * send release fences correctly. In particular, both the renderer and the
  * backend need to support explicit synchronization.
+ *
+ * Fences provided here may not yet be ready to consume. See
+ * wlr_compositor_buffer_waiter_create for a way to wait for fences to be
+ * materialized or completed before application.
  */
 struct wlr_linux_drm_syncobj_manager_v1 *wlr_linux_drm_syncobj_manager_v1_create(
 	struct wl_display *display, uint32_t version, int drm_fd);