Add support for explicit-sync-v2

See https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4262

src/steamcompmgr.cpp

@@ -943,6 +943,8 @@ struct WaitListEntry_t
 	bool mangoapp_nudge;
 	uint64_t commitID;
 	uint64_t desiredPresentTime;
+	struct wlr_render_timeline wait_timeline;
+	uint64_t wait_point;
 };
 
 sem waitListSem;
@@ -982,12 +984,27 @@ void imageWaitThreadMain( void )
 
 	assert( bFound == true );
 
+	int timeout_ms = 100;
+
 	gpuvis_trace_begin_ctx_printf( entry.commitID, "wait fence" );
-	struct pollfd fd = { entry.fence, POLLIN, 0 };
-	int ret = poll( &fd, 1, 100 );
-	if ( ret < 0 )
+	if (entry.wait_point != 0)
 	{
-		xwm_log.errorf_errno( "failed to poll fence FD" );
+		uint32_t flags = DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT;
+		uint64_t timeout_ns = (uint64_t)timeout_ms * 1000 * 1000;
+		int ret = drmSyncobjTimelineWait(entry.wait_timeline.drm_fd, &entry.wait_timeline.handle, &entry.wait_point, 1, timeout_ns, flags, nullptr);
+		if (ret < 0)
+		{
+			xwm_log.errorf("failed to wait timeline point");
+		}
+	}
+	else
+	{
+		struct pollfd fd = { entry.fence, POLLIN, 0 };
+		int ret = poll( &fd, 1, timeout_ms );
+		if ( ret < 0 )
+		{
+			xwm_log.errorf_errno( "failed to poll fence FD" );
+		}
 	}
 	gpuvis_trace_end_ctx_printf( entry.commitID, "wait fence" );
 

src/wlserver.cpp

@@ -33,6 +33,7 @@ extern "C" {
 #include <wlr/util/log.h>
 #include <wlr/xwayland/server.h>
 #include <wlr/types/wlr_xdg_shell.h>
+#include <wlr/types/wlr_linux_explicit_synchronization_v2.h>
 #undef static
 #undef class
 }
@@ -113,9 +114,18 @@ void gamescope_xwayland_server_t::wayland_commit(struct wlr_surface *surf, struc
 			.present_id = wl_surf->present_id,
 			.desired_present_time = wl_surf->desired_present_time,
 		};
+
+		auto sync_v2_state = wlr_linux_explicit_sync_v2_get_surface_state(wlserver.wlr.explicit_sync_v2, surf);
+		if (sync_v2_state != nullptr)
+		{
+			newEntry.wait_timeline = *sync_v2_state->acquire_timeline;
+			newEntry.wait_point = sync_v2_state->acquire_point;
+		}
+
 		wl_surf->present_id = std::nullopt;
 		wl_surf->desired_present_time = 0;
 		wl_surf->pending_presentation_feedbacks.clear();
+
 		wayland_commit_queue.push_back( newEntry );
 	}
 
@@ -1458,6 +1468,9 @@ bool wlserver_init( void ) {
 
 	create_presentation_time();
 
+	int drm_fd = wlr_renderer_get_drm_fd(wlserver.wlr.renderer);
+	wlserver.wlr.explicit_sync_v2 = wlr_linux_explicit_sync_v2_create(wlserver.display, drm_fd);
+
 	wlserver.xdg_shell = wlr_xdg_shell_create(wlserver.display, 3);
 	if (!wlserver.xdg_shell)
 	{

src/wlserver.hpp

@@ -21,6 +21,12 @@
 struct _XDisplay;
 struct xwayland_ctx_t;
 
+// TODO: add getter for timeline handle
+struct wlr_render_timeline {
+	int drm_fd;
+	uint32_t handle;
+};
+
 struct wlserver_vk_swapchain_feedback
 {
 	uint32_t image_count;
@@ -42,6 +48,8 @@ struct ResListEntry_t {
 	std::vector<struct wl_resource*> presentation_feedbacks;
 	std::optional<uint32_t> present_id;
 	uint64_t desired_present_time;
+	struct wlr_render_timeline wait_timeline;
+	uint64_t wait_point;
 };
 
 struct wlserver_content_override;
@@ -106,6 +114,7 @@ struct wlserver_t {
 		struct wlr_compositor *compositor;
 		struct wlr_session *session;
 		struct wlr_seat *seat;
+		struct wlr_linux_explicit_sync_v2 *explicit_sync_v2;
 
 		// Used to simulate key events and set the keymap
 		struct wlr_keyboard *virtual_keyboard_device;