backend/drm: scan leases on uevent

Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3181

backend/drm/backend.c

@@ -133,12 +133,15 @@ static void handle_dev_change(struct wl_listener *listener, void *data) {
 		return;
 	}
 
-	// TODO: add and handle lease uevents
 	switch (change->type) {
-	case WLR_DEVICE_HOTPLUG:;
+	case WLR_DEVICE_HOTPLUG:
 		wlr_log(WLR_DEBUG, "Received hotplug event for %s", drm->name);
 		scan_drm_connectors(drm, &change->hotplug);
 		break;
+	case WLR_DEVICE_LEASE:
+		wlr_log(WLR_DEBUG, "Received lease event for %s", drm->name);
+		scan_drm_leases(drm);
+		break;
 	default:
 		wlr_log(WLR_DEBUG, "Received unknown change event for %s", drm->name);
 	}

backend/drm/drm.c

@@ -1425,6 +1425,36 @@ void scan_drm_connectors(struct wlr_drm_backend *drm,
 	}
 }
 
+void scan_drm_leases(struct wlr_drm_backend *drm) {
+	drmModeLesseeListRes *list = drmModeListLessees(drm->fd);
+	if (list == NULL) {
+		wlr_log_errno(WLR_ERROR, "drmModeListLessees failed");
+		return;
+	}
+
+	struct wlr_drm_connector *conn;
+	wl_list_for_each(conn, &drm->outputs, link) {
+		if (conn->lease == NULL) {
+			continue;
+		}
+
+		bool found = false;
+		for (size_t i = 0; i < list->count; i++) {
+			if (list->lessees[i] == conn->lease->lessee_id) {
+				found = true;
+				break;
+			}
+		}
+		if (!found) {
+			wlr_log(WLR_DEBUG, "DRM lease %"PRIu32" has been terminated",
+				conn->lease->lessee_id);
+			drm_lease_destroy(conn->lease);
+		}
+	}
+
+	drmFree(list);
+}
+
 static int mhz_to_nsec(int mhz) {
 	return 1000000000000LL / mhz;
 }

include/backend/drm/drm.h

@@ -149,6 +149,7 @@ bool init_drm_resources(struct wlr_drm_backend *drm);
 void finish_drm_resources(struct wlr_drm_backend *drm);
 void scan_drm_connectors(struct wlr_drm_backend *state,
 	struct wlr_device_hotplug_event *event);
+void scan_drm_leases(struct wlr_drm_backend *drm);
 int handle_drm_event(int fd, uint32_t mask, void *data);
 void destroy_drm_connector(struct wlr_drm_connector *conn);
 bool drm_connector_commit_state(struct wlr_drm_connector *conn,