diff --git a/filter.c b/filter.c
index fef70052..5075bd1f 100644
--- a/filter.c
+++ b/filter.c
@@ -1,7 +1,7 @@
 /*
  * This file is part of the sigrok project.
  *
- * Copyright (C) 2010 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -101,11 +101,6 @@ int sr_filter_probes(int in_unitsize, int out_unitsize, const int *probelist,
 		return SR_ERR_ARG;
 	}
 
-	if (!length_out) {
-		sr_err("filter: %s: length_out was NULL", __func__);
-		return SR_ERR_ARG;
-	}
-
 	num_enabled_probes = 0;
 	for (i = 0; probelist[i]; i++)
 		num_enabled_probes++;