Index: uspace/lib/c/include/errno.h
===================================================================
--- uspace/lib/c/include/errno.h	(revision 8ab1ad4c341628998ad75b1426cac4eb97cccbea)
+++ uspace/lib/c/include/errno.h	(revision 9df965ecd12f98404d30661bd60c4c76bef24352)
@@ -59,4 +59,7 @@
 #define EBADCHECKSUM  (-300)
 
+/** USB: stalled operation. */
+#define ESTALL (-301)
+
 /** An API function is called while another blocking function is in progress. */
 #define EINPROGRESS  (-10036)