diff --git a/slides/kernel-driver-development-concurrency/kernel-driver-development-concurrency.tex b/slides/kernel-driver-development-concurrency/kernel-driver-development-concurrency.tex
index 1722c1f72a..f3fa31e70a 100644
--- a/slides/kernel-driver-development-concurrency/kernel-driver-development-concurrency.tex
+++ b/slides/kernel-driver-development-concurrency/kernel-driver-development-concurrency.tex
@@ -83,8 +83,8 @@ \section{Concurrent Access to Resources: Locking}
   \begin{itemize}
   \item \mint{c}+int mutex_trylock(struct mutex *lock);+
     \begin{itemize}
-    \item Never waits. Returns a non zero value if the mutex is not
-      available.
+    \item Never waits. Returns 1 if the mutex has been acquired
+      successfully, and 0 if the mutex was not available.
     \end{itemize}
   \item \mint{c}+int mutex_is_locked(struct mutex *lock);+
     \begin{itemize}