1 files changed, 2 insertions, 0 deletions
diff --git a/dix/ffs.c b/dix/ffs.c
index f84f7b47f..b75657d29 100644
--- a/dix/ffs.c
+++ b/dix/ffs.c
@@ -36,6 +36,8 @@ int
 ffs(int i)
 {
     int j;
+    if (i == 0)
+        return 0;
     for (j = 1; (i & 1) == 0; j++)
 	i >>= 1;
     return j;