diff --git a/doc/ffmpeg-doc.texi b/doc/ffmpeg-doc.texi
index 22558e96c1..cd24255454 100644
--- a/doc/ffmpeg-doc.texi
+++ b/doc/ffmpeg-doc.texi
@@ -1691,6 +1691,8 @@ do not attach several unrelated patches to the same mail.
     applied with @code{patch -p0}?
 @item
     Does the patch not mix functional and cosmetic changes?
+@item
+    Did you add tabs or trailing whitespace to the code? Both are forbidden.
 @item
     Is the patch attached to the email you send?
 @item