diff --git a/Makefile b/Makefile
index d7c4231..d43429f 100644
--- a/Makefile
+++ b/Makefile
@@ -103,7 +103,7 @@
 endif
 
 ifeq ("$(origin W)", "command line")
-  export KBUILD_ENABLE_EXTRA_GCC_CHECKS := 1
+  export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W)
 endif
 
 # That's our default target when none is given on the command line
@@ -1274,7 +1274,11 @@
 	@echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
 	@echo  '  make C=1   [targets] Check all c source with $$CHECK (sparse by default)'
 	@echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
-	@echo  '  make W=1   [targets] Enable extra gcc checks'
+	@echo  '  make W=n   [targets] Enable extra gcc checks, n=1,2,3 where'
+	@echo  '		1: warnings which may be relevant and do not occur too often'
+	@echo  '		2: warnings which occur quite often but may still be relevant'
+	@echo  '		3: more obscure warnings, can most likely be ignored'
+
 	@echo  ''
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
 	@echo  'For further info see the ./README file'