diff --git a/Mk/Uses/display.mk b/Mk/Uses/display.mk
index 886d65b01ad7..e46fb10d1bba 100644
--- a/Mk/Uses/display.mk
+++ b/Mk/Uses/display.mk
@@ -1,35 +1,37 @@
 # Feature:	display
 # Usage:	USES=display or USES=display:ARGS
 # Valid ARGS:	install (default, implicit), any target
 # 
 # Except the target where the DISPLAY is needed
 #
 # MAINTAINER: x11@FreeBSD.org
 
 .if !defined(_INCLUDE_USES_DISPLAY_MK)
 _INCLUDE_USES_DISPLAY_MK=	yes
 
 .  if empty(display_ARGS)
 display_ARGS=	install
 .  endif
 
 .  if !defined(DISPLAY)
 BUILD_DEPENDS+=	Xvfb:x11-servers/xorg-server@xvfb \
 	${LOCALBASE}/share/fonts/misc/8x13O.pcf.gz:x11-fonts/xorg-fonts-miscbitmaps \
 	${LOCALBASE}/share/fonts/misc/fonts.alias:x11-fonts/font-alias \
 	${LOCALBASE}/share/X11/xkb/rules/base:x11/xkeyboard-config \
 	xkbcomp:x11/xkbcomp
 
 XVFBPORT!=	port=0; while test -S /tmp/.X11-unix/X$${port} ; do port=$$(( port + 1 )) ; done ; ${ECHO_CMD} $$port
+PREV_XVFBPORT!=	${ECHO_CMD} $$(( ${XVFBPORT} - 1))
 XVFBPIDFILE=	/tmp/.xvfb-${XVFBPORT}.pid
+PREV_XVFBPIDFILE=	/tmp/.xvfb-${PREV_XVFBPORT}.pid
 MAKE_ENV+=	DISPLAY=":${XVFBPORT}"
 
 _USES_${display_ARGS}+=	290:start-display 860:stop-display
 start-display:
 	daemon -p ${XVFBPIDFILE} Xvfb :${XVFBPORT}
 
 stop-display:
-	pkill -15 -F ${XVFBPIDFILE}
+	pkill -15 -F ${PREV_XVFBPIDFILE}
 
 .  endif
 .endif