diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,10 @@
+concurrent-output (1.9.0) unstable; urgency=medium
+
+  * Replaced displayUpdateNotifier with a simpler and safer
+    waitDisplayChange interface.
+
+ -- Joey Hess <id@joeyh.name>  Fri, 12 May 2017 17:17:09 -0400
+
 concurrent-output (1.8.0) unstable; urgency=medium
 
   * Added displayUpdateNotifier, which can be used to wait for
diff --git a/System/Console/Regions.hs b/System/Console/Regions.hs
--- a/System/Console/Regions.hs
+++ b/System/Console/Regions.hs
@@ -108,8 +108,7 @@
 	consoleWidth,
 	consoleHeight,
 	regionList,
-	displayUpdateNotifier,
-	DisplayChange(..),
+	waitDisplayChange,
 ) where
 
 import Data.Monoid
@@ -213,13 +212,6 @@
 regionDisplayEnabled :: IO Bool
 regionDisplayEnabled = atomically $ not <$> isEmptyTMVar regionList
 
--- | This is a broadcast TChan, which gets a DisplayChange written to it
--- after the display has been updated. It can be used to wait for something
--- to be displayed.
-{-# NOINLINE displayUpdateNotifier #-}
-displayUpdateNotifier :: TChan DisplayChange
-displayUpdateNotifier = unsafePerformIO $ newBroadcastTChanIO
-
 -- | Many actions in this module can be run in either the IO monad
 -- or the STM monad. Using STM allows making several changes to the
 -- displayed regions atomically, with the display updated a single time.
@@ -450,19 +442,57 @@
 	| RegionListChange RegionSnapshot
 	| TerminalResize Width
 	| Shutdown
+	| DisplayChangeBarrier Barrier
 
 type BufferSnapshot = (StdHandle, OutputBuffer)
 type RegionSnapshot = ([ConsoleRegion], [R], [[Text]])
+type Barrier = Integer
 
+-- | This is a broadcast TChan, which gets a DisplayChange written to it
+-- after the display has been updated. It can be used to wait for something
+-- to be displayed.
+{-# NOINLINE displayUpdateNotifier #-}
+displayUpdateNotifier :: TChan DisplayChange
+displayUpdateNotifier = unsafePerformIO $ newBroadcastTChanIO
+
+{-# NOINLINE displayChangeBarrier #-}
+displayChangeBarrier :: TVar Barrier
+displayChangeBarrier = unsafePerformIO $ newTVarIO 0
+
+-- | Runs a STM action, and waits for the display to be fully updated
+-- before returning.
+waitDisplayChange :: STM a -> IO a
+waitDisplayChange a = do
+	r <- atomically a
+	c <- atomically $ dupTChan displayUpdateNotifier
+	b <- atomically $ do
+		!b <- succ <$> readTVar displayChangeBarrier
+		writeTVar displayChangeBarrier b
+		return b
+	atomically $ waitchange c b
+	return r
+  where
+	waitchange c b = do
+		change <- readTChan c
+		case change of
+			DisplayChangeBarrier b' | b' == b -> return ()
+			_ -> waitchange c b
+
 displayThread :: Bool -> TSem -> IO ()
 displayThread isterm endsignal = do
 	origwidth <- atomically consoleWidth
-	go ([], [], []) origwidth
+	origbarrier <- atomically (readTVar displayChangeBarrier)
+	go ([], [], []) origwidth origbarrier
   where
-	go origsnapshot@(orighandles, origregions, origlines) origwidth = do
+	go origsnapshot@(orighandles, origregions, origlines) origwidth origbarrier = do
 		let waitwidthchange = do
 			w <- consoleWidth
 			if w == origwidth then retry else return w
+		let waitbarrierchange = do
+			b <- readTVar displayChangeBarrier
+			if b /= origbarrier
+				then return b
+				else retry
 		let waitanychange =
 			(RegionChange <$> regionWaiter origsnapshot origwidth)
 				`orElse`
@@ -473,6 +503,10 @@
 			(TerminalResize <$> waitwidthchange)
 				`orElse`
 			(waitTSem endsignal >> pure Shutdown)
+				`orElse`
+			-- Must come last, so the changes above are
+			-- processed before barriers.
+			(DisplayChangeBarrier <$> waitbarrierchange)
 		(change, height) <- atomically $ (,)
 			<$> waitanychange
 			<*> consoleHeight
@@ -480,7 +514,7 @@
 		let update snapshot@(_, _, newlines) = do
 			when isterm $ do
 				changedLines (onscreen origlines) (onscreen newlines)
-			return $ go snapshot origwidth
+			return $ go snapshot origwidth origbarrier
 		next <- case change of
 			RegionChange snapshot -> update snapshot
 			RegionListChange snapshot -> update snapshot
@@ -493,13 +527,16 @@
 				let origlines' = onscreen origlines
 				inAreaAbove isterm (length origlines') origlines' $
 					emitOutputBuffer h buf
-				return $ go origsnapshot origwidth
+				return $ go origsnapshot origwidth origbarrier
 			TerminalResize newwidth -> do
 				newlines <- atomically (mapM (resizeRegion newwidth) orighandles)
 				when isterm $ do
 					resizeRecovery (onscreen newlines)
-				return $ go (orighandles, origregions, newlines) newwidth
-			Shutdown -> return $ return ()
+				return $ go (orighandles, origregions, newlines) newwidth origbarrier
+			Shutdown ->
+				return $ return ()
+			DisplayChangeBarrier b ->
+				return $ go origsnapshot origwidth b
 		atomically $ writeTChan displayUpdateNotifier change
 		next
 
diff --git a/concurrent-output.cabal b/concurrent-output.cabal
--- a/concurrent-output.cabal
+++ b/concurrent-output.cabal
@@ -1,5 +1,5 @@
 Name: concurrent-output
-Version: 1.8.0
+Version: 1.9.0
 Cabal-Version: >= 1.8
 License: BSD2
 Maintainer: Joey Hess <id@joeyh.name>
diff --git a/stmdemo.hs b/stmdemo.hs
--- a/stmdemo.hs
+++ b/stmdemo.hs
@@ -83,18 +83,9 @@
 
 runBash :: IO ()
 runBash = do
-	c <- atomically $ dupTChan displayUpdateNotifier
 	-- Temporarily clear whatever console regions are open.
-	rs <- atomically $ swapTMVar regionList []
-	atomically $ waitDisplayUpdate c
+	rs <- waitDisplayChange $ swapTMVar regionList []
 	putStrLn "We interrupt this demo to run a shell prompt. exit to continue!"
 	callCommand "bash"
 	-- Restore the console regions.
 	void $ atomically $ swapTMVar regionList rs
-
-waitDisplayUpdate :: TChan DisplayChange -> STM ()
-waitDisplayUpdate c = do
-	v <- readTChan c
-	case v of
-		RegionListChange ([],_,_) -> return ()
-		_ -> waitDisplayUpdate c