Index: generic/tclIO.c
==================================================================
--- generic/tclIO.c
+++ generic/tclIO.c
@@ -1705,11 +1705,10 @@
     statePtr->inQueueTail	= NULL;
     statePtr->chPtr		= NULL;
     statePtr->interestMask	= 0;
     statePtr->scriptRecordPtr	= NULL;
     statePtr->bufSize		= CHANNELBUFFER_DEFAULT_SIZE;
-    statePtr->timer		= NULL;
     statePtr->timerChanPtr	= NULL;
     statePtr->csPtrR		= NULL;
     statePtr->csPtrW		= NULL;
     statePtr->outputStage	= NULL;
 
@@ -8698,28 +8697,25 @@
 	     * testsuite on all of them.
 	     */
 
 	    mask &= ~TCL_EXCEPTION;
 
-	    if (!statePtr->timer) {
+	    if (!statePtr->timerChanPtr) {
 		TclChannelPreserve((Tcl_Channel)chanPtr);
 		statePtr->timerChanPtr = chanPtr;
-		statePtr->timer = Tcl_CreateTimerHandler(SYNTHETIC_EVENT_TIME,
-			ChannelTimerProc, chanPtr);
+		Tcl_DoWhenIdle(ChannelTimerProc, chanPtr);
 	    }
 	}
     }
 
-    if (!statePtr->timer
+    if (!statePtr->timerChanPtr
 	    && mask & TCL_WRITABLE
 	    && GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
 	TclChannelPreserve((Tcl_Channel)chanPtr);
 	statePtr->timerChanPtr = chanPtr;
-	statePtr->timer = Tcl_CreateTimerHandler(SYNTHETIC_EVENT_TIME,
-		ChannelTimerProc,chanPtr);
+	Tcl_DoWhenIdle(ChannelTimerProc,chanPtr);
     }
-
 
     ChanWatch(chanPtr, mask);
 }
 
 /*
@@ -8755,20 +8751,18 @@
 
     if (chanPtr->typePtr == NULL) {
 	CleanupTimerHandler(statePtr);
     } else {
 	Tcl_Preserve(statePtr);
-	statePtr->timer = NULL;
 	if (statePtr->interestMask & TCL_WRITABLE
 		&& GotFlag(statePtr, CHANNEL_NONBLOCKING)
 		&& !GotFlag(statePtr, BG_FLUSH_SCHEDULED)) {
 	    /*
 	     * Restart the timer in case a channel handler reenters the event loop
 	     * before UpdateInterest gets called by Tcl_NotifyChannel.
 	     */
-	    statePtr->timer = Tcl_CreateTimerHandler(SYNTHETIC_EVENT_TIME,
-		ChannelTimerProc,chanPtr);
+	    Tcl_DoWhenIdle(ChannelTimerProc,chanPtr);
 	    Tcl_NotifyChannel((Tcl_Channel) chanPtr, TCL_WRITABLE);
 	} else {
 	    /* The channel may have just been closed from within Tcl_NotifyChannel */
 	    if (!GotFlag(statePtr, CHANNEL_INCLOSE)) {
 		if (!GotFlag(statePtr, CHANNEL_NEED_MORE_DATA)
@@ -8778,12 +8772,11 @@
 		    /*
 		     * Restart the timer in case a channel handler reenters the event loop
 		     * before UpdateInterest gets called by Tcl_NotifyChannel.
 		     */
 
-		    statePtr->timer = Tcl_CreateTimerHandler(SYNTHETIC_EVENT_TIME,
-			ChannelTimerProc,chanPtr);
+		    Tcl_DoWhenIdle(ChannelTimerProc,chanPtr);
 		    Tcl_NotifyChannel((Tcl_Channel) chanPtr, TCL_READABLE);
 		} else {
 		    CleanupTimerHandler(statePtr);
 		    UpdateInterest(chanPtr);
 		}
@@ -8798,21 +8791,20 @@
 static void
 DeleteTimerHandler(
     ChannelState *statePtr
 )
 {
-    if (statePtr->timer != NULL) {
-	Tcl_DeleteTimerHandler(statePtr->timer);
+    if (statePtr->timerChanPtr != NULL) {
+	Tcl_CancelIdleCall(ChannelTimerProc,statePtr->timerChanPtr);
 	CleanupTimerHandler(statePtr);
     }
 }
 static void
 CleanupTimerHandler(
     ChannelState *statePtr
 ){
     TclChannelRelease((Tcl_Channel)statePtr->timerChanPtr);
-    statePtr->timer = NULL;
     statePtr->timerChanPtr = NULL;
 }
 
 /*
  *----------------------------------------------------------------------

Index: generic/tclIO.h
==================================================================
--- generic/tclIO.h
+++ generic/tclIO.h
@@ -187,11 +187,10 @@
 				 * handlers for. */
     EventScriptRecord *scriptRecordPtr;
 				/* Chain of all scripts registered for event
 				 * handlers ("fileevent") on this channel. */
     Tcl_Size bufSize;		/* What size buffers to allocate? */
-    Tcl_TimerToken timer;	/* Handle to wakeup timer for this channel. */
     Channel *timerChanPtr;	/* Needed in order to decrement the refCount of
 				   the right channel when the timer is
 				   deleted. */
     struct CopyState *csPtrR;	/* State of background copy for which channel
 				 * is input, or NULL. */

Index: tests/io.test
==================================================================
--- tests/io.test
+++ tests/io.test
@@ -6235,11 +6235,11 @@
 } -result {initial foo eof}
 
 close $f
 
 test io-44.6 {FileEventProc procedure: write-only non-blocking channel} -setup {
-} -constraints {stdio fileevent openpipe} -body {
+} -constraints {stdio fileevent} -body {
 
     namespace eval refchan {
 	namespace ensemble create
 	namespace export *
 
@@ -6286,10 +6286,87 @@
 	if {$count > 262144} {
 	    chan event $f writable {}
 	    set x done
 	}
     }]
+    set token [after 10000 [namespace code {
+	set x timeout
+    }]]
+    vwait [namespace which -variable x]
+    return $x
+} -cleanup {
+    after cancel $token
+    catch {chan close $f}
+} -result done
+
+
+test io-44.7 {
+    FileEventProc procedure: write-only non-blocking channel postevent idle
+} -setup {
+} -constraints {stdio fileevent} -body {
+
+    namespace eval refchan2 {
+	namespace ensemble create
+	namespace export *
+
+	proc finalize {chan args} {
+	    namespace delete c_$chan
+	}
+
+	proc initialize {chan args} {
+	    namespace eval c_$chan {}
+	    namespace upvar c_$chan watching watching
+	    set watching {}
+	    list finalize initialize seek watch write
+	}
+
+	proc watch {chan args} {
+	    namespace upvar c_$chan watching watching
+	    foreach arg $args {
+		switch $arg {
+		    write {
+			if {$arg ni $watching} {
+			    lappend watching $arg
+			}
+			after idle after 0 chan postevent $chan $arg
+		    }
+		}
+	    }
+	}
+
+	proc write {chan args} {
+	    incr ::counter
+	    after idle after 0 chan postevent $chan write
+	    return 1
+	}
+    }
+
+    set f [chan create w [namespace which refchan2]]
+    chan configure $f -blocking 0
+    chan event $f writable [namespace code {
+	puts $f X
+    }]
+
+    variable x {}
+
+    apply [list {} {
+	set script {
+	    set lambda [list ::apply [list script {
+		variable count
+		variable x
+		if {[incr count] < 1000} {
+		    try $script
+		} else {
+		    set x done
+		}
+	    } [namespace current]] $script]
+	    after idle [list after 0 $lambda]
+	}
+	try $script
+    } [namespace current]]
+
+
     set token [after 10000 [namespace code {
 	set x timeout
     }]]
     vwait [namespace which -variable x]
     return $x