diff --git a/sys/amd64/amd64/intr_machdep.c b/sys/amd64/amd64/intr_machdep.c
index 2864868d731d..6ed8c80c52b1 100644
--- a/sys/amd64/amd64/intr_machdep.c
+++ b/sys/amd64/amd64/intr_machdep.c
@@ -310,7 +310,7 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 	struct thread *td;
 	struct intr_event *ie;
 	struct intr_handler *ih;
-	int error, vector, thread;
+	int error, vector, thread, ret;
 
 	td = curthread;
 
@@ -356,6 +356,7 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 	 * a trapframe as its argument.
 	 */
 	td->td_intr_nesting_level++;
+	ret = 0;
 	thread = 0;
 	critical_enter();
 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
@@ -367,9 +368,17 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 		    ih->ih_filter, ih->ih_argument == NULL ? frame :
 		    ih->ih_argument, ih->ih_name);
 		if (ih->ih_argument == NULL)
-			ih->ih_filter(frame);
+			ret = ih->ih_filter(frame);
 		else
-			ih->ih_filter(ih->ih_argument);
+			ret = ih->ih_filter(ih->ih_argument);
+		/*
+		 * Wrapper handler special case: see
+		 * i386/intr_machdep.c::intr_execute_handlers()
+		 */
+		if (!thread) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				thread = 1;
+		}
 	}
 
 	/*
diff --git a/sys/arm/arm/intr.c b/sys/arm/arm/intr.c
index c5bbb51954a2..8d573dcedc02 100644
--- a/sys/arm/arm/intr.c
+++ b/sys/arm/arm/intr.c
@@ -104,7 +104,7 @@ arm_handler_execute(struct trapframe *frame, int irqnb)
 	struct intr_event *event;
 	struct intr_handler *ih;
 	struct thread *td = curthread;
-	int i, thread;
+	int i, thread, ret;
 
 	PCPU_LAZY_INC(cnt.v_intr);
 	td->td_intr_nesting_level++;
@@ -116,13 +116,22 @@ arm_handler_execute(struct trapframe *frame, int irqnb)
 			continue;
 
 		/* Execute fast handlers. */
+		ret = 0;
 		thread = 0;
 		TAILQ_FOREACH(ih, &event->ie_handlers, ih_next) {
 			if (ih->ih_filter == NULL)
 				thread = 1;
 			else
-				ih->ih_filter(ih->ih_argument ?
+				ret = ih->ih_filter(ih->ih_argument ?
 				    ih->ih_argument : frame);
+			/*
+			 * Wrapper handler special case: see
+			 * i386/intr_machdep.c::intr_execute_handlers()
+			 */
+			if (!thread) {
+				if (ret == FILTER_SCHEDULE_THREAD)
+					thread = 1;
+			}
 		}
 
 		/* Schedule thread if needed. */
diff --git a/sys/i386/i386/intr_machdep.c b/sys/i386/i386/intr_machdep.c
index 0fa44ad78062..65e67e2644d1 100644
--- a/sys/i386/i386/intr_machdep.c
+++ b/sys/i386/i386/intr_machdep.c
@@ -301,7 +301,7 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 	struct thread *td;
 	struct intr_event *ie;
 	struct intr_handler *ih;
-	int error, vector, thread;
+	int error, vector, thread, ret;
 
 	td = curthread;
 
@@ -347,6 +347,7 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 	 * a trapframe as its argument.
 	 */
 	td->td_intr_nesting_level++;
+	ret = 0;
 	thread = 0;
 	critical_enter();
 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
@@ -358,9 +359,27 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 		    ih->ih_filter, ih->ih_argument == NULL ? frame :
 		    ih->ih_argument, ih->ih_name);
 		if (ih->ih_argument == NULL)
-			ih->ih_filter(frame);
+			ret = ih->ih_filter(frame);
 		else
-			ih->ih_filter(ih->ih_argument);
+			ret = ih->ih_filter(ih->ih_argument);
+		/* 
+		 * Wrapper handler special handling:
+		 *
+		 * in some particular cases (like pccard and pccbb), 
+		 * the _real_ device handler is wrapped in a couple of
+		 * functions - a filter wrapper and an ithread wrapper.
+		 * In this case (and just in this case), the filter wrapper 
+		 * could ask the system to schedule the ithread and mask
+		 * the interrupt source if the wrapped handler is composed
+		 * of just an ithread handler.
+		 *
+		 * TODO: write a generic wrapper to avoid people rolling 
+		 * their own
+		 */
+		if (!thread) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				thread = 1;
+		}
 	}
 
 	/*
diff --git a/sys/ia64/ia64/interrupt.c b/sys/ia64/ia64/interrupt.c
index 61d1bdcecd8f..8cf18b49d247 100644
--- a/sys/ia64/ia64/interrupt.c
+++ b/sys/ia64/ia64/interrupt.c
@@ -353,7 +353,7 @@ ia64_dispatch_intr(void *frame, unsigned long vector)
 	struct ia64_intr *i;
 	struct intr_event *ie;			/* our interrupt event */
 	struct intr_handler *ih;
-	int error, thread;
+	int error, thread, ret;
 
 	/*
 	 * Find the interrupt thread for this vector.
@@ -379,6 +379,7 @@ ia64_dispatch_intr(void *frame, unsigned long vector)
 	 * Execute all fast interrupt handlers directly without Giant.  Note
 	 * that this means that any fast interrupt handler must be MP safe.
 	 */
+	ret = 0;
 	thread = 0;
 	critical_enter();
 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
@@ -388,7 +389,15 @@ ia64_dispatch_intr(void *frame, unsigned long vector)
 		}
 		CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
 		    ih->ih_filter, ih->ih_argument, ih->ih_name);
-		ih->ih_filter(ih->ih_argument);
+		ret = ih->ih_filter(ih->ih_argument);
+		/*
+		 * Wrapper handler special case: see
+		 * i386/intr_machdep.c::intr_execute_handlers()
+		 */
+		if (!thread) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				thread = 1;
+		}
 	}
 	critical_exit();
 
diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c
index a9adaa1f88e4..aa79bfa86bb1 100644
--- a/sys/kern/kern_intr.c
+++ b/sys/kern/kern_intr.c
@@ -1264,9 +1264,6 @@ intr_filter_loop(struct intr_event *ie, struct trapframe *frame,
 			continue;
 		}
 
-		KASSERT(ret != FILTER_SCHEDULE_THREAD, 
-			("intr_filter_loop: FILTER_SCHEDULE_THREAD from filter"));
-
 		if (ret & FILTER_STRAY)
 			continue;
 		else { 
diff --git a/sys/powerpc/powerpc/intr_machdep.c b/sys/powerpc/powerpc/intr_machdep.c
index f4931473bbb8..287df911232a 100644
--- a/sys/powerpc/powerpc/intr_machdep.c
+++ b/sys/powerpc/powerpc/intr_machdep.c
@@ -198,7 +198,7 @@ intr_handle(u_int irq)
 	struct ppc_intr *i;
 	struct intr_event *ie;
 	struct intr_handler *ih;
-	int error, sched;
+	int error, sched, ret;
 
 	i = ppc_intrs[irq];
 	if (i == NULL)
@@ -216,6 +216,7 @@ intr_handle(u_int irq)
 	 * Execute all fast interrupt handlers directly without Giant.  Note
 	 * that this means that any fast interrupt handler must be MP safe.
 	 */
+	ret = 0;
 	sched = 0;
 	critical_enter();
 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
@@ -225,7 +226,15 @@ intr_handle(u_int irq)
 		}
 		CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
 		    ih->ih_filter, ih->ih_argument, ih->ih_name);
-		ih->ih_filter(ih->ih_argument);
+		ret = ih->ih_filter(ih->ih_argument);
+		/*
+		 * Wrapper handler special case: see
+		 * i386/intr_machdep.c::intr_execute_handlers()
+		 */
+		if (!sched) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				sched = 1;
+		}
 	}
 	critical_exit();
 
diff --git a/sys/sparc64/sparc64/intr_machdep.c b/sys/sparc64/sparc64/intr_machdep.c
index 66c9ab726b72..66b285eaedeb 100644
--- a/sys/sparc64/sparc64/intr_machdep.c
+++ b/sys/sparc64/sparc64/intr_machdep.c
@@ -236,7 +236,7 @@ intr_execute_handlers(void *cookie)
 	struct intr_vector *iv;
 	struct intr_event *ie;
 	struct intr_handler *ih;
-	int error, thread;
+	int error, thread, ret;
 
 	iv = cookie;
 	ie = iv->iv_event;
@@ -246,6 +246,7 @@ intr_execute_handlers(void *cookie)
 	}
 
 	/* Execute fast interrupt handlers directly. */
+	ret = 0;
 	thread = 0;
 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
 		if (ih->ih_filter == NULL) {
@@ -255,7 +256,15 @@ intr_execute_handlers(void *cookie)
 		MPASS(ih->ih_filter != NULL && ih->ih_argument != NULL);
 		CTR3(KTR_INTR, "%s: executing handler %p(%p)", __func__,
 		    ih->ih_filter, ih->ih_argument);
-		ih->ih_filter(ih->ih_argument);
+		ret = ih->ih_filter(ih->ih_argument);
+		/*
+		 * Wrapper handler special case: see
+		 * i386/intr_machdep.c::intr_execute_handlers()
+		 */
+		if (!thread) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				thread = 1;
+		}
 	}
 
 	/* Schedule a heavyweight interrupt process. */
diff --git a/sys/sun4v/sun4v/intr_machdep.c b/sys/sun4v/sun4v/intr_machdep.c
index 559bf8f9e878..6b9f1fb0a534 100644
--- a/sys/sun4v/sun4v/intr_machdep.c
+++ b/sys/sun4v/sun4v/intr_machdep.c
@@ -283,7 +283,7 @@ intr_execute_handlers(void *cookie)
 	struct intr_vector *iv;
 	struct intr_event *ie;
 	struct intr_handler *ih;
-	int fast, thread;
+	int fast, thread, ret;
 
 	iv = cookie;
 	ie = iv->iv_event;
@@ -292,6 +292,7 @@ intr_execute_handlers(void *cookie)
 		return;
 	}
 	
+	ret = 0;
 	fast = thread = 0;
 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
 		if (ih->ih_filter == NULL) {
@@ -301,8 +302,16 @@ intr_execute_handlers(void *cookie)
 		MPASS(ih->ih_filter != NULL && ih->ih_argument != NULL);
 		CTR3(KTR_INTR, "%s: executing handler %p(%p)", __func__,
 		    ih->ih_filter, ih->ih_argument);
-		ih->ih_filter(ih->ih_argument);
+		ret = ih->ih_filter(ih->ih_argument);
 		fast = 1;
+		/*
+		 * Wrapper handler special case: see
+		 * i386/intr_machdep.c::intr_execute_handlers()
+		 */
+		if (!thread) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				thread = 1;
+		}
 	}
 
 	/* Schedule a heavyweight interrupt process. */