Index: src/sys/arch/amd64/amd64/machdep.c
===================================================================
--- src.orig/sys/arch/amd64/amd64/machdep.c	2010-06-05 00:19:26.220727715 +0100
+++ src/sys/arch/amd64/amd64/machdep.c	2010-06-06 11:39:57.679154664 +0100
@@ -1800,3 +1800,29 @@
 {
 	return memseg_baseaddr(l, seg, ldtp, len, NULL);
 }
+
+/* Number of times to warn about an unhandled interrupt */
+#define NUM_WARNINGS	10
+
+static struct timeval lasttime;
+static struct timeval intervaltime = { 5, 0 }; /* interval time is 5 seconds */
+
+static unsigned long long intr_count[MAX_INTR_SOURCES];
+static int warn_count[MAX_INTR_SOURCES];
+
+void unhandled_intr(int slot)
+{
+	intr_count[slot]++;
+
+	if (ratecheck(&lasttime, &intervaltime)) {
+		if (warn_count[slot] == NUM_WARNINGS) {
+			warn_count[slot]++;	/* So we don't warn again. */
+			printf("Warned about unhandled interrupt %d times. Shutting up now.\n",
+			       NUM_WARNINGS);
+		} else if (warn_count[slot] < NUM_WARNINGS) {
+			warn_count[slot]++;
+			printf("Unhandled interrupt! slot #%d, count %llu\n",
+			       slot, intr_count[slot]);
+		}
+	}
+}
Index: src/sys/arch/amd64/amd64/vector.S
===================================================================
--- src.orig/sys/arch/amd64/amd64/vector.S	2010-06-05 00:19:26.221322897 +0100
+++ src/sys/arch/amd64/amd64/vector.S	2010-06-05 00:19:34.732863852 +0100
@@ -682,6 +682,7 @@
 	sti								;\
 	incl	CPUVAR(IDEPTH)						;\
 	movq	IS_HANDLERS(%r14),%rbx					;\
+	pushq	$0			/* push 'handled' */		;\
 6:									\
 	movl	IH_LEVEL(%rbx),%r12d					;\
 	cmpl	%r13d,%r12d						;\
@@ -691,15 +692,22 @@
 	movl	%r12d,CPUVAR(ILEVEL)					;\
 	call	*IH_FUN(%rbx)		/* call it */			;\
 	movq	IH_NEXT(%rbx),%rbx	/* next handler in chain */	;\
+	addl	%eax,(%rsp)						;\
 	testq	%rbx,%rbx						;\
 	jnz	6b							;\
+	cmpl	$0,(%rsp)		/* was the intr handled? */	;\
+	jne	5f		  					;\
+	movl	$num,%edi						;\
+	call	_C_LABEL(unhandled_intr) 				;\
 5:									\
+	addq	$8,%rsp			/* pop 'handled' */		;\
 	cli								;\
 	unmask(num)			/* unmask it in hardware */	;\
 	late_ack(num)							;\
 	sti								;\
 	jmp	_C_LABEL(Xdoreti)	/* lower spl and do ASTs */	;\
 7:									\
+	addq	$8,%rsp			/* pop 'handled' */		;\
 	cli								;\
 	orl     $(1 << num),CPUVAR(IPENDING)				;\
 	level_mask(num)							;\
Index: src/sys/arch/amd64/include/intr.h
===================================================================
--- src.orig/sys/arch/amd64/include/intr.h	2010-06-05 00:19:26.222315979 +0100
+++ src/sys/arch/amd64/include/intr.h	2010-06-05 00:19:34.734404421 +0100
@@ -1,3 +1,5 @@
 /*	$NetBSD: intr.h,v 1.1 2003/04/26 18:39:42 fvdl Exp $	*/
 
 #include <x86/intr.h>
+
+extern void unhandled_intr(int);