diff --git a/sys/x86/include/intr_machdep.h b/sys/x86/include/intr_machdep.h
--- a/sys/x86/include/intr_machdep.h
+++ b/sys/x86/include/intr_machdep.h
@@ -82,7 +82,6 @@
 	void (*pic_eoi_source)(struct intsrc *);
 	void (*pic_enable_intr)(struct intsrc *);
 	void (*pic_disable_intr)(struct intsrc *);
-	int (*pic_vector)(struct intsrc *);
 	int (*pic_source_pending)(struct intsrc *);
 	void (*pic_suspend)(struct pic *);
 	void (*pic_resume)(struct pic *, bool suspend_cancelled);
@@ -148,7 +147,7 @@
 u_int	intr_next_cpu(int domain);
 struct intsrc *intr_lookup_source(int vector);
 int	intr_register_pic(struct pic *pic);
-int	intr_register_source(struct intsrc *isrc);
+int	intr_register_source(u_int vector, struct intsrc *isrc);
 int	intr_remove_handler(void *cookie);
 void	intr_resume(bool suspend_cancelled);
 void	intr_suspend(void);
diff --git a/sys/x86/include/xen/arch-intr.h b/sys/x86/include/xen/arch-intr.h
--- a/sys/x86/include/xen/arch-intr.h
+++ b/sys/x86/include/xen/arch-intr.h
@@ -34,7 +34,6 @@
 
 typedef struct {
 	struct intsrc		intsrc;		/* @TOP -> *xen_arch_isrc */
-	u_int			vector;		/* Global isrc vector number */
 } xen_arch_isrc_t;
 
 #include <dev/xen/bus/intr-internal.h>
diff --git a/sys/x86/isa/atpic.c b/sys/x86/isa/atpic.c
--- a/sys/x86/isa/atpic.c
+++ b/sys/x86/isa/atpic.c
@@ -100,7 +100,6 @@
 			.pic_eoi_source = (eoi),			\
 			.pic_enable_intr = atpic_enable_intr,		\
 			.pic_disable_intr = atpic_disable_intr,		\
-			.pic_vector = atpic_vector,			\
 			.pic_source_pending = atpic_source_pending,	\
 			.pic_resume = atpic_resume,			\
 			.pic_config_intr = atpic_config_intr,		\
@@ -235,7 +234,7 @@
 	for (i = 0, ai = atintrs; i < NUM_ISA_IRQS; i++, ai++) {
 		if (i == ICU_SLAVEID)
 			continue;
-		intr_register_source(&ai->at_intsrc);
+		intr_register_source(i, &ai->at_intsrc);
 	}
 }
 
diff --git a/sys/x86/x86/intr_machdep.c b/sys/x86/x86/intr_machdep.c
--- a/sys/x86/x86/intr_machdep.c
+++ b/sys/x86/x86/intr_machdep.c
@@ -216,12 +216,11 @@
  * called.
  */
 int
-intr_register_source(struct intsrc *isrc)
+intr_register_source(u_int vector, struct intsrc *isrc)
 {
-	int error, vector;
+	int error;
 
 	KASSERT(intr_pic_registered(isrc->is_pic), ("unregistered PIC"));
-	vector = isrc->is_pic->pic_vector(isrc);
 	KASSERT(vector < num_io_irqs, ("IRQ %d too large (%u irqs)", vector,
 	    num_io_irqs));
 	if (interrupt_sources[vector] != NULL)
@@ -336,7 +335,7 @@
 	 * XXX: We assume that IRQ 0 is only used for the ISA timer
 	 * device (clk).
 	 */
-	vector = isrc->is_pic->pic_vector(isrc);
+	vector = isrc->is_event->ie_irq;
 	if (vector == 0)
 		clkintr_pending = 1;
 
@@ -436,7 +435,7 @@
 	is->is_index = intrcnt_index;
 	intrcnt_index += 2;
 	snprintf(straystr, sizeof(straystr), "stray irq%d",
-	    is->is_pic->pic_vector(is));
+	    is->is_event->ie_irq);
 	intrcnt_updatename(is);
 	is->is_count = &intrcnt[is->is_index];
 	intrcnt_setname(straystr, is->is_index + 1);
diff --git a/sys/x86/x86/io_apic.c b/sys/x86/x86/io_apic.c
--- a/sys/x86/x86/io_apic.c
+++ b/sys/x86/x86/io_apic.c
@@ -117,7 +117,6 @@
 static void	ioapic_eoi_source(struct intsrc *isrc);
 static void	ioapic_enable_intr(struct intsrc *isrc);
 static void	ioapic_disable_intr(struct intsrc *isrc);
-static int	ioapic_vector(struct intsrc *isrc);
 static int	ioapic_source_pending(struct intsrc *isrc);
 static int	ioapic_config_intr(struct intsrc *isrc, enum intr_trigger trig,
 		    enum intr_polarity pol);
@@ -134,7 +133,6 @@
 	.pic_eoi_source = ioapic_eoi_source,
 	.pic_enable_intr = ioapic_enable_intr,
 	.pic_disable_intr = ioapic_disable_intr,
-	.pic_vector = ioapic_vector,
 	.pic_source_pending = ioapic_source_pending,
 	.pic_suspend = NULL,
 	.pic_resume = ioapic_resume,
@@ -528,15 +526,6 @@
 	}
 }
 
-static int
-ioapic_vector(struct intsrc *isrc)
-{
-	struct ioapic_intsrc *pin;
-
-	pin = (struct ioapic_intsrc *)isrc;
-	return (pin->io_irq);
-}
-
 static int
 ioapic_source_pending(struct intsrc *isrc)
 {
@@ -949,7 +938,7 @@
 	io = (struct ioapic *)pic;
 	for (i = 0, pin = io->io_pins; i < io->io_numintr; i++, pin++) {
 		if (pin->io_irq >= 0)
-			intr_register_source(&pin->io_intsrc);
+			intr_register_source(pin->io_irq, &pin->io_intsrc);
 	}
 }
 
diff --git a/sys/x86/x86/msi.c b/sys/x86/x86/msi.c
--- a/sys/x86/x86/msi.c
+++ b/sys/x86/x86/msi.c
@@ -131,7 +131,6 @@
 static void	msi_eoi_source(struct intsrc *isrc);
 static void	msi_enable_intr(struct intsrc *isrc);
 static void	msi_disable_intr(struct intsrc *isrc);
-static int	msi_vector(struct intsrc *isrc);
 static int	msi_source_pending(struct intsrc *isrc);
 static int	msi_config_intr(struct intsrc *isrc, enum intr_trigger trig,
 		    enum intr_polarity pol);
@@ -143,7 +142,6 @@
 	.pic_eoi_source = msi_eoi_source,
 	.pic_enable_intr = msi_enable_intr,
 	.pic_disable_intr = msi_disable_intr,
-	.pic_vector = msi_vector,
 	.pic_source_pending = msi_source_pending,
 	.pic_suspend = NULL,
 	.pic_resume = NULL,
@@ -226,14 +224,6 @@
 	}
 }
 
-static int
-msi_vector(struct intsrc *isrc)
-{
-	struct msi_intsrc *msi = (struct msi_intsrc *)isrc;
-
-	return (msi->msi_irq);
-}
-
 static int
 msi_source_pending(struct intsrc *isrc)
 {
@@ -392,7 +382,7 @@
 	msi = malloc(sizeof(struct msi_intsrc), M_MSI, M_WAITOK | M_ZERO);
 	msi->msi_intsrc.is_pic = &msi_pic;
 	msi->msi_irq = irq;
-	intr_register_source(&msi->msi_intsrc);
+	intr_register_source(irq, &msi->msi_intsrc);
 	nexus_add_irq(irq);
 }
 
diff --git a/sys/x86/xen/xen_arch_intr.c b/sys/x86/xen/xen_arch_intr.c
--- a/sys/x86/xen/xen_arch_intr.c
+++ b/sys/x86/xen/xen_arch_intr.c
@@ -191,24 +191,6 @@
 	xen_intr_disable_intr((struct xenisrc *)isrc);
 }
 
-/**
- * Determine the global interrupt vector number for
- * a Xen interrupt source.
- *
- * \param isrc  The interrupt source to query.
- *
- * \return  The vector number corresponding to the given interrupt source.
- */
-static int
-xen_intr_pic_vector(struct intsrc *isrc)
-{
-
-	_Static_assert(offsetof(struct xenisrc, xi_arch.intsrc) == 0,
-	    "xi_arch MUST be at top of xenisrc for x86");
-
-	return (((struct xenisrc *)isrc)->xi_arch.vector);
-}
-
 /**
  * Determine whether or not interrupt events are pending on the
  * the given interrupt source.
@@ -282,7 +264,6 @@
 	.pic_eoi_source     = xen_intr_pic_eoi_source,
 	.pic_enable_intr    = xen_intr_pic_enable_intr,
 	.pic_disable_intr   = xen_intr_pic_disable_intr,
-	.pic_vector         = xen_intr_pic_vector,
 	.pic_source_pending = xen_intr_pic_source_pending,
 	.pic_suspend        = xen_intr_pic_suspend,
 	.pic_resume         = xen_intr_pic_resume,
@@ -354,8 +335,7 @@
 	mtx_unlock(&xen_intr_x86_lock);
 	isrc = malloc(sizeof(*isrc), M_XENINTR, M_WAITOK | M_ZERO);
 	isrc->xi_arch.intsrc.is_pic = &xen_intr_pic;
-	isrc->xi_arch.vector = vector;
-	error = intr_register_source(&isrc->xi_arch.intsrc);
+	error = intr_register_source(vector, &isrc->xi_arch.intsrc);
 	if (error != 0)
 		panic("%s(): failed registering interrupt %u, error=%d\n",
 		    __func__, vector, error);