Index: src/sys/dev/pci/vga_pci.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/pci/vga_pci.c,v
retrieving revision 1.5
diff -u -r1.5 vga_pci.c
--- src/sys/dev/pci/vga_pci.c	1 Feb 2006 15:45:29 -0000	1.5
+++ src/sys/dev/pci/vga_pci.c	5 May 2009 13:39:01 -0000
@@ -42,10 +42,21 @@
 #include <sys/bus.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
+#include <sys/rman.h>
+#include <sys/systm.h>
 
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcivar.h>
 
+struct vga_resource {
+      struct resource *vr_res;
+      int     vr_refs;
+};
+
+struct vga_pci_softc {
+      struct vga_resource vga_res[PCIR_MAX_BAR_0 + 1];
+};
+
 static int
 vga_pci_probe(device_t dev)
 {
@@ -110,7 +121,27 @@
 vga_pci_alloc_resource(device_t dev, device_t child, int type, int *rid,
     u_long start, u_long end, u_long count, u_int flags)
 {
+	struct vga_pci_softc *sc;
+	int bar;
 
+	switch (type) {
+	case SYS_RES_MEMORY:
+	case SYS_RES_IOPORT:
+		/*
+		 * For BARs, we cache the resource so that we only allocate it
+		 * from the PCI bus once.
+		 */
+		bar = PCI_RID2BAR(*rid);
+		if (bar < 0 || bar > PCIR_MAX_BAR_0)
+			return (NULL);
+		sc = device_get_softc(dev);
+		if (sc->vga_res[bar].vr_res == NULL)
+			sc->vga_res[bar].vr_res = bus_alloc_resource(dev, type,
+			    rid, start, end, count, flags);
+		if (sc->vga_res[bar].vr_res != NULL)
+			sc->vga_res[bar].vr_refs++;
+		return (sc->vga_res[bar].vr_res);
+	}
 	return (bus_alloc_resource(dev, type, rid, start, end, count, flags));
 }
 
@@ -118,6 +149,37 @@
 vga_pci_release_resource(device_t dev, device_t child, int type, int rid,
     struct resource *r)
 {
+	struct vga_pci_softc *sc;
+	int bar, error;
+
+	switch (type) {
+	case SYS_RES_MEMORY:
+	case SYS_RES_IOPORT:
+		/*
+		 * For BARs, we release the resource from the PCI bus
+		 * when the last child reference goes away.
+		 */
+		bar = PCI_RID2BAR(rid);
+		if (bar < 0 || bar > PCIR_MAX_BAR_0)
+			return (EINVAL);
+		sc = device_get_softc(dev);
+		if (sc->vga_res[bar].vr_res == NULL)
+			return (EINVAL);
+		KASSERT(sc->vga_res[bar].vr_res == r,
+		    ("vga_pci resource mismatch"));
+		if (sc->vga_res[bar].vr_refs > 1) {
+			sc->vga_res[bar].vr_refs--;
+			return (0);
+		}
+		KASSERT(sc->vga_res[bar].vr_refs > 0,
+		    ("vga_pci resource reference count underflow"));
+		error = bus_release_resource(dev, type, rid, r);
+		if (error == 0) {
+			sc->vga_res[bar].vr_res = NULL;
+			sc->vga_res[bar].vr_refs = 0;
+		}
+		return (error);
+	}
 
 	return (bus_release_resource(dev, type, rid, r));
 }
@@ -247,7 +309,7 @@
 static driver_t vga_pci_driver = {
 	"vgapci",
 	vga_pci_methods,
-	1,
+	sizeof(struct vga_pci_softc),
 };
 
 static devclass_t vga_devclass;