Index: include/pci_cfgreg.h
===================================================================
RCS file: /home/ncvs/src/sys/i386/include/pci_cfgreg.h,v
retrieving revision 1.4
diff -u -r1.4 pci_cfgreg.h
--- include/pci_cfgreg.h	2000/10/16 19:49:30	1.4
+++ include/pci_cfgreg.h	2001/08/20 10:13:46
@@ -51,3 +51,5 @@
 extern u_int32_t	pci_cfgregread(int bus, int slot, int func, int reg, int bytes);
 extern void		pci_cfgregwrite(int bus, int slot, int func, int reg, u_int32_t data, int bytes);
 extern int		pci_cfgintr(int bus, int device, int pin);
+extern int		pci_kill_pcibios(void);
+extern int		pci_pcibios_active(void);
Index: pci/pci_bus.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/pci/pci_bus.c,v
retrieving revision 1.75
diff -u -r1.75 pci_bus.c
--- pci/pci_bus.c	2000/12/08 22:11:06	1.75
+++ pci/pci_bus.c	2001/08/20 10:13:46
@@ -268,6 +268,7 @@
 	int pcifunchigh;
 	int found824xx = 0;
 	int found_orion = 0;
+	int found_pcibios_flaming_death = 0;
 	device_t child;
 	devclass_t pci_devclass;
 
@@ -355,6 +356,23 @@
 	}
 	if (found824xx && bus == 0) {
 		bus++;
+		goto retry;
+	}
+
+	/*
+	 * This is just freaking brilliant!  Some BIOS writers have
+	 * decided that we must be forcibly prevented from using
+	 * PCIBIOS to query the host->pci bridges.  If you try and
+	 * access configuration registers, it pretends there is
+	 * no pci device at that bus:device:function address.
+	 */
+	if (!found && pci_pcibios_active() && !found_pcibios_flaming_death) {
+		/* retry with the old mechanism, or fail */
+		if (pci_kill_pcibios())
+			return;
+		printf("nexus_pcib_identify: found broken PCIBIOS - disabling it and retrying.\n");
+		printf("nexus_pcib_identify: it is bogusly censoring host->pci bridges.\n");
+		found_pcibios_flaming_death = 1;
 		goto retry;
 	}
 
Index: pci/pci_cfgreg.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/pci/pci_cfgreg.c,v
retrieving revision 1.76
diff -u -r1.76 pci_cfgreg.c
--- pci/pci_cfgreg.c	2001/05/11 04:52:29	1.76
+++ pci/pci_cfgreg.c	2001/08/20 10:13:46
@@ -71,6 +71,19 @@
 static struct PIR_table	*pci_route_table;
 static int		pci_route_count;
 
+int
+pci_pcibios_active(void)
+{
+    return usebios;
+}
+
+int
+pci_kill_pcibios(void)
+{
+    usebios = 0;
+    return pcireg_cfgopen();
+}
+
 /* 
  * Initialise access to PCI configuration space 
  */