For some dark reason there's a bit on the VLINK device of this chipset

that makes the PCIE device show up as a host bridge instead of a
PCI-PCI bridge.  As a result any devices sitting behind it won't be
detected.  Whack the device into PCI-PCI mode such that we can walk the
PCI bus hierarchy the normal way and detect all devices.  Fixes PR 6215.

ok dlg@

1 files changed, 19 insertions, 1 deletions

diff --git a/sys/arch/amd64/pci/pchb.c b/sys/arch/amd64/pci/pchb.c
index 5e2f7b627be..1eb74fed4b2 100644
--- a/sys/arch/amd64/pci/pchb.c
+++ b/sys/arch/amd64/pci/pchb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pchb.c,v 1.29 2009/04/11 14:59:59 kettenis Exp $	*/
+/*	$OpenBSD: pchb.c,v 1.30 2009/09/18 20:17:17 kettenis Exp $	*/
 /*	$NetBSD: pchb.c,v 1.1 2003/04/26 18:39:50 fvdl Exp $	*/
 /*
  * Copyright (c) 2000 Michael Shalayeff
@@ -142,6 +142,7 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 {
 	struct pchb_softc *sc = (struct pchb_softc *)self;
 	struct pci_attach_args *pa = aux;
+	pcireg_t bcreg;
 	int i, r;
 
 	switch (PCI_VENDOR(pa->pa_id)) {
@@ -197,6 +198,23 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 		}
 		printf("\n");
 		break;
+	case PCI_VENDOR_VIATECH:
+		switch (PCI_PRODUCT(pa->pa_id)) {
+		case PCI_PRODUCT_VIATECH_VT8251_VLINK:
+			/*
+			 * For some strange reason, the VIA VT8251
+			 * chipset can be configured to its PCIe
+			 * bridge show up as a host bridge.  We whack
+			 * it into PCI bridge mode here such that we
+			 * can see the devices behind it.
+			 */
+			bcreg = pci_conf_read(pa->pa_pc, pa->pa_tag, 0xfc);
+			bcreg &= ~0x00000004; /* XXX Magic */
+			pci_conf_write(pa->pa_pc, pa->pa_tag, 0xfc, bcreg);
+			break;
+		}
+		printf("\n");
+		break;
 	default:
 		printf("\n");
 		break;