[PATCH 1/2] eisa, PCI: Fix bus res reference

[Yinghai Lu <yinghai@kernel.org>]

Matthem found that 3.8.3 is having problems with an old (ancient)
PCI-to-EISA bridge, the Intel 82375. It worked with the 3.2 kernel.
He identified the 82375, but doesn't assign the struct resource *res
pointer inside the struct eisa_root_device, and panics.

After looking at pci_eisa_init(), found it referring bus resource
directly instead of pci_bus_resource_n().

After commit 45ca9e97 (PCI: add helpers for building PCI bus resource lists)
and commit 0efd5aab (PCI: add struct pci_host_bridge_window with CPU/bus
address offset), bus->resource[] is not used for pci root bus any more.

Fix it by using pci_bus_resource_n() and correct idx for root bus.

Reported-by: Matthew Whitehead <mwhitehe@redhat.com>
Tested-by: Matthew Whitehead <mwhitehe@redhat.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: stable@kernel.org

---
 drivers/eisa/pci_eisa.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/eisa/pci_eisa.c
===================================================================
--- linux-2.6.orig/drivers/eisa/pci_eisa.c
+++ linux-2.6/drivers/eisa/pci_eisa.c
@@ -22,7 +22,8 @@ static struct eisa_root_device pci_eisa_
 static int __init pci_eisa_init(struct pci_dev *pdev,
 				const struct pci_device_id *ent)
 {
-	int rc;
+	int rc, n = 0;
+	struct resource *bus_res;
 
 	if ((rc = pci_enable_device (pdev))) {
 		printk (KERN_ERR "pci_eisa : Could not enable device %s\n",
@@ -30,9 +31,12 @@ static int __init pci_eisa_init(struct p
 		return rc;
 	}
 
+	if (pci_is_root_bus(pdev->bus))
+		n = PCI_BRIDGE_RESOURCE_NUM;
+	bus_res = pci_bus_resource_n(pdev->bus, n);
 	pci_eisa_root.dev              = &pdev->dev;
-	pci_eisa_root.res	       = pdev->bus->resource[0];
-	pci_eisa_root.bus_base_addr    = pdev->bus->resource[0]->start;
+	pci_eisa_root.res	       = bus_res;
+	pci_eisa_root.bus_base_addr    = bus_res->start;
 	pci_eisa_root.slots	       = EISA_MAX_SLOTS;
 	pci_eisa_root.dma_mask         = pdev->dma_mask;
 	dev_set_drvdata(pci_eisa_root.dev, &pci_eisa_root);