On Fri, Mar 29, 2013 at 12:10:37PM -0700, Yinghai Lu wrote:
> On Fri, Mar 29, 2013 at 11:10 AM, Bjorn Helgaas <bhelg...@google.com> wrote:
> > On Wed, Mar 27, 2013 at 10:28 PM, Yinghai Lu <ying...@kernel.org> wrote:
> >> 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 <mwhit...@redhat.com>
> >> Tested-by: Matthew Whitehead <mwhit...@redhat.com>
> >> Signed-off-by: Yinghai Lu <ying...@kernel.org>
> >> Cc: sta...@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);
> >
> > I haven't figured out why the pci_is_root_bus() test is here. Can you
> > explain, maybe with a sample dmesg log and "lspci -vvx" output?
>
> Just forwarded two boot.log.
>
> for root bus, pci_bus_resource_n[0, PCI_BRIDGE_RESOURCE_NUM) all
> equal to 0.
Thanks. The patch below is what I was thinking. That should work
even in this scenario, I think, and it's nicer if we don't have to
have this root bus internal knowledge here.
diff --git a/drivers/eisa/pci_eisa.c b/drivers/eisa/pci_eisa.c
index cdae207..3e9dee9 100644
--- a/drivers/eisa/pci_eisa.c
+++ b/drivers/eisa/pci_eisa.c
@@ -22,7 +22,8 @@ static struct eisa_root_device pci_eisa_root;
static int __init pci_eisa_init(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
- int rc;
+ int rc, i;
+ struct resource *res;
if ((rc = pci_enable_device (pdev))) {
printk (KERN_ERR "pci_eisa : Could not enable device %s\n",
@@ -30,9 +31,28 @@ static int __init pci_eisa_init(struct pci_dev *pdev,
return rc;
}
+ /*
+ * The Intel 82375 PCI-EISA bridge is a subtractive-decode PCI
+ * device, so the resources available on EISA are the same as those
+ * available on the 82375 bus. This works the same as a PCI-PCI
+ * bridge in subtractive-decode mode (see pci_read_bridge_bases()).
+ * We assume other PCI-EISA bridges are similar.
+ *
+ * eisa_root_register() can only deal with a single resource, so we
+ * use the first valid one.
+ */
+ pci_bus_for_each_resource(pdev->bus, res, i)
+ if (res)
+ break;
+
+ if (!res) {
+ dev_err(&pdev->dev, "No resources available\n");
+ return -1;
+ }
+
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 = res;
+ pci_eisa_root.bus_base_addr = 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);
--
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