Re: [Bugfix] x86/PCI: Fix regression caused by commit 4d6b4e69a245

Bjorn Helgaas
2015-11-24T16:49:14Z

On Mon, Nov 16, 2015 at 12:27:37PM +0800, Jiang Liu wrote:
> From: Liu Jiang <jiang.liu@linux.intel.com>
>
> Commit 4d6b4e69a245 ("x86/PCI/ACPI: Use common interface to support
> PCI host bridge") converted x86 to use the common interface
> acpi_pci_root_create, but the conversion missed on code piece in
> arch/x86/pci/bus_numa.c, which causes regression on some legacy
> AMD platforms as reported by Arthur Marsh <arthur.marsh@internode.on.net>.
> The root causes is that acpi_pci_root_create() fails to insert
> host bridge resources into iomem_resource/ioport_resource because
> x86_pci_root_bus_resources() has already inserted those resources.
> So change x86_pci_root_bus_resources() to not insert resources into
> iomem_resource/ioport_resource.

Fixes: 4d6b4e69a245 ("x86/PCI/ACPI: Use common interface to support PCI host bridge")

> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> Reported-and-tested-by: Arthur Marsh <arthur.marsh@internode.on.net>

What's the status of this? It looks like a regression we need to fix
for v4.4.

AFAICT, Arthur did *not* test this patch (rather, his response says he
did test it and the test failed).

4d6b4e69a245 was merged by Rafael, and I assume he'll merge the fix
unless I hear otherwise.

Bjorn

> Cc: Keith Busch <keith.busch@intel.com>
> Cc: Arthur Marsh <arthur.marsh@internode.on.net>
> ---
> arch/x86/pci/bus_numa.c | 16 +++-------------
> drivers/acpi/pci_root.c | 7 +++++++
> 2 files changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/pci/bus_numa.c b/arch/x86/pci/bus_numa.c
> index 7bcf06a7cd12..ce53b5b64f51 100644
> --- a/arch/x86/pci/bus_numa.c
> +++ b/arch/x86/pci/bus_numa.c
> @@ -41,27 +41,17 @@ void x86_pci_root_bus_resources(int bus, struct list_head *resources)
> bus);
>
> /* already added by acpi ? */
> - resource_list_for_each_entry(window, resources)
> + resource_list_for_each_entry(window, &info->resources)
> if (window->res->flags & IORESOURCE_BUS) {
> found = true;
> break;
> }
> -
> if (!found)
> pci_add_resource(resources, &info->busn);
>
> - list_for_each_entry(root_res, &info->resources, list) {
> - struct resource *res;
> - struct resource *root;
> + list_for_each_entry(root_res, &info->resources, list)
> + pci_add_resource(resources, &root_res->res);
>
> - res = &root_res->res;
> - pci_add_resource(resources, res);
> - if (res->flags & IORESOURCE_IO)
> - root = &ioport_resource;
> - else
> - root = &iomem_resource;
> - insert_resource(root, res);
> - }
> return;
>
> default_resources:
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 850d7bf0c873..ae3fe4e64203 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -768,6 +768,13 @@ static void pci_acpi_root_add_resources(struct acpi_pci_root_info *info)
> else
> continue;
>
> + /*
> + * Some legacy x86 host bridge drivers use iomem_resource and
> + * ioport_resource as default resource pool, skip it.
> + */
> + if (res == root)
> + continue;
> +
> conflict = insert_resource_conflict(root, res);
> if (conflict) {
> dev_info(&info->bridge->dev,
> --
> 1.7.10.4
>
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