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SubjectRe: [PATCH 0/4, v3] Physical PCI slot objects
> Hi Gary, Kenji-san, et. al,
>
> * Gary Hade <garyhade@us.ibm.com>:
>> Alex, What I was trying to suggest is a boot-time kernel
>> option, not a kernel configuration option. The basic idea is
>> to give the user (with a single binary kernel) the ability to
>> include your ACPI-PCI slot driver feature changes only when
>> they are really needed. In addition to reducing the number of
>> system/PCI hotplug driver combinations where your changes would
>> need to be validated, I believe would also help alleviate other
>> worries (e.g. Andi Kleen's memory consumption concern). I
>> believe this goal could also be achieved with the kernel config
>> option by making the pci_slot module runtime loadable with the
>> PCI hotplug drivers only visiting your new code when the
>> pci_slot driver is loaded, although I think this would be more
>> difficult to implement.
>
> I have modified my patch series so that the final patch that
> introduces my ACPI-PCI slot driver is a full-fledged module, that
> has a tristate Kconfig option.
>

Thank you for your good job.

I tested shpchp and pciehp both with and without pci_slot module. There
seems no regression from shpchp and pciehp's point of view.
(I had a little concern about the hotplug slots' name that vary depending
on whether pci_slot functionality is enabled or disabled. But, now that we
can build pci_slot driver as a kernel module, I don't think it is a big
problem).

Only the problems is that I got Call Traces with the following error
messages when pci_slot driver was loaded, and one strange slot named
'1023' was registered (other slots are fine). This is the same problem
I reported before.

sysfs: duplicate filename '1023' can not be created
WARNING: at fs/sysfs/dir.c:424 sysfs_add_one()

kobject_add failed for 1023 with -EEXIST, don't try to register
things with the same name in the same directory.

On my system, hotplug slots themselves can be added, removed and replaced
with the ohter type of I/O box. The ACPI firmware tells OS the presence of
those slots using _STA method (That is, it doesn't use 'LoadTable()' AML
operator). On the other hand, current pci_slot driver doesn't check _STA.
As a result, pci_slot driver tryied to register the invalid (non-existing)
slots. The ACPI firmware of my system returns '1023' if the invalid slot's
_SUN is evaluated. This is the cause of Call Traces mentioned above. To
fix this problem, pci_slot driver need to check _STA when scanning ACPI
Namespace.

I'm sorry for reporting this so late. I'm attaching the patch to fix the
problem. This is against 2.6.24-rc3 with your patches applied. Could you
try it?

BTW, acpiphp also seems to have the same problem...

Thanks,
Kenji Kaneshige

---
drivers/acpi/pci_slot.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

Index: linux-2.6.24-rc3/drivers/acpi/pci_slot.c
===================================================================
--- linux-2.6.24-rc3.orig/drivers/acpi/pci_slot.c
+++ linux-2.6.24-rc3/drivers/acpi/pci_slot.c
@@ -113,10 +113,17 @@ register_slot(acpi_handle handle, u32 lv
int device;
unsigned long sun;
char name[KOBJ_NAME_LEN];
+ acpi_status status;
+ struct acpi_device *dummy_device;

struct pci_slot *pci_slot;
struct pci_bus *pci_bus = context;

+ /* Skip non-existing device object. */
+ status = acpi_bus_get_device(handle, &dummy_device);
+ if (ACPI_FAILURE(status))
+ return AE_OK;
+
if (check_slot(handle, &device, &sun))
return AE_OK;

@@ -150,12 +157,18 @@ walk_p2p_bridge(acpi_handle handle, u32
acpi_status status;
acpi_handle dummy_handle;
acpi_walk_callback user_function;
+ struct acpi_device *dummy_device;

struct pci_dev *dev;
struct pci_bus *pci_bus;
struct p2p_bridge_context child_context;
struct p2p_bridge_context *parent_context = context;

+ /* Skip non-existing device object. */
+ status = acpi_bus_get_device(handle, &dummy_device);
+ if (ACPI_FAILURE(status))
+ return AE_OK;
+
pci_bus = parent_context->pci_bus;
user_function = parent_context->user_function;

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