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ACPI / hotplug / PCI: Allow slots without new devices to be rescanned

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Currently, enable_device() checks the return value of pci_scan_slot()
and returns immediately if that's 0 (meaning that no new functions
have been found in the slot).  However, if one of the functions in
the slot is a bridge, some new devices may appear below it even if
the bridge itself is present continuously, so it generally is
necessary to do the rescan anyway just in case.  [In particular,
that's necessary with the Thunderbolt daisy chaining in which case
new devices may be connected to the existing ones down the chain.]

The correctness of this change relies on the ability of
pcibios_resource_survey_bus() to detect if it has already been called
for the given bus and to skip it if so.  Failure to do that will lead
to resource allocation conflicts.

[rjw: Changelog]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Kirill A. Shutemov 2013-07-13 23:27:26 +02:00 committed by Rafael J. Wysocki
parent 55502ddb2d
commit b91182a67c
1 changed files with 2 additions and 9 deletions
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11
drivers/pci/hotplug/acpiphp_glue.c
View file

@ -542,18 +542,13 @@ static int __ref enable_device(struct acpiphp_slot *slot)
struct pci_dev *dev; struct pci_dev *dev;
struct pci_bus *bus = slot->bus; struct pci_bus *bus = slot->bus;
struct acpiphp_func *func; struct acpiphp_func *func;
int num, max, pass; int max, pass;
LIST_HEAD(add_list); LIST_HEAD(add_list);
list_for_each_entry(func, &slot->funcs, sibling) list_for_each_entry(func, &slot->funcs, sibling)
acpiphp_bus_add(func_to_handle(func)); acpiphp_bus_add(func_to_handle(func));
num = pci_scan_slot(bus, PCI_DEVFN(slot->device, 0)); pci_scan_slot(bus, PCI_DEVFN(slot->device, 0));
if (num == 0) {
/* Maybe only part of funcs are added. */
dbg("No new device found\n");
goto err_exit;
}
max = acpiphp_max_busnr(bus); max = acpiphp_max_busnr(bus);
for (pass = 0; pass < 2; pass++) { for (pass = 0; pass < 2; pass++) {
@ -599,8 +594,6 @@ static int __ref enable_device(struct acpiphp_slot *slot)
} }
} }
err_exit:
return 0; return 0;
} }