[PATCH 2/6] PCI: acpiphp: enable_device(): rescan even if no new devices on slot

From: Mika Westerberg
Date: Tue Jun 25 2013 - 12:21:24 EST


From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>

pci_scan_slot() returns number of new devices connected *directly*
connected to the slot. Current enable_device() checks the return value
and stops if it doesn't see a new device.

In Thunderbolt chaining case the new device can be deeper in hierarchy, so
do the rescan anyway.

Because of that we must make sure that pcibios_resource_survey_bus() and
check_hotplug_bridge() get called only for a just found bus and not the
ones already added to the system. Failure to do so will lead to resource
conflicts.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/pci/hotplug/acpiphp_glue.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index b983e29..80a6ea1 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -685,18 +685,13 @@ static int __ref enable_device(struct acpiphp_slot *slot)
struct pci_dev *dev;
struct pci_bus *bus = slot->bridge->pci_bus;
struct acpiphp_func *func;
- int num, max, pass;
+ int max, pass;
LIST_HEAD(add_list);

list_for_each_entry(func, &slot->funcs, sibling)
acpiphp_bus_add(func);

- num = 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;
- }
+ pci_scan_slot(bus, PCI_DEVFN(slot->device, 0));

max = acpiphp_max_busnr(bus);
for (pass = 0; pass < 2; pass++) {
@@ -707,8 +702,11 @@ static int __ref enable_device(struct acpiphp_slot *slot)
dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
max = pci_scan_bridge(bus, dev, max, pass);
if (pass && dev->subordinate) {
- check_hotplug_bridge(slot, dev);
- pcibios_resource_survey_bus(dev->subordinate);
+ if (!dev->subordinate->is_added) {
+ check_hotplug_bridge(slot, dev);
+ pcibios_resource_survey_bus(
+ dev->subordinate);
+ }
__pci_bus_size_bridges(dev->subordinate,
&add_list);
}
@@ -742,8 +740,6 @@ static int __ref enable_device(struct acpiphp_slot *slot)
}
}

-
- err_exit:
return 0;
}

--
1.8.3.1

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