[PATCH 2/3] PCI: correctly detect ACPI PCI host bridge objects

From: Yinghai Lu
Date: Thu Oct 18 2012 - 16:55:47 EST


From: Jiang Liu <jiang.liu@xxxxxxxxxx>

The code in pci_root_hp.c depends on function acpi_is_root_bridge()
to check whether an ACPI object is a PCI host bridge or not.
If an ACPI device hasn't been created for the ACPI object yet,
function acpi_is_root_bridge() will return false even if the object
is a PCI host bridge object. That behavior will cause two issues:
1) No ACPI notification handler installed for PCI host bridges absent
at startup, so hotplug events for those bridges won't be handled.
2) rescan_root_bridge() can't reenumerate offlined PCI host bridges
because the ACPI devices have been already destroyed.

So use acpi_match_object_info_ids() to correctly detect PCI host bridges.

-v2: update to use acpi_match_object_info_ids() from Tang Chen - Yinghai

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
---
drivers/acpi/pci_root_hp.c | 25 ++++++++++++++++++++++++-
1 files changed, 24 insertions(+), 1 deletions(-)

diff --git a/drivers/acpi/pci_root_hp.c b/drivers/acpi/pci_root_hp.c
index 2aebf78..3edec7f 100644
--- a/drivers/acpi/pci_root_hp.c
+++ b/drivers/acpi/pci_root_hp.c
@@ -19,6 +19,12 @@ struct acpi_root_bridge {
u32 flags;
};

+static const struct acpi_device_id root_device_ids[] = {
+ {"PNP0A03", 0},
+ {"PNP0A08", 0},
+ {"", 0},
+};
+
/* bridge flags */
#define ROOT_BRIDGE_HAS_EJ0 (0x00000002)
#define ROOT_BRIDGE_HAS_PS3 (0x00000080)
@@ -256,6 +262,23 @@ static void handle_hotplug_event_root(acpi_handle handle, u32 type,
_handle_hotplug_event_root);
}

+static bool acpi_is_root_bridge_object(acpi_handle handle)
+{
+ struct acpi_device_info *info = NULL;
+ acpi_status status;
+ bool ret;
+
+ status = acpi_get_object_info(handle, &info);
+ if (ACPI_FAILURE(status))
+ return false;
+
+ ret = !acpi_match_object_info_ids(info, root_device_ids);
+
+ kfree(info);
+
+ return ret;
+}
+
static acpi_status __init
find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
@@ -264,7 +287,7 @@ find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
.pointer = objname };
int *count = (int *)context;

- if (!acpi_is_root_bridge(handle))
+ if (!acpi_is_root_bridge_object(handle))
return AE_OK;

(*count)++;
--
1.7.7

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