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[PATCH 1/2] PCI: make pci_claim_resource() work with conflict resources

To: jbarnes@virtuousgeek.org, torvalds@linux-foundation.org
Subject: [PATCH 1/2] PCI: make pci_claim_resource() work with conflict resources as appropriate
From: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Date: Thu, 28 Jul 2011 19:28:31 +0800
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, eyal@mips.com, zenon@mips.com, dengcheng.zhu@gmail.com
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In resolving a network driver issue with the MIPS Malta platform, the root
cause was traced into pci_claim_resource():

MIPS System Controller's PCI I/O resources stay in 0x1000-0xffffff. When
PCI quirks start claiming resources using request_resource_conflict(),
collisions happen and -EBUSY is returned, thereby rendering the onboard AMD
PCnet32 NIC unaware of quirks' region and preventing the NIC from functioning.
For PCI quirks, PIIX4 ACPI is expected to claim 0x1000-0x103f, and PIIX4 SMB to
claim 0x1100-0x110f, both of which fall into the MSC I/O range. Certainly, we
can increase the start point of this range in arch/mips/mti-malta/malta-pci.c to
avoid the collisions. But a fix in here looks more justified, though it seems to
have a wider impact. Using insert_xxx as opposed to request_xxx will register
PCI quirks' resources as children of MSC I/O and return OK, instead of seeing
collisions which are actually resolvable.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 drivers/pci/setup-res.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index bc0e6ee..40d767e 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -102,7 +102,7 @@ int pci_claim_resource(struct pci_dev *dev, int resource)
                return -EINVAL;
        }
 
-       conflict = request_resource_conflict(root, res);
+       conflict = insert_resource_conflict(root, res);
        if (conflict) {
                dev_info(&dev->dev,
                         "address space collision: %pR conflicts with %s %pR\n",
-- 
1.7.1


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