linux-kernel - [PATCH 1/1] ia64/pci: set mmio decoding on for some host bridge

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Date:	Mon,  8 Jul 2013 08:16:53 +0800
From:	"Li, Zhen-Hua" <zhen-hual@...com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>, <linux-pci@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Cc:	"Li, Zhen-Hua" <zhen-hual@...com>
Subject: [PATCH 1/1] ia64/pci: set mmio decoding on for some host bridge

On some IA64 platforms with intel PCI bridge, for example, HP BL890c i2 
with  Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port,
when kernel tries to disable the mmio decoding on the PCI bridge devices,
kernel may crash. 

And in the comment of function quirk_mmio_always_on, it also says:
"But doing so (disable the mmio decoding) may cause problems on host bridge
 and perhaps other key system devices"

So, for these PCI bridges,  dev->mmio_always_on bit should be set to 1.


Signed-off-by: Li, Zhen-Hua <zhen-hual@...com>
---
 drivers/pci/quirks.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index e85d230..24b8024 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -44,6 +44,21 @@ static void quirk_mmio_always_on(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID,
 				PCI_CLASS_BRIDGE_HOST, 8, quirk_mmio_always_on);
 
+#ifdef CONFIG_IA64
+/*
+ * On some IA64 platforms, for some intel PCI bridge devices, for example,
+ * the Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port,
+ * disable the mmio decoding on these devices may cause system crash.
+ * So dev->mmio_always_on bit should be set to 1.
+ */
+static void quirk_mmio_on_intel_pcibridge(struct pci_dev *dev)
+{
+	dev->mmio_always_on = 1;
+}
+DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_ANY_ID, PCI_ANY_ID,
+			PCI_CLASS_BRIDGE_PCI, 8, quirk_mmio_on_intel_pcibridge);
+#endif
+
 /* The Mellanox Tavor device gives false positive parity errors
  * Mark this device with a broken_parity_status, to allow
  * PCI scanning code to "skip" this now blacklisted device.
-- 
1.7.10.4

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