From b0cc6020e1cc62f1253215f189611b34be4a83c7 Mon Sep 17 00:00:00 2001
From: Yijing Wang <wangyijing@huawei.com>
Date: Tue, 15 Jan 2013 11:12:16 +0800
Subject: [PATCH] PCI: Enable ARI if dev and upstream bridge support it;
disable otherwise
Currently, we enable ARI in a device's upstream bridge if the bridge and
the device support it. But we never disable ARI, even if the device is
removed and replaced with a device that doesn't support ARI.
This means that if we hot-remove an ARI device and replace it with a
non-ARI multi-function device, we find only function 0 of the new device
because the upstream bridge still has ARI enabled, and next_ari_fn()
only returns function 0 for the new non-ARI device.
This patch disables ARI in the upstream bridge if the device doesn't
support ARI. See the PCIe spec, r3.0, sec 6.13.
[bhelgaas: changelog, function comment]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/pci.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 5cb5820fae40..8b47f70b7d8f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2069,6 +2069,9 @@ void pci_free_cap_save_buffers(struct pci_dev *dev)
/**
* pci_enable_ari - enable ARI forwarding if hardware support it
* @dev: the PCI device
+ *
+ * If @dev and its upstream bridge both support ARI, enable ARI in the
+ * bridge. Otherwise, disable ARI in the bridge.
*/
void pci_enable_ari(struct pci_dev *dev)
{
@@ -2078,9 +2081,6 @@ void pci_enable_ari(struct pci_dev *dev)
if (pcie_ari_disabled || !pci_is_pcie(dev) || dev->devfn)
return;
- if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI))
- return;
-
bridge = dev->bus->self;
if (!bridge)
return;
@@ -2089,8 +2089,15 @@ void pci_enable_ari(struct pci_dev *dev)
if (!(cap & PCI_EXP_DEVCAP2_ARI))
return;
- pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2, PCI_EXP_DEVCTL2_ARI);
- bridge->ari_enabled = 1;
+ if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI)) {
+ pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_ARI);
+ bridge->ari_enabled = 1;
+ } else {
+ pcie_capability_clear_word(bridge, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_ARI);
+ bridge->ari_enabled = 0;
+ }
}
/**