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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>
This commit is contained in:
Yijing Wang 2013-01-15 11:12:16 +08:00 committed by Bjorn Helgaas
parent d1c3ed669a
commit b0cc6020e1
1 changed files with 12 additions and 5 deletions
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17
drivers/pci/pci.c
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@ -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;
}
}
/**