From b0cc6020e1cc62f1253215f189611b34be4a83c7 Mon Sep 17 00:00:00 2001 From: Yijing Wang 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 Signed-off-by: Jiang Liu Signed-off-by: Bjorn Helgaas --- 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; + } } /** -- 2.34.1