Merge branch 'linus' into perf/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c31310db0404..e6a917b4acd3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1762,6 +1762,48 @@ static void pci_configure_extended_tags(struct pci_dev *dev)
 					 PCI_EXP_DEVCTL_EXT_TAG);
 }
 
+/**
+ * pcie_relaxed_ordering_enabled - Probe for PCIe relaxed ordering enable
+ * @dev: PCI device to query
+ *
+ * Returns true if the device has enabled relaxed ordering attribute.
+ */
+bool pcie_relaxed_ordering_enabled(struct pci_dev *dev)
+{
+	u16 v;
+
+	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &v);
+
+	return !!(v & PCI_EXP_DEVCTL_RELAX_EN);
+}
+EXPORT_SYMBOL(pcie_relaxed_ordering_enabled);
+
+static void pci_configure_relaxed_ordering(struct pci_dev *dev)
+{
+	struct pci_dev *root;
+
+	/* PCI_EXP_DEVICE_RELAX_EN is RsvdP in VFs */
+	if (dev->is_virtfn)
+		return;
+
+	if (!pcie_relaxed_ordering_enabled(dev))
+		return;
+
+	/*
+	 * For now, we only deal with Relaxed Ordering issues with Root
+	 * Ports. Peer-to-Peer DMA is another can of worms.
+	 */
+	root = pci_find_pcie_root_port(dev);
+	if (!root)
+		return;
+
+	if (root->dev_flags & PCI_DEV_FLAGS_NO_RELAXED_ORDERING) {
+		pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
+					   PCI_EXP_DEVCTL_RELAX_EN);
+		dev_info(&dev->dev, "Disable Relaxed Ordering because the Root Port didn't support it\n");
+	}
+}
+
 static void pci_configure_device(struct pci_dev *dev)
 {
 	struct hotplug_params hpp;
@@ -1769,6 +1811,7 @@ static void pci_configure_device(struct pci_dev *dev)
 
 	pci_configure_mps(dev);
 	pci_configure_extended_tags(dev);
+	pci_configure_relaxed_ordering(dev);
 
 	memset(&hpp, 0, sizeof(hpp));
 	ret = pci_get_hp_params(dev, &hpp);