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path: root/drivers/pci/probe.c
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Diffstat (limited to 'drivers/pci/probe.c')
-rw-r--r--drivers/pci/probe.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b1187ff31d8..6ab6bd3df4b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1351,7 +1351,8 @@ static int pcie_find_smpss(struct pci_dev *dev, void *data)
* will occur as normal.
*/
if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
- dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))
+ (dev->bus->self &&
+ dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)))
*smpss = 0;
if (*smpss > dev->pcie_mpss)
@@ -1457,12 +1458,24 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
*/
void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss)
{
- u8 smpss = mpss;
+ u8 smpss;
if (!pci_is_pcie(bus->self))
return;
+ if (pcie_bus_config == PCIE_BUS_TUNE_OFF)
+ return;
+
+ /* FIXME - Peer to peer DMA is possible, though the endpoint would need
+ * to be aware to the MPS of the destination. To work around this,
+ * simply force the MPS of the entire system to the smallest possible.
+ */
+ if (pcie_bus_config == PCIE_BUS_PEER2PEER)
+ smpss = 0;
+
if (pcie_bus_config == PCIE_BUS_SAFE) {
+ smpss = mpss;
+
pcie_find_smpss(bus->self, &smpss);
pci_walk_bus(bus, pcie_find_smpss, &smpss);
}