diff options
Diffstat (limited to 'drivers/pci/Kconfig')
| -rw-r--r-- | drivers/pci/Kconfig | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 438a792d2cf7..0c473d75e625 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -190,6 +190,68 @@ config PCI_HYPERV The PCI device frontend driver allows the kernel to import arbitrary PCI devices from a PCI backend to support PCI driver domains. +choice + prompt "PCI Express hierarchy optimization setting" + default PCIE_BUS_DEFAULT + depends on PCI && EXPERT + help + MPS (Max Payload Size) and MRRS (Max Read Request Size) are PCIe + device parameters that affect performance and the ability to + support hotplug and peer-to-peer DMA. + + The following choices set the MPS and MRRS optimization strategy + at compile-time. The choices are the same as those offered for + the kernel command-line parameter 'pci', i.e., + 'pci=pcie_bus_tune_off', 'pci=pcie_bus_safe', + 'pci=pcie_bus_perf', and 'pci=pcie_bus_peer2peer'. + + This is a compile-time setting and can be overridden by the above + command-line parameters. If unsure, choose PCIE_BUS_DEFAULT. + +config PCIE_BUS_TUNE_OFF + bool "Tune Off" + depends on PCI + help + Use the BIOS defaults; don't touch MPS at all. This is the same + as booting with 'pci=pcie_bus_tune_off'. + +config PCIE_BUS_DEFAULT + bool "Default" + depends on PCI + help + Default choice; ensure that the MPS matches upstream bridge. + +config PCIE_BUS_SAFE + bool "Safe" + depends on PCI + help + Use largest MPS that boot-time devices support. If you have a + closed system with no possibility of adding new devices, this + will use the largest MPS that's supported by all devices. This + is the same as booting with 'pci=pcie_bus_safe'. + +config PCIE_BUS_PERFORMANCE + bool "Performance" + depends on PCI + help + Use MPS and MRRS for best performance. Ensure that a given + device's MPS is no larger than its parent MPS, which allows us to + keep all switches/bridges to the max MPS supported by their + parent. This is the same as booting with 'pci=pcie_bus_perf'. + +config PCIE_BUS_PEER2PEER + bool "Peer2peer" + depends on PCI + help + Set MPS = 128 for all devices. MPS configuration effected by the + other options could cause the MPS on one root port to be + different than that of the MPS on another, which may cause + hot-added devices or peer-to-peer DMA to fail. Set MPS to the + smallest possible value (128B) system-wide to avoid these issues. + This is the same as booting with 'pci=pcie_bus_peer2peer'. + +endchoice + source "drivers/pci/hotplug/Kconfig" source "drivers/pci/controller/Kconfig" source "drivers/pci/endpoint/Kconfig" |