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Subject[PATCH v2] PCI: Document PCIE BUS MPS parameters
Date
v0->v1: Update MPS parameters as non-arch and add MRRS
description into pcie_bus_perf parameter suggested
by Andrew Murray.
v1->v2: Update some semantic problems and add MPS and MRRS
explanation suggested by Joe Lawrence and Randy Dunlap.

Document PCIE BUS MPS parameters pcie_bus_tune_off, pcie_bus_safe,
pcie_bus_peer2peer, pcie_bus_perf into Documentation/kernel-parameters.txt.
These parameters were introduced by Jon Mason <mason@myri.com> at
commit 5f39e6705 and commit b03e7495a8.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
Documentation/kernel-parameters.txt | 16 ++++++++++++++++
1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 363e348..0bb279f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2227,6 +2227,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
This sorting is done to get a device
order compatible with older (<= 2.4) kernels.
nobfsort Don't sort PCI devices into breadth-first order.
+ pcie_bus_tune_off Disable PCIe MPS (Max Payload Size)
+ turning and using the BIOS-configured MPS defaults.
+ pcie_bus_safe Use the smallest common denominator MPS
+ of the entire tree below a root complex for every
+ device on that fabric. Can avoid inconsistent MPS
+ problem caused by hotplug.
+ pcie_bus_perf Configure pcie device MPS to the largest
+ allowable MPS based on its parent bus. Also set
+ MRRS (Max Read Request Size) to the largest supported
+ value (no larger than the MPS that the device or bus
+ can support) for Max performance.
+ pcie_bus_peer2peer Make the system-wide MPS the smallest
+ possible value (128B). This configuration could prevent
+ peer to peer DMA transmission from working by having
+ the MPS on one root port different than the MPS on
+ another.
cbiosize=nn[KMG] The fixed amount of bus space which is
reserved for the CardBus bridge's IO window.
The default value is 256 bytes.
--
1.7.1



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