PCI: Update "pci=resource_alignment" documentation
Some uio based PCI drivers, e.g., uio_cif, do not work if the assigned PCI
memory resources are not page aligned. By using the kernel option
"pci=resource_alignment=<align>@<bus>:<slot>.<func>" it is possible to
request page alignment for memory resources of devices.
However, this is cumbersome when using several devices, and the
bus/slot/func addresses may change if devices are added to or removed from
the system.
Extend the "pci=resource_alignment" option so we can specify the relevant
devices via PCI vendor, device, subvendor, and subdevice IDs. The
specification of the devices via IDs is indicated by a leading string
"pci:" as argument to "pci=resource_alignment".
The format of the specification is
pci:<vendor>:<device>[:<subvendor>:<subdevice>]
Examples:
pci=resource_alignment=4096@pci:8086:9c22:103c:198f
pci=resource_alignment=pci:8086:9c22 # defaults to PAGE_SIZE align
[bhelgaas: changelog, use actual vendor/device IDs in examples]
Signed-off-by: Mathias Koehrer <mathias.koehrer@etas.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 46c030a..a4f4d69 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3032,6 +3032,10 @@
PAGE_SIZE is used as alignment.
PCI-PCI bridge can be specified, if resource
windows need to be expanded.
+ To specify the alignment for several
+ instances of a device, the PCI vendor,
+ device, subvendor, and subdevice may be
+ specified, e.g., 4096@pci:8086:9c22:103c:198f
ecrc= Enable/disable PCIe ECRC (transaction layer
end-to-end CRC checking).
bios: Use BIOS/firmware settings. This is the