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authorBjorn Helgaas <bjorn.helgaas@hp.com>2010-02-23 10:24:41 -0700
committerJesse Barnes <jbarnes@virtuousgeek.org>2010-02-23 09:43:42 -0800
commit7bc5e3f2be32ae6fb0c74cd0f707f986b3a01a26 (patch)
tree25db7dccd13f5826a91389c25810425ce36ba2d4 /Documentation/kernel-parameters.txt
parent2fe2abf896c1e7a0ee65faaf3ef0ce654848abbd (diff)
x86/PCI: use host bridge _CRS info by default on 2008 and newer machines
The main benefit of using ACPI host bridge window information is that we can do better resource allocation in systems with multiple host bridges, e.g., http://bugzilla.kernel.org/show_bug.cgi?id=14183 Sometimes we need _CRS information even if we only have one host bridge, e.g., https://bugs.launchpad.net/ubuntu/+source/linux/+bug/341681 Most of these systems are relatively new, so this patch turns on "pci=use_crs" only on machines with a BIOS date of 2008 or newer. Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt8
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 516225a864f..3e69c1c4f50 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1948,8 +1948,12 @@ and is between 256 and 4096 characters. It is defined in the file
IRQ routing is enabled.
noacpi [X86] Do not use ACPI for IRQ routing
or for PCI scanning.
- use_crs [X86] Use _CRS for PCI resource
- allocation.
+ use_crs [X86] Use PCI host bridge window information
+ from ACPI. On BIOSes from 2008 or later, this
+ is enabled by default. If you need to use this,
+ please report a bug.
+ nocrs [X86] Ignore PCI host bridge windows from ACPI.
+ If you need to use this, please report a bug.
routeirq Do IRQ routing for all PCI devices.
This is normally done in pci_enable_device(),
so this option is a temporary workaround