Re: [PATCH v2 0/7] PCI: try "pci=use_crs" again

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Mon, 08 Feb 2010 15:44:18 -0700
Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:

> Historically, Linux has assumed a single PCI host bridge, with that
> bridge claiming all the address space left after RAM and legacy
> devices are taken out.
> 
> If the system contains multiple host bridges, we can no longer
> operate under that assumption.  We have to know what parts of the
> address space are claimed by each bridge so that when we assign
> resources to a PCI device, we take them from a range claimed by the
> upstream host bridge.
> 
> We use ACPI to enumerate all the PCI host bridges in the system, and
> part of the host bridge description is the "_CRS" (current resource
> settings" property, which lists the address space used by the
> bridge.  On x86, we currently ignore most of the _CRS information.
> This patch series changes this, so we will use _CRS to learn about
> the host bridge windows.
> 
> Since most x86 machines with multiple host bridges are relatively
> new, this series only turns this on for machines with BIOS dates of
> 2010 or newer and for a few machines we know to require it.
> 
> These apply on be6e9f7853e.  I added an initial patch to clean up the
> formatting of the disabled window printk.
> 
> Changes since v1:
>     - rebase to be6e9f7853e
>     - add patch to clean up "disabled window" printk
>     - add bugzilla reference comment in use_crs DMI quirk

A 2010 default is probably too conservative, but we can always add a
whitelist or change the default later.  Applied the series to my
linux-next branch, thanks.

-- 
Jesse Barnes, Intel Open Source Technology Center