Re: [PATCH PING] Fix coalescing of host bridge windows in arch/x86/pci/acpi.c

[Peter Hurley]

[ +cc Bjorn Helgaas, Rafael Wysocki, linux-acpi ]

On 09/16/2013 12:41 PM, Alexey Neyman wrote:
> Hi all,
>
> Could anybody review/commit the patch?

LKML is a pretty general list and maintainers don't typically
trawl the list for more work to do. The get_maintainer script
can be used to help determine to whom to address a patch.

peter@thor:~/src/kernels/next$ ./scripts/get_maintainer.pl -f arch/x86/pci/acpi.c
Thomas Gleixner <tglx@xxxxxxxxxxxxx> (maintainer:X86 ARCHITECTURE...)
Ingo Molnar <mingo@xxxxxxxxxx> (maintainer:X86 ARCHITECTURE...)
"H. Peter Anvin" <hpa@xxxxxxxxx> (maintainer:X86 ARCHITECTURE...)
x86@xxxxxxxxxx (maintainer:X86 ARCHITECTURE...)
Bjorn Helgaas <bhelgaas@xxxxxxxxxx> (commit_signer:5/8=62%)
"Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> (commit_signer:3/8=38%)
Feng Tang <feng.tang@xxxxxxxxx> (commit_signer:1/8=12%)
Yijing Wang <wangyijing@xxxxxxxxxx> (commit_signer:1/8=12%)
Mike Yoknis <mike.yoknis@xxxxxx> (commit_signer:1/8=12%)
linux-kernel@xxxxxxxxxxxxxxx (open list)

Regards,
Peter Hurley

PS - You'll want to inline your patch as well because as you can see
replies don't include it.

> Regards,
> Alexey.
>
> On Thursday, September 12, 2013 05:19:16 pm Alexey Neyman wrote:
> > Hi all,
> >
> > I have a board with a BIOS bug that reports the following I/O port regions
> > in _CRS on one of the host bridges:
> >
> > 0x0000-0x03af // #0
> > 0x03e0-0x0cf7 // #1
> > 0x03b0-0x03bb // #2
> > 0x03c0-0x03df // #3
> > 0x0000-0xdfff // #4
> > 0xf000-0xffff // #5
> >
> > Obviously, region number #4 is erroneous as it overlaps with regions #0..3.
> > However, code in coalesce_windows() in arch/x86/pci/acpi.c attempts to
> > recover from such kind of BIOS bugs by merging the overlapping regions.
> > Current code expands region #0 to 0x0000-0xdffff and makes region #4
> > ignored. As a result, overlap of the expanded region #0 with regions #1..3
> > remains undetected. As a result, regions #1..3 are inserted into the
> > resource tree as if they were consumers of the 0x0000-0xdfff regions, and
> > devices that have resources in one of these regions (e.g. 0x3f6 for legacy
> > IDE) have a resource conflict - the kernel does not initialize them.
> >
> > The attached patch makes the code in coalesce_windows() instead ignore res1
> > (which is already dealt with), possibly expanding res2 instead. As res2 has
> > not been reached in the outer loop in coalesce_windows(), the code will
> > then check for overlaps of the just-expanded resource with the rest of the
> > resources.
> >
> > Regards,
> > Alexey.

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