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Commit 2c62e849 authored by Jiang Liu's avatar Jiang Liu Committed by Rafael J. Wysocki
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x86/PCI/ACPI: Make all resources except [io 0xcf8-0xcff] available on PCI bus

An IO port or MMIO resource assigned to a PCI host bridge may be
consumed by the host bridge itself or available to its child
bus/devices. The ACPI specification defines a bit (Producer/Consumer)
to tell whether the resource is consumed by the host bridge itself,
but firmware hasn't used that bit consistently, so we can't rely on it.

Before commit 593669c2 ("x86/PCI/ACPI: Use common ACPI resource
interfaces to simplify implementation"), arch/x86/pci/acpi.c ignored
all IO port resources defined by acpi_resource_io and
acpi_resource_fixed_io to filter out IO ports consumed by the host
bridge itself.

Commit 593669c2 ("x86/PCI/ACPI: Use common ACPI resource interfaces
to simplify implementation") started accepting all IO port and MMIO
resources, which caused a regression that IO port resources consumed
by the host bridge itself became available to its child devices.

Then commit 63f1789e ("x86/PCI/ACPI: Ignore resources consumed by
host bridge itself") ignored resources consumed by the host bridge
itself by checking the IORESOURCE_WINDOW flag, which accidently removed
MMIO resources defined by acpi_resource_memory24, acpi_resource_memory32
and acpi_resource_fixed_memory32.

On x86 and IA64 platforms, all IO port and MMIO resources are assumed
to be available to child bus/devices except one special case:
    IO port [0xCF8-0xCFF] is consumed by the host bridge itself
    to access PCI configuration space.

So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF]. This solution
will also ease the way to consolidate ACPI PCI host bridge common code
from x86, ia64 and ARM64.

Related ACPI table are archived at:
https://bugzilla.kernel.org/show_bug.cgi?id=94221

Related discussions at:
http://patchwork.ozlabs.org/patch/461633/
https://lkml.org/lkml/2015/3/29/304

Fixes: 63f1789e

 (Ignore resources consumed by host bridge itself)
Reported-by: default avatarBernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
Reviewed-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent b787f68c
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