linux-kernel - [PATCH] x86/PCI: ignore Consumer/Producer bit in ACPI window descriptions

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Date:	Tue, 06 Apr 2010 13:24:08 -0600
From:	Bjorn Helgaas <bjorn.helgaas@...com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Thomas Renninger <trenn@...e.de>
Subject: [PATCH] x86/PCI: ignore Consumer/Producer bit in ACPI window
	descriptions


ACPI Address Space Descriptors (used in _CRS) have a Consumer/Producer
bit that is supposed to distinguish regions that are consumed directly
by a device from those that are forwarded ("produced") by a bridge.
But BIOSes have apparently not used this consistently, and Windows
seems to ignore it, so I think Linux should ignore it as well.

I can't point to any of these supposed broken BIOSes, but since we
now rely on _CRS by default, I think it's safer to ignore this bit
from the start.

Here are details of my experiments with how Windows handles it:
    https://bugzilla.kernel.org/show_bug.cgi?id=15701

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@...com>
---

 arch/x86/pci/acpi.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)


diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index c7b1ebf..334153c 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -71,8 +71,7 @@ resource_to_addr(struct acpi_resource *resource,
 	if (ACPI_SUCCESS(status) &&
 	    (addr->resource_type == ACPI_MEMORY_RANGE ||
 	    addr->resource_type == ACPI_IO_RANGE) &&
-	    addr->address_length > 0 &&
-	    addr->producer_consumer == ACPI_PRODUCER) {
+	    addr->address_length > 0) {
 		return AE_OK;
 	}
 	return AE_ERROR;

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