From: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date: Tue, 6 Apr 2010 19:24:08 +0000 (-0600)
Subject: x86/PCI: ignore Consumer/Producer bit in ACPI window descriptions
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=73a0e614580fb650846be1e9315f6b7b6069b9cc;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

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@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index c7b1ebfb7da7..334153ca4c30 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;