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Subject[Bugfix v5] x86/PCI/ACPI: Fix regression caused by commit 63f1789ec716
Date
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. 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.

But the ACPI and PCI Firmware specifications haven't provided a method
to tell whether a resource is consumed by the host bridge itself.
So before commit 593669c2ac0f ("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 593669c2ac0f ("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 63f1789ec716 ("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.

So revert to the behavior before v3.19 to fix the regression.

There is also a discussion about ignoring the Producer/Consumer flag on
IA64 platforms at:
http://patchwork.ozlabs.org/patch/461633/

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

Fixes: 63f1789ec716("Ignore resources consumed by host bridge itself")
Reported-by: Bernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
arch/x86/pci/acpi.c | 25 ++++++++++++++++++++++---
drivers/acpi/resource.c | 6 +++++-
2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index e4695985f9de..fc2da98985c3 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -332,12 +332,32 @@ static void probe_pci_root_info(struct pci_root_info *info,
{
int ret;
struct resource_entry *entry, *tmp;
+ unsigned long res_flags;

sprintf(info->name, "PCI Bus %04x:%02x", domain, busnum);
info->bridge = device;
+
+ /*
+ * An IO or MMIO resource assigned to PCI host bridge may be consumed
+ * by the host bridge itself or available to its child bus/devices.
+ * On x86 and IA64 platforms, all IO and MMIO resources are assumed to
+ * be available to child bus/devices except one special case:
+ * IO port [0xCF8-0xCFF] is consumed by host bridge itself to
+ * access PCI configuration space.
+ *
+ * Due to lack of specification to define resources consumed by host
+ * bridge itself, all IO port resources defined by acpi_resource_io
+ * and acpi_resource_fixed_io are ignored to filter out IO
+ * port[0xCF8-0xCFF]. Seems this solution works with all BIOSes, though
+ * it's not perfect.
+ *
+ * Another possible solution is to explicitly filter out IO
+ * port[0xCF8-0xCFF].
+ */
+ res_flags = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_IO_FIXED;
ret = acpi_dev_get_resources(device, list,
acpi_dev_filter_resource_type_cb,
- (void *)(IORESOURCE_IO | IORESOURCE_MEM));
+ (void *)res_flags);
if (ret < 0)
dev_warn(&device->dev,
"failed to parse _CRS method, error code %d\n", ret);
@@ -346,8 +366,7 @@ static void probe_pci_root_info(struct pci_root_info *info,
"no IO and memory resources present in _CRS\n");
else
resource_list_for_each_entry_safe(entry, tmp, list) {
- if ((entry->res->flags & IORESOURCE_WINDOW) == 0 ||
- (entry->res->flags & IORESOURCE_DISABLED))
+ if (entry->res->flags & IORESOURCE_DISABLED)
resource_list_destroy_entry(entry);
else
entry->res->name = info->name;
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 5589a6e2a023..79b6d3b5ffd2 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -575,6 +575,9 @@ EXPORT_SYMBOL_GPL(acpi_dev_get_resources);
*
* This is a hepler function to support acpi_dev_get_resources(), which filters
* ACPI resource objects according to resource types.
+ *
+ * Flag IORESOURCE_IO_FIXED is used to opt out io and fixed_io resource
+ * descriptors for ACPI host bridges on x86 and IA64 platforms.
*/
int acpi_dev_filter_resource_type(struct acpi_resource *ares,
unsigned long types)
@@ -589,7 +592,8 @@ int acpi_dev_filter_resource_type(struct acpi_resource *ares,
break;
case ACPI_RESOURCE_TYPE_IO:
case ACPI_RESOURCE_TYPE_FIXED_IO:
- type = IORESOURCE_IO;
+ if ((types & IORESOURCE_IO_FIXED) == 0)
+ type = IORESOURCE_IO;
break;
case ACPI_RESOURCE_TYPE_IRQ:
case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
--
1.7.10.4


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