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Commit d558b483 authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Jesse Barnes
Browse files

x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1 

Yanko's GA-MA78GM-S2H (BIOS F11) reports the following resource in a PCI
host bridge _CRS:

    [07] 32-Bit DWORD Address Space Resource
         Min Relocatability : MinFixed
         Max Relocatability : MaxFixed
            Address Minimum : CFF00000  (_MIN)
            Address Maximum : FEBFFFFF  (_MAX)
             Address Length : 3EE10000  (_LEN)

This is invalid per spec (ACPI 4.0, 6.4.3.5) because it's a fixed size,
fixed location descriptor, but _LEN != _MAX - _MIN + 1.

Based on https://bugzilla.kernel.org/show_bug.cgi?id=15480#c15, I think
Windows handles this by truncating the window so it fits between _MIN and
_MAX.  I also verified this by modifying the SeaBIOS DSDT and booting
Windows 2008 R2 with qemu.

This patch makes Linux truncate the window, too, which fixes:
    http://bugzilla.kernel.org/show_bug.cgi?id=15480



Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Tested-by: default avatarYanko Kaneti <yaneti@declera.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent eb9fc8ef

arch/x86/pci/acpi.c

+12 −1
Original line number Diff line number Diff line
@@ -123,7 +123,7 @@ setup_resource(struct acpi_resource *acpi_res, void *data) 
	acpi_status status;

	unsigned long flags;

	struct resource *root, *conflict;

	u64 start, end;

	u64 start, end, max_len;



	status = resource_to_addr(acpi_res, &addr);

	if (!ACPI_SUCCESS(status))
@@ -140,6 +140,17 @@ setup_resource(struct acpi_resource *acpi_res, void *data) 
	} else

		return AE_OK;



	max_len = addr.maximum - addr.minimum + 1;

	if (addr.address_length > max_len) {

		dev_printk(KERN_DEBUG, &info->bridge->dev,

			   "host bridge window length %#llx doesn't fit in "

			   "%#llx-%#llx, trimming\n",

			   (unsigned long long) addr.address_length,

			   (unsigned long long) addr.minimum,

			   (unsigned long long) addr.maximum);

		addr.address_length = max_len;

	}



	start = addr.minimum + addr.translation_offset;

	end = start + addr.address_length - 1;