From: Greg KH on
2.6.34-stable review patch. If anyone has any objections, please let us know.


From: Bjorn Helgaas <bjorn.helgaas(a)>

commit 2491762cfb475dbdfa3db11ebea6de49f58b7fac upstream.

This DMI quirk turns on "pci=use_crs" for the ALiveSATA2-GLAN because
amd_bus.c doesn't handle this system correctly.

The system has a single HyperTransport I/O chain, but has two PCI host
bridges to buses 00 and 80. amd_bus.c learns the MMIO range associated
with buses 00-ff and that this range is routed to the HT chain hosted at
node 0, link 0:

bus: [00, ff] on node 0 link 0
bus: 00 index 1 [mem 0x80000000-0xfcffffffff]

This includes the address space for both bus 00 and bus 80, and amd_bus.c
assumes it's all routed to bus 00.

We find device 80:01.0, which BIOS left in the middle of that space, but
we don't find a bridge from bus 00 to bus 80, so we conclude that 80:01.0
is unreachable from bus 00, and we move it from the original, working,
address to something outside the bus 00 aperture, which does not work:

pci 0000:80:01.0: reg 10: [mem 0xfebfc000-0xfebfffff 64bit]
pci 0000:80:01.0: BAR 0: assigned [mem 0xfd00000000-0xfd00003fff 64bit]

The BIOS told us everything we need to know to handle this correctly,
so we're better off if we just pay attention, which lets us leave the
80:01.0 device at the original, working, address:

ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-7f])
pci_root PNP0A03:00: host bridge window [mem 0x80000000-0xff37ffff]
ACPI: PCI Root Bridge [PCI1] (domain 0000 [bus 80-ff])
pci_root PNP0A08:00: host bridge window [mem 0xfebfc000-0xfebfffff]

This was a regression between 2.6.33 and 2.6.34. In 2.6.33, amd_bus.c
was used only when we found multiple HT chains. 3e3da00c01d050, which
enabled amd_bus.c even on systems with a single HT chain, caused this

This quirk was written by Graham. If we ever enable "pci=use_crs" for
machines from 2006 or earlir, this quirk should be removed.


Reported-by: Graham Ramsey <ramsey.graham(a)>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas(a)>
Signed-off-by: Jesse Barnes <jbarnes(a)>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)>

arch/x86/pci/acpi.c | 9 +++++++++
1 file changed, 9 insertions(+)

--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -34,6 +34,15 @@ static const struct dmi_system_id pci_us
+ /* */
+ /* 2006 AMD HT/VIA system with two host bridges */
+ {
+ .callback = set_use_crs,
+ .ident = "ASRock ALiveSATA2-GLAN",
+ .matches = {
+ },
+ },

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