x86: Fix boot on Twinhead H12Y

commit 80b3e557 upstream.

Despite lots of investigation into why this is needed we don't
know or have an elegant cure. The only answer found on this
laptop is to mark a problem region as used so that Linux doesn't
put anything there.

Currently all the users add reserve= command lines and anyone
not knowing this needs to find the magic page that documents it.
Automate it instead.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Tested-and-bugfixed-by: Arne Fitzenreiter <arne@fitzenreiter.de>
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=10231
Link: http://lkml.kernel.org/r/20120515174347.5109.94551.stgit@bluebookSigned-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/x86/pci/fixup.c

@@ -521,3 +521,20 @@ static void sb600_disable_hpet_bar(struct pci_dev *dev)
 	}
 }
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_ATI, 0x4385, sb600_disable_hpet_bar);
+
+/*
+ * Twinhead H12Y needs us to block out a region otherwise we map devices
+ * there and any access kills the box.
+ *
+ *   See: https://bugzilla.kernel.org/show_bug.cgi?id=10231
+ *
+ * Match off the LPC and svid/sdid (older kernels lose the bridge subvendor)
+ */
+static void __devinit twinhead_reserve_killing_zone(struct pci_dev *dev)
+{
+        if (dev->subsystem_vendor == 0x14FF && dev->subsystem_device == 0xA003) {
+                pr_info("Reserving memory on Twinhead H12Y\n");
+                request_mem_region(0xFFB00000, 0x100000, "twinhead");
+        }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x27B9, twinhead_reserve_killing_zone);