ACPI: tables: complete searching upon RSDP w/ bad checksum.

ACPI tables follow a tree structure in memory.
The root of the tree is the RSDP (Root System Description Pointer).

To find the RSDP, the OS searches for the signature "RSD PTR "
in well known physical memory locations.  Then the OS computes
a table checksum to verify that the signature is really part
of a valid table header.

Some systems have a proper signature but an invalid checksum;
followed elsewhere by a proper signature with valid checksum.

http://bugzilla.kernel.org/show_bug.cgi?id=9444

The Linux RSDP scanning code bailed out on those systems
and as a result they booted with ACPI disabled.

Fix this by deleting the Linux RSDP scanning code and
plugging in the ACPICA RSDP scanning code.

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index aabc6ca4a81c..101691ef66cb 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -207,8 +207,12 @@ acpi_physical_address __init acpi_os_get_root_pointer(void)
                                "System description tables not found\n");
                         return 0;
                 }
-        } else
-                return acpi_find_rsdp();
+        } else {
+                acpi_physical_address pa = 0;
+
+                acpi_find_root_pointer(&pa);
+                return pa;
+        }
 }
 
 void __iomem *acpi_os_map_memory(acpi_physical_address phys, acpi_size size)