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>

3 files changed, 8 insertions, 6 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)
diff --git a/drivers/acpi/tables/Makefile b/drivers/acpi/tables/Makefile
index 0a7d7afac255..7385efa61622 100644
--- a/drivers/acpi/tables/Makefile
+++ b/drivers/acpi/tables/Makefile
@@ -2,6 +2,6 @@
 # Makefile for all Linux ACPI interpreter subdirectories
 #
 
-obj-y := tbxface.o tbinstal.o  tbutils.o tbfind.o tbfadt.o
+obj-y := tbxface.o tbinstal.o tbutils.o tbfind.o tbfadt.o tbxfroot.o
 
 EXTRA_CFLAGS += $(ACPI_CFLAGS)
diff --git a/drivers/acpi/tables/tbxfroot.c b/drivers/acpi/tables/tbxfroot.c
index cf8fa514189f..9ecb4b6c1e7d 100644
--- a/drivers/acpi/tables/tbxfroot.c
+++ b/drivers/acpi/tables/tbxfroot.c
@@ -100,7 +100,7 @@ static acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp)
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_tb_find_rsdp
+ * FUNCTION:    acpi_find_root_pointer
  *
  * PARAMETERS:  table_address           - Where the table pointer is returned
  *
@@ -219,8 +219,6 @@ acpi_status acpi_find_root_pointer(acpi_native_uint * table_address)
         return_ACPI_STATUS(AE_NOT_FOUND);
 }
 
-ACPI_EXPORT_SYMBOL(acpi_find_root_pointer)
-
 /*******************************************************************************
  *
  * FUNCTION:    acpi_tb_scan_memory_for_rsdp