5 files changed, 56 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/acglobal.h b/drivers/acpi/acpica/acglobal.h
index a419fe98a5fc..e3813d290b4f 100644
--- a/drivers/acpi/acpica/acglobal.h
+++ b/drivers/acpi/acpica/acglobal.h
@@ -117,6 +117,14 @@ u8 ACPI_INIT_GLOBAL(acpi_gbl_use_default_register_widths, TRUE);
  */
 u8 ACPI_INIT_GLOBAL(acpi_gbl_enable_aml_debug_object, FALSE);
 
+/*
+ * Optionally copy the entire DSDT to local memory (instead of simply
+ * mapping it.) There are some BIOSs that corrupt or replace the original
+ * DSDT, creating the need for this option. Default is FALSE, do not copy
+ * the DSDT.
+ */
+u8 ACPI_INIT_GLOBAL(acpi_gbl_copy_dsdt_locally, FALSE);
+
 /* acpi_gbl_FADT is a local copy of the FADT, converted to a common format. */
 
 struct acpi_table_fadt acpi_gbl_FADT;
diff --git a/drivers/acpi/acpica/actables.h b/drivers/acpi/acpica/actables.h
index fc52b6f2d69c..b7197bf4af0b 100644
--- a/drivers/acpi/acpica/actables.h
+++ b/drivers/acpi/acpica/actables.h
@@ -109,6 +109,8 @@ acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length);
 
 void acpi_tb_check_dsdt_header(void);
 
+void acpi_tb_copy_dsdt(struct acpi_table_desc *table_desc);
+
 void
 acpi_tb_install_table(acpi_physical_address address,
 		      char *signature, u32 table_index);
diff --git a/drivers/acpi/acpica/psxface.c b/drivers/acpi/acpica/psxface.c
index 67e7ad517051..c42f067cff9d 100644
--- a/drivers/acpi/acpica/psxface.c
+++ b/drivers/acpi/acpica/psxface.c
@@ -46,6 +46,7 @@
 #include "acparser.h"
 #include "acdispat.h"
 #include "acinterp.h"
+#include "actables.h"
 #include "amlcode.h"
 
 #define _COMPONENT          ACPI_PARSER
diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
index 07bc7437f82b..1efb0940e8b2 100644
--- a/drivers/acpi/acpica/tbutils.c
+++ b/drivers/acpi/acpica/tbutils.c
@@ -387,6 +387,41 @@ void acpi_tb_check_dsdt_header(void)
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_tb_copy_dsdt
+ *
+ * PARAMETERS:  table_desc          - Installed table to copy
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
+ *              Some very bad BIOSs are known to either corrupt the DSDT or
+ *              install a new, bad DSDT. This copy works around the problem.
+ *
+ ******************************************************************************/
+
+void acpi_tb_copy_dsdt(struct acpi_table_desc *table_desc)
+{
+	struct acpi_table_header *new_table;
+
+	new_table = ACPI_ALLOCATE(table_desc->length);
+	if (!new_table) {
+		ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
+			    table_desc->length));
+		return;
+	}
+
+	ACPI_MEMCPY(new_table, table_desc->pointer, table_desc->length);
+	acpi_tb_delete_table(table_desc);
+	table_desc->pointer = new_table;
+	table_desc->flags = ACPI_TABLE_ORIGIN_ALLOCATED;
+
+	ACPI_INFO((AE_INFO,
+		   "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
+		   new_table->length));
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_tb_install_table
  *
  * PARAMETERS:  Address                 - Physical address of DSDT or FACS
diff --git a/drivers/acpi/acpica/tbxface.c b/drivers/acpi/acpica/tbxface.c
index 30565100b94c..f5378fc302b3 100644
--- a/drivers/acpi/acpica/tbxface.c
+++ b/drivers/acpi/acpica/tbxface.c
@@ -532,6 +532,16 @@ static acpi_status acpi_tb_load_namespace(void)
 	}
 
 	/*
+	 * Optionally copy the entire DSDT to local memory (instead of simply
+	 * mapping it.) There are some BIOSs that corrupt or replace the original
+	 * DSDT, creating the need for this option. Default is FALSE, do not copy
+	 * the DSDT.
+	 */
+	if (acpi_gbl_copy_dsdt_locally) {
+		acpi_tb_copy_dsdt(acpi_gbl_DSDT);
+	}
+
+	/*
 	 * Save the original DSDT header for detection of table corruption
 	 * and/or replacement of the DSDT from outside the OS.
 	 */