1 files changed, 32 insertions, 2 deletions

diff --git a/drivers/acpi/acpica/evxfregn.c b/drivers/acpi/acpica/evxfregn.c
index eb7386763712..c85c8c45599d 100644
--- a/drivers/acpi/acpica/evxfregn.c
+++ b/drivers/acpi/acpica/evxfregn.c
@@ -110,9 +110,39 @@ acpi_install_address_space_handler(acpi_handle device,
                 goto unlock_and_exit;
         }
 
-        /* Run all _REG methods for this address space */
+        /*
+         * For the default space_iDs, (the IDs for which there are default region handlers
+         * installed) Only execute the _REG methods if the global initialization _REG
+         * methods have already been run (via acpi_initialize_objects). In other words,
+         * we will defer the execution of the _REG methods for these space_iDs until
+         * execution of acpi_initialize_objects. This is done because we need the handlers
+         * for the default spaces (mem/io/pci/table) to be installed before we can run
+         * any control methods (or _REG methods). There is known BIOS code that depends
+         * on this.
+         *
+         * For all other space_iDs, we can safely execute the _REG methods immediately.
+         * This means that for IDs like embedded_controller, this function should be called
+         * only after acpi_enable_subsystem has been called.
+         */
+        switch (space_id) {
+        case ACPI_ADR_SPACE_SYSTEM_MEMORY:
+        case ACPI_ADR_SPACE_SYSTEM_IO:
+        case ACPI_ADR_SPACE_PCI_CONFIG:
+        case ACPI_ADR_SPACE_DATA_TABLE:
+
+                if (acpi_gbl_reg_methods_executed) {
+
+                        /* Run all _REG methods for this address space */
+
+                        status = acpi_ev_execute_reg_methods(node, space_id);
+                }
+                break;
+
+        default:
 
-        status = acpi_ev_execute_reg_methods(node, space_id);
+                status = acpi_ev_execute_reg_methods(node, space_id);
+                break;
+        }
 
       unlock_and_exit:
         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);