ACPICA: Namespace: Change namespace override to avoid node deletion

ACPICA commit c0ce529e1fbb8ec47d2522a3aa10f3ab77e16e41

There is no reference counting implemented for struct acpi_namespace_node, so it
is currently not removable during runtime.
This patch changes the namespace override code to keep the old
struct acpi_namespace_node undeleted so that the override mechanism can happen
during runtime. Bob Moore.

Link: https://github.com/acpica/acpica/commit/c0ce529e
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpica/nssearch.c b/drivers/acpi/acpica/nssearch.c
index 47fbe5b335247c97b7a12a1f2e430f49adde2ee6..d7390401383043d7af82cf51233cdfea4f825566 100644 (file)
--- a/drivers/acpi/acpica/nssearch.c
+++ b/drivers/acpi/acpica/nssearch.c
@@ -331,13 +331,28 @@ acpi_ns_search_and_enter(u32 target_name,
 
                        /*
                         * If the namespace override feature is enabled for this node,
-                        * delete any existing node. This can only happen during the
-                        * boot stage, thus it is safe to remove the node here.
+                        * delete any existing attached sub-object and make the node
+                        * look like a new node that is owned by the override table.
                         */
                        if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
+                               ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
+                                                 "Namespace override: %4.4s pass %u type %X Owner %X\n",
+                                                 ACPI_CAST_PTR(char,
+                                                               &target_name),
+                                                 interpreter_mode,
+                                                 (*return_node)->type,
+                                                 walk_state->owner_id));
+
                                acpi_ns_delete_children(*return_node);
-                               acpi_ns_remove_node(*return_node);
-                               *return_node = ACPI_ENTRY_NOT_FOUND;
+                               if (acpi_gbl_runtime_namespace_override) {
+                                       acpi_ut_remove_reference((*return_node)->object);
+                                       (*return_node)->object = NULL;
+                                       (*return_node)->owner_id =
+                                           walk_state->owner_id;
+                               } else {
+                                       acpi_ns_remove_node(*return_node);
+                                       *return_node = ACPI_ENTRY_NOT_FOUND;
+                               }
                        }
 
                        /* Return an error if we don't expect to find the object */

diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 213ed7ecfd8d479e2714890255c321168de7e087..f6d8071703467301b3196e3e83260d45c731e752 100644 (file)
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -228,6 +228,11 @@ ACPI_INIT_GLOBAL(u8, acpi_gbl_disable_auto_repair, FALSE);
  */
 ACPI_INIT_GLOBAL(u8, acpi_gbl_disable_ssdt_table_install, FALSE);
 
+/*
+ * Optionally enable runtime namespace override.
+ */
+ACPI_INIT_GLOBAL(u8, acpi_gbl_runtime_namespace_override, TRUE);
+
 /*
  * We keep track of the latest version of Windows that has been requested by
  * the BIOS. ACPI 5.0.