ACPICA: Add mechanism to defer _REG methods for some installed handlers

The memory/io/pci/dataTable regions must always be available. For
any user installed handlers for these spaces, defer execution
of _REG methods until acpi_enable_subsystem. This prevents any
chicken/egg problems and ensures that no methods are executed
until all of these regions are ready and available.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

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);