ACPICA: Misc comments to minimize code divergence
Modify/add some comments to minimize ACPICA/linux GPE code divergence.
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/evgpeinit.c b/drivers/acpi/acpica/evgpeinit.c
index 734a494..c59dc23 100644
--- a/drivers/acpi/acpica/evgpeinit.c
+++ b/drivers/acpi/acpica/evgpeinit.c
@@ -45,11 +45,27 @@
#include "accommon.h"
#include "acevents.h"
#include "acnamesp.h"
-#include "acinterp.h"
#define _COMPONENT ACPI_EVENTS
ACPI_MODULE_NAME("evgpeinit")
+/*
+ * Note: History of _PRW support in ACPICA
+ *
+ * Originally (2000 - 2010), the GPE initialization code performed a walk of
+ * the entire namespace to execute the _PRW methods and detect all GPEs
+ * capable of waking the system.
+ *
+ * As of 10/2010, the _PRW method execution has been removed since it is
+ * actually unnecessary. The host OS must in fact execute all _PRW methods
+ * in order to identify the device/power-resource dependencies. We now put
+ * the onus on the host OS to identify the wake GPEs as part of this process
+ * and to inform ACPICA of these GPEs via the acpi_setup_gpe_for_wake interface. This
+ * not only reduces the complexity of the ACPICA initialization code, but in
+ * some cases (on systems with very large namespaces) it should reduce the
+ * kernel boot time as well.
+ */
+
/*******************************************************************************
*
* FUNCTION: acpi_ev_gpe_initialize
@@ -222,7 +238,7 @@
acpi_status status = AE_OK;
/*
- * 2) Find any _Lxx/_Exx GPE methods that have just been loaded.
+ * Find any _Lxx/_Exx GPE methods that have just been loaded.
*
* Any GPEs that correspond to new _Lxx/_Exx methods are immediately
* enabled.
@@ -235,9 +251,9 @@
return;
}
+ walk_info.count = 0;
walk_info.owner_id = table_owner_id;
walk_info.execute_by_owner_id = TRUE;
- walk_info.count = 0;
/* Walk the interrupt level descriptor list */
@@ -298,7 +314,7 @@
* xx - is the GPE number [in HEX]
*
* If walk_info->execute_by_owner_id is TRUE, we only execute examine GPE methods
- * with that owner.
+ * with that owner.
*
******************************************************************************/