ACPI / ACPICA: Do not execute _PRW methods during initialization

Currently, during initialization ACPICA walks the entire ACPI
namespace in search of any device objects with assciated _PRW
methods.  All of the _PRW methods found are executed in the process
to extract the GPE information returned by them, so that the GPEs in
question can be marked as "able to wakeup" (more precisely, the
ACPI_GPE_CAN_WAKE flag is set for them).  The only purpose of this
exercise is to avoid enabling the CAN_WAKE GPEs automatically, even
if there are _Lxx/_Exx methods associated with them.  However, it is
both costly and unnecessary, because the host OS has to execute the
_PRW methods anyway to check which devices can wake up the system
from sleep states.  Moreover, it then uses full information
returned by _PRW, including the GPE information, so it can take care
of disabling the GPEs if necessary.

Remove the code that walks the namespace and executes _PRW from
ACPICA and modify comments to reflect that change.  Make
acpi_bus_set_run_wake_flags() disable GPEs for wakeup devices
so that they don't cause spurious wakeup events to be signaled.
This not only reduces the complexity of the ACPICA initialization
code, but in some cases it should reduce the kernel boot time as
well.

Unfortunately, for this purpose we need a new ACPICA function,
acpi_gpe_can_wake(), to be called by the host OS in order to disable
the GPEs that can wake up the system and were previously enabled by
acpi_ev_initialize_gpe_block() or acpi_ev_update_gpes() (such a GPE
should be disabled only once, because the initialization code enables
it only once, but it may be pointed to by _PRW for multiple devices
and that's why the additional function is necessary).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 17 insertions, 218 deletions

diff --git a/drivers/acpi/acpica/evgpeinit.c b/drivers/acpi/acpica/evgpeinit.c
index 8db9e076a53b..3084c5de1bba 100644
--- a/drivers/acpi/acpica/evgpeinit.c
+++ b/drivers/acpi/acpica/evgpeinit.c
@@ -211,9 +211,7 @@ acpi_status acpi_ev_gpe_initialize(void)
  * DESCRIPTION: Check for new GPE methods (_Lxx/_Exx) made available as a
  *              result of a Load() or load_table() operation. If new GPE
  *              methods have been installed, register the new methods and
- *              enable and runtime GPEs that are associated with them. Also,
- *              run any newly loaded _PRW methods in order to discover any
- *              new CAN_WAKE GPEs.
+ *              enable and runtime GPEs that are associated with them.
  *
  ******************************************************************************/
 
@@ -223,49 +221,12 @@ void acpi_ev_update_gpes(acpi_owner_id table_owner_id)
         struct acpi_gpe_block_info *gpe_block;
         struct acpi_gpe_walk_info walk_info;
         acpi_status status = AE_OK;
-        u32 new_wake_gpe_count = 0;
-
-        /* We will examine only _PRW/_Lxx/_Exx methods owned by this table */
-
-        walk_info.owner_id = table_owner_id;
-        walk_info.execute_by_owner_id = TRUE;
-        walk_info.count = 0;
-
-        if (acpi_gbl_leave_wake_gpes_disabled) {
-                /*
-                 * 1) Run any newly-loaded _PRW methods to find any GPEs that
-                 * can now be marked as CAN_WAKE GPEs. Note: We must run the
-                 * _PRW methods before we process the _Lxx/_Exx methods because
-                 * we will enable all runtime GPEs associated with the new
-                 * _Lxx/_Exx methods at the time we process those methods.
-                 *
-                 * Unlock interpreter so that we can run the _PRW methods.
-                 */
-                walk_info.gpe_block = NULL;
-                walk_info.gpe_device = NULL;
-
-                acpi_ex_exit_interpreter();
-
-                status =
-                    acpi_ns_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
-                                           ACPI_UINT32_MAX,
-                                           ACPI_NS_WALK_NO_UNLOCK,
-                                           acpi_ev_match_prw_and_gpe, NULL,
-                                           &walk_info, NULL);
-                if (ACPI_FAILURE(status)) {
-                        ACPI_EXCEPTION((AE_INFO, status,
-                                        "While executing _PRW methods"));
-                }
-
-                acpi_ex_enter_interpreter();
-                new_wake_gpe_count = walk_info.count;
-        }
 
         /*
          * 2) Find any _Lxx/_Exx GPE methods that have just been loaded.
          *
-         * Any GPEs that correspond to new _Lxx/_Exx methods and are not
-         * marked as CAN_WAKE are immediately enabled.
+         * Any GPEs that correspond to new _Lxx/_Exx methods are immediately
+         * enabled.
          *
          * Examine the namespace underneath each gpe_device within the
          * gpe_block lists.
@@ -275,6 +236,8 @@ void acpi_ev_update_gpes(acpi_owner_id table_owner_id)
                 return;
         }
 
+        walk_info.owner_id = table_owner_id;
+        walk_info.execute_by_owner_id = TRUE;
         walk_info.count = 0;
         walk_info.enable_this_gpe = TRUE;
 
@@ -307,10 +270,8 @@ void acpi_ev_update_gpes(acpi_owner_id table_owner_id)
                 gpe_xrupt_info = gpe_xrupt_info->next;
         }
 
-        if (walk_info.count || new_wake_gpe_count) {
-                ACPI_INFO((AE_INFO,
-                           "Enabled %u new runtime GPEs, added %u new wakeup GPEs",
-                           walk_info.count, new_wake_gpe_count));
+        if (walk_info.count) {
+                ACPI_INFO((AE_INFO, "Enabled %u new GPEs", walk_info.count));
         }
 
         (void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
@@ -386,9 +347,6 @@ acpi_ev_match_gpe_method(acpi_handle obj_handle,
         /*
          * 3) Edge/Level determination is based on the 2nd character
          *    of the method name
-         *
-         * NOTE: Default GPE type is RUNTIME only. Later, if a _PRW object is
-         * found that points to this GPE, the ACPI_GPE_CAN_WAKE flag is set.
          */
         switch (name[1]) {
         case 'L':
@@ -471,23 +429,18 @@ acpi_ev_match_gpe_method(acpi_handle obj_handle,
          */
         if (walk_info->enable_this_gpe) {
 
-                /* Ignore GPEs that can wake the system */
+                walk_info->count++;
+                gpe_device = walk_info->gpe_device;
 
-                if (!(gpe_event_info->flags & ACPI_GPE_CAN_WAKE) ||
-                    !acpi_gbl_leave_wake_gpes_disabled) {
-                        walk_info->count++;
-                        gpe_device = walk_info->gpe_device;
-
-                        if (gpe_device == acpi_gbl_fadt_gpe_device) {
-                                gpe_device = NULL;
-                        }
+                if (gpe_device == acpi_gbl_fadt_gpe_device) {
+                        gpe_device = NULL;
+                }
 
-                        status = acpi_enable_gpe(gpe_device, gpe_number);
-                        if (ACPI_FAILURE(status)) {
-                                ACPI_EXCEPTION((AE_INFO, status,
-                                                "Could not enable GPE 0x%02X",
-                                                gpe_number));
-                        }
+                status = acpi_enable_gpe(gpe_device, gpe_number);
+                if (ACPI_FAILURE(status)) {
+                        ACPI_EXCEPTION((AE_INFO, status,
+                                        "Could not enable GPE 0x%02X",
+                                        gpe_number));
                 }
         }
 
@@ -496,157 +449,3 @@ acpi_ev_match_gpe_method(acpi_handle obj_handle,
                           name, gpe_number));
         return_ACPI_STATUS(AE_OK);
 }
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ev_match_prw_and_gpe
- *
- * PARAMETERS:  Callback from walk_namespace
- *
- * RETURN:      Status. NOTE: We ignore errors so that the _PRW walk is
- *              not aborted on a single _PRW failure.
- *
- * DESCRIPTION: Called from acpi_walk_namespace. Expects each object to be a
- *              Device. Run the _PRW method. If present, extract the GPE
- *              number and mark the GPE as a CAN_WAKE GPE. Allows a
- *              per-owner_id execution if execute_by_owner_id is TRUE in the
- *              walk_info parameter block.
- *
- * If walk_info->execute_by_owner_id is TRUE, we only execute _PRWs with that
- *    owner.
- * If walk_info->gpe_device is NULL, we execute every _PRW found. Otherwise,
- *    we only execute _PRWs that refer to the input gpe_device.
- *
- ******************************************************************************/
-
-acpi_status
-acpi_ev_match_prw_and_gpe(acpi_handle obj_handle,
-                          u32 level, void *context, void **return_value)
-{
-        struct acpi_gpe_walk_info *walk_info =
-            ACPI_CAST_PTR(struct acpi_gpe_walk_info, context);
-        struct acpi_namespace_node *gpe_device;
-        struct acpi_gpe_block_info *gpe_block;
-        struct acpi_namespace_node *target_gpe_device;
-        struct acpi_namespace_node *prw_node;
-        struct acpi_gpe_event_info *gpe_event_info;
-        union acpi_operand_object *pkg_desc;
-        union acpi_operand_object *obj_desc;
-        u32 gpe_number;
-        acpi_status status;
-
-        ACPI_FUNCTION_TRACE(ev_match_prw_and_gpe);
-
-        /* Check for a _PRW method under this device */
-
-        status = acpi_ns_get_node(obj_handle, METHOD_NAME__PRW,
-                                  ACPI_NS_NO_UPSEARCH, &prw_node);
-        if (ACPI_FAILURE(status)) {
-                return_ACPI_STATUS(AE_OK);
-        }
-
-        /* Check if requested owner_id matches this owner_id */
-
-        if ((walk_info->execute_by_owner_id) &&
-            (prw_node->owner_id != walk_info->owner_id)) {
-                return_ACPI_STATUS(AE_OK);
-        }
-
-        /* Execute the _PRW */
-
-        status = acpi_ut_evaluate_object(prw_node, NULL,
-                                         ACPI_BTYPE_PACKAGE, &pkg_desc);
-        if (ACPI_FAILURE(status)) {
-                return_ACPI_STATUS(AE_OK);
-        }
-
-        /* The returned _PRW package must have at least two elements */
-
-        if (pkg_desc->package.count < 2) {
-                goto cleanup;
-        }
-
-        /* Extract pointers from the input context */
-
-        gpe_device = walk_info->gpe_device;
-        gpe_block = walk_info->gpe_block;
-
-        /*
-         * The _PRW object must return a package, we are only interested
-         * in the first element
-         */
-        obj_desc = pkg_desc->package.elements[0];
-
-        if (obj_desc->common.type == ACPI_TYPE_INTEGER) {
-
-                /* Use FADT-defined GPE device (from definition of _PRW) */
-
-                target_gpe_device = NULL;
-                if (gpe_device) {
-                        target_gpe_device = acpi_gbl_fadt_gpe_device;
-                }
-
-                /* Integer is the GPE number in the FADT described GPE blocks */
-
-                gpe_number = (u32)obj_desc->integer.value;
-        } else if (obj_desc->common.type == ACPI_TYPE_PACKAGE) {
-
-                /* Package contains a GPE reference and GPE number within a GPE block */
-
-                if ((obj_desc->package.count < 2) ||
-                    ((obj_desc->package.elements[0])->common.type !=
-                     ACPI_TYPE_LOCAL_REFERENCE) ||
-                    ((obj_desc->package.elements[1])->common.type !=
-                     ACPI_TYPE_INTEGER)) {
-                        goto cleanup;
-                }
-
-                /* Get GPE block reference and decode */
-
-                target_gpe_device =
-                    obj_desc->package.elements[0]->reference.node;
-                gpe_number = (u32)obj_desc->package.elements[1]->integer.value;
-        } else {
-                /* Unknown type, just ignore it */
-
-                goto cleanup;
-        }
-
-        /* Get the gpe_event_info for this GPE */
-
-        if (gpe_device) {
-                /*
-                 * Is this GPE within this block?
-                 *
-                 * TRUE if and only if these conditions are true:
-                 *     1) The GPE devices match.
-                 *     2) The GPE index(number) is within the range of the Gpe Block
-                 *          associated with the GPE device.
-                 */
-                if (gpe_device != target_gpe_device) {
-                        goto cleanup;
-                }
-
-                gpe_event_info =
-                    acpi_ev_low_get_gpe_info(gpe_number, gpe_block);
-        } else {
-                /* gpe_device is NULL, just match the target_device and gpe_number */
-
-                gpe_event_info =
-                    acpi_ev_get_gpe_event_info(target_gpe_device, gpe_number);
-        }
-
-        if (gpe_event_info) {
-                if (!(gpe_event_info->flags & ACPI_GPE_CAN_WAKE)) {
-
-                        /* This GPE can wake the system */
-
-                        gpe_event_info->flags |= ACPI_GPE_CAN_WAKE;
-                        walk_info->count++;
-                }
-        }
-
-      cleanup:
-        acpi_ut_remove_reference(pkg_desc);
-        return_ACPI_STATUS(AE_OK);
-}