ACPICA: AcpiGetDevices: Eliminate unnecessary _STA calls
In the case where a specific _HID is requested, do not run _STA
until a _HID match is found. This eliminates potentially dozens
of _STA calls during a search for a particular device/HID.
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c
index c5a5357..ebef8a7 100644
--- a/drivers/acpi/acpica/nsxfeval.c
+++ b/drivers/acpi/acpica/nsxfeval.c
@@ -562,25 +562,20 @@
return (AE_BAD_PARAMETER);
}
- /* Run _STA to determine if device is present */
-
- status = acpi_ut_execute_STA(node, &flags);
- if (ACPI_FAILURE(status)) {
- return (AE_CTRL_DEPTH);
- }
-
- if (!(flags & ACPI_STA_DEVICE_PRESENT) &&
- !(flags & ACPI_STA_DEVICE_FUNCTIONING)) {
- /*
- * Don't examine the children of the device only when the
- * device is neither present nor functional. See ACPI spec,
- * description of _STA for more information.
- */
- return (AE_CTRL_DEPTH);
- }
-
- /* Filter based on device HID & CID */
-
+ /*
+ * First, filter based on the device HID and CID.
+ *
+ * 01/2010: For this case where a specific HID is requested, we don't
+ * want to run _STA until we have an actual HID match. Thus, we will
+ * not unnecessarily execute _STA on devices for which the caller
+ * doesn't care about. Previously, _STA was executed unconditionally
+ * on all devices found here.
+ *
+ * A side-effect of this change is that now we will continue to search
+ * for a matching HID even under device trees where the parent device
+ * would have returned a _STA that indicates it is not present or
+ * not functioning (thus aborting the search on that branch).
+ */
if (info->hid != NULL) {
status = acpi_ut_execute_HID(node, &hid);
if (status == AE_NOT_FOUND) {
@@ -620,6 +615,25 @@
}
}
+ /* Run _STA to determine if device is present */
+
+ status = acpi_ut_execute_STA(node, &flags);
+ if (ACPI_FAILURE(status)) {
+ return (AE_CTRL_DEPTH);
+ }
+
+ if (!(flags & ACPI_STA_DEVICE_PRESENT) &&
+ !(flags & ACPI_STA_DEVICE_FUNCTIONING)) {
+ /*
+ * Don't examine the children of the device only when the
+ * device is neither present nor functional. See ACPI spec,
+ * description of _STA for more information.
+ */
+ return (AE_CTRL_DEPTH);
+ }
+
+ /* We have a valid device, invoke the user function */
+
status = info->user_function(obj_handle, nesting_level, info->context,
return_value);
return (status);