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authorBob Moore <robert.moore@intel.com>2013-07-17 09:48:15 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-07-23 01:06:49 +0200
commita7d5caf6d21814a855422df75c2d8c093cb2019a (patch)
tree9c86c64aa1f4b020f17af3db44d9f17ee2dcedff /drivers/acpi/acpica/uteval.c
parent3b2f64d00c46e1e4e9bd0bb9bb12619adac27a4b (diff)
ACPICA: Update comments about behavior when _STA does not exist
No functional change. Add some comments concerning behavior when the _STA method does not exist. According to the ACPI specification, in this case the device should be assumed to be present, functional, and enabled. Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Acked-by: Len Brown <len.brown@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/acpica/uteval.c')
-rw-r--r--drivers/acpi/acpica/uteval.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/acpi/acpica/uteval.c b/drivers/acpi/acpica/uteval.c
index ee83adb97b1..4fd68971019 100644
--- a/drivers/acpi/acpica/uteval.c
+++ b/drivers/acpi/acpica/uteval.c
@@ -239,7 +239,8 @@ acpi_ut_evaluate_numeric_object(char *object_name,
* RETURN: Status
*
* DESCRIPTION: Executes _STA for selected device and stores results in
- * *Flags.
+ * *Flags. If _STA does not exist, then the device is assumed
+ * to be present/functional/enabled (as per the ACPI spec).
*
* NOTE: Internal function, no parameter validation
*
@@ -257,6 +258,11 @@ acpi_ut_execute_STA(struct acpi_namespace_node *device_node, u32 * flags)
ACPI_BTYPE_INTEGER, &obj_desc);
if (ACPI_FAILURE(status)) {
if (AE_NOT_FOUND == status) {
+ /*
+ * if _STA does not exist, then (as per the ACPI specification),
+ * the returned flags will indicate that the device is present,
+ * functional, and enabled.
+ */
ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
"_STA on %4.4s was not found, assuming device is present\n",
acpi_ut_get_node_name(device_node)));