From: Bob Moore <robert.moore@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
Acked-by: Len Brown <len.brown@xxxxxxxxx>
---
drivers/acpi/acpica/nsxfname.c | 7 ++++++-
drivers/acpi/acpica/uteval.c | 8 +++++++-
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/acpica/nsxfname.c b/drivers/acpi/acpica/nsxfname.c
index f3a4d95..21a2ef3 100644
--- a/drivers/acpi/acpica/nsxfname.c
+++ b/drivers/acpi/acpica/nsxfname.c
@@ -379,9 +379,14 @@ acpi_get_object_info(acpi_handle handle,
* Get extra info for ACPI Device/Processor objects only:
* Run the _STA, _ADR and, sx_w, and _sx_d methods.
*
- * Note: none of these methods are required, so they may or may
+ * Notes: none of these methods are required, so they may or may
* not be present for this device. The Info->Valid bitfield is used
* to indicate which methods were found and run successfully.
+ *
+ * For _STA, if the method does not exist, then (as per the ACPI
+ * specification), the returned current_status flags will indicate
+ * that the device is present/functional/enabled. Otherwise, the
+ * current_status flags reflect the value returned from _STA.
*/
/* Execute the Device._STA method */
diff --git a/drivers/acpi/acpica/uteval.c b/drivers/acpi/acpica/uteval.c
index ee83adb..4fd6897 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)));
--
1.7.10
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