diff options
| author | Bob Moore <robert.moore@intel.com> | 2013-07-17 09:48:15 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-07-23 01:06:49 +0200 |
| commit | a7d5caf6d21814a855422df75c2d8c093cb2019a (patch) | |
| tree | 9c86c64aa1f4b020f17af3db44d9f17ee2dcedff /drivers/acpi | |
| parent | 3b2f64d00c46e1e4e9bd0bb9bb12619adac27a4b (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')
| -rw-r--r-- | drivers/acpi/acpica/nsxfname.c | 7 | ||||
| -rw-r--r-- | 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 f3a4d95899f..21a2ef363ad 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 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))); |