ACPI: add acpi_bus_get_status_handle()

Add acpi_bus_get_status_handle() so we can get the status of a namespace
object before building a struct acpi_device.

This removes a use of "device->flags.dynamic_status", a cached indicator of
whether _STA exists.  It seems simpler and more reliable to just evaluate
_STA and catch AE_NOT_FOUND errors.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 24 insertions, 27 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 135fbfe1825c..741191524353 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -94,36 +94,33 @@ int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
 
 EXPORT_SYMBOL(acpi_bus_get_device);
 
-int acpi_bus_get_status(struct acpi_device *device)
+acpi_status acpi_bus_get_status_handle(acpi_handle handle,
+                                       unsigned long long *sta)
 {
-        acpi_status status = AE_OK;
-        unsigned long long sta = 0;
-
+        acpi_status status;
 
-        if (!device)
-                return -EINVAL;
+        status = acpi_evaluate_integer(handle, "_STA", NULL, sta);
+        if (ACPI_SUCCESS(status))
+                return AE_OK;
 
-        /*
-         * Evaluate _STA if present.
-         */
-        if (device->flags.dynamic_status) {
-                status =
-                    acpi_evaluate_integer(device->handle, "_STA", NULL, &sta);
-                if (ACPI_FAILURE(status))
-                        return -ENODEV;
-                STRUCT_TO_INT(device->status) = (int)sta;
+        if (status == AE_NOT_FOUND) {
+                *sta = ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
+                       ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
+                return AE_OK;
         }
+        return status;
+}
 
-        /*
-         * According to ACPI spec some device can be present and functional
-         * even if the parent is not present but functional.
-         * In such conditions the child device should not inherit the status
-         * from the parent.
-         */
-        else
-                STRUCT_TO_INT(device->status) =
-                    ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
-                    ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
+int acpi_bus_get_status(struct acpi_device *device)
+{
+        acpi_status status;
+        unsigned long long sta;
+
+        status = acpi_bus_get_status_handle(device->handle, &sta);
+        if (ACPI_FAILURE(status))
+                return -ENODEV;
+
+        STRUCT_TO_INT(device->status) = (int) sta;
 
         if (device->status.functional && !device->status.present) {
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]: "
@@ -135,10 +132,8 @@ int acpi_bus_get_status(struct acpi_device *device)
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
                           device->pnp.bus_id,
                           (u32) STRUCT_TO_INT(device->status)));
-
         return 0;
 }
-
 EXPORT_SYMBOL(acpi_bus_get_status);
 
 void acpi_bus_private_data_handler(acpi_handle handle,
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index bc7a69516dce..670f7f33837e 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -322,6 +322,8 @@ extern void unregister_acpi_bus_notifier(struct notifier_block *nb);
 
 int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device);
 void acpi_bus_data_handler(acpi_handle handle, void *context);
+acpi_status acpi_bus_get_status_handle(acpi_handle handle,
+                                       unsigned long long *sta);
 int acpi_bus_get_status(struct acpi_device *device);
 int acpi_bus_get_power(acpi_handle handle, int *state);
 int acpi_bus_set_power(acpi_handle handle, int state);