ACPI: Execute _PRW for devices reported as inactive or not present

If a device is reported as inactive or not present by its _STA
control method, acpi_bus_check_add() skips it without evaluating its
_PRW method.  This leads to a problem when the device's _PRW method
points to a GPE, because in that case the GPE may be enabled by
ACPICA during the subsequent acpi_update_gpes() call which, in
turn, may cause a GPE storm to appear.

To avoid this issue, make acpi_bus_check_add() evaluate _PRW for
inactive or not present devices and register the wakeup GPE
information returned by them, so that acpi_update_gpes() does not
enable their GPEs unnecessarily.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 2b6c21d86b9885571b41679586636fff3b6c53bb..29ef505c487b92efe1b12e79c2231aa85c0298ce 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -705,54 +705,85 @@ static int acpi_bus_get_perf_flags(struct acpi_device *device)
 }
 
 static acpi_status
-acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
-                                            union acpi_object *package)
+acpi_bus_extract_wakeup_device_power_package(acpi_handle handle,
+                                            struct acpi_device_wakeup *wakeup)
 {
-       int i = 0;
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       union acpi_object *package = NULL;
        union acpi_object *element = NULL;
+       acpi_status status;
+       int i = 0;
 
-       if (!device || !package || (package->package.count < 2))
+       if (!wakeup)
                return AE_BAD_PARAMETER;
 
+       /* _PRW */
+       status = acpi_evaluate_object(handle, "_PRW", NULL, &buffer);
+       if (ACPI_FAILURE(status)) {
+               ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRW"));
+               return status;
+       }
+
+       package = (union acpi_object *)buffer.pointer;
+
+       if (!package || (package->package.count < 2)) {
+               status = AE_BAD_DATA;
+               goto out;
+       }
+
        element = &(package->package.elements[0]);
-       if (!element)
-               return AE_BAD_PARAMETER;
+       if (!element) {
+               status = AE_BAD_DATA;
+               goto out;
+       }
        if (element->type == ACPI_TYPE_PACKAGE) {
                if ((element->package.count < 2) ||
                    (element->package.elements[0].type !=
                     ACPI_TYPE_LOCAL_REFERENCE)
-                   || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
-                       return AE_BAD_DATA;
-               device->wakeup.gpe_device =
+                   || (element->package.elements[1].type != ACPI_TYPE_INTEGER)) {
+                       status = AE_BAD_DATA;
+                       goto out;
+               }
+               wakeup->gpe_device =
                    element->package.elements[0].reference.handle;
-               device->wakeup.gpe_number =
+               wakeup->gpe_number =
                    (u32) element->package.elements[1].integer.value;
        } else if (element->type == ACPI_TYPE_INTEGER) {
-               device->wakeup.gpe_number = element->integer.value;
-       } else
-               return AE_BAD_DATA;
+               wakeup->gpe_device = NULL;
+               wakeup->gpe_number = element->integer.value;
+       } else {
+               status = AE_BAD_DATA;
+               goto out;
+       }
 
        element = &(package->package.elements[1]);
        if (element->type != ACPI_TYPE_INTEGER) {
-               return AE_BAD_DATA;
+               status = AE_BAD_DATA;
+               goto out;
        }
-       device->wakeup.sleep_state = element->integer.value;
+       wakeup->sleep_state = element->integer.value;
 
        if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
-               return AE_NO_MEMORY;
+               status = AE_NO_MEMORY;
+               goto out;
        }
-       device->wakeup.resources.count = package->package.count - 2;
-       for (i = 0; i < device->wakeup.resources.count; i++) {
+       wakeup->resources.count = package->package.count - 2;
+       for (i = 0; i < wakeup->resources.count; i++) {
                element = &(package->package.elements[i + 2]);
-               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
-                       return AE_BAD_DATA;
+               if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
+                       status = AE_BAD_DATA;
+                       goto out;
+               }
 
-               device->wakeup.resources.handles[i] = element->reference.handle;
+               wakeup->resources.handles[i] = element->reference.handle;
        }
 
-       acpi_gpe_can_wake(device->wakeup.gpe_device, device->wakeup.gpe_number);
+       acpi_gpe_can_wake(wakeup->gpe_device, wakeup->gpe_number);
 
-       return AE_OK;
+ out:
+       kfree(buffer.pointer);
+
+       return status;
 }
 
 static void acpi_bus_set_run_wake_flags(struct acpi_device *device)
@@ -787,26 +818,15 @@ static void acpi_bus_set_run_wake_flags(struct acpi_device *device)
 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
 {
        acpi_status status = 0;
-       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-       union acpi_object *package = NULL;
        int psw_error;
 
-       /* _PRW */
-       status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
-       if (ACPI_FAILURE(status)) {
-               ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRW"));
-               goto end;
-       }
-
-       package = (union acpi_object *)buffer.pointer;
-       status = acpi_bus_extract_wakeup_device_power_package(device, package);
+       status = acpi_bus_extract_wakeup_device_power_package(device->handle,
+                                                             &device->wakeup);
        if (ACPI_FAILURE(status)) {
                ACPI_EXCEPTION((AE_INFO, status, "Extracting _PRW package"));
                goto end;
        }
 
-       kfree(buffer.pointer);
-
        device->wakeup.flags.valid = 1;
        device->wakeup.prepare_count = 0;
        acpi_bus_set_run_wake_flags(device);
@@ -1351,6 +1371,7 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
        struct acpi_bus_ops *ops = context;
        int type;
        unsigned long long sta;
+       struct acpi_device_wakeup wakeup;
        struct acpi_device *device;
        acpi_status status;
        int result;
@@ -1360,8 +1381,10 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
                return AE_OK;
 
        if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
-           !(sta & ACPI_STA_DEVICE_FUNCTIONING))
+           !(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
+               acpi_bus_extract_wakeup_device_power_package(handle, &wakeup);
                return AE_CTRL_DEPTH;
+       }
 
        /*
         * We may already have an acpi_device from a previous enumeration.  If