blob: 3e87c9c538aaf376488593b3d7e28a05121396db [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * acpi_utils.c - ACPI Utility Functions ($Revision: 10 $)
3 *
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 *
7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or (at
12 * your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
22 *
23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24 */
25
26#include <linux/kernel.h>
27#include <linux/module.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090028#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/init.h>
30#include <linux/types.h>
31#include <acpi/acpi_bus.h>
32#include <acpi/acpi_drivers.h>
33
Len Browna192a952009-07-28 16:45:54 -040034#include "internal.h"
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#define _COMPONENT ACPI_BUS_COMPONENT
Len Brownf52fd662007-02-12 22:42:12 -050037ACPI_MODULE_NAME("utils");
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39/* --------------------------------------------------------------------------
40 Object Evaluation Helpers
41 -------------------------------------------------------------------------- */
Harvey Harrison4fd7f512008-02-15 17:07:19 -080042static void
43acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
44{
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#ifdef ACPI_DEBUG_OUTPUT
Harvey Harrison4fd7f512008-02-15 17:07:19 -080046 char prefix[80] = {'\0'};
47 struct acpi_buffer buffer = {sizeof(prefix), prefix};
48 acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);
49 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluate [%s.%s]: %s\n",
50 (char *) prefix, p, acpi_format_exception(s)));
Linus Torvalds1da177e2005-04-16 15:20:36 -070051#else
Harvey Harrison4fd7f512008-02-15 17:07:19 -080052 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#endif
Harvey Harrison4fd7f512008-02-15 17:07:19 -080054}
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056acpi_status
Len Brown4be44fc2005-08-05 00:44:28 -040057acpi_extract_package(union acpi_object *package,
58 struct acpi_buffer *format, struct acpi_buffer *buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -070059{
Len Brown4be44fc2005-08-05 00:44:28 -040060 u32 size_required = 0;
61 u32 tail_offset = 0;
62 char *format_string = NULL;
63 u32 format_count = 0;
64 u32 i = 0;
65 u8 *head = NULL;
66 u8 *tail = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
Len Brown4be44fc2005-08-05 00:44:28 -040069 if (!package || (package->type != ACPI_TYPE_PACKAGE)
70 || (package->package.count < 1)) {
Len Browncece9292006-06-26 23:04:31 -040071 printk(KERN_WARNING PREFIX "Invalid package argument\n");
Patrick Mocheld550d982006-06-27 00:41:40 -040072 return AE_BAD_PARAMETER;
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 }
74
75 if (!format || !format->pointer || (format->length < 1)) {
Len Browncece9292006-06-26 23:04:31 -040076 printk(KERN_WARNING PREFIX "Invalid format argument\n");
Patrick Mocheld550d982006-06-27 00:41:40 -040077 return AE_BAD_PARAMETER;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 }
79
80 if (!buffer) {
Len Browncece9292006-06-26 23:04:31 -040081 printk(KERN_WARNING PREFIX "Invalid buffer argument\n");
Patrick Mocheld550d982006-06-27 00:41:40 -040082 return AE_BAD_PARAMETER;
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 }
84
Len Brown4be44fc2005-08-05 00:44:28 -040085 format_count = (format->length / sizeof(char)) - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 if (format_count > package->package.count) {
Len Browncece9292006-06-26 23:04:31 -040087 printk(KERN_WARNING PREFIX "Format specifies more objects [%d]"
88 " than exist in package [%d].\n",
89 format_count, package->package.count);
Patrick Mocheld550d982006-06-27 00:41:40 -040090 return AE_BAD_DATA;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 }
92
Jan Engelhardt50dd0962006-10-01 00:28:50 +020093 format_string = format->pointer;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95 /*
96 * Calculate size_required.
97 */
Len Brown4be44fc2005-08-05 00:44:28 -040098 for (i = 0; i < format_count; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 union acpi_object *element = &(package->package.elements[i]);
101
102 if (!element) {
Patrick Mocheld550d982006-06-27 00:41:40 -0400103 return AE_BAD_DATA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 }
105
106 switch (element->type) {
107
108 case ACPI_TYPE_INTEGER:
109 switch (format_string[i]) {
110 case 'N':
Lin Ming439913f2010-01-28 10:53:19 +0800111 size_required += sizeof(u64);
112 tail_offset += sizeof(u64);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 break;
114 case 'S':
Len Brown4be44fc2005-08-05 00:44:28 -0400115 size_required +=
Lin Ming439913f2010-01-28 10:53:19 +0800116 sizeof(char *) + sizeof(u64) +
Len Brown4be44fc2005-08-05 00:44:28 -0400117 sizeof(char);
118 tail_offset += sizeof(char *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 break;
120 default:
Len Browncece9292006-06-26 23:04:31 -0400121 printk(KERN_WARNING PREFIX "Invalid package element"
Thomas Renningera6fc6722006-06-26 23:58:43 -0400122 " [%d]: got number, expecing"
Len Browncece9292006-06-26 23:04:31 -0400123 " [%c]\n",
124 i, format_string[i]);
Patrick Mocheld550d982006-06-27 00:41:40 -0400125 return AE_BAD_DATA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 break;
127 }
128 break;
129
130 case ACPI_TYPE_STRING:
131 case ACPI_TYPE_BUFFER:
132 switch (format_string[i]) {
133 case 'S':
Len Brown4be44fc2005-08-05 00:44:28 -0400134 size_required +=
135 sizeof(char *) +
136 (element->string.length * sizeof(char)) +
137 sizeof(char);
138 tail_offset += sizeof(char *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 break;
140 case 'B':
Len Brown4be44fc2005-08-05 00:44:28 -0400141 size_required +=
142 sizeof(u8 *) +
143 (element->buffer.length * sizeof(u8));
144 tail_offset += sizeof(u8 *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 break;
146 default:
Len Browncece9292006-06-26 23:04:31 -0400147 printk(KERN_WARNING PREFIX "Invalid package element"
Thomas Renningera6fc6722006-06-26 23:58:43 -0400148 " [%d] got string/buffer,"
Len Browncece9292006-06-26 23:04:31 -0400149 " expecing [%c]\n",
150 i, format_string[i]);
Patrick Mocheld550d982006-06-27 00:41:40 -0400151 return AE_BAD_DATA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 break;
153 }
154 break;
155
156 case ACPI_TYPE_PACKAGE:
157 default:
Len Brown4be44fc2005-08-05 00:44:28 -0400158 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
159 "Found unsupported element at index=%d\n",
160 i));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 /* TBD: handle nested packages... */
Patrick Mocheld550d982006-06-27 00:41:40 -0400162 return AE_SUPPORT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 break;
164 }
165 }
166
167 /*
168 * Validate output buffer.
169 */
170 if (buffer->length < size_required) {
171 buffer->length = size_required;
Patrick Mocheld550d982006-06-27 00:41:40 -0400172 return AE_BUFFER_OVERFLOW;
Len Brown4be44fc2005-08-05 00:44:28 -0400173 } else if (buffer->length != size_required || !buffer->pointer) {
Patrick Mocheld550d982006-06-27 00:41:40 -0400174 return AE_BAD_PARAMETER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 }
176
177 head = buffer->pointer;
178 tail = buffer->pointer + tail_offset;
179
180 /*
181 * Extract package data.
182 */
Len Brown4be44fc2005-08-05 00:44:28 -0400183 for (i = 0; i < format_count; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
185 u8 **pointer = NULL;
186 union acpi_object *element = &(package->package.elements[i]);
187
188 if (!element) {
Patrick Mocheld550d982006-06-27 00:41:40 -0400189 return AE_BAD_DATA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 }
191
192 switch (element->type) {
193
194 case ACPI_TYPE_INTEGER:
195 switch (format_string[i]) {
196 case 'N':
Lin Ming439913f2010-01-28 10:53:19 +0800197 *((u64 *) head) =
Len Brown4be44fc2005-08-05 00:44:28 -0400198 element->integer.value;
Lin Ming439913f2010-01-28 10:53:19 +0800199 head += sizeof(u64);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 break;
201 case 'S':
Len Brown4be44fc2005-08-05 00:44:28 -0400202 pointer = (u8 **) head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 *pointer = tail;
Lin Ming439913f2010-01-28 10:53:19 +0800204 *((u64 *) tail) =
Len Brown4be44fc2005-08-05 00:44:28 -0400205 element->integer.value;
Lin Ming439913f2010-01-28 10:53:19 +0800206 head += sizeof(u64 *);
207 tail += sizeof(u64);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 /* NULL terminate string */
209 *tail = (char)0;
210 tail += sizeof(char);
211 break;
212 default:
213 /* Should never get here */
214 break;
215 }
216 break;
217
218 case ACPI_TYPE_STRING:
219 case ACPI_TYPE_BUFFER:
220 switch (format_string[i]) {
221 case 'S':
Len Brown4be44fc2005-08-05 00:44:28 -0400222 pointer = (u8 **) head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 *pointer = tail;
Len Brown4be44fc2005-08-05 00:44:28 -0400224 memcpy(tail, element->string.pointer,
225 element->string.length);
226 head += sizeof(char *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 tail += element->string.length * sizeof(char);
228 /* NULL terminate string */
229 *tail = (char)0;
230 tail += sizeof(char);
231 break;
232 case 'B':
Len Brown4be44fc2005-08-05 00:44:28 -0400233 pointer = (u8 **) head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 *pointer = tail;
Len Brown4be44fc2005-08-05 00:44:28 -0400235 memcpy(tail, element->buffer.pointer,
236 element->buffer.length);
237 head += sizeof(u8 *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 tail += element->buffer.length * sizeof(u8);
239 break;
240 default:
241 /* Should never get here */
242 break;
243 }
244 break;
245
246 case ACPI_TYPE_PACKAGE:
247 /* TBD: handle nested packages... */
248 default:
249 /* Should never get here */
250 break;
251 }
252 }
253
Patrick Mocheld550d982006-06-27 00:41:40 -0400254 return AE_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255}
Len Brown4be44fc2005-08-05 00:44:28 -0400256
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257EXPORT_SYMBOL(acpi_extract_package);
258
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259acpi_status
Len Brown4be44fc2005-08-05 00:44:28 -0400260acpi_evaluate_integer(acpi_handle handle,
261 acpi_string pathname,
Matthew Wilcox27663c52008-10-10 02:22:59 -0400262 struct acpi_object_list *arguments, unsigned long long *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263{
Len Brown4be44fc2005-08-05 00:44:28 -0400264 acpi_status status = AE_OK;
Pavel Machek40599072008-11-25 12:05:08 +0100265 union acpi_object element;
Len Brown4be44fc2005-08-05 00:44:28 -0400266 struct acpi_buffer buffer = { 0, NULL };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 if (!data)
Patrick Mocheld550d982006-06-27 00:41:40 -0400269 return AE_BAD_PARAMETER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 buffer.length = sizeof(union acpi_object);
Pavel Machek40599072008-11-25 12:05:08 +0100272 buffer.pointer = &element;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
274 if (ACPI_FAILURE(status)) {
275 acpi_util_eval_error(handle, pathname, status);
Patrick Mocheld550d982006-06-27 00:41:40 -0400276 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 }
278
Pavel Machek40599072008-11-25 12:05:08 +0100279 if (element.type != ACPI_TYPE_INTEGER) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
Patrick Mocheld550d982006-06-27 00:41:40 -0400281 return AE_BAD_DATA;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 }
283
Pavel Machek40599072008-11-25 12:05:08 +0100284 *data = element.integer.value;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285
Matthew Wilcox27663c52008-10-10 02:22:59 -0400286 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Return value [%llu]\n", *data));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
Patrick Mocheld550d982006-06-27 00:41:40 -0400288 return AE_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
Len Brown4be44fc2005-08-05 00:44:28 -0400291EXPORT_SYMBOL(acpi_evaluate_integer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293acpi_status
Len Brown4be44fc2005-08-05 00:44:28 -0400294acpi_evaluate_reference(acpi_handle handle,
295 acpi_string pathname,
296 struct acpi_object_list *arguments,
297 struct acpi_handle_list *list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298{
Len Brown4be44fc2005-08-05 00:44:28 -0400299 acpi_status status = AE_OK;
300 union acpi_object *package = NULL;
301 union acpi_object *element = NULL;
302 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
303 u32 i = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305
306 if (!list) {
Patrick Mocheld550d982006-06-27 00:41:40 -0400307 return AE_BAD_PARAMETER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 }
309
310 /* Evaluate object. */
311
312 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
313 if (ACPI_FAILURE(status))
314 goto end;
315
Jan Engelhardt50dd0962006-10-01 00:28:50 +0200316 package = buffer.pointer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
318 if ((buffer.length == 0) || !package) {
Len Brown64684632006-06-26 23:41:38 -0400319 printk(KERN_ERR PREFIX "No return object (len %X ptr %p)\n",
320 (unsigned)buffer.length, package);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 status = AE_BAD_DATA;
322 acpi_util_eval_error(handle, pathname, status);
323 goto end;
324 }
325 if (package->type != ACPI_TYPE_PACKAGE) {
Len Brown64684632006-06-26 23:41:38 -0400326 printk(KERN_ERR PREFIX "Expecting a [Package], found type %X\n",
327 package->type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 status = AE_BAD_DATA;
329 acpi_util_eval_error(handle, pathname, status);
330 goto end;
331 }
332 if (!package->package.count) {
Len Brown64684632006-06-26 23:41:38 -0400333 printk(KERN_ERR PREFIX "[Package] has zero elements (%p)\n",
334 package);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 status = AE_BAD_DATA;
336 acpi_util_eval_error(handle, pathname, status);
337 goto end;
338 }
339
340 if (package->package.count > ACPI_MAX_HANDLES) {
Patrick Mocheld550d982006-06-27 00:41:40 -0400341 return AE_NO_MEMORY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 }
343 list->count = package->package.count;
344
345 /* Extract package data. */
346
347 for (i = 0; i < list->count; i++) {
348
349 element = &(package->package.elements[i]);
350
Bob Moorecd0b2242008-04-10 19:06:43 +0400351 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 status = AE_BAD_DATA;
Len Brown64684632006-06-26 23:41:38 -0400353 printk(KERN_ERR PREFIX
354 "Expecting a [Reference] package element, found type %X\n",
355 element->type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 acpi_util_eval_error(handle, pathname, status);
357 break;
358 }
359
Thomas Renningerb6a16382008-03-12 01:06:24 +0100360 if (!element->reference.handle) {
361 printk(KERN_WARNING PREFIX "Invalid reference in"
362 " package %s\n", pathname);
363 status = AE_NULL_ENTRY;
364 break;
365 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 /* Get the acpi_handle. */
367
368 list->handles[i] = element->reference.handle;
369 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found reference [%p]\n",
Len Brown4be44fc2005-08-05 00:44:28 -0400370 list->handles[i]));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 }
372
Len Brown4be44fc2005-08-05 00:44:28 -0400373 end:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 if (ACPI_FAILURE(status)) {
375 list->count = 0;
376 //kfree(list->handles);
377 }
378
Len Brown02438d82006-06-30 03:19:10 -0400379 kfree(buffer.pointer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380
Patrick Mocheld550d982006-06-27 00:41:40 -0400381 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383
Len Brown4be44fc2005-08-05 00:44:28 -0400384EXPORT_SYMBOL(acpi_evaluate_reference);
Matthew Garrett38ac0f12012-05-11 16:08:26 +0800385
386acpi_status
387acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld *pld)
388{
389 acpi_status status;
390 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
391 union acpi_object *output;
392
393 status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
394
395 if (ACPI_FAILURE(status))
396 return status;
397
398 output = buffer.pointer;
399
400 if (!output || output->type != ACPI_TYPE_PACKAGE
401 || !output->package.count
402 || output->package.elements[0].type != ACPI_TYPE_BUFFER
403 || output->package.elements[0].buffer.length > sizeof(*pld)) {
404 status = AE_TYPE;
405 goto out;
406 }
407
408 memcpy(pld, output->package.elements[0].buffer.pointer,
409 output->package.elements[0].buffer.length);
410out:
411 kfree(buffer.pointer);
412 return status;
413}
414EXPORT_SYMBOL(acpi_get_physical_device_location);
Toshi Kani275c58d2012-05-23 20:25:19 -0600415
416/**
417 * acpi_evaluate_hotplug_ost: Evaluate _OST for hotplug operations
418 * @handle: ACPI device handle
419 * @source_event: source event code
420 * @status_code: status code
421 * @status_buf: optional detailed information (NULL if none)
422 *
423 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
424 * must call this function when evaluating _OST for hotplug operations.
425 * When the platform does not support _OST, this function has no effect.
426 */
427acpi_status
428acpi_evaluate_hotplug_ost(acpi_handle handle, u32 source_event,
429 u32 status_code, struct acpi_buffer *status_buf)
430{
431#ifdef ACPI_HOTPLUG_OST
432 union acpi_object params[3] = {
433 {.type = ACPI_TYPE_INTEGER,},
434 {.type = ACPI_TYPE_INTEGER,},
435 {.type = ACPI_TYPE_BUFFER,}
436 };
437 struct acpi_object_list arg_list = {3, params};
438 acpi_status status;
439
440 params[0].integer.value = source_event;
441 params[1].integer.value = status_code;
442 if (status_buf != NULL) {
443 params[2].buffer.pointer = status_buf->pointer;
444 params[2].buffer.length = status_buf->length;
445 } else {
446 params[2].buffer.pointer = NULL;
447 params[2].buffer.length = 0;
448 }
449
450 status = acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
451 return status;
452#else
453 return AE_OK;
454#endif
455}
456EXPORT_SYMBOL(acpi_evaluate_hotplug_ost);