aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/acpi/utilities/uteval.c
blob: 13d5879cd98b92148acb215ac411a8280b862090 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
/******************************************************************************
 *
 * Module Name: uteval - Object evaluation
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2007, R. Byron Moore
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include <acpi/acnamesp.h>
#include <acpi/acinterp.h>

#define _COMPONENT          ACPI_UTILITIES
ACPI_MODULE_NAME("uteval")

/* Local prototypes */
static void
acpi_ut_copy_id_string(char *destination, char *source, acpi_size max_length);

static acpi_status
acpi_ut_translate_one_cid(union acpi_operand_object *obj_desc,
			  struct acpi_compatible_id *one_cid);

/*
 * Strings supported by the _OSI predefined (internal) method.
 */
static const char *acpi_interfaces_supported[] = {
	/* Operating System Vendor Strings */

	"Linux",
	"Windows 2000",
	"Windows 2001",
	"Windows 2001 SP0",
	"Windows 2001 SP1",
	"Windows 2001 SP2",
	"Windows 2001 SP3",
	"Windows 2001 SP4",
	"Windows 2001.1",
	"Windows 2001.1 SP1",	/* Added 03/2006 */
	"Windows 2006",		/* Added 03/2006 */

	/* Feature Group Strings */

	"Extended Address Space Descriptor"
	    /*
	     * All "optional" feature group strings (features that are implemented
	     * by the host) should be implemented in the host version of
	     * acpi_os_validate_interface and should not be added here.
	     */
};

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_osi_implementation
 *
 * PARAMETERS:  walk_state          - Current walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Implementation of the _OSI predefined control method
 *
 ******************************************************************************/

acpi_status acpi_ut_osi_implementation(struct acpi_walk_state *walk_state)
{
	acpi_status status;
	union acpi_operand_object *string_desc;
	union acpi_operand_object *return_desc;
	acpi_native_uint i;

	ACPI_FUNCTION_TRACE(ut_osi_implementation);

	/* Validate the string input argument */

	string_desc = walk_state->arguments[0].object;
	if (!string_desc || (string_desc->common.type != ACPI_TYPE_STRING)) {
		return_ACPI_STATUS(AE_TYPE);
	}

	/* Create a return object */

	return_desc = acpi_ut_create_internal_object(ACPI_TYPE_INTEGER);
	if (!return_desc) {
		return_ACPI_STATUS(AE_NO_MEMORY);
	}

	/* Default return value is SUPPORTED */

	return_desc->integer.value = ACPI_UINT32_MAX;
	walk_state->return_desc = return_desc;

	/* Compare input string to static table of supported interfaces */

	for (i = 0; i < ACPI_ARRAY_LENGTH(acpi_interfaces_supported); i++) {
		if (!ACPI_STRCMP
		    (string_desc->string.pointer,
		     acpi_interfaces_supported[i])) {

			/* The interface is supported */

			return_ACPI_STATUS(AE_CTRL_TERMINATE);
		}
	}

	/*
	 * Did not match the string in the static table, call the host OSL to
	 * check for a match with one of the optional strings (such as
	 * "Module Device", "3.0 Thermal Model", etc.)
	 */
	status = acpi_os_validate_interface(string_desc->string.pointer);
	if (ACPI_SUCCESS(status)) {

		/* The interface is supported */

		return_ACPI_STATUS(AE_CTRL_TERMINATE);
	}

	/* The interface is not supported */

	return_desc->integer.value = 0;
	return_ACPI_STATUS(AE_CTRL_TERMINATE);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_evaluate_object
 *
 * PARAMETERS:  prefix_node         - Starting node
 *              Path                - Path to object from starting node
 *              expected_return_types - Bitmap of allowed return types
 *              return_desc         - Where a return value is stored
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Evaluates a namespace object and verifies the type of the
 *              return object.  Common code that simplifies accessing objects
 *              that have required return objects of fixed types.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_evaluate_object(struct acpi_namespace_node *prefix_node,
			char *path,
			u32 expected_return_btypes,
			union acpi_operand_object **return_desc)
{
	struct acpi_evaluate_info *info;
	acpi_status status;
	u32 return_btype;

	ACPI_FUNCTION_TRACE(ut_evaluate_object);

	/* Allocate the evaluation information block */

	info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
	if (!info) {
		return_ACPI_STATUS(AE_NO_MEMORY);
	}

	info->prefix_node = prefix_node;
	info->pathname = path;
	info->parameter_type = ACPI_PARAM_ARGS;

	/* Evaluate the object/method */

	status = acpi_ns_evaluate(info);
	if (ACPI_FAILURE(status)) {
		if (status == AE_NOT_FOUND) {
			ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
					  "[%4.4s.%s] was not found\n",
					  acpi_ut_get_node_name(prefix_node),
					  path));
		} else {
			ACPI_ERROR_METHOD("Method execution failed",
					  prefix_node, path, status);
		}

		goto cleanup;
	}

	/* Did we get a return object? */

	if (!info->return_object) {
		if (expected_return_btypes) {
			ACPI_ERROR_METHOD("No object was returned from",
					  prefix_node, path, AE_NOT_EXIST);

			status = AE_NOT_EXIST;
		}

		goto cleanup;
	}

	/* Map the return object type to the bitmapped type */

	switch (ACPI_GET_OBJECT_TYPE(info->return_object)) {
	case ACPI_TYPE_INTEGER:
		return_btype = ACPI_BTYPE_INTEGER;
		break;

	case ACPI_TYPE_BUFFER:
		return_btype = ACPI_BTYPE_BUFFER;
		break;

	case ACPI_TYPE_STRING:
		return_btype = ACPI_BTYPE_STRING;
		break;

	case ACPI_TYPE_PACKAGE:
		return_btype = ACPI_BTYPE_PACKAGE;
		break;

	default:
		return_btype = 0;
		break;
	}

	if ((acpi_gbl_enable_interpreter_slack) && (!expected_return_btypes)) {
		/*
		 * We received a return object, but one was not expected.  This can
		 * happen frequently if the "implicit return" feature is enabled.
		 * Just delete the return object and return AE_OK.
		 */
		acpi_ut_remove_reference(info->return_object);
		goto cleanup;
	}

	/* Is the return object one of the expected types? */

	if (!(expected_return_btypes & return_btype)) {
		ACPI_ERROR_METHOD("Return object type is incorrect",
				  prefix_node, path, AE_TYPE);

		ACPI_ERROR((AE_INFO,
			    "Type returned from %s was incorrect: %s, expected Btypes: %X",
			    path,
			    acpi_ut_get_object_type_name(info->return_object),
			    expected_return_btypes));

		/* On error exit, we must delete the return object */

		acpi_ut_remove_reference(info->return_object);
		status = AE_TYPE;
		goto cleanup;
	}

	/* Object type is OK, return it */

	*return_desc = info->return_object;

      cleanup:
	ACPI_FREE(info);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_evaluate_numeric_object
 *
 * PARAMETERS:  object_name         - Object name to be evaluated
 *              device_node         - Node for the device
 *              Address             - Where the value is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Evaluates a numeric namespace object for a selected device
 *              and stores result in *Address.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_evaluate_numeric_object(char *object_name,
				struct acpi_namespace_node *device_node,
				acpi_integer * address)
{
	union acpi_operand_object *obj_desc;
	acpi_status status;

	ACPI_FUNCTION_TRACE(ut_evaluate_numeric_object);

	status = acpi_ut_evaluate_object(device_node, object_name,
					 ACPI_BTYPE_INTEGER, &obj_desc);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Get the returned Integer */

	*address = obj_desc->integer.value;

	/* On exit, we must delete the return object */

	acpi_ut_remove_reference(obj_desc);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_copy_id_string
 *
 * PARAMETERS:  Destination         - Where to copy the string
 *              Source              - Source string
 *              max_length          - Length of the destination buffer
 *
 * RETURN:      None
 *
 * DESCRIPTION: Copies an ID string for the _HID, _CID, and _UID methods.
 *              Performs removal of a leading asterisk if present -- workaround
 *              for a known issue on a bunch of machines.
 *
 ******************************************************************************/

static void
acpi_ut_copy_id_string(char *destination, char *source, acpi_size max_length)
{

	/*
	 * Workaround for ID strings that have a leading asterisk. This construct
	 * is not allowed by the ACPI specification  (ID strings must be
	 * alphanumeric), but enough existing machines have this embedded in their
	 * ID strings that the following code is useful.
	 */
	if (*source == '*') {
		source++;
	}

	/* Do the actual copy */

	ACPI_STRNCPY(destination, source, max_length);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_execute_HID
 *
 * PARAMETERS:  device_node         - Node for the device
 *              Hid                 - Where the HID is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Executes the _HID control method that returns the hardware
 *              ID of the device.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_execute_HID(struct acpi_namespace_node *device_node,
		    struct acpi_device_id *hid)
{
	union acpi_operand_object *obj_desc;
	acpi_status status;

	ACPI_FUNCTION_TRACE(ut_execute_HID);

	status = acpi_ut_evaluate_object(device_node, METHOD_NAME__HID,
					 ACPI_BTYPE_INTEGER | ACPI_BTYPE_STRING,
					 &obj_desc);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_INTEGER) {

		/* Convert the Numeric HID to string */

		acpi_ex_eisa_id_to_string((u32) obj_desc->integer.value,
					  hid->value);
	} else {
		/* Copy the String HID from the returned object */

		acpi_ut_copy_id_string(hid->value, obj_desc->string.pointer,
				       sizeof(hid->value));
	}

	/* On exit, we must delete the return object */

	acpi_ut_remove_reference(obj_desc);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_translate_one_cid
 *
 * PARAMETERS:  obj_desc            - _CID object, must be integer or string
 *              one_cid             - Where the CID string is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Return a numeric or string _CID value as a string.
 *              (Compatible ID)
 *
 *              NOTE:  Assumes a maximum _CID string length of
 *                     ACPI_MAX_CID_LENGTH.
 *
 ******************************************************************************/

static acpi_status
acpi_ut_translate_one_cid(union acpi_operand_object *obj_desc,
			  struct acpi_compatible_id *one_cid)
{

	switch (ACPI_GET_OBJECT_TYPE(obj_desc)) {
	case ACPI_TYPE_INTEGER:

		/* Convert the Numeric CID to string */

		acpi_ex_eisa_id_to_string((u32) obj_desc->integer.value,
					  one_cid->value);
		return (AE_OK);

	case ACPI_TYPE_STRING:

		if (obj_desc->string.length > ACPI_MAX_CID_LENGTH) {
			return (AE_AML_STRING_LIMIT);
		}

		/* Copy the String CID from the returned object */

		acpi_ut_copy_id_string(one_cid->value, obj_desc->string.pointer,
				       ACPI_MAX_CID_LENGTH);
		return (AE_OK);

	default:

		return (AE_TYPE);
	}
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_execute_CID
 *
 * PARAMETERS:  device_node         - Node for the device
 *              return_cid_list     - Where the CID list is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Executes the _CID control method that returns one or more
 *              compatible hardware IDs for the device.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_execute_CID(struct acpi_namespace_node * device_node,
		    struct acpi_compatible_id_list ** return_cid_list)
{
	union acpi_operand_object *obj_desc;
	acpi_status status;
	u32 count;
	u32 size;
	struct acpi_compatible_id_list *cid_list;
	acpi_native_uint i;

	ACPI_FUNCTION_TRACE(ut_execute_CID);

	/* Evaluate the _CID method for this device */

	status = acpi_ut_evaluate_object(device_node, METHOD_NAME__CID,
					 ACPI_BTYPE_INTEGER | ACPI_BTYPE_STRING
					 | ACPI_BTYPE_PACKAGE, &obj_desc);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Get the number of _CIDs returned */

	count = 1;
	if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_PACKAGE) {
		count = obj_desc->package.count;
	}

	/* Allocate a worst-case buffer for the _CIDs */

	size = (((count - 1) * sizeof(struct acpi_compatible_id)) +
		sizeof(struct acpi_compatible_id_list));

	cid_list = ACPI_ALLOCATE_ZEROED((acpi_size) size);
	if (!cid_list) {
		return_ACPI_STATUS(AE_NO_MEMORY);
	}

	/* Init CID list */

	cid_list->count = count;
	cid_list->size = size;

	/*
	 *  A _CID can return either a single compatible ID or a package of
	 *  compatible IDs.  Each compatible ID can be one of the following:
	 *  1) Integer (32 bit compressed EISA ID) or
	 *  2) String (PCI ID format, e.g. "PCI\VEN_vvvv&DEV_dddd&SUBSYS_ssssssss")
	 */

	/* The _CID object can be either a single CID or a package (list) of CIDs */

	if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_PACKAGE) {

		/* Translate each package element */

		for (i = 0; i < count; i++) {
			status =
			    acpi_ut_translate_one_cid(obj_desc->package.
						      elements[i],
						      &cid_list->id[i]);
			if (ACPI_FAILURE(status)) {
				break;
			}
		}
	} else {
		/* Only one CID, translate to a string */

		status = acpi_ut_translate_one_cid(obj_desc, cid_list->id);
	}

	/* Cleanup on error */

	if (ACPI_FAILURE(status)) {
		ACPI_FREE(cid_list);
	} else {
		*return_cid_list = cid_list;
	}

	/* On exit, we must delete the _CID return object */

	acpi_ut_remove_reference(obj_desc);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_execute_UID
 *
 * PARAMETERS:  device_node         - Node for the device
 *              Uid                 - Where the UID is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Executes the _UID control method that returns the hardware
 *              ID of the device.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_execute_UID(struct acpi_namespace_node *device_node,
		    struct acpi_device_id *uid)
{
	union acpi_operand_object *obj_desc;
	acpi_status status;

	ACPI_FUNCTION_TRACE(ut_execute_UID);

	status = acpi_ut_evaluate_object(device_node, METHOD_NAME__UID,
					 ACPI_BTYPE_INTEGER | ACPI_BTYPE_STRING,
					 &obj_desc);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_INTEGER) {

		/* Convert the Numeric UID to string */

		acpi_ex_unsigned_integer_to_string(obj_desc->integer.value,
						   uid->value);
	} else {
		/* Copy the String UID from the returned object */

		acpi_ut_copy_id_string(uid->value, obj_desc->string.pointer,
				       sizeof(uid->value));
	}

	/* On exit, we must delete the return object */

	acpi_ut_remove_reference(obj_desc);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_execute_STA
 *
 * PARAMETERS:  device_node         - Node for the device
 *              Flags               - Where the status flags are returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Executes _STA for selected device and stores results in
 *              *Flags.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_execute_STA(struct acpi_namespace_node *device_node, u32 * flags)
{
	union acpi_operand_object *obj_desc;
	acpi_status status;

	ACPI_FUNCTION_TRACE(ut_execute_STA);

	status = acpi_ut_evaluate_object(device_node, METHOD_NAME__STA,
					 ACPI_BTYPE_INTEGER, &obj_desc);
	if (ACPI_FAILURE(status)) {
		if (AE_NOT_FOUND == status) {
			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)));

			*flags = ACPI_UINT32_MAX;
			status = AE_OK;
		}

		return_ACPI_STATUS(status);
	}

	/* Extract the status flags */

	*flags = (u32) obj_desc->integer.value;

	/* On exit, we must delete the return object */

	acpi_ut_remove_reference(obj_desc);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_execute_Sxds
 *
 * PARAMETERS:  device_node         - Node for the device
 *              Flags               - Where the status flags are returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Executes _STA for selected device and stores results in
 *              *Flags.
 *
 *              NOTE: Internal function, no parameter validation
 *
 ******************************************************************************/

acpi_status
acpi_ut_execute_sxds(struct acpi_namespace_node *device_node, u8 * highest)
{
	union acpi_operand_object *obj_desc;
	acpi_status status;
	u32 i;

	ACPI_FUNCTION_TRACE(ut_execute_sxds);

	for (i = 0; i < 4; i++) {
		highest[i] = 0xFF;
		status = acpi_ut_evaluate_object(device_node,
						 ACPI_CAST_PTR(char,
							       acpi_gbl_highest_dstate_names
							       [i]),
						 ACPI_BTYPE_INTEGER, &obj_desc);
		if (ACPI_FAILURE(status)) {
			if (status != AE_NOT_FOUND) {
				ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
						  "%s on Device %4.4s, %s\n",
						  ACPI_CAST_PTR(char,
								acpi_gbl_highest_dstate_names
								[i]),
						  acpi_ut_get_node_name
						  (device_node),
						  acpi_format_exception
						  (status)));

				return_ACPI_STATUS(status);
			}
		} else {
			/* Extract the Dstate value */

			highest[i] = (u8) obj_desc->integer.value;

			/* Delete the return object */

			acpi_ut_remove_reference(obj_desc);
		}
	}

	return_ACPI_STATUS(AE_OK);
}