wmi_acpi.c revision 1.8 1 /* $NetBSD: wmi_acpi.c,v 1.8 2010/10/24 15:07:20 jmcneill Exp $ */
2
3 /*-
4 * Copyright (c) 2009, 2010 Jukka Ruohonen <jruohonen (at) iki.fi>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: wmi_acpi.c,v 1.8 2010/10/24 15:07:20 jmcneill Exp $");
31
32 #include <sys/param.h>
33 #include <sys/device.h>
34 #include <sys/endian.h>
35 #include <sys/kmem.h>
36 #include <sys/systm.h>
37
38 #include <dev/acpi/acpireg.h>
39 #include <dev/acpi/acpivar.h>
40 #include <dev/acpi/wmi/wmi_acpivar.h>
41
42 #define _COMPONENT ACPI_RESOURCE_COMPONENT
43 ACPI_MODULE_NAME ("wmi_acpi")
44
45 /*
46 * This implements something called "Microsoft Windows Management
47 * Instrumentation" (WMI). This subset of ACPI is desribed in:
48 *
49 * http://www.microsoft.com/whdc/system/pnppwr/wmi/wmi-acpi.mspx
50 *
51 * (Obtained on Thu Feb 12 18:21:44 EET 2009.)
52 */
53
54 static int acpi_wmi_match(device_t, cfdata_t, void *);
55 static void acpi_wmi_attach(device_t, device_t, void *);
56 static int acpi_wmi_detach(device_t, int);
57 static int acpi_wmi_rescan(device_t, const char *, const int *);
58 static void acpi_wmi_childdet(device_t, device_t);
59 static int acpi_wmi_print(void *, const char *);
60 static bool acpi_wmi_init(struct acpi_wmi_softc *);
61 static bool acpi_wmi_add(struct acpi_wmi_softc *, ACPI_OBJECT *);
62 static void acpi_wmi_del(struct acpi_wmi_softc *);
63 static void acpi_wmi_dump(struct acpi_wmi_softc *);
64
65 static ACPI_STATUS acpi_wmi_guid_get(struct acpi_wmi_softc *,
66 const char *, struct wmi_t **);
67 static void acpi_wmi_event_add(struct acpi_wmi_softc *);
68 static void acpi_wmi_event_del(struct acpi_wmi_softc *);
69 static void acpi_wmi_event_handler(ACPI_HANDLE, uint32_t, void *);
70 static bool acpi_wmi_suspend(device_t, const pmf_qual_t *);
71 static bool acpi_wmi_resume(device_t, const pmf_qual_t *);
72 static ACPI_STATUS acpi_wmi_enable(ACPI_HANDLE, const char *, bool, bool);
73 static bool acpi_wmi_input(struct wmi_t *, uint8_t, uint8_t);
74
75 const char * const acpi_wmi_ids[] = {
76 "PNP0C14",
77 "pnp0c14",
78 NULL
79 };
80
81 CFATTACH_DECL2_NEW(acpiwmi, sizeof(struct acpi_wmi_softc),
82 acpi_wmi_match, acpi_wmi_attach, acpi_wmi_detach, NULL,
83 acpi_wmi_rescan, acpi_wmi_childdet);
84
85 static int
86 acpi_wmi_match(device_t parent, cfdata_t match, void *aux)
87 {
88 struct acpi_attach_args *aa = aux;
89
90 if (aa->aa_node->ad_type != ACPI_TYPE_DEVICE)
91 return 0;
92
93 return acpi_match_hid(aa->aa_node->ad_devinfo, acpi_wmi_ids);
94 }
95
96 static void
97 acpi_wmi_attach(device_t parent, device_t self, void *aux)
98 {
99 struct acpi_wmi_softc *sc = device_private(self);
100 struct acpi_attach_args *aa = aux;
101
102 sc->sc_dev = self;
103 sc->sc_node = aa->aa_node;
104
105 sc->sc_child = NULL;
106 sc->sc_handler = NULL;
107
108 aprint_naive("\n");
109 aprint_normal(": ACPI WMI Interface\n");
110
111 if (acpi_wmi_init(sc) != true)
112 return;
113
114 acpi_wmi_dump(sc);
115 acpi_wmi_event_add(sc);
116
117 acpi_wmi_rescan(self, NULL, NULL);
118
119 (void)pmf_device_register(self, acpi_wmi_suspend, acpi_wmi_resume);
120 }
121
122 static int
123 acpi_wmi_detach(device_t self, int flags)
124 {
125 struct acpi_wmi_softc *sc = device_private(self);
126
127 acpi_wmi_event_del(sc);
128
129 if (sc->sc_child != NULL)
130 (void)config_detach(sc->sc_child, flags);
131
132 acpi_wmi_del(sc);
133 pmf_device_deregister(self);
134
135 return 0;
136 }
137
138 static int
139 acpi_wmi_rescan(device_t self, const char *ifattr, const int *locators)
140 {
141 struct acpi_wmi_softc *sc = device_private(self);
142
143 if (ifattr_match(ifattr, "acpiwmibus") && sc->sc_child == NULL)
144 sc->sc_child = config_found_ia(self, "acpiwmibus",
145 NULL, acpi_wmi_print);
146
147 return 0;
148 }
149
150 static void
151 acpi_wmi_childdet(device_t self, device_t child)
152 {
153 struct acpi_wmi_softc *sc = device_private(self);
154
155 if (sc->sc_child == child)
156 sc->sc_child = NULL;
157 }
158
159 static int
160 acpi_wmi_print(void *aux, const char *pnp)
161 {
162
163 if (pnp != NULL)
164 aprint_normal("acpiwmibus at %s", pnp);
165
166 return UNCONF;
167 }
168
169 static bool
170 acpi_wmi_init(struct acpi_wmi_softc *sc)
171 {
172 ACPI_OBJECT *obj;
173 ACPI_BUFFER buf;
174 ACPI_STATUS rv;
175 uint32_t len;
176
177 rv = acpi_eval_struct(sc->sc_node->ad_handle, "_WDG", &buf);
178
179 if (ACPI_FAILURE(rv))
180 goto fail;
181
182 obj = buf.Pointer;
183
184 if (obj->Type != ACPI_TYPE_BUFFER) {
185 rv = AE_TYPE;
186 goto fail;
187 }
188
189 len = obj->Buffer.Length;
190
191 if (len != obj->Package.Count) {
192 rv = AE_BAD_VALUE;
193 goto fail;
194 }
195
196 CTASSERT(sizeof(struct guid_t) == 20);
197
198 if (len < sizeof(struct guid_t) ||
199 len % sizeof(struct guid_t) != 0) {
200 rv = AE_BAD_DATA;
201 goto fail;
202 }
203
204 return acpi_wmi_add(sc, obj);
205
206 fail:
207 aprint_error_dev(sc->sc_dev, "failed to evaluate _WDG: %s\n",
208 AcpiFormatException(rv));
209
210 if (buf.Pointer != NULL)
211 ACPI_FREE(buf.Pointer);
212
213 return false;
214 }
215
216 static bool
217 acpi_wmi_add(struct acpi_wmi_softc *sc, ACPI_OBJECT *obj)
218 {
219 struct wmi_t *wmi;
220 size_t i, n, offset, siz;
221
222 siz = sizeof(struct guid_t);
223 n = obj->Buffer.Length / siz;
224
225 SIMPLEQ_INIT(&sc->wmi_head);
226
227 for (i = offset = 0; i < n; ++i) {
228
229 if ((wmi = kmem_zalloc(sizeof(*wmi), KM_NOSLEEP)) == NULL)
230 goto fail;
231
232 (void)memcpy(&wmi->guid, obj->Buffer.Pointer + offset, siz);
233
234 wmi->eevent = false;
235 offset = offset + siz;
236
237 SIMPLEQ_INSERT_TAIL(&sc->wmi_head, wmi, wmi_link);
238 }
239
240 ACPI_FREE(obj);
241
242 return true;
243
244 fail:
245 ACPI_FREE(obj);
246 acpi_wmi_del(sc);
247
248 return false;
249 }
250
251 static void
252 acpi_wmi_del(struct acpi_wmi_softc *sc)
253 {
254 struct wmi_t *wmi;
255
256 if (SIMPLEQ_EMPTY(&sc->wmi_head) != 0)
257 return;
258
259 while (SIMPLEQ_FIRST(&sc->wmi_head) != NULL) {
260
261 wmi = SIMPLEQ_FIRST(&sc->wmi_head);
262 SIMPLEQ_REMOVE_HEAD(&sc->wmi_head, wmi_link);
263
264 KASSERT(wmi != NULL);
265
266 kmem_free(wmi, sizeof(*wmi));
267 }
268 }
269
270 static void
271 acpi_wmi_dump(struct acpi_wmi_softc *sc)
272 {
273 struct wmi_t *wmi;
274
275 KASSERT(SIMPLEQ_EMPTY(&sc->wmi_head) == 0);
276
277 SIMPLEQ_FOREACH(wmi, &sc->wmi_head, wmi_link) {
278
279 aprint_debug_dev(sc->sc_dev, "{%08X-%04X-%04X-",
280 wmi->guid.data1, wmi->guid.data2, wmi->guid.data3);
281
282 aprint_debug("%02X%02X-%02X%02X%02X%02X%02X%02X} ",
283 wmi->guid.data4[0], wmi->guid.data4[1],
284 wmi->guid.data4[2], wmi->guid.data4[3],
285 wmi->guid.data4[4], wmi->guid.data4[5],
286 wmi->guid.data4[6], wmi->guid.data4[7]);
287
288 aprint_debug("oid %04X count %02X flags %02X\n",
289 UGET16(wmi->guid.oid), wmi->guid.count, wmi->guid.flags);
290 }
291 }
292
293 static ACPI_STATUS
294 acpi_wmi_guid_get(struct acpi_wmi_softc *sc,
295 const char *src, struct wmi_t **out)
296 {
297 struct wmi_t *wmi;
298 struct guid_t *guid;
299 char bin[16];
300 char hex[2];
301 const char *ptr;
302 uint8_t i;
303
304 if (sc == NULL || src == NULL || strlen(src) != 36)
305 return AE_BAD_PARAMETER;
306
307 for (ptr = src, i = 0; i < 16; i++) {
308
309 if (*ptr == '-')
310 ptr++;
311
312 (void)memcpy(hex, ptr, 2);
313
314 if (HEXCHAR(hex[0]) == 0 || HEXCHAR(hex[1]) == 0)
315 return AE_BAD_HEX_CONSTANT;
316
317 bin[i] = strtoul(hex, NULL, 16) & 0xFF;
318
319 ptr++;
320 ptr++;
321 }
322
323 guid = (struct guid_t *)bin;
324 guid->data1 = be32toh(guid->data1);
325 guid->data2 = be16toh(guid->data2);
326 guid->data3 = be16toh(guid->data3);
327
328 SIMPLEQ_FOREACH(wmi, &sc->wmi_head, wmi_link) {
329
330 if (GUIDCMP(guid, &wmi->guid) != 0) {
331
332 if (out != NULL)
333 *out = wmi;
334
335 return AE_OK;
336 }
337 }
338
339 return AE_NOT_FOUND;
340 }
341
342 /*
343 * Checks if a GUID is present. Child devices
344 * can use this in their autoconf(9) routines.
345 */
346 int
347 acpi_wmi_guid_match(device_t self, const char *guid)
348 {
349 struct acpi_wmi_softc *sc = device_private(self);
350 ACPI_STATUS rv;
351
352 rv = acpi_wmi_guid_get(sc, guid, NULL);
353
354 if (ACPI_SUCCESS(rv))
355 return 1;
356
357 return 0;
358 }
359
360 /*
361 * Adds internal event handler.
362 */
363 static void
364 acpi_wmi_event_add(struct acpi_wmi_softc *sc)
365 {
366 struct wmi_t *wmi;
367 ACPI_STATUS rv;
368
369 if (acpi_register_notify(sc->sc_node, acpi_wmi_event_handler) != true)
370 return;
371
372 /*
373 * Enable possible expensive events.
374 */
375 SIMPLEQ_FOREACH(wmi, &sc->wmi_head, wmi_link) {
376
377 if ((wmi->guid.flags & ACPI_WMI_FLAG_EVENT) != 0 &&
378 (wmi->guid.flags & ACPI_WMI_FLAG_EXPENSIVE) != 0) {
379
380 rv = acpi_wmi_enable(sc->sc_node->ad_handle,
381 wmi->guid.oid, false, true);
382
383 if (ACPI_SUCCESS(rv)) {
384 wmi->eevent = true;
385 continue;
386 }
387
388 aprint_debug_dev(sc->sc_dev, "failed to enable "
389 "expensive WExx: %s\n", AcpiFormatException(rv));
390 }
391 }
392 }
393
394 /*
395 * Removes the internal event handler.
396 */
397 static void
398 acpi_wmi_event_del(struct acpi_wmi_softc *sc)
399 {
400 struct wmi_t *wmi;
401 ACPI_STATUS rv;
402
403 acpi_deregister_notify(sc->sc_node);
404
405 SIMPLEQ_FOREACH(wmi, &sc->wmi_head, wmi_link) {
406
407 if (wmi->eevent != true)
408 continue;
409
410 KASSERT((wmi->guid.flags & ACPI_WMI_FLAG_EVENT) != 0);
411 KASSERT((wmi->guid.flags & ACPI_WMI_FLAG_EXPENSIVE) != 0);
412
413 rv = acpi_wmi_enable(sc->sc_node->ad_handle,
414 wmi->guid.oid, false, false);
415
416 if (ACPI_SUCCESS(rv)) {
417 wmi->eevent = false;
418 continue;
419 }
420
421 aprint_debug_dev(sc->sc_dev, "failed to disable "
422 "expensive WExx: %s\n", AcpiFormatException(rv));
423 }
424 }
425
426 /*
427 * Returns extra information possibly associated with an event.
428 */
429 ACPI_STATUS
430 acpi_wmi_event_get(device_t self, uint32_t event, ACPI_BUFFER *obuf)
431 {
432 struct acpi_wmi_softc *sc = device_private(self);
433 struct wmi_t *wmi;
434 ACPI_OBJECT_LIST arg;
435 ACPI_OBJECT obj;
436 ACPI_HANDLE hdl;
437
438 if (sc == NULL || obuf == NULL)
439 return AE_BAD_PARAMETER;
440
441 if (sc->sc_handler == NULL)
442 return AE_ABORT_METHOD;
443
444 hdl = sc->sc_node->ad_handle;
445
446 obj.Type = ACPI_TYPE_INTEGER;
447 obj.Integer.Value = event;
448
449 arg.Count = 0x01;
450 arg.Pointer = &obj;
451
452 obuf->Pointer = NULL;
453 obuf->Length = ACPI_ALLOCATE_LOCAL_BUFFER;
454
455 SIMPLEQ_FOREACH(wmi, &sc->wmi_head, wmi_link) {
456
457 if ((wmi->guid.flags & ACPI_WMI_FLAG_EVENT) == 0)
458 continue;
459
460 if (wmi->guid.nid != event)
461 continue;
462
463 return AcpiEvaluateObject(hdl, "_WED", &arg, obuf);
464 }
465
466 return AE_NOT_FOUND;
467 }
468
469 /*
470 * Forwards events to the external handler through the internal one.
471 */
472 static void
473 acpi_wmi_event_handler(ACPI_HANDLE hdl, uint32_t evt, void *aux)
474 {
475 struct acpi_wmi_softc *sc;
476 device_t self = aux;
477
478 sc = device_private(self);
479
480 if (sc->sc_child == NULL)
481 return;
482
483 if (sc->sc_handler == NULL)
484 return;
485
486 (*sc->sc_handler)(NULL, evt, sc->sc_child);
487 }
488
489 ACPI_STATUS
490 acpi_wmi_event_register(device_t self, ACPI_NOTIFY_HANDLER handler)
491 {
492 struct acpi_wmi_softc *sc = device_private(self);
493
494 if (sc == NULL)
495 return AE_BAD_PARAMETER;
496
497 if (handler != NULL && sc->sc_handler != NULL)
498 return AE_ALREADY_EXISTS;
499
500 sc->sc_handler = handler;
501
502 return AE_OK;
503 }
504
505 ACPI_STATUS
506 acpi_wmi_event_deregister(device_t self)
507 {
508 return acpi_wmi_event_register(self, NULL);
509 }
510
511 /*
512 * As there is no prior knowledge about the expensive
513 * events that cause "significant overhead", try to
514 * disable (enable) these before suspending (resuming).
515 */
516 static bool
517 acpi_wmi_suspend(device_t self, const pmf_qual_t *qual)
518 {
519 struct acpi_wmi_softc *sc = device_private(self);
520
521 acpi_wmi_event_del(sc);
522
523 return true;
524 }
525
526 static bool
527 acpi_wmi_resume(device_t self, const pmf_qual_t *qual)
528 {
529 struct acpi_wmi_softc *sc = device_private(self);
530
531 acpi_wmi_event_add(sc);
532
533 return true;
534 }
535
536 /*
537 * Enables or disables data collection (WCxx) or an event (WExx).
538 */
539 static ACPI_STATUS
540 acpi_wmi_enable(ACPI_HANDLE hdl, const char *oid, bool data, bool flag)
541 {
542 char path[5];
543 const char *str;
544
545 str = (data != false) ? "WC" : "WE";
546
547 (void)strlcpy(path, str, sizeof(path));
548 (void)strlcat(path, oid, sizeof(path));
549
550 return acpi_eval_set_integer(hdl, path, (flag != false) ? 0x01 : 0x00);
551 }
552
553 static bool
554 acpi_wmi_input(struct wmi_t *wmi, uint8_t flag, uint8_t idx)
555 {
556
557 if ((wmi->guid.flags & flag) == 0)
558 return false;
559
560 if (wmi->guid.count == 0x00)
561 return false;
562
563 if (wmi->guid.count < idx)
564 return false;
565
566 return true;
567 }
568
569 /*
570 * Makes a WMI data block query (WQxx). The corresponding control
571 * method for data collection will be invoked if it is available.
572 */
573 ACPI_STATUS
574 acpi_wmi_data_query(device_t self, const char *guid,
575 uint8_t idx, ACPI_BUFFER *obuf)
576 {
577 struct acpi_wmi_softc *sc = device_private(self);
578 struct wmi_t *wmi;
579 char path[5] = "WQ";
580 ACPI_OBJECT_LIST arg;
581 ACPI_STATUS rv, rvxx;
582 ACPI_OBJECT obj;
583
584 rvxx = AE_SUPPORT;
585
586 if (obuf == NULL)
587 return AE_BAD_PARAMETER;
588
589 rv = acpi_wmi_guid_get(sc, guid, &wmi);
590
591 if (ACPI_FAILURE(rv))
592 return rv;
593
594 if (acpi_wmi_input(wmi, ACPI_WMI_FLAG_DATA, idx) != true)
595 return AE_BAD_DATA;
596
597 (void)strlcat(path, wmi->guid.oid, sizeof(path));
598
599 obj.Type = ACPI_TYPE_INTEGER;
600 obj.Integer.Value = idx;
601
602 arg.Count = 0x01;
603 arg.Pointer = &obj;
604
605 obuf->Pointer = NULL;
606 obuf->Length = ACPI_ALLOCATE_LOCAL_BUFFER;
607
608 /*
609 * If the expensive flag is set, we should enable
610 * data collection before evaluating the WQxx buffer.
611 */
612 if ((wmi->guid.flags & ACPI_WMI_FLAG_EXPENSIVE) != 0) {
613
614 rvxx = acpi_wmi_enable(sc->sc_node->ad_handle,
615 wmi->guid.oid, true, true);
616 }
617
618 rv = AcpiEvaluateObject(sc->sc_node->ad_handle, path, &arg, obuf);
619
620 /* No longer needed. */
621 if (ACPI_SUCCESS(rvxx)) {
622
623 (void)acpi_wmi_enable(sc->sc_node->ad_handle,
624 wmi->guid.oid, true, false);
625 }
626
627 #ifdef DIAGNOSTIC
628 /*
629 * XXX: It appears that quite a few laptops have WQxx
630 * methods that are declared as expensive, but lack the
631 * corresponding WCxx control method.
632 *
633 * -- Acer Aspire One is one example <jruohonen (at) iki.fi>.
634 */
635 if (ACPI_FAILURE(rvxx) && rvxx != AE_SUPPORT)
636 aprint_error_dev(sc->sc_dev, "failed to evaluate WCxx "
637 "for %s: %s\n", path, AcpiFormatException(rvxx));
638 #endif
639 return rv;
640 }
641
642 /*
643 * Writes to a data block (WSxx).
644 */
645 ACPI_STATUS
646 acpi_wmi_data_write(device_t self, const char *guid,
647 uint8_t idx, ACPI_BUFFER *ibuf)
648 {
649 struct acpi_wmi_softc *sc = device_private(self);
650 struct wmi_t *wmi;
651 ACPI_OBJECT_LIST arg;
652 ACPI_OBJECT obj[2];
653 char path[5] = "WS";
654 ACPI_STATUS rv;
655
656 if (ibuf == NULL)
657 return AE_BAD_PARAMETER;
658
659 rv = acpi_wmi_guid_get(sc, guid, &wmi);
660
661 if (ACPI_FAILURE(rv))
662 return rv;
663
664 if (acpi_wmi_input(wmi, ACPI_WMI_FLAG_DATA, idx) != true)
665 return AE_BAD_DATA;
666
667 (void)strlcat(path, wmi->guid.oid, sizeof(path));
668
669 obj[0].Integer.Value = idx;
670 obj[0].Type = ACPI_TYPE_INTEGER;
671
672 obj[1].Buffer.Length = ibuf->Length;
673 obj[1].Buffer.Pointer = ibuf->Pointer;
674
675 obj[1].Type = ((wmi->guid.flags & ACPI_WMI_FLAG_STRING) != 0) ?
676 ACPI_TYPE_STRING : ACPI_TYPE_BUFFER;
677
678 arg.Count = 0x02;
679 arg.Pointer = obj;
680
681 return AcpiEvaluateObject(sc->sc_node->ad_handle, path, &arg, NULL);
682 }
683
684 /*
685 * Executes a method (WMxx).
686 */
687 ACPI_STATUS
688 acpi_wmi_method(device_t self, const char *guid, uint8_t idx,
689 uint32_t mid, ACPI_BUFFER *ibuf, ACPI_BUFFER *obuf)
690 {
691 struct acpi_wmi_softc *sc = device_private(self);
692 struct wmi_t *wmi;
693 ACPI_OBJECT_LIST arg;
694 ACPI_OBJECT obj[3];
695 char path[5] = "WM";
696 ACPI_STATUS rv;
697
698 if (ibuf == NULL || obuf == NULL)
699 return AE_BAD_PARAMETER;
700
701 rv = acpi_wmi_guid_get(sc, guid, &wmi);
702
703 if (ACPI_FAILURE(rv))
704 return rv;
705
706 if (acpi_wmi_input(wmi, ACPI_WMI_FLAG_METHOD, idx) != true)
707 return AE_BAD_DATA;
708
709 (void)strlcat(path, wmi->guid.oid, sizeof(path));
710
711 obj[0].Integer.Value = idx;
712 obj[1].Integer.Value = mid;
713 obj[0].Type = obj[1].Type = ACPI_TYPE_INTEGER;
714
715 obj[2].Buffer.Length = ibuf->Length;
716 obj[2].Buffer.Pointer = ibuf->Pointer;
717
718 obj[2].Type = ((wmi->guid.flags & ACPI_WMI_FLAG_STRING) != 0) ?
719 ACPI_TYPE_STRING : ACPI_TYPE_BUFFER;
720
721 arg.Count = 0x03;
722 arg.Pointer = obj;
723
724 obuf->Pointer = NULL;
725 obuf->Length = ACPI_ALLOCATE_LOCAL_BUFFER;
726
727 return AcpiEvaluateObject(sc->sc_node->ad_handle, path, &arg, obuf);
728 }
729