Merge branch 'topic/usb-caiaq' into for-linus
[linux-2.6] / drivers / platform / x86 / wmi.c
1 /*
2  *  ACPI-WMI mapping driver
3  *
4  *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
5  *
6  *  GUID parsing code from ldm.c is:
7  *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
8  *   Copyright (c) 2001-2007 Anton Altaparmakov
9  *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
10  *
11  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12  *
13  *  This program is free software; you can redistribute it and/or modify
14  *  it under the terms of the GNU General Public License as published by
15  *  the Free Software Foundation; either version 2 of the License, or (at
16  *  your option) any later version.
17  *
18  *  This program is distributed in the hope that it will be useful, but
19  *  WITHOUT ANY WARRANTY; without even the implied warranty of
20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  *  General Public License for more details.
22  *
23  *  You should have received a copy of the GNU General Public License along
24  *  with this program; if not, write to the Free Software Foundation, Inc.,
25  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
26  *
27  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
28  */
29
30 #include <linux/kernel.h>
31 #include <linux/init.h>
32 #include <linux/types.h>
33 #include <linux/list.h>
34 #include <linux/acpi.h>
35 #include <acpi/acpi_bus.h>
36 #include <acpi/acpi_drivers.h>
37
38 ACPI_MODULE_NAME("wmi");
39 MODULE_AUTHOR("Carlos Corbacho");
40 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
41 MODULE_LICENSE("GPL");
42
43 #define ACPI_WMI_CLASS "wmi"
44
45 #undef PREFIX
46 #define PREFIX "ACPI: WMI: "
47
48 static DEFINE_MUTEX(wmi_data_lock);
49
50 struct guid_block {
51         char guid[16];
52         union {
53                 char object_id[2];
54                 struct {
55                         unsigned char notify_id;
56                         unsigned char reserved;
57                 };
58         };
59         u8 instance_count;
60         u8 flags;
61 };
62
63 struct wmi_block {
64         struct list_head list;
65         struct guid_block gblock;
66         acpi_handle handle;
67         wmi_notify_handler handler;
68         void *handler_data;
69 };
70
71 static struct wmi_block wmi_blocks;
72
73 /*
74  * If the GUID data block is marked as expensive, we must enable and
75  * explicitily disable data collection.
76  */
77 #define ACPI_WMI_EXPENSIVE   0x1
78 #define ACPI_WMI_METHOD      0x2        /* GUID is a method */
79 #define ACPI_WMI_STRING      0x4        /* GUID takes & returns a string */
80 #define ACPI_WMI_EVENT       0x8        /* GUID is an event */
81
82 static int acpi_wmi_remove(struct acpi_device *device, int type);
83 static int acpi_wmi_add(struct acpi_device *device);
84
85 static const struct acpi_device_id wmi_device_ids[] = {
86         {"PNP0C14", 0},
87         {"pnp0c14", 0},
88         {"", 0},
89 };
90 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
91
92 static struct acpi_driver acpi_wmi_driver = {
93         .name = "wmi",
94         .class = ACPI_WMI_CLASS,
95         .ids = wmi_device_ids,
96         .ops = {
97                 .add = acpi_wmi_add,
98                 .remove = acpi_wmi_remove,
99                 },
100 };
101
102 /*
103  * GUID parsing functions
104  */
105
106 /**
107  * wmi_parse_hexbyte - Convert a ASCII hex number to a byte
108  * @src:  Pointer to at least 2 characters to convert.
109  *
110  * Convert a two character ASCII hex string to a number.
111  *
112  * Return:  0-255  Success, the byte was parsed correctly
113  *          -1     Error, an invalid character was supplied
114  */
115 static int wmi_parse_hexbyte(const u8 *src)
116 {
117         unsigned int x; /* For correct wrapping */
118         int h;
119
120         /* high part */
121         x = src[0];
122         if (x - '0' <= '9' - '0') {
123                 h = x - '0';
124         } else if (x - 'a' <= 'f' - 'a') {
125                 h = x - 'a' + 10;
126         } else if (x - 'A' <= 'F' - 'A') {
127                 h = x - 'A' + 10;
128         } else {
129                 return -1;
130         }
131         h <<= 4;
132
133         /* low part */
134         x = src[1];
135         if (x - '0' <= '9' - '0')
136                 return h | (x - '0');
137         if (x - 'a' <= 'f' - 'a')
138                 return h | (x - 'a' + 10);
139         if (x - 'A' <= 'F' - 'A')
140                 return h | (x - 'A' + 10);
141         return -1;
142 }
143
144 /**
145  * wmi_swap_bytes - Rearrange GUID bytes to match GUID binary
146  * @src:   Memory block holding binary GUID (16 bytes)
147  * @dest:  Memory block to hold byte swapped binary GUID (16 bytes)
148  *
149  * Byte swap a binary GUID to match it's real GUID value
150  */
151 static void wmi_swap_bytes(u8 *src, u8 *dest)
152 {
153         int i;
154
155         for (i = 0; i <= 3; i++)
156                 memcpy(dest + i, src + (3 - i), 1);
157
158         for (i = 0; i <= 1; i++)
159                 memcpy(dest + 4 + i, src + (5 - i), 1);
160
161         for (i = 0; i <= 1; i++)
162                 memcpy(dest + 6 + i, src + (7 - i), 1);
163
164         memcpy(dest + 8, src + 8, 8);
165 }
166
167 /**
168  * wmi_parse_guid - Convert GUID from ASCII to binary
169  * @src:   36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
170  * @dest:  Memory block to hold binary GUID (16 bytes)
171  *
172  * N.B. The GUID need not be NULL terminated.
173  *
174  * Return:  'true'   @dest contains binary GUID
175  *          'false'  @dest contents are undefined
176  */
177 static bool wmi_parse_guid(const u8 *src, u8 *dest)
178 {
179         static const int size[] = { 4, 2, 2, 2, 6 };
180         int i, j, v;
181
182         if (src[8]  != '-' || src[13] != '-' ||
183                 src[18] != '-' || src[23] != '-')
184                 return false;
185
186         for (j = 0; j < 5; j++, src++) {
187                 for (i = 0; i < size[j]; i++, src += 2, *dest++ = v) {
188                         v = wmi_parse_hexbyte(src);
189                         if (v < 0)
190                                 return false;
191                 }
192         }
193
194         return true;
195 }
196
197 static bool find_guid(const char *guid_string, struct wmi_block **out)
198 {
199         char tmp[16], guid_input[16];
200         struct wmi_block *wblock;
201         struct guid_block *block;
202         struct list_head *p;
203
204         wmi_parse_guid(guid_string, tmp);
205         wmi_swap_bytes(tmp, guid_input);
206
207         list_for_each(p, &wmi_blocks.list) {
208                 wblock = list_entry(p, struct wmi_block, list);
209                 block = &wblock->gblock;
210
211                 if (memcmp(block->guid, guid_input, 16) == 0) {
212                         if (out)
213                                 *out = wblock;
214                         return 1;
215                 }
216         }
217         return 0;
218 }
219
220 static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
221 {
222         struct guid_block *block = NULL;
223         char method[5];
224         struct acpi_object_list input;
225         union acpi_object params[1];
226         acpi_status status;
227         acpi_handle handle;
228
229         block = &wblock->gblock;
230         handle = wblock->handle;
231
232         if (!block)
233                 return AE_NOT_EXIST;
234
235         input.count = 1;
236         input.pointer = params;
237         params[0].type = ACPI_TYPE_INTEGER;
238         params[0].integer.value = enable;
239
240         snprintf(method, 5, "WE%02X", block->notify_id);
241         status = acpi_evaluate_object(handle, method, &input, NULL);
242
243         if (status != AE_OK && status != AE_NOT_FOUND)
244                 return status;
245         else
246                 return AE_OK;
247 }
248
249 /*
250  * Exported WMI functions
251  */
252 /**
253  * wmi_evaluate_method - Evaluate a WMI method
254  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
255  * @instance: Instance index
256  * @method_id: Method ID to call
257  * &in: Buffer containing input for the method call
258  * &out: Empty buffer to return the method results
259  *
260  * Call an ACPI-WMI method
261  */
262 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance,
263 u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
264 {
265         struct guid_block *block = NULL;
266         struct wmi_block *wblock = NULL;
267         acpi_handle handle;
268         acpi_status status;
269         struct acpi_object_list input;
270         union acpi_object params[3];
271         char method[4] = "WM";
272
273         if (!find_guid(guid_string, &wblock))
274                 return AE_ERROR;
275
276         block = &wblock->gblock;
277         handle = wblock->handle;
278
279         if (!(block->flags & ACPI_WMI_METHOD))
280                 return AE_BAD_DATA;
281
282         if (block->instance_count < instance)
283                 return AE_BAD_PARAMETER;
284
285         input.count = 2;
286         input.pointer = params;
287         params[0].type = ACPI_TYPE_INTEGER;
288         params[0].integer.value = instance;
289         params[1].type = ACPI_TYPE_INTEGER;
290         params[1].integer.value = method_id;
291
292         if (in) {
293                 input.count = 3;
294
295                 if (block->flags & ACPI_WMI_STRING) {
296                         params[2].type = ACPI_TYPE_STRING;
297                 } else {
298                         params[2].type = ACPI_TYPE_BUFFER;
299                 }
300                 params[2].buffer.length = in->length;
301                 params[2].buffer.pointer = in->pointer;
302         }
303
304         strncat(method, block->object_id, 2);
305
306         status = acpi_evaluate_object(handle, method, &input, out);
307
308         return status;
309 }
310 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
311
312 /**
313  * wmi_query_block - Return contents of a WMI block
314  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
315  * @instance: Instance index
316  * &out: Empty buffer to return the contents of the data block to
317  *
318  * Return the contents of an ACPI-WMI data block to a buffer
319  */
320 acpi_status wmi_query_block(const char *guid_string, u8 instance,
321 struct acpi_buffer *out)
322 {
323         struct guid_block *block = NULL;
324         struct wmi_block *wblock = NULL;
325         acpi_handle handle, wc_handle;
326         acpi_status status, wc_status = AE_ERROR;
327         struct acpi_object_list input, wc_input;
328         union acpi_object wc_params[1], wq_params[1];
329         char method[4];
330         char wc_method[4] = "WC";
331
332         if (!guid_string || !out)
333                 return AE_BAD_PARAMETER;
334
335         if (!find_guid(guid_string, &wblock))
336                 return AE_ERROR;
337
338         block = &wblock->gblock;
339         handle = wblock->handle;
340
341         if (block->instance_count < instance)
342                 return AE_BAD_PARAMETER;
343
344         /* Check GUID is a data block */
345         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
346                 return AE_ERROR;
347
348         input.count = 1;
349         input.pointer = wq_params;
350         wq_params[0].type = ACPI_TYPE_INTEGER;
351         wq_params[0].integer.value = instance;
352
353         /*
354          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
355          * enable collection.
356          */
357         if (block->flags & ACPI_WMI_EXPENSIVE) {
358                 wc_input.count = 1;
359                 wc_input.pointer = wc_params;
360                 wc_params[0].type = ACPI_TYPE_INTEGER;
361                 wc_params[0].integer.value = 1;
362
363                 strncat(wc_method, block->object_id, 2);
364
365                 /*
366                  * Some GUIDs break the specification by declaring themselves
367                  * expensive, but have no corresponding WCxx method. So we
368                  * should not fail if this happens.
369                  */
370                 wc_status = acpi_get_handle(handle, wc_method, &wc_handle);
371                 if (ACPI_SUCCESS(wc_status))
372                         wc_status = acpi_evaluate_object(handle, wc_method,
373                                 &wc_input, NULL);
374         }
375
376         strcpy(method, "WQ");
377         strncat(method, block->object_id, 2);
378
379         status = acpi_evaluate_object(handle, method, &input, out);
380
381         /*
382          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
383          * the WQxx method failed - we should disable collection anyway.
384          */
385         if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
386                 wc_params[0].integer.value = 0;
387                 status = acpi_evaluate_object(handle,
388                 wc_method, &wc_input, NULL);
389         }
390
391         return status;
392 }
393 EXPORT_SYMBOL_GPL(wmi_query_block);
394
395 /**
396  * wmi_set_block - Write to a WMI block
397  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
398  * @instance: Instance index
399  * &in: Buffer containing new values for the data block
400  *
401  * Write the contents of the input buffer to an ACPI-WMI data block
402  */
403 acpi_status wmi_set_block(const char *guid_string, u8 instance,
404 const struct acpi_buffer *in)
405 {
406         struct guid_block *block = NULL;
407         struct wmi_block *wblock = NULL;
408         acpi_handle handle;
409         struct acpi_object_list input;
410         union acpi_object params[2];
411         char method[4] = "WS";
412
413         if (!guid_string || !in)
414                 return AE_BAD_DATA;
415
416         if (!find_guid(guid_string, &wblock))
417                 return AE_ERROR;
418
419         block = &wblock->gblock;
420         handle = wblock->handle;
421
422         if (block->instance_count < instance)
423                 return AE_BAD_PARAMETER;
424
425         /* Check GUID is a data block */
426         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
427                 return AE_ERROR;
428
429         input.count = 2;
430         input.pointer = params;
431         params[0].type = ACPI_TYPE_INTEGER;
432         params[0].integer.value = instance;
433
434         if (block->flags & ACPI_WMI_STRING) {
435                 params[1].type = ACPI_TYPE_STRING;
436         } else {
437                 params[1].type = ACPI_TYPE_BUFFER;
438         }
439         params[1].buffer.length = in->length;
440         params[1].buffer.pointer = in->pointer;
441
442         strncat(method, block->object_id, 2);
443
444         return acpi_evaluate_object(handle, method, &input, NULL);
445 }
446 EXPORT_SYMBOL_GPL(wmi_set_block);
447
448 /**
449  * wmi_install_notify_handler - Register handler for WMI events
450  * @handler: Function to handle notifications
451  * @data: Data to be returned to handler when event is fired
452  *
453  * Register a handler for events sent to the ACPI-WMI mapper device.
454  */
455 acpi_status wmi_install_notify_handler(const char *guid,
456 wmi_notify_handler handler, void *data)
457 {
458         struct wmi_block *block;
459         acpi_status status;
460
461         if (!guid || !handler)
462                 return AE_BAD_PARAMETER;
463
464         find_guid(guid, &block);
465         if (!block)
466                 return AE_NOT_EXIST;
467
468         if (block->handler)
469                 return AE_ALREADY_ACQUIRED;
470
471         block->handler = handler;
472         block->handler_data = data;
473
474         status = wmi_method_enable(block, 1);
475
476         return status;
477 }
478 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
479
480 /**
481  * wmi_uninstall_notify_handler - Unregister handler for WMI events
482  *
483  * Unregister handler for events sent to the ACPI-WMI mapper device.
484  */
485 acpi_status wmi_remove_notify_handler(const char *guid)
486 {
487         struct wmi_block *block;
488         acpi_status status;
489
490         if (!guid)
491                 return AE_BAD_PARAMETER;
492
493         find_guid(guid, &block);
494         if (!block)
495                 return AE_NOT_EXIST;
496
497         if (!block->handler)
498                 return AE_NULL_ENTRY;
499
500         status = wmi_method_enable(block, 0);
501
502         block->handler = NULL;
503         block->handler_data = NULL;
504
505         return status;
506 }
507 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
508
509 /**
510  * wmi_get_event_data - Get WMI data associated with an event
511  *
512  * @event - Event to find
513  * &out - Buffer to hold event data
514  *
515  * Returns extra data associated with an event in WMI.
516  */
517 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
518 {
519         struct acpi_object_list input;
520         union acpi_object params[1];
521         struct guid_block *gblock;
522         struct wmi_block *wblock;
523         struct list_head *p;
524
525         input.count = 1;
526         input.pointer = params;
527         params[0].type = ACPI_TYPE_INTEGER;
528         params[0].integer.value = event;
529
530         list_for_each(p, &wmi_blocks.list) {
531                 wblock = list_entry(p, struct wmi_block, list);
532                 gblock = &wblock->gblock;
533
534                 if ((gblock->flags & ACPI_WMI_EVENT) &&
535                         (gblock->notify_id == event))
536                         return acpi_evaluate_object(wblock->handle, "_WED",
537                                 &input, out);
538         }
539
540         return AE_NOT_FOUND;
541 }
542 EXPORT_SYMBOL_GPL(wmi_get_event_data);
543
544 /**
545  * wmi_has_guid - Check if a GUID is available
546  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
547  *
548  * Check if a given GUID is defined by _WDG
549  */
550 bool wmi_has_guid(const char *guid_string)
551 {
552         return find_guid(guid_string, NULL);
553 }
554 EXPORT_SYMBOL_GPL(wmi_has_guid);
555
556 /*
557  * Parse the _WDG method for the GUID data blocks
558  */
559 static __init acpi_status parse_wdg(acpi_handle handle)
560 {
561         struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
562         union acpi_object *obj;
563         struct guid_block *gblock;
564         struct wmi_block *wblock;
565         acpi_status status;
566         u32 i, total;
567
568         status = acpi_evaluate_object(handle, "_WDG", NULL, &out);
569
570         if (ACPI_FAILURE(status))
571                 return status;
572
573         obj = (union acpi_object *) out.pointer;
574
575         if (obj->type != ACPI_TYPE_BUFFER)
576                 return AE_ERROR;
577
578         total = obj->buffer.length / sizeof(struct guid_block);
579
580         gblock = kzalloc(obj->buffer.length, GFP_KERNEL);
581         if (!gblock)
582                 return AE_NO_MEMORY;
583
584         memcpy(gblock, obj->buffer.pointer, obj->buffer.length);
585
586         for (i = 0; i < total; i++) {
587                 wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
588                 if (!wblock)
589                         return AE_NO_MEMORY;
590
591                 wblock->gblock = gblock[i];
592                 wblock->handle = handle;
593                 list_add_tail(&wblock->list, &wmi_blocks.list);
594         }
595
596         kfree(out.pointer);
597         kfree(gblock);
598
599         return status;
600 }
601
602 /*
603  * WMI can have EmbeddedControl access regions. In which case, we just want to
604  * hand these off to the EC driver.
605  */
606 static acpi_status
607 acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
608                       u32 bits, acpi_integer * value,
609                       void *handler_context, void *region_context)
610 {
611         int result = 0, i = 0;
612         u8 temp = 0;
613
614         if ((address > 0xFF) || !value)
615                 return AE_BAD_PARAMETER;
616
617         if (function != ACPI_READ && function != ACPI_WRITE)
618                 return AE_BAD_PARAMETER;
619
620         if (bits != 8)
621                 return AE_BAD_PARAMETER;
622
623         if (function == ACPI_READ) {
624                 result = ec_read(address, &temp);
625                 (*value) |= ((acpi_integer)temp) << i;
626         } else {
627                 temp = 0xff & ((*value) >> i);
628                 result = ec_write(address, temp);
629         }
630
631         switch (result) {
632         case -EINVAL:
633                 return AE_BAD_PARAMETER;
634                 break;
635         case -ENODEV:
636                 return AE_NOT_FOUND;
637                 break;
638         case -ETIME:
639                 return AE_TIME;
640                 break;
641         default:
642                 return AE_OK;
643         }
644 }
645
646 static void acpi_wmi_notify(acpi_handle handle, u32 event, void *data)
647 {
648         struct guid_block *block;
649         struct wmi_block *wblock;
650         struct list_head *p;
651         struct acpi_device *device = data;
652
653         list_for_each(p, &wmi_blocks.list) {
654                 wblock = list_entry(p, struct wmi_block, list);
655                 block = &wblock->gblock;
656
657                 if ((block->flags & ACPI_WMI_EVENT) &&
658                         (block->notify_id == event)) {
659                         if (wblock->handler)
660                                 wblock->handler(event, wblock->handler_data);
661
662                         acpi_bus_generate_netlink_event(
663                                 device->pnp.device_class, dev_name(&device->dev),
664                                 event, 0);
665                         break;
666                 }
667         }
668 }
669
670 static int acpi_wmi_remove(struct acpi_device *device, int type)
671 {
672         acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
673                 acpi_wmi_notify);
674
675         acpi_remove_address_space_handler(device->handle,
676                                 ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
677
678         return 0;
679 }
680
681 static int __init acpi_wmi_add(struct acpi_device *device)
682 {
683         acpi_status status;
684         int result = 0;
685
686         status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
687                 acpi_wmi_notify, device);
688         if (ACPI_FAILURE(status)) {
689                 printk(KERN_ERR PREFIX "Error installing notify handler\n");
690                 return -ENODEV;
691         }
692
693         status = acpi_install_address_space_handler(device->handle,
694                                                     ACPI_ADR_SPACE_EC,
695                                                     &acpi_wmi_ec_space_handler,
696                                                     NULL, NULL);
697         if (ACPI_FAILURE(status))
698                 return -ENODEV;
699
700         status = parse_wdg(device->handle);
701         if (ACPI_FAILURE(status)) {
702                 printk(KERN_ERR PREFIX "Error installing EC region handler\n");
703                 return -ENODEV;
704         }
705
706         return result;
707 }
708
709 static int __init acpi_wmi_init(void)
710 {
711         int result;
712
713         INIT_LIST_HEAD(&wmi_blocks.list);
714
715         if (acpi_disabled)
716                 return -ENODEV;
717
718         result = acpi_bus_register_driver(&acpi_wmi_driver);
719
720         if (result < 0) {
721                 printk(KERN_INFO PREFIX "Error loading mapper\n");
722         } else {
723                 printk(KERN_INFO PREFIX "Mapper loaded\n");
724         }
725
726         return result;
727 }
728
729 static void __exit acpi_wmi_exit(void)
730 {
731         struct list_head *p, *tmp;
732         struct wmi_block *wblock;
733
734         acpi_bus_unregister_driver(&acpi_wmi_driver);
735
736         list_for_each_safe(p, tmp, &wmi_blocks.list) {
737                 wblock = list_entry(p, struct wmi_block, list);
738
739                 list_del(p);
740                 kfree(wblock);
741         }
742
743         printk(KERN_INFO PREFIX "Mapper unloaded\n");
744 }
745
746 subsys_initcall(acpi_wmi_init);
747 module_exit(acpi_wmi_exit);