1 /*
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 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
20 */
21
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/init.h>
26 #include <linux/types.h>
27 #include <linux/hardirq.h>
28 #include <linux/acpi.h>
29 #include <linux/dynamic_debug.h>
30
31 #include "internal.h"
32 #include "sleep.h"
33
34 #define _COMPONENT ACPI_BUS_COMPONENT
35 ACPI_MODULE_NAME("utils");
36
37 /* --------------------------------------------------------------------------
38 Object Evaluation Helpers
39 -------------------------------------------------------------------------- */
40 static void
acpi_util_eval_error(acpi_handle h,acpi_string p,acpi_status s)41 acpi_util_eval_error(acpi_handle h, acpi_string p, acpi_status s)
42 {
43 #ifdef ACPI_DEBUG_OUTPUT
44 char prefix[80] = {'\0'};
45 struct acpi_buffer buffer = {sizeof(prefix), prefix};
46 acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);
47 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluate [%s.%s]: %s\n",
48 (char *) prefix, p, acpi_format_exception(s)));
49 #else
50 return;
51 #endif
52 }
53
54 acpi_status
acpi_extract_package(union acpi_object * package,struct acpi_buffer * format,struct acpi_buffer * buffer)55 acpi_extract_package(union acpi_object *package,
56 struct acpi_buffer *format, struct acpi_buffer *buffer)
57 {
58 u32 size_required = 0;
59 u32 tail_offset = 0;
60 char *format_string = NULL;
61 u32 format_count = 0;
62 u32 i = 0;
63 u8 *head = NULL;
64 u8 *tail = NULL;
65
66
67 if (!package || (package->type != ACPI_TYPE_PACKAGE)
68 || (package->package.count < 1)) {
69 printk(KERN_WARNING PREFIX "Invalid package argument\n");
70 return AE_BAD_PARAMETER;
71 }
72
73 if (!format || !format->pointer || (format->length < 1)) {
74 printk(KERN_WARNING PREFIX "Invalid format argument\n");
75 return AE_BAD_PARAMETER;
76 }
77
78 if (!buffer) {
79 printk(KERN_WARNING PREFIX "Invalid buffer argument\n");
80 return AE_BAD_PARAMETER;
81 }
82
83 format_count = (format->length / sizeof(char)) - 1;
84 if (format_count > package->package.count) {
85 printk(KERN_WARNING PREFIX "Format specifies more objects [%d]"
86 " than exist in package [%d].\n",
87 format_count, package->package.count);
88 return AE_BAD_DATA;
89 }
90
91 format_string = format->pointer;
92
93 /*
94 * Calculate size_required.
95 */
96 for (i = 0; i < format_count; i++) {
97
98 union acpi_object *element = &(package->package.elements[i]);
99
100 switch (element->type) {
101
102 case ACPI_TYPE_INTEGER:
103 switch (format_string[i]) {
104 case 'N':
105 size_required += sizeof(u64);
106 tail_offset += sizeof(u64);
107 break;
108 case 'S':
109 size_required +=
110 sizeof(char *) + sizeof(u64) +
111 sizeof(char);
112 tail_offset += sizeof(char *);
113 break;
114 default:
115 printk(KERN_WARNING PREFIX "Invalid package element"
116 " [%d]: got number, expecting"
117 " [%c]\n",
118 i, format_string[i]);
119 return AE_BAD_DATA;
120 break;
121 }
122 break;
123
124 case ACPI_TYPE_STRING:
125 case ACPI_TYPE_BUFFER:
126 switch (format_string[i]) {
127 case 'S':
128 size_required +=
129 sizeof(char *) +
130 (element->string.length * sizeof(char)) +
131 sizeof(char);
132 tail_offset += sizeof(char *);
133 break;
134 case 'B':
135 size_required +=
136 sizeof(u8 *) + element->buffer.length;
137 tail_offset += sizeof(u8 *);
138 break;
139 default:
140 printk(KERN_WARNING PREFIX "Invalid package element"
141 " [%d] got string/buffer,"
142 " expecting [%c]\n",
143 i, format_string[i]);
144 return AE_BAD_DATA;
145 break;
146 }
147 break;
148 case ACPI_TYPE_LOCAL_REFERENCE:
149 switch (format_string[i]) {
150 case 'R':
151 size_required += sizeof(void *);
152 tail_offset += sizeof(void *);
153 break;
154 default:
155 printk(KERN_WARNING PREFIX "Invalid package element"
156 " [%d] got reference,"
157 " expecting [%c]\n",
158 i, format_string[i]);
159 return AE_BAD_DATA;
160 break;
161 }
162 break;
163
164 case ACPI_TYPE_PACKAGE:
165 default:
166 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
167 "Found unsupported element at index=%d\n",
168 i));
169 /* TBD: handle nested packages... */
170 return AE_SUPPORT;
171 break;
172 }
173 }
174
175 /*
176 * Validate output buffer.
177 */
178 if (buffer->length == ACPI_ALLOCATE_BUFFER) {
179 buffer->pointer = ACPI_ALLOCATE_ZEROED(size_required);
180 if (!buffer->pointer)
181 return AE_NO_MEMORY;
182 buffer->length = size_required;
183 } else {
184 if (buffer->length < size_required) {
185 buffer->length = size_required;
186 return AE_BUFFER_OVERFLOW;
187 } else if (buffer->length != size_required ||
188 !buffer->pointer) {
189 return AE_BAD_PARAMETER;
190 }
191 }
192
193 head = buffer->pointer;
194 tail = buffer->pointer + tail_offset;
195
196 /*
197 * Extract package data.
198 */
199 for (i = 0; i < format_count; i++) {
200
201 u8 **pointer = NULL;
202 union acpi_object *element = &(package->package.elements[i]);
203
204 switch (element->type) {
205
206 case ACPI_TYPE_INTEGER:
207 switch (format_string[i]) {
208 case 'N':
209 *((u64 *) head) =
210 element->integer.value;
211 head += sizeof(u64);
212 break;
213 case 'S':
214 pointer = (u8 **) head;
215 *pointer = tail;
216 *((u64 *) tail) =
217 element->integer.value;
218 head += sizeof(u64 *);
219 tail += sizeof(u64);
220 /* NULL terminate string */
221 *tail = (char)0;
222 tail += sizeof(char);
223 break;
224 default:
225 /* Should never get here */
226 break;
227 }
228 break;
229
230 case ACPI_TYPE_STRING:
231 case ACPI_TYPE_BUFFER:
232 switch (format_string[i]) {
233 case 'S':
234 pointer = (u8 **) head;
235 *pointer = tail;
236 memcpy(tail, element->string.pointer,
237 element->string.length);
238 head += sizeof(char *);
239 tail += element->string.length * sizeof(char);
240 /* NULL terminate string */
241 *tail = (char)0;
242 tail += sizeof(char);
243 break;
244 case 'B':
245 pointer = (u8 **) head;
246 *pointer = tail;
247 memcpy(tail, element->buffer.pointer,
248 element->buffer.length);
249 head += sizeof(u8 *);
250 tail += element->buffer.length;
251 break;
252 default:
253 /* Should never get here */
254 break;
255 }
256 break;
257 case ACPI_TYPE_LOCAL_REFERENCE:
258 switch (format_string[i]) {
259 case 'R':
260 *(void **)head =
261 (void *)element->reference.handle;
262 head += sizeof(void *);
263 break;
264 default:
265 /* Should never get here */
266 break;
267 }
268 break;
269 case ACPI_TYPE_PACKAGE:
270 /* TBD: handle nested packages... */
271 default:
272 /* Should never get here */
273 break;
274 }
275 }
276
277 return AE_OK;
278 }
279
280 EXPORT_SYMBOL(acpi_extract_package);
281
282 acpi_status
acpi_evaluate_integer(acpi_handle handle,acpi_string pathname,struct acpi_object_list * arguments,unsigned long long * data)283 acpi_evaluate_integer(acpi_handle handle,
284 acpi_string pathname,
285 struct acpi_object_list *arguments, unsigned long long *data)
286 {
287 acpi_status status = AE_OK;
288 union acpi_object element;
289 struct acpi_buffer buffer = { 0, NULL };
290
291 if (!data)
292 return AE_BAD_PARAMETER;
293
294 buffer.length = sizeof(union acpi_object);
295 buffer.pointer = &element;
296 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
297 if (ACPI_FAILURE(status)) {
298 acpi_util_eval_error(handle, pathname, status);
299 return status;
300 }
301
302 if (element.type != ACPI_TYPE_INTEGER) {
303 acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
304 return AE_BAD_DATA;
305 }
306
307 *data = element.integer.value;
308
309 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Return value [%llu]\n", *data));
310
311 return AE_OK;
312 }
313
314 EXPORT_SYMBOL(acpi_evaluate_integer);
315
316 acpi_status
acpi_evaluate_reference(acpi_handle handle,acpi_string pathname,struct acpi_object_list * arguments,struct acpi_handle_list * list)317 acpi_evaluate_reference(acpi_handle handle,
318 acpi_string pathname,
319 struct acpi_object_list *arguments,
320 struct acpi_handle_list *list)
321 {
322 acpi_status status = AE_OK;
323 union acpi_object *package = NULL;
324 union acpi_object *element = NULL;
325 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
326 u32 i = 0;
327
328
329 if (!list) {
330 return AE_BAD_PARAMETER;
331 }
332
333 /* Evaluate object. */
334
335 status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
336 if (ACPI_FAILURE(status))
337 goto end;
338
339 package = buffer.pointer;
340
341 if ((buffer.length == 0) || !package) {
342 status = AE_BAD_DATA;
343 acpi_util_eval_error(handle, pathname, status);
344 goto end;
345 }
346 if (package->type != ACPI_TYPE_PACKAGE) {
347 status = AE_BAD_DATA;
348 acpi_util_eval_error(handle, pathname, status);
349 goto end;
350 }
351 if (!package->package.count) {
352 status = AE_BAD_DATA;
353 acpi_util_eval_error(handle, pathname, status);
354 goto end;
355 }
356
357 if (package->package.count > ACPI_MAX_HANDLES) {
358 return AE_NO_MEMORY;
359 }
360 list->count = package->package.count;
361
362 /* Extract package data. */
363
364 for (i = 0; i < list->count; i++) {
365
366 element = &(package->package.elements[i]);
367
368 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
369 status = AE_BAD_DATA;
370 acpi_util_eval_error(handle, pathname, status);
371 break;
372 }
373
374 if (!element->reference.handle) {
375 status = AE_NULL_ENTRY;
376 acpi_util_eval_error(handle, pathname, status);
377 break;
378 }
379 /* Get the acpi_handle. */
380
381 list->handles[i] = element->reference.handle;
382 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found reference [%p]\n",
383 list->handles[i]));
384 }
385
386 end:
387 if (ACPI_FAILURE(status)) {
388 list->count = 0;
389 //kfree(list->handles);
390 }
391
392 kfree(buffer.pointer);
393
394 return status;
395 }
396
397 EXPORT_SYMBOL(acpi_evaluate_reference);
398
399 acpi_status
acpi_get_physical_device_location(acpi_handle handle,struct acpi_pld_info ** pld)400 acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld)
401 {
402 acpi_status status;
403 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
404 union acpi_object *output;
405
406 status = acpi_evaluate_object(handle, "_PLD", NULL, &buffer);
407
408 if (ACPI_FAILURE(status))
409 return status;
410
411 output = buffer.pointer;
412
413 if (!output || output->type != ACPI_TYPE_PACKAGE
414 || !output->package.count
415 || output->package.elements[0].type != ACPI_TYPE_BUFFER
416 || output->package.elements[0].buffer.length < ACPI_PLD_REV1_BUFFER_SIZE) {
417 status = AE_TYPE;
418 goto out;
419 }
420
421 status = acpi_decode_pld_buffer(
422 output->package.elements[0].buffer.pointer,
423 output->package.elements[0].buffer.length,
424 pld);
425
426 out:
427 kfree(buffer.pointer);
428 return status;
429 }
430 EXPORT_SYMBOL(acpi_get_physical_device_location);
431
432 /**
433 * acpi_evaluate_ost: Evaluate _OST for hotplug operations
434 * @handle: ACPI device handle
435 * @source_event: source event code
436 * @status_code: status code
437 * @status_buf: optional detailed information (NULL if none)
438 *
439 * Evaluate _OST for hotplug operations. All ACPI hotplug handlers
440 * must call this function when evaluating _OST for hotplug operations.
441 * When the platform does not support _OST, this function has no effect.
442 */
443 acpi_status
acpi_evaluate_ost(acpi_handle handle,u32 source_event,u32 status_code,struct acpi_buffer * status_buf)444 acpi_evaluate_ost(acpi_handle handle, u32 source_event, u32 status_code,
445 struct acpi_buffer *status_buf)
446 {
447 union acpi_object params[3] = {
448 {.type = ACPI_TYPE_INTEGER,},
449 {.type = ACPI_TYPE_INTEGER,},
450 {.type = ACPI_TYPE_BUFFER,}
451 };
452 struct acpi_object_list arg_list = {3, params};
453
454 params[0].integer.value = source_event;
455 params[1].integer.value = status_code;
456 if (status_buf != NULL) {
457 params[2].buffer.pointer = status_buf->pointer;
458 params[2].buffer.length = status_buf->length;
459 } else {
460 params[2].buffer.pointer = NULL;
461 params[2].buffer.length = 0;
462 }
463
464 return acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
465 }
466 EXPORT_SYMBOL(acpi_evaluate_ost);
467
468 /**
469 * acpi_handle_path: Return the object path of handle
470 *
471 * Caller must free the returned buffer
472 */
acpi_handle_path(acpi_handle handle)473 static char *acpi_handle_path(acpi_handle handle)
474 {
475 struct acpi_buffer buffer = {
476 .length = ACPI_ALLOCATE_BUFFER,
477 .pointer = NULL
478 };
479
480 if (in_interrupt() ||
481 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer) != AE_OK)
482 return NULL;
483 return buffer.pointer;
484 }
485
486 /**
487 * acpi_handle_printk: Print message with ACPI prefix and object path
488 *
489 * This function is called through acpi_handle_<level> macros and prints
490 * a message with ACPI prefix and object path. This function acquires
491 * the global namespace mutex to obtain an object path. In interrupt
492 * context, it shows the object path as <n/a>.
493 */
494 void
acpi_handle_printk(const char * level,acpi_handle handle,const char * fmt,...)495 acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
496 {
497 struct va_format vaf;
498 va_list args;
499 const char *path;
500
501 va_start(args, fmt);
502 vaf.fmt = fmt;
503 vaf.va = &args;
504
505 path = acpi_handle_path(handle);
506 printk("%sACPI: %s: %pV", level, path ? path : "<n/a>" , &vaf);
507
508 va_end(args);
509 kfree(path);
510 }
511 EXPORT_SYMBOL(acpi_handle_printk);
512
513 #if defined(CONFIG_DYNAMIC_DEBUG)
514 /**
515 * __acpi_handle_debug: pr_debug with ACPI prefix and object path
516 *
517 * This function is called through acpi_handle_debug macro and debug
518 * prints a message with ACPI prefix and object path. This function
519 * acquires the global namespace mutex to obtain an object path. In
520 * interrupt context, it shows the object path as <n/a>.
521 */
522 void
__acpi_handle_debug(struct _ddebug * descriptor,acpi_handle handle,const char * fmt,...)523 __acpi_handle_debug(struct _ddebug *descriptor, acpi_handle handle,
524 const char *fmt, ...)
525 {
526 struct va_format vaf;
527 va_list args;
528 const char *path;
529
530 va_start(args, fmt);
531 vaf.fmt = fmt;
532 vaf.va = &args;
533
534 path = acpi_handle_path(handle);
535 __dynamic_pr_debug(descriptor, "ACPI: %s: %pV", path ? path : "<n/a>", &vaf);
536
537 va_end(args);
538 kfree(path);
539 }
540 EXPORT_SYMBOL(__acpi_handle_debug);
541 #endif
542
543 /**
544 * acpi_has_method: Check whether @handle has a method named @name
545 * @handle: ACPI device handle
546 * @name: name of object or method
547 *
548 * Check whether @handle has a method named @name.
549 */
acpi_has_method(acpi_handle handle,char * name)550 bool acpi_has_method(acpi_handle handle, char *name)
551 {
552 acpi_handle tmp;
553
554 return ACPI_SUCCESS(acpi_get_handle(handle, name, &tmp));
555 }
556 EXPORT_SYMBOL(acpi_has_method);
557
acpi_execute_simple_method(acpi_handle handle,char * method,u64 arg)558 acpi_status acpi_execute_simple_method(acpi_handle handle, char *method,
559 u64 arg)
560 {
561 union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
562 struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
563
564 obj.integer.value = arg;
565
566 return acpi_evaluate_object(handle, method, &arg_list, NULL);
567 }
568 EXPORT_SYMBOL(acpi_execute_simple_method);
569
570 /**
571 * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
572 * @handle: ACPI device handle
573 *
574 * Evaluate device's _EJ0 method for hotplug operations.
575 */
acpi_evaluate_ej0(acpi_handle handle)576 acpi_status acpi_evaluate_ej0(acpi_handle handle)
577 {
578 acpi_status status;
579
580 status = acpi_execute_simple_method(handle, "_EJ0", 1);
581 if (status == AE_NOT_FOUND)
582 acpi_handle_warn(handle, "No _EJ0 support for device\n");
583 else if (ACPI_FAILURE(status))
584 acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
585
586 return status;
587 }
588
589 /**
590 * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
591 * @handle: ACPI device handle
592 * @lock: lock device if non-zero, otherwise unlock device
593 *
594 * Evaluate device's _LCK method if present to lock/unlock device
595 */
acpi_evaluate_lck(acpi_handle handle,int lock)596 acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
597 {
598 acpi_status status;
599
600 status = acpi_execute_simple_method(handle, "_LCK", !!lock);
601 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
602 if (lock)
603 acpi_handle_warn(handle,
604 "Locking device failed (0x%x)\n", status);
605 else
606 acpi_handle_warn(handle,
607 "Unlocking device failed (0x%x)\n", status);
608 }
609
610 return status;
611 }
612
613 /**
614 * acpi_evaluate_dsm - evaluate device's _DSM method
615 * @handle: ACPI device handle
616 * @uuid: UUID of requested functions, should be 16 bytes
617 * @rev: revision number of requested function
618 * @func: requested function number
619 * @argv4: the function specific parameter
620 *
621 * Evaluate device's _DSM method with specified UUID, revision id and
622 * function number. Caller needs to free the returned object.
623 *
624 * Though ACPI defines the fourth parameter for _DSM should be a package,
625 * some old BIOSes do expect a buffer or an integer etc.
626 */
627 union acpi_object *
acpi_evaluate_dsm(acpi_handle handle,const u8 * uuid,u64 rev,u64 func,union acpi_object * argv4)628 acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid, u64 rev, u64 func,
629 union acpi_object *argv4)
630 {
631 acpi_status ret;
632 struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
633 union acpi_object params[4];
634 struct acpi_object_list input = {
635 .count = 4,
636 .pointer = params,
637 };
638
639 params[0].type = ACPI_TYPE_BUFFER;
640 params[0].buffer.length = 16;
641 params[0].buffer.pointer = (char *)uuid;
642 params[1].type = ACPI_TYPE_INTEGER;
643 params[1].integer.value = rev;
644 params[2].type = ACPI_TYPE_INTEGER;
645 params[2].integer.value = func;
646 if (argv4) {
647 params[3] = *argv4;
648 } else {
649 params[3].type = ACPI_TYPE_PACKAGE;
650 params[3].package.count = 0;
651 params[3].package.elements = NULL;
652 }
653
654 ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
655 if (ACPI_SUCCESS(ret))
656 return (union acpi_object *)buf.pointer;
657
658 if (ret != AE_NOT_FOUND)
659 acpi_handle_warn(handle,
660 "failed to evaluate _DSM (0x%x)\n", ret);
661
662 return NULL;
663 }
664 EXPORT_SYMBOL(acpi_evaluate_dsm);
665
666 /**
667 * acpi_check_dsm - check if _DSM method supports requested functions.
668 * @handle: ACPI device handle
669 * @uuid: UUID of requested functions, should be 16 bytes at least
670 * @rev: revision number of requested functions
671 * @funcs: bitmap of requested functions
672 *
673 * Evaluate device's _DSM method to check whether it supports requested
674 * functions. Currently only support 64 functions at maximum, should be
675 * enough for now.
676 */
acpi_check_dsm(acpi_handle handle,const u8 * uuid,u64 rev,u64 funcs)677 bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, u64 rev, u64 funcs)
678 {
679 int i;
680 u64 mask = 0;
681 union acpi_object *obj;
682
683 if (funcs == 0)
684 return false;
685
686 obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL);
687 if (!obj)
688 return false;
689
690 /* For compatibility, old BIOSes may return an integer */
691 if (obj->type == ACPI_TYPE_INTEGER)
692 mask = obj->integer.value;
693 else if (obj->type == ACPI_TYPE_BUFFER)
694 for (i = 0; i < obj->buffer.length && i < 8; i++)
695 mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
696 ACPI_FREE(obj);
697
698 /*
699 * Bit 0 indicates whether there's support for any functions other than
700 * function 0 for the specified UUID and revision.
701 */
702 if ((mask & 0x1) && (mask & funcs) == funcs)
703 return true;
704
705 return false;
706 }
707 EXPORT_SYMBOL(acpi_check_dsm);
708
709 /**
710 * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
711 * @hid: Hardware ID of the device.
712 *
713 * Return %true if the device was present at the moment of invocation.
714 * Note that if the device is pluggable, it may since have disappeared.
715 *
716 * For this function to work, acpi_bus_scan() must have been executed
717 * which happens in the subsys_initcall() subsection. Hence, do not
718 * call from a subsys_initcall() or earlier (use acpi_get_devices()
719 * instead). Calling from module_init() is fine (which is synonymous
720 * with device_initcall()).
721 */
acpi_dev_found(const char * hid)722 bool acpi_dev_found(const char *hid)
723 {
724 struct acpi_device_bus_id *acpi_device_bus_id;
725 bool found = false;
726
727 mutex_lock(&acpi_device_lock);
728 list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
729 if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
730 found = true;
731 break;
732 }
733 mutex_unlock(&acpi_device_lock);
734
735 return found;
736 }
737 EXPORT_SYMBOL(acpi_dev_found);
738
739 /*
740 * acpi_backlight= handling, this is done here rather then in video_detect.c
741 * because __setup cannot be used in modules.
742 */
743 char acpi_video_backlight_string[16];
744 EXPORT_SYMBOL(acpi_video_backlight_string);
745
acpi_backlight(char * str)746 static int __init acpi_backlight(char *str)
747 {
748 strlcpy(acpi_video_backlight_string, str,
749 sizeof(acpi_video_backlight_string));
750 return 1;
751 }
752 __setup("acpi_backlight=", acpi_backlight);
753