bus.c revision 99e0d2fc6c60ca44f56203eeda9fc0e07b508f06 
1/*
2 *  acpi_bus.c - ACPI Bus Driver ($Revision: 80 $)
3 *
4 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
5 *
6 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7 *
8 *  This program is free software; you can redistribute it and/or modify
9 *  it under the terms of the GNU General Public License as published by
10 *  the Free Software Foundation; either version 2 of the License, or (at
11 *  your option) any later version.
12 *
13 *  This program is distributed in the hope that it will be useful, but
14 *  WITHOUT ANY WARRANTY; without even the implied warranty of
15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 *  General Public License for more details.
17 *
18 *  You should have received a copy of the GNU General Public License along
19 *  with this program; if not, write to the Free Software Foundation, Inc.,
20 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
21 *
22 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23 */
24
25#include <linux/module.h>
26#include <linux/init.h>
27#include <linux/ioport.h>
28#include <linux/kernel.h>
29#include <linux/list.h>
30#include <linux/sched.h>
31#include <linux/pm.h>
32#include <linux/device.h>
33#include <linux/proc_fs.h>
34#ifdef CONFIG_X86
35#include <asm/mpspec.h>
36#endif
37#include <acpi/acpi_bus.h>
38#include <acpi/acpi_drivers.h>
39
40#define _COMPONENT		ACPI_BUS_COMPONENT
41ACPI_MODULE_NAME("bus");
42#ifdef	CONFIG_X86
43extern void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger);
44#endif
45
46struct acpi_device *acpi_root;
47struct proc_dir_entry *acpi_root_dir;
48EXPORT_SYMBOL(acpi_root_dir);
49
50#define STRUCT_TO_INT(s)	(*((int*)&s))
51
52/* --------------------------------------------------------------------------
53                                Device Management
54   -------------------------------------------------------------------------- */
55
56int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
57{
58	acpi_status status = AE_OK;
59
60
61	if (!device)
62		return -EINVAL;
63
64	/* TBD: Support fixed-feature devices */
65
66	status = acpi_get_data(handle, acpi_bus_data_handler, (void **)device);
67	if (ACPI_FAILURE(status) || !*device) {
68		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
69				  handle));
70		return -ENODEV;
71	}
72
73	return 0;
74}
75
76EXPORT_SYMBOL(acpi_bus_get_device);
77
78int acpi_bus_get_status(struct acpi_device *device)
79{
80	acpi_status status = AE_OK;
81	unsigned long sta = 0;
82
83
84	if (!device)
85		return -EINVAL;
86
87	/*
88	 * Evaluate _STA if present.
89	 */
90	if (device->flags.dynamic_status) {
91		status =
92		    acpi_evaluate_integer(device->handle, "_STA", NULL, &sta);
93		if (ACPI_FAILURE(status))
94			return -ENODEV;
95		STRUCT_TO_INT(device->status) = (int)sta;
96	}
97
98	/*
99	 * Otherwise we assume the status of our parent (unless we don't
100	 * have one, in which case status is implied).
101	 */
102	else if (device->parent)
103		device->status = device->parent->status;
104	else
105		STRUCT_TO_INT(device->status) =
106		    ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
107		    ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
108
109	if (device->status.functional && !device->status.present) {
110		printk(KERN_WARNING PREFIX "Device [%s] status [%08x]: "
111		       "functional but not present; setting present\n",
112		       device->pnp.bus_id, (u32) STRUCT_TO_INT(device->status));
113		device->status.present = 1;
114	}
115
116	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
117			  device->pnp.bus_id,
118			  (u32) STRUCT_TO_INT(device->status)));
119
120	return 0;
121}
122
123EXPORT_SYMBOL(acpi_bus_get_status);
124
125/* --------------------------------------------------------------------------
126                                 Power Management
127   -------------------------------------------------------------------------- */
128
129int acpi_bus_get_power(acpi_handle handle, int *state)
130{
131	int result = 0;
132	acpi_status status = 0;
133	struct acpi_device *device = NULL;
134	unsigned long psc = 0;
135
136
137	result = acpi_bus_get_device(handle, &device);
138	if (result)
139		return result;
140
141	*state = ACPI_STATE_UNKNOWN;
142
143	if (!device->flags.power_manageable) {
144		/* TBD: Non-recursive algorithm for walking up hierarchy */
145		if (device->parent)
146			*state = device->parent->power.state;
147		else
148			*state = ACPI_STATE_D0;
149	} else {
150		/*
151		 * Get the device's power state either directly (via _PSC) or
152		 * indirectly (via power resources).
153		 */
154		if (device->power.flags.explicit_get) {
155			status = acpi_evaluate_integer(device->handle, "_PSC",
156						       NULL, &psc);
157			if (ACPI_FAILURE(status))
158				return -ENODEV;
159			device->power.state = (int)psc;
160		} else if (device->power.flags.power_resources) {
161			result = acpi_power_get_inferred_state(device);
162			if (result)
163				return result;
164		}
165
166		*state = device->power.state;
167	}
168
169	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is D%d\n",
170			  device->pnp.bus_id, device->power.state));
171
172	return 0;
173}
174
175EXPORT_SYMBOL(acpi_bus_get_power);
176
177int acpi_bus_set_power(acpi_handle handle, int state)
178{
179	int result = 0;
180	acpi_status status = AE_OK;
181	struct acpi_device *device = NULL;
182	char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
183
184
185	result = acpi_bus_get_device(handle, &device);
186	if (result)
187		return result;
188
189	if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
190		return -EINVAL;
191
192	/* Make sure this is a valid target state */
193
194	if (!device->flags.power_manageable) {
195		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",
196				kobject_name(&device->dev.kobj)));
197		return -ENODEV;
198	}
199	/*
200	 * Get device's current power state
201	 */
202	acpi_bus_get_power(device->handle, &device->power.state);
203	if ((state == device->power.state) && !device->flags.force_power_state) {
204		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",
205				  state));
206		return 0;
207	}
208
209	if (!device->power.states[state].flags.valid) {
210		printk(KERN_WARNING PREFIX "Device does not support D%d\n", state);
211		return -ENODEV;
212	}
213	if (device->parent && (state < device->parent->power.state)) {
214		printk(KERN_WARNING PREFIX
215			      "Cannot set device to a higher-powered"
216			      " state than parent\n");
217		return -ENODEV;
218	}
219
220	/*
221	 * Transition Power
222	 * ----------------
223	 * On transitions to a high-powered state we first apply power (via
224	 * power resources) then evalute _PSx.  Conversly for transitions to
225	 * a lower-powered state.
226	 */
227	if (state < device->power.state) {
228		if (device->power.flags.power_resources) {
229			result = acpi_power_transition(device, state);
230			if (result)
231				goto end;
232		}
233		if (device->power.states[state].flags.explicit_set) {
234			status = acpi_evaluate_object(device->handle,
235						      object_name, NULL, NULL);
236			if (ACPI_FAILURE(status)) {
237				result = -ENODEV;
238				goto end;
239			}
240		}
241	} else {
242		if (device->power.states[state].flags.explicit_set) {
243			status = acpi_evaluate_object(device->handle,
244						      object_name, NULL, NULL);
245			if (ACPI_FAILURE(status)) {
246				result = -ENODEV;
247				goto end;
248			}
249		}
250		if (device->power.flags.power_resources) {
251			result = acpi_power_transition(device, state);
252			if (result)
253				goto end;
254		}
255	}
256
257      end:
258	if (result)
259		printk(KERN_WARNING PREFIX
260			      "Transitioning device [%s] to D%d\n",
261			      device->pnp.bus_id, state);
262	else {
263		device->power.state = state;
264		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
265				  "Device [%s] transitioned to D%d\n",
266				  device->pnp.bus_id, state));
267	}
268
269	return result;
270}
271
272EXPORT_SYMBOL(acpi_bus_set_power);
273
274/* --------------------------------------------------------------------------
275                                Event Management
276   -------------------------------------------------------------------------- */
277
278#ifdef CONFIG_ACPI_PROC_EVENT
279static DEFINE_SPINLOCK(acpi_bus_event_lock);
280
281LIST_HEAD(acpi_bus_event_list);
282DECLARE_WAIT_QUEUE_HEAD(acpi_bus_event_queue);
283
284extern int event_is_open;
285
286int acpi_bus_generate_proc_event4(const char *device_class, const char *bus_id, u8 type, int data)
287{
288	struct acpi_bus_event *event;
289	unsigned long flags = 0;
290
291	/* drop event on the floor if no one's listening */
292	if (!event_is_open)
293		return 0;
294
295	event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC);
296	if (!event)
297		return -ENOMEM;
298
299	strcpy(event->device_class, device_class);
300	strcpy(event->bus_id, bus_id);
301	event->type = type;
302	event->data = data;
303
304	spin_lock_irqsave(&acpi_bus_event_lock, flags);
305	list_add_tail(&event->node, &acpi_bus_event_list);
306	spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
307
308	wake_up_interruptible(&acpi_bus_event_queue);
309
310	return 0;
311
312}
313
314EXPORT_SYMBOL_GPL(acpi_bus_generate_proc_event4);
315
316int acpi_bus_generate_proc_event(struct acpi_device *device, u8 type, int data)
317{
318	if (!device)
319		return -EINVAL;
320	return acpi_bus_generate_proc_event4(device->pnp.device_class,
321					     device->pnp.bus_id, type, data);
322}
323
324EXPORT_SYMBOL(acpi_bus_generate_proc_event);
325
326int acpi_bus_receive_event(struct acpi_bus_event *event)
327{
328	unsigned long flags = 0;
329	struct acpi_bus_event *entry = NULL;
330
331	DECLARE_WAITQUEUE(wait, current);
332
333
334	if (!event)
335		return -EINVAL;
336
337	if (list_empty(&acpi_bus_event_list)) {
338
339		set_current_state(TASK_INTERRUPTIBLE);
340		add_wait_queue(&acpi_bus_event_queue, &wait);
341
342		if (list_empty(&acpi_bus_event_list))
343			schedule();
344
345		remove_wait_queue(&acpi_bus_event_queue, &wait);
346		set_current_state(TASK_RUNNING);
347
348		if (signal_pending(current))
349			return -ERESTARTSYS;
350	}
351
352	spin_lock_irqsave(&acpi_bus_event_lock, flags);
353	entry =
354	    list_entry(acpi_bus_event_list.next, struct acpi_bus_event, node);
355	if (entry)
356		list_del(&entry->node);
357	spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
358
359	if (!entry)
360		return -ENODEV;
361
362	memcpy(event, entry, sizeof(struct acpi_bus_event));
363
364	kfree(entry);
365
366	return 0;
367}
368
369EXPORT_SYMBOL(acpi_bus_receive_event);
370#endif	/* CONFIG_ACPI_PROC_EVENT */
371
372/* --------------------------------------------------------------------------
373                             Notification Handling
374   -------------------------------------------------------------------------- */
375
376static int
377acpi_bus_check_device(struct acpi_device *device, int *status_changed)
378{
379	acpi_status status = 0;
380	struct acpi_device_status old_status;
381
382
383	if (!device)
384		return -EINVAL;
385
386	if (status_changed)
387		*status_changed = 0;
388
389	old_status = device->status;
390
391	/*
392	 * Make sure this device's parent is present before we go about
393	 * messing with the device.
394	 */
395	if (device->parent && !device->parent->status.present) {
396		device->status = device->parent->status;
397		if (STRUCT_TO_INT(old_status) != STRUCT_TO_INT(device->status)) {
398			if (status_changed)
399				*status_changed = 1;
400		}
401		return 0;
402	}
403
404	status = acpi_bus_get_status(device);
405	if (ACPI_FAILURE(status))
406		return -ENODEV;
407
408	if (STRUCT_TO_INT(old_status) == STRUCT_TO_INT(device->status))
409		return 0;
410
411	if (status_changed)
412		*status_changed = 1;
413
414	/*
415	 * Device Insertion/Removal
416	 */
417	if ((device->status.present) && !(old_status.present)) {
418		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n"));
419		/* TBD: Handle device insertion */
420	} else if (!(device->status.present) && (old_status.present)) {
421		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device removal detected\n"));
422		/* TBD: Handle device removal */
423	}
424
425	return 0;
426}
427
428static int acpi_bus_check_scope(struct acpi_device *device)
429{
430	int result = 0;
431	int status_changed = 0;
432
433
434	if (!device)
435		return -EINVAL;
436
437	/* Status Change? */
438	result = acpi_bus_check_device(device, &status_changed);
439	if (result)
440		return result;
441
442	if (!status_changed)
443		return 0;
444
445	/*
446	 * TBD: Enumerate child devices within this device's scope and
447	 *       run acpi_bus_check_device()'s on them.
448	 */
449
450	return 0;
451}
452
453/**
454 * acpi_bus_notify
455 * ---------------
456 * Callback for all 'system-level' device notifications (values 0x00-0x7F).
457 */
458static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
459{
460	int result = 0;
461	struct acpi_device *device = NULL;
462
463
464	if (acpi_bus_get_device(handle, &device))
465		return;
466
467	switch (type) {
468
469	case ACPI_NOTIFY_BUS_CHECK:
470		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
471				  "Received BUS CHECK notification for device [%s]\n",
472				  device->pnp.bus_id));
473		result = acpi_bus_check_scope(device);
474		/*
475		 * TBD: We'll need to outsource certain events to non-ACPI
476		 *      drivers via the device manager (device.c).
477		 */
478		break;
479
480	case ACPI_NOTIFY_DEVICE_CHECK:
481		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
482				  "Received DEVICE CHECK notification for device [%s]\n",
483				  device->pnp.bus_id));
484		result = acpi_bus_check_device(device, NULL);
485		/*
486		 * TBD: We'll need to outsource certain events to non-ACPI
487		 *      drivers via the device manager (device.c).
488		 */
489		break;
490
491	case ACPI_NOTIFY_DEVICE_WAKE:
492		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
493				  "Received DEVICE WAKE notification for device [%s]\n",
494				  device->pnp.bus_id));
495		/* TBD */
496		break;
497
498	case ACPI_NOTIFY_EJECT_REQUEST:
499		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
500				  "Received EJECT REQUEST notification for device [%s]\n",
501				  device->pnp.bus_id));
502		/* TBD */
503		break;
504
505	case ACPI_NOTIFY_DEVICE_CHECK_LIGHT:
506		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
507				  "Received DEVICE CHECK LIGHT notification for device [%s]\n",
508				  device->pnp.bus_id));
509		/* TBD: Exactly what does 'light' mean? */
510		break;
511
512	case ACPI_NOTIFY_FREQUENCY_MISMATCH:
513		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
514				  "Received FREQUENCY MISMATCH notification for device [%s]\n",
515				  device->pnp.bus_id));
516		/* TBD */
517		break;
518
519	case ACPI_NOTIFY_BUS_MODE_MISMATCH:
520		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
521				  "Received BUS MODE MISMATCH notification for device [%s]\n",
522				  device->pnp.bus_id));
523		/* TBD */
524		break;
525
526	case ACPI_NOTIFY_POWER_FAULT:
527		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
528				  "Received POWER FAULT notification for device [%s]\n",
529				  device->pnp.bus_id));
530		/* TBD */
531		break;
532
533	default:
534		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
535				  "Received unknown/unsupported notification [%08x]\n",
536				  type));
537		break;
538	}
539
540	return;
541}
542
543/* --------------------------------------------------------------------------
544                             Initialization/Cleanup
545   -------------------------------------------------------------------------- */
546
547static int __init acpi_bus_init_irq(void)
548{
549	acpi_status status = AE_OK;
550	union acpi_object arg = { ACPI_TYPE_INTEGER };
551	struct acpi_object_list arg_list = { 1, &arg };
552	char *message = NULL;
553
554
555	/*
556	 * Let the system know what interrupt model we are using by
557	 * evaluating the \_PIC object, if exists.
558	 */
559
560	switch (acpi_irq_model) {
561	case ACPI_IRQ_MODEL_PIC:
562		message = "PIC";
563		break;
564	case ACPI_IRQ_MODEL_IOAPIC:
565		message = "IOAPIC";
566		break;
567	case ACPI_IRQ_MODEL_IOSAPIC:
568		message = "IOSAPIC";
569		break;
570	case ACPI_IRQ_MODEL_PLATFORM:
571		message = "platform specific model";
572		break;
573	default:
574		printk(KERN_WARNING PREFIX "Unknown interrupt routing model\n");
575		return -ENODEV;
576	}
577
578	printk(KERN_INFO PREFIX "Using %s for interrupt routing\n", message);
579
580	arg.integer.value = acpi_irq_model;
581
582	status = acpi_evaluate_object(NULL, "\\_PIC", &arg_list, NULL);
583	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
584		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PIC"));
585		return -ENODEV;
586	}
587
588	return 0;
589}
590
591acpi_native_uint acpi_gbl_permanent_mmap;
592
593
594void __init acpi_early_init(void)
595{
596	acpi_status status = AE_OK;
597
598	if (acpi_disabled)
599		return;
600
601	printk(KERN_INFO PREFIX "Core revision %08x\n", ACPI_CA_VERSION);
602
603	/* enable workarounds, unless strict ACPI spec. compliance */
604	if (!acpi_strict)
605		acpi_gbl_enable_interpreter_slack = TRUE;
606
607	acpi_gbl_permanent_mmap = 1;
608
609	status = acpi_reallocate_root_table();
610	if (ACPI_FAILURE(status)) {
611		printk(KERN_ERR PREFIX
612		       "Unable to reallocate ACPI tables\n");
613		goto error0;
614	}
615
616	status = acpi_initialize_subsystem();
617	if (ACPI_FAILURE(status)) {
618		printk(KERN_ERR PREFIX
619		       "Unable to initialize the ACPI Interpreter\n");
620		goto error0;
621	}
622
623	status = acpi_load_tables();
624	if (ACPI_FAILURE(status)) {
625		printk(KERN_ERR PREFIX
626		       "Unable to load the System Description Tables\n");
627		goto error0;
628	}
629
630#ifdef CONFIG_X86
631	if (!acpi_ioapic) {
632		extern u8 acpi_sci_flags;
633
634		/* compatible (0) means level (3) */
635		if (!(acpi_sci_flags & ACPI_MADT_TRIGGER_MASK)) {
636			acpi_sci_flags &= ~ACPI_MADT_TRIGGER_MASK;
637			acpi_sci_flags |= ACPI_MADT_TRIGGER_LEVEL;
638		}
639		/* Set PIC-mode SCI trigger type */
640		acpi_pic_sci_set_trigger(acpi_gbl_FADT.sci_interrupt,
641					 (acpi_sci_flags & ACPI_MADT_TRIGGER_MASK) >> 2);
642	} else {
643		extern int acpi_sci_override_gsi;
644		/*
645		 * now that acpi_gbl_FADT is initialized,
646		 * update it with result from INT_SRC_OVR parsing
647		 */
648		acpi_gbl_FADT.sci_interrupt = acpi_sci_override_gsi;
649	}
650#endif
651
652	status =
653	    acpi_enable_subsystem(~
654				  (ACPI_NO_HARDWARE_INIT |
655				   ACPI_NO_ACPI_ENABLE));
656	if (ACPI_FAILURE(status)) {
657		printk(KERN_ERR PREFIX "Unable to enable ACPI\n");
658		goto error0;
659	}
660
661	return;
662
663      error0:
664	disable_acpi();
665	return;
666}
667
668static int __init acpi_bus_init(void)
669{
670	int result = 0;
671	acpi_status status = AE_OK;
672	extern acpi_status acpi_os_initialize1(void);
673
674
675	status = acpi_os_initialize1();
676
677	status =
678	    acpi_enable_subsystem(ACPI_NO_HARDWARE_INIT | ACPI_NO_ACPI_ENABLE);
679	if (ACPI_FAILURE(status)) {
680		printk(KERN_ERR PREFIX
681		       "Unable to start the ACPI Interpreter\n");
682		goto error1;
683	}
684
685	if (ACPI_FAILURE(status)) {
686		printk(KERN_ERR PREFIX
687		       "Unable to initialize ACPI OS objects\n");
688		goto error1;
689	}
690#ifdef CONFIG_ACPI_EC
691	/*
692	 * ACPI 2.0 requires the EC driver to be loaded and work before
693	 * the EC device is found in the namespace (i.e. before acpi_initialize_objects()
694	 * is called).
695	 *
696	 * This is accomplished by looking for the ECDT table, and getting
697	 * the EC parameters out of that.
698	 */
699	status = acpi_ec_ecdt_probe();
700	/* Ignore result. Not having an ECDT is not fatal. */
701#endif
702
703	status = acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
704	if (ACPI_FAILURE(status)) {
705		printk(KERN_ERR PREFIX "Unable to initialize ACPI objects\n");
706		goto error1;
707	}
708
709	printk(KERN_INFO PREFIX "Interpreter enabled\n");
710
711	/* Initialize sleep structures */
712	acpi_sleep_init();
713
714	/*
715	 * Get the system interrupt model and evaluate \_PIC.
716	 */
717	result = acpi_bus_init_irq();
718	if (result)
719		goto error1;
720
721	/*
722	 * Register the for all standard device notifications.
723	 */
724	status =
725	    acpi_install_notify_handler(ACPI_ROOT_OBJECT, ACPI_SYSTEM_NOTIFY,
726					&acpi_bus_notify, NULL);
727	if (ACPI_FAILURE(status)) {
728		printk(KERN_ERR PREFIX
729		       "Unable to register for device notifications\n");
730		goto error1;
731	}
732
733	/*
734	 * Create the top ACPI proc directory
735	 */
736	acpi_root_dir = proc_mkdir(ACPI_BUS_FILE_ROOT, NULL);
737
738	return 0;
739
740	/* Mimic structured exception handling */
741      error1:
742	acpi_terminate();
743	return -ENODEV;
744}
745
746struct kobject *acpi_kobj;
747
748static int __init acpi_init(void)
749{
750	int result = 0;
751
752
753	if (acpi_disabled) {
754		printk(KERN_INFO PREFIX "Interpreter disabled.\n");
755		return -ENODEV;
756	}
757
758	acpi_kobj = kobject_create_and_add("acpi", &firmware_kset->kobj);
759	if (!acpi_kobj) {
760		printk(KERN_WARNING "%s: kset create error\n", __FUNCTION__);
761		acpi_kobj = NULL;
762	}
763
764	result = acpi_bus_init();
765
766	if (!result) {
767		if (!(pm_flags & PM_APM))
768			pm_flags |= PM_ACPI;
769		else {
770			printk(KERN_INFO PREFIX
771			       "APM is already active, exiting\n");
772			disable_acpi();
773			result = -ENODEV;
774		}
775	} else
776		disable_acpi();
777
778	return result;
779}
780
781subsys_initcall(acpi_init);
782