ACPI: fix hotplug race
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / acpi / bus.c
blob0dc44945725ef1c53e0ae0c5f9ebbbd220256675
1 /*
2 * acpi_bus.c - ACPI Bus Driver ($Revision: 80 $)
4 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
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.
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.
22 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 #include <linux/acpi.h>
35 #ifdef CONFIG_X86
36 #include <asm/mpspec.h>
37 #endif
38 #include <linux/pci.h>
39 #include <acpi/acpi_bus.h>
40 #include <acpi/acpi_drivers.h>
42 #define _COMPONENT ACPI_BUS_COMPONENT
43 ACPI_MODULE_NAME("bus");
45 struct acpi_device *acpi_root;
46 struct proc_dir_entry *acpi_root_dir;
47 EXPORT_SYMBOL(acpi_root_dir);
49 #define STRUCT_TO_INT(s) (*((int*)&s))
51 /* --------------------------------------------------------------------------
52 Device Management
53 -------------------------------------------------------------------------- */
55 int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
57 acpi_status status = AE_OK;
60 if (!device)
61 return -EINVAL;
63 /* TBD: Support fixed-feature devices */
65 status = acpi_get_data(handle, acpi_bus_data_handler, (void **)device);
66 if (ACPI_FAILURE(status) || !*device) {
67 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
68 handle));
69 return -ENODEV;
72 return 0;
75 EXPORT_SYMBOL(acpi_bus_get_device);
77 int acpi_bus_get_status(struct acpi_device *device)
79 acpi_status status = AE_OK;
80 unsigned long sta = 0;
83 if (!device)
84 return -EINVAL;
87 * Evaluate _STA if present.
89 if (device->flags.dynamic_status) {
90 status =
91 acpi_evaluate_integer(device->handle, "_STA", NULL, &sta);
92 if (ACPI_FAILURE(status))
93 return -ENODEV;
94 STRUCT_TO_INT(device->status) = (int)sta;
98 * Otherwise we assume the status of our parent (unless we don't
99 * have one, in which case status is implied).
101 else if (device->parent)
102 device->status = device->parent->status;
103 else
104 STRUCT_TO_INT(device->status) =
105 ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
106 ACPI_STA_DEVICE_UI | ACPI_STA_DEVICE_FUNCTIONING;
108 if (device->status.functional && !device->status.present) {
109 printk(KERN_WARNING PREFIX "Device [%s] status [%08x]: "
110 "functional but not present; setting present\n",
111 device->pnp.bus_id, (u32) STRUCT_TO_INT(device->status));
112 device->status.present = 1;
115 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
116 device->pnp.bus_id,
117 (u32) STRUCT_TO_INT(device->status)));
119 return 0;
122 EXPORT_SYMBOL(acpi_bus_get_status);
124 void acpi_bus_private_data_handler(acpi_handle handle,
125 u32 function, void *context)
127 return;
129 EXPORT_SYMBOL(acpi_bus_private_data_handler);
131 int acpi_bus_get_private_data(acpi_handle handle, void **data)
133 acpi_status status = AE_OK;
135 if (!*data)
136 return -EINVAL;
138 status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
139 if (ACPI_FAILURE(status) || !*data) {
140 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
141 handle));
142 return -ENODEV;
145 return 0;
147 EXPORT_SYMBOL(acpi_bus_get_private_data);
149 /* --------------------------------------------------------------------------
150 Power Management
151 -------------------------------------------------------------------------- */
153 int acpi_bus_get_power(acpi_handle handle, int *state)
155 int result = 0;
156 acpi_status status = 0;
157 struct acpi_device *device = NULL;
158 unsigned long psc = 0;
161 result = acpi_bus_get_device(handle, &device);
162 if (result)
163 return result;
165 *state = ACPI_STATE_UNKNOWN;
167 if (!device->flags.power_manageable) {
168 /* TBD: Non-recursive algorithm for walking up hierarchy */
169 if (device->parent)
170 *state = device->parent->power.state;
171 else
172 *state = ACPI_STATE_D0;
173 } else {
175 * Get the device's power state either directly (via _PSC) or
176 * indirectly (via power resources).
178 if (device->power.flags.explicit_get) {
179 status = acpi_evaluate_integer(device->handle, "_PSC",
180 NULL, &psc);
181 if (ACPI_FAILURE(status))
182 return -ENODEV;
183 device->power.state = (int)psc;
184 } else if (device->power.flags.power_resources) {
185 result = acpi_power_get_inferred_state(device);
186 if (result)
187 return result;
190 *state = device->power.state;
193 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is D%d\n",
194 device->pnp.bus_id, device->power.state));
196 return 0;
199 EXPORT_SYMBOL(acpi_bus_get_power);
201 int acpi_bus_set_power(acpi_handle handle, int state)
203 int result = 0;
204 acpi_status status = AE_OK;
205 struct acpi_device *device = NULL;
206 char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
209 result = acpi_bus_get_device(handle, &device);
210 if (result)
211 return result;
213 if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
214 return -EINVAL;
216 /* Make sure this is a valid target state */
218 if (!device->flags.power_manageable) {
219 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",
220 kobject_name(&device->dev.kobj)));
221 return -ENODEV;
224 * Get device's current power state
226 acpi_bus_get_power(device->handle, &device->power.state);
227 if ((state == device->power.state) && !device->flags.force_power_state) {
228 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",
229 state));
230 return 0;
233 if (!device->power.states[state].flags.valid) {
234 printk(KERN_WARNING PREFIX "Device does not support D%d\n", state);
235 return -ENODEV;
237 if (device->parent && (state < device->parent->power.state)) {
238 printk(KERN_WARNING PREFIX
239 "Cannot set device to a higher-powered"
240 " state than parent\n");
241 return -ENODEV;
245 * Transition Power
246 * ----------------
247 * On transitions to a high-powered state we first apply power (via
248 * power resources) then evalute _PSx. Conversly for transitions to
249 * a lower-powered state.
251 if (state < device->power.state) {
252 if (device->power.flags.power_resources) {
253 result = acpi_power_transition(device, state);
254 if (result)
255 goto end;
257 if (device->power.states[state].flags.explicit_set) {
258 status = acpi_evaluate_object(device->handle,
259 object_name, NULL, NULL);
260 if (ACPI_FAILURE(status)) {
261 result = -ENODEV;
262 goto end;
265 } else {
266 if (device->power.states[state].flags.explicit_set) {
267 status = acpi_evaluate_object(device->handle,
268 object_name, NULL, NULL);
269 if (ACPI_FAILURE(status)) {
270 result = -ENODEV;
271 goto end;
274 if (device->power.flags.power_resources) {
275 result = acpi_power_transition(device, state);
276 if (result)
277 goto end;
281 end:
282 if (result)
283 printk(KERN_WARNING PREFIX
284 "Transitioning device [%s] to D%d\n",
285 device->pnp.bus_id, state);
286 else {
287 device->power.state = state;
288 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
289 "Device [%s] transitioned to D%d\n",
290 device->pnp.bus_id, state));
293 return result;
296 EXPORT_SYMBOL(acpi_bus_set_power);
298 bool acpi_bus_power_manageable(acpi_handle handle)
300 struct acpi_device *device;
301 int result;
303 result = acpi_bus_get_device(handle, &device);
304 return result ? false : device->flags.power_manageable;
307 EXPORT_SYMBOL(acpi_bus_power_manageable);
309 bool acpi_bus_can_wakeup(acpi_handle handle)
311 struct acpi_device *device;
312 int result;
314 result = acpi_bus_get_device(handle, &device);
315 return result ? false : device->wakeup.flags.valid;
318 EXPORT_SYMBOL(acpi_bus_can_wakeup);
320 /* --------------------------------------------------------------------------
321 Event Management
322 -------------------------------------------------------------------------- */
324 #ifdef CONFIG_ACPI_PROC_EVENT
325 static DEFINE_SPINLOCK(acpi_bus_event_lock);
327 LIST_HEAD(acpi_bus_event_list);
328 DECLARE_WAIT_QUEUE_HEAD(acpi_bus_event_queue);
330 extern int event_is_open;
332 int acpi_bus_generate_proc_event4(const char *device_class, const char *bus_id, u8 type, int data)
334 struct acpi_bus_event *event;
335 unsigned long flags = 0;
337 /* drop event on the floor if no one's listening */
338 if (!event_is_open)
339 return 0;
341 event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC);
342 if (!event)
343 return -ENOMEM;
345 strcpy(event->device_class, device_class);
346 strcpy(event->bus_id, bus_id);
347 event->type = type;
348 event->data = data;
350 spin_lock_irqsave(&acpi_bus_event_lock, flags);
351 list_add_tail(&event->node, &acpi_bus_event_list);
352 spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
354 wake_up_interruptible(&acpi_bus_event_queue);
356 return 0;
360 EXPORT_SYMBOL_GPL(acpi_bus_generate_proc_event4);
362 int acpi_bus_generate_proc_event(struct acpi_device *device, u8 type, int data)
364 if (!device)
365 return -EINVAL;
366 return acpi_bus_generate_proc_event4(device->pnp.device_class,
367 device->pnp.bus_id, type, data);
370 EXPORT_SYMBOL(acpi_bus_generate_proc_event);
372 int acpi_bus_receive_event(struct acpi_bus_event *event)
374 unsigned long flags = 0;
375 struct acpi_bus_event *entry = NULL;
377 DECLARE_WAITQUEUE(wait, current);
380 if (!event)
381 return -EINVAL;
383 if (list_empty(&acpi_bus_event_list)) {
385 set_current_state(TASK_INTERRUPTIBLE);
386 add_wait_queue(&acpi_bus_event_queue, &wait);
388 if (list_empty(&acpi_bus_event_list))
389 schedule();
391 remove_wait_queue(&acpi_bus_event_queue, &wait);
392 set_current_state(TASK_RUNNING);
394 if (signal_pending(current))
395 return -ERESTARTSYS;
398 spin_lock_irqsave(&acpi_bus_event_lock, flags);
399 if (!list_empty(&acpi_bus_event_list)) {
400 entry = list_entry(acpi_bus_event_list.next,
401 struct acpi_bus_event, node);
402 list_del(&entry->node);
404 spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
406 if (!entry)
407 return -ENODEV;
409 memcpy(event, entry, sizeof(struct acpi_bus_event));
411 kfree(entry);
413 return 0;
416 #endif /* CONFIG_ACPI_PROC_EVENT */
418 /* --------------------------------------------------------------------------
419 Notification Handling
420 -------------------------------------------------------------------------- */
422 static int
423 acpi_bus_check_device(struct acpi_device *device, int *status_changed)
425 acpi_status status = 0;
426 struct acpi_device_status old_status;
429 if (!device)
430 return -EINVAL;
432 if (status_changed)
433 *status_changed = 0;
435 old_status = device->status;
438 * Make sure this device's parent is present before we go about
439 * messing with the device.
441 if (device->parent && !device->parent->status.present) {
442 device->status = device->parent->status;
443 if (STRUCT_TO_INT(old_status) != STRUCT_TO_INT(device->status)) {
444 if (status_changed)
445 *status_changed = 1;
447 return 0;
450 status = acpi_bus_get_status(device);
451 if (ACPI_FAILURE(status))
452 return -ENODEV;
454 if (STRUCT_TO_INT(old_status) == STRUCT_TO_INT(device->status))
455 return 0;
457 if (status_changed)
458 *status_changed = 1;
461 * Device Insertion/Removal
463 if ((device->status.present) && !(old_status.present)) {
464 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n"));
465 /* TBD: Handle device insertion */
466 } else if (!(device->status.present) && (old_status.present)) {
467 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device removal detected\n"));
468 /* TBD: Handle device removal */
471 return 0;
474 static int acpi_bus_check_scope(struct acpi_device *device)
476 int result = 0;
477 int status_changed = 0;
480 if (!device)
481 return -EINVAL;
483 /* Status Change? */
484 result = acpi_bus_check_device(device, &status_changed);
485 if (result)
486 return result;
488 if (!status_changed)
489 return 0;
492 * TBD: Enumerate child devices within this device's scope and
493 * run acpi_bus_check_device()'s on them.
496 return 0;
499 static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
500 int register_acpi_bus_notifier(struct notifier_block *nb)
502 return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
504 EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);
506 void unregister_acpi_bus_notifier(struct notifier_block *nb)
508 blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
510 EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);
513 * acpi_bus_notify
514 * ---------------
515 * Callback for all 'system-level' device notifications (values 0x00-0x7F).
517 static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
519 int result = 0;
520 struct acpi_device *device = NULL;
522 blocking_notifier_call_chain(&acpi_bus_notify_list,
523 type, (void *)handle);
525 if (acpi_bus_get_device(handle, &device))
526 return;
528 switch (type) {
530 case ACPI_NOTIFY_BUS_CHECK:
531 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
532 "Received BUS CHECK notification for device [%s]\n",
533 device->pnp.bus_id));
534 result = acpi_bus_check_scope(device);
536 * TBD: We'll need to outsource certain events to non-ACPI
537 * drivers via the device manager (device.c).
539 break;
541 case ACPI_NOTIFY_DEVICE_CHECK:
542 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
543 "Received DEVICE CHECK notification for device [%s]\n",
544 device->pnp.bus_id));
545 result = acpi_bus_check_device(device, NULL);
547 * TBD: We'll need to outsource certain events to non-ACPI
548 * drivers via the device manager (device.c).
550 break;
552 case ACPI_NOTIFY_DEVICE_WAKE:
553 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
554 "Received DEVICE WAKE notification for device [%s]\n",
555 device->pnp.bus_id));
556 /* TBD */
557 break;
559 case ACPI_NOTIFY_EJECT_REQUEST:
560 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
561 "Received EJECT REQUEST notification for device [%s]\n",
562 device->pnp.bus_id));
563 /* TBD */
564 break;
566 case ACPI_NOTIFY_DEVICE_CHECK_LIGHT:
567 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
568 "Received DEVICE CHECK LIGHT notification for device [%s]\n",
569 device->pnp.bus_id));
570 /* TBD: Exactly what does 'light' mean? */
571 break;
573 case ACPI_NOTIFY_FREQUENCY_MISMATCH:
574 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
575 "Received FREQUENCY MISMATCH notification for device [%s]\n",
576 device->pnp.bus_id));
577 /* TBD */
578 break;
580 case ACPI_NOTIFY_BUS_MODE_MISMATCH:
581 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
582 "Received BUS MODE MISMATCH notification for device [%s]\n",
583 device->pnp.bus_id));
584 /* TBD */
585 break;
587 case ACPI_NOTIFY_POWER_FAULT:
588 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
589 "Received POWER FAULT notification for device [%s]\n",
590 device->pnp.bus_id));
591 /* TBD */
592 break;
594 default:
595 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
596 "Received unknown/unsupported notification [%08x]\n",
597 type));
598 break;
601 return;
604 /* --------------------------------------------------------------------------
605 Initialization/Cleanup
606 -------------------------------------------------------------------------- */
608 static int __init acpi_bus_init_irq(void)
610 acpi_status status = AE_OK;
611 union acpi_object arg = { ACPI_TYPE_INTEGER };
612 struct acpi_object_list arg_list = { 1, &arg };
613 char *message = NULL;
617 * Let the system know what interrupt model we are using by
618 * evaluating the \_PIC object, if exists.
621 switch (acpi_irq_model) {
622 case ACPI_IRQ_MODEL_PIC:
623 message = "PIC";
624 break;
625 case ACPI_IRQ_MODEL_IOAPIC:
626 message = "IOAPIC";
627 break;
628 case ACPI_IRQ_MODEL_IOSAPIC:
629 message = "IOSAPIC";
630 break;
631 case ACPI_IRQ_MODEL_PLATFORM:
632 message = "platform specific model";
633 break;
634 default:
635 printk(KERN_WARNING PREFIX "Unknown interrupt routing model\n");
636 return -ENODEV;
639 printk(KERN_INFO PREFIX "Using %s for interrupt routing\n", message);
641 arg.integer.value = acpi_irq_model;
643 status = acpi_evaluate_object(NULL, "\\_PIC", &arg_list, NULL);
644 if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
645 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PIC"));
646 return -ENODEV;
649 return 0;
652 u8 acpi_gbl_permanent_mmap;
655 void __init acpi_early_init(void)
657 acpi_status status = AE_OK;
659 if (acpi_disabled)
660 return;
662 printk(KERN_INFO PREFIX "Core revision %08x\n", ACPI_CA_VERSION);
664 /* enable workarounds, unless strict ACPI spec. compliance */
665 if (!acpi_strict)
666 acpi_gbl_enable_interpreter_slack = TRUE;
668 acpi_gbl_permanent_mmap = 1;
670 status = acpi_reallocate_root_table();
671 if (ACPI_FAILURE(status)) {
672 printk(KERN_ERR PREFIX
673 "Unable to reallocate ACPI tables\n");
674 goto error0;
677 status = acpi_initialize_subsystem();
678 if (ACPI_FAILURE(status)) {
679 printk(KERN_ERR PREFIX
680 "Unable to initialize the ACPI Interpreter\n");
681 goto error0;
684 status = acpi_load_tables();
685 if (ACPI_FAILURE(status)) {
686 printk(KERN_ERR PREFIX
687 "Unable to load the System Description Tables\n");
688 goto error0;
691 #ifdef CONFIG_X86
692 if (!acpi_ioapic) {
693 /* compatible (0) means level (3) */
694 if (!(acpi_sci_flags & ACPI_MADT_TRIGGER_MASK)) {
695 acpi_sci_flags &= ~ACPI_MADT_TRIGGER_MASK;
696 acpi_sci_flags |= ACPI_MADT_TRIGGER_LEVEL;
698 /* Set PIC-mode SCI trigger type */
699 acpi_pic_sci_set_trigger(acpi_gbl_FADT.sci_interrupt,
700 (acpi_sci_flags & ACPI_MADT_TRIGGER_MASK) >> 2);
701 } else {
703 * now that acpi_gbl_FADT is initialized,
704 * update it with result from INT_SRC_OVR parsing
706 acpi_gbl_FADT.sci_interrupt = acpi_sci_override_gsi;
708 #endif
710 status =
711 acpi_enable_subsystem(~
712 (ACPI_NO_HARDWARE_INIT |
713 ACPI_NO_ACPI_ENABLE));
714 if (ACPI_FAILURE(status)) {
715 printk(KERN_ERR PREFIX "Unable to enable ACPI\n");
716 goto error0;
719 return;
721 error0:
722 disable_acpi();
723 return;
726 static int __init acpi_bus_init(void)
728 int result = 0;
729 acpi_status status = AE_OK;
730 extern acpi_status acpi_os_initialize1(void);
733 status = acpi_os_initialize1();
735 status =
736 acpi_enable_subsystem(ACPI_NO_HARDWARE_INIT | ACPI_NO_ACPI_ENABLE);
737 if (ACPI_FAILURE(status)) {
738 printk(KERN_ERR PREFIX
739 "Unable to start the ACPI Interpreter\n");
740 goto error1;
743 if (ACPI_FAILURE(status)) {
744 printk(KERN_ERR PREFIX
745 "Unable to initialize ACPI OS objects\n");
746 goto error1;
748 #ifdef CONFIG_ACPI_EC
750 * ACPI 2.0 requires the EC driver to be loaded and work before
751 * the EC device is found in the namespace (i.e. before acpi_initialize_objects()
752 * is called).
754 * This is accomplished by looking for the ECDT table, and getting
755 * the EC parameters out of that.
757 status = acpi_ec_ecdt_probe();
758 /* Ignore result. Not having an ECDT is not fatal. */
759 #endif
761 status = acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
762 if (ACPI_FAILURE(status)) {
763 printk(KERN_ERR PREFIX "Unable to initialize ACPI objects\n");
764 goto error1;
767 printk(KERN_INFO PREFIX "Interpreter enabled\n");
769 /* Initialize sleep structures */
770 acpi_sleep_init();
773 * Get the system interrupt model and evaluate \_PIC.
775 result = acpi_bus_init_irq();
776 if (result)
777 goto error1;
780 * Register the for all standard device notifications.
782 status =
783 acpi_install_notify_handler(ACPI_ROOT_OBJECT, ACPI_SYSTEM_NOTIFY,
784 &acpi_bus_notify, NULL);
785 if (ACPI_FAILURE(status)) {
786 printk(KERN_ERR PREFIX
787 "Unable to register for device notifications\n");
788 goto error1;
792 * Create the top ACPI proc directory
794 acpi_root_dir = proc_mkdir(ACPI_BUS_FILE_ROOT, NULL);
796 return 0;
798 /* Mimic structured exception handling */
799 error1:
800 acpi_terminate();
801 return -ENODEV;
804 struct kobject *acpi_kobj;
806 static int __init acpi_init(void)
808 int result = 0;
811 if (acpi_disabled) {
812 printk(KERN_INFO PREFIX "Interpreter disabled.\n");
813 return -ENODEV;
816 acpi_kobj = kobject_create_and_add("acpi", firmware_kobj);
817 if (!acpi_kobj) {
818 printk(KERN_WARNING "%s: kset create error\n", __func__);
819 acpi_kobj = NULL;
822 result = acpi_bus_init();
824 if (!result) {
825 pci_mmcfg_late_init();
826 if (!(pm_flags & PM_APM))
827 pm_flags |= PM_ACPI;
828 else {
829 printk(KERN_INFO PREFIX
830 "APM is already active, exiting\n");
831 disable_acpi();
832 result = -ENODEV;
834 } else
835 disable_acpi();
837 return result;
840 subsys_initcall(acpi_init);