ACPI: remove unused return values from Bus Check & Device Check handling
[linux-2.6/linux-acpi-2.6.git] / drivers / acpi / bus.c
blob2b08c3dc79da8168cfca2b20ecf1443dd49224a3
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 #include "internal.h"
44 #define _COMPONENT ACPI_BUS_COMPONENT
45 ACPI_MODULE_NAME("bus");
47 struct acpi_device *acpi_root;
48 struct proc_dir_entry *acpi_root_dir;
49 EXPORT_SYMBOL(acpi_root_dir);
51 #define STRUCT_TO_INT(s) (*((int*)&s))
53 static int set_power_nocheck(const struct dmi_system_id *id)
55 printk(KERN_NOTICE PREFIX "%s detected - "
56 "disable power check in power transistion\n", id->ident);
57 acpi_power_nocheck = 1;
58 return 0;
60 static struct dmi_system_id __cpuinitdata power_nocheck_dmi_table[] = {
62 set_power_nocheck, "HP Pavilion 05", {
63 DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
64 DMI_MATCH(DMI_SYS_VENDOR, "HP Pavilion 05"),
65 DMI_MATCH(DMI_PRODUCT_VERSION, "2001211RE101GLEND") }, NULL},
66 {},
70 /* --------------------------------------------------------------------------
71 Device Management
72 -------------------------------------------------------------------------- */
74 int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
76 acpi_status status = AE_OK;
79 if (!device)
80 return -EINVAL;
82 /* TBD: Support fixed-feature devices */
84 status = acpi_get_data(handle, acpi_bus_data_handler, (void **)device);
85 if (ACPI_FAILURE(status) || !*device) {
86 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
87 handle));
88 return -ENODEV;
91 return 0;
94 EXPORT_SYMBOL(acpi_bus_get_device);
96 int acpi_bus_get_status(struct acpi_device *device)
98 acpi_status status = AE_OK;
99 unsigned long long sta = 0;
102 if (!device)
103 return -EINVAL;
106 * Evaluate _STA if present.
108 if (device->flags.dynamic_status) {
109 status =
110 acpi_evaluate_integer(device->handle, "_STA", NULL, &sta);
111 if (ACPI_FAILURE(status))
112 return -ENODEV;
113 STRUCT_TO_INT(device->status) = (int)sta;
117 * According to ACPI spec some device can be present and functional
118 * even if the parent is not present but functional.
119 * In such conditions the child device should not inherit the status
120 * from the parent.
122 else
123 STRUCT_TO_INT(device->status) =
124 ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
125 ACPI_STA_DEVICE_UI | ACPI_STA_DEVICE_FUNCTIONING;
127 if (device->status.functional && !device->status.present) {
128 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]: "
129 "functional but not present;\n",
130 device->pnp.bus_id,
131 (u32) STRUCT_TO_INT(device->status)));
134 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
135 device->pnp.bus_id,
136 (u32) STRUCT_TO_INT(device->status)));
138 return 0;
141 EXPORT_SYMBOL(acpi_bus_get_status);
143 void acpi_bus_private_data_handler(acpi_handle handle,
144 u32 function, void *context)
146 return;
148 EXPORT_SYMBOL(acpi_bus_private_data_handler);
150 int acpi_bus_get_private_data(acpi_handle handle, void **data)
152 acpi_status status = AE_OK;
154 if (!*data)
155 return -EINVAL;
157 status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
158 if (ACPI_FAILURE(status) || !*data) {
159 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
160 handle));
161 return -ENODEV;
164 return 0;
166 EXPORT_SYMBOL(acpi_bus_get_private_data);
168 /* --------------------------------------------------------------------------
169 Power Management
170 -------------------------------------------------------------------------- */
172 int acpi_bus_get_power(acpi_handle handle, int *state)
174 int result = 0;
175 acpi_status status = 0;
176 struct acpi_device *device = NULL;
177 unsigned long long psc = 0;
180 result = acpi_bus_get_device(handle, &device);
181 if (result)
182 return result;
184 *state = ACPI_STATE_UNKNOWN;
186 if (!device->flags.power_manageable) {
187 /* TBD: Non-recursive algorithm for walking up hierarchy */
188 if (device->parent)
189 *state = device->parent->power.state;
190 else
191 *state = ACPI_STATE_D0;
192 } else {
194 * Get the device's power state either directly (via _PSC) or
195 * indirectly (via power resources).
197 if (device->power.flags.explicit_get) {
198 status = acpi_evaluate_integer(device->handle, "_PSC",
199 NULL, &psc);
200 if (ACPI_FAILURE(status))
201 return -ENODEV;
202 device->power.state = (int)psc;
203 } else if (device->power.flags.power_resources) {
204 result = acpi_power_get_inferred_state(device);
205 if (result)
206 return result;
209 *state = device->power.state;
212 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is D%d\n",
213 device->pnp.bus_id, device->power.state));
215 return 0;
218 EXPORT_SYMBOL(acpi_bus_get_power);
220 int acpi_bus_set_power(acpi_handle handle, int state)
222 int result = 0;
223 acpi_status status = AE_OK;
224 struct acpi_device *device = NULL;
225 char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
228 result = acpi_bus_get_device(handle, &device);
229 if (result)
230 return result;
232 if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
233 return -EINVAL;
235 /* Make sure this is a valid target state */
237 if (!device->flags.power_manageable) {
238 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",
239 kobject_name(&device->dev.kobj)));
240 return -ENODEV;
243 * Get device's current power state
245 if (!acpi_power_nocheck) {
247 * Maybe the incorrect power state is returned on the bogus
248 * bios, which is different with the real power state.
249 * For example: the bios returns D0 state and the real power
250 * state is D3. OS expects to set the device to D0 state. In
251 * such case if OS uses the power state returned by the BIOS,
252 * the device can't be transisted to the correct power state.
253 * So if the acpi_power_nocheck is set, it is unnecessary to
254 * get the power state by calling acpi_bus_get_power.
256 acpi_bus_get_power(device->handle, &device->power.state);
258 if ((state == device->power.state) && !device->flags.force_power_state) {
259 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",
260 state));
261 return 0;
264 if (!device->power.states[state].flags.valid) {
265 printk(KERN_WARNING PREFIX "Device does not support D%d\n", state);
266 return -ENODEV;
268 if (device->parent && (state < device->parent->power.state)) {
269 printk(KERN_WARNING PREFIX
270 "Cannot set device to a higher-powered"
271 " state than parent\n");
272 return -ENODEV;
276 * Transition Power
277 * ----------------
278 * On transitions to a high-powered state we first apply power (via
279 * power resources) then evalute _PSx. Conversly for transitions to
280 * a lower-powered state.
282 if (state < device->power.state) {
283 if (device->power.flags.power_resources) {
284 result = acpi_power_transition(device, state);
285 if (result)
286 goto end;
288 if (device->power.states[state].flags.explicit_set) {
289 status = acpi_evaluate_object(device->handle,
290 object_name, NULL, NULL);
291 if (ACPI_FAILURE(status)) {
292 result = -ENODEV;
293 goto end;
296 } else {
297 if (device->power.states[state].flags.explicit_set) {
298 status = acpi_evaluate_object(device->handle,
299 object_name, NULL, NULL);
300 if (ACPI_FAILURE(status)) {
301 result = -ENODEV;
302 goto end;
305 if (device->power.flags.power_resources) {
306 result = acpi_power_transition(device, state);
307 if (result)
308 goto end;
312 end:
313 if (result)
314 printk(KERN_WARNING PREFIX
315 "Device [%s] failed to transition to D%d\n",
316 device->pnp.bus_id, state);
317 else {
318 device->power.state = state;
319 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
320 "Device [%s] transitioned to D%d\n",
321 device->pnp.bus_id, state));
324 return result;
327 EXPORT_SYMBOL(acpi_bus_set_power);
329 bool acpi_bus_power_manageable(acpi_handle handle)
331 struct acpi_device *device;
332 int result;
334 result = acpi_bus_get_device(handle, &device);
335 return result ? false : device->flags.power_manageable;
338 EXPORT_SYMBOL(acpi_bus_power_manageable);
340 bool acpi_bus_can_wakeup(acpi_handle handle)
342 struct acpi_device *device;
343 int result;
345 result = acpi_bus_get_device(handle, &device);
346 return result ? false : device->wakeup.flags.valid;
349 EXPORT_SYMBOL(acpi_bus_can_wakeup);
351 /* --------------------------------------------------------------------------
352 Event Management
353 -------------------------------------------------------------------------- */
355 #ifdef CONFIG_ACPI_PROC_EVENT
356 static DEFINE_SPINLOCK(acpi_bus_event_lock);
358 LIST_HEAD(acpi_bus_event_list);
359 DECLARE_WAIT_QUEUE_HEAD(acpi_bus_event_queue);
361 extern int event_is_open;
363 int acpi_bus_generate_proc_event4(const char *device_class, const char *bus_id, u8 type, int data)
365 struct acpi_bus_event *event;
366 unsigned long flags = 0;
368 /* drop event on the floor if no one's listening */
369 if (!event_is_open)
370 return 0;
372 event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC);
373 if (!event)
374 return -ENOMEM;
376 strcpy(event->device_class, device_class);
377 strcpy(event->bus_id, bus_id);
378 event->type = type;
379 event->data = data;
381 spin_lock_irqsave(&acpi_bus_event_lock, flags);
382 list_add_tail(&event->node, &acpi_bus_event_list);
383 spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
385 wake_up_interruptible(&acpi_bus_event_queue);
387 return 0;
391 EXPORT_SYMBOL_GPL(acpi_bus_generate_proc_event4);
393 int acpi_bus_generate_proc_event(struct acpi_device *device, u8 type, int data)
395 if (!device)
396 return -EINVAL;
397 return acpi_bus_generate_proc_event4(device->pnp.device_class,
398 device->pnp.bus_id, type, data);
401 EXPORT_SYMBOL(acpi_bus_generate_proc_event);
403 int acpi_bus_receive_event(struct acpi_bus_event *event)
405 unsigned long flags = 0;
406 struct acpi_bus_event *entry = NULL;
408 DECLARE_WAITQUEUE(wait, current);
411 if (!event)
412 return -EINVAL;
414 if (list_empty(&acpi_bus_event_list)) {
416 set_current_state(TASK_INTERRUPTIBLE);
417 add_wait_queue(&acpi_bus_event_queue, &wait);
419 if (list_empty(&acpi_bus_event_list))
420 schedule();
422 remove_wait_queue(&acpi_bus_event_queue, &wait);
423 set_current_state(TASK_RUNNING);
425 if (signal_pending(current))
426 return -ERESTARTSYS;
429 spin_lock_irqsave(&acpi_bus_event_lock, flags);
430 if (!list_empty(&acpi_bus_event_list)) {
431 entry = list_entry(acpi_bus_event_list.next,
432 struct acpi_bus_event, node);
433 list_del(&entry->node);
435 spin_unlock_irqrestore(&acpi_bus_event_lock, flags);
437 if (!entry)
438 return -ENODEV;
440 memcpy(event, entry, sizeof(struct acpi_bus_event));
442 kfree(entry);
444 return 0;
447 #endif /* CONFIG_ACPI_PROC_EVENT */
449 /* --------------------------------------------------------------------------
450 Notification Handling
451 -------------------------------------------------------------------------- */
453 static void acpi_bus_check_device(struct acpi_device *device)
455 acpi_status status;
456 struct acpi_device_status old_status;
458 if (!device)
459 return;
461 old_status = device->status;
464 * Make sure this device's parent is present before we go about
465 * messing with the device.
467 if (device->parent && !device->parent->status.present) {
468 device->status = device->parent->status;
469 return;
472 status = acpi_bus_get_status(device);
473 if (ACPI_FAILURE(status))
474 return;
476 if (STRUCT_TO_INT(old_status) == STRUCT_TO_INT(device->status))
477 return;
480 * Device Insertion/Removal
482 if ((device->status.present) && !(old_status.present)) {
483 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n"));
484 /* TBD: Handle device insertion */
485 } else if (!(device->status.present) && (old_status.present)) {
486 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device removal detected\n"));
487 /* TBD: Handle device removal */
491 static void acpi_bus_check_scope(struct acpi_device *device)
493 if (!device)
494 return;
496 /* Status Change? */
497 acpi_bus_check_device(device);
500 * TBD: Enumerate child devices within this device's scope and
501 * run acpi_bus_check_device()'s on them.
505 static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
506 int register_acpi_bus_notifier(struct notifier_block *nb)
508 return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
510 EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);
512 void unregister_acpi_bus_notifier(struct notifier_block *nb)
514 blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
516 EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);
519 * acpi_bus_notify
520 * ---------------
521 * Callback for all 'system-level' device notifications (values 0x00-0x7F).
523 static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
525 struct acpi_device *device = NULL;
526 struct acpi_driver *driver;
528 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Notification %#02x to handle %p\n",
529 type, handle));
531 blocking_notifier_call_chain(&acpi_bus_notify_list,
532 type, (void *)handle);
534 if (acpi_bus_get_device(handle, &device))
535 return;
537 switch (type) {
539 case ACPI_NOTIFY_BUS_CHECK:
540 acpi_bus_check_scope(device);
542 * TBD: We'll need to outsource certain events to non-ACPI
543 * drivers via the device manager (device.c).
545 break;
547 case ACPI_NOTIFY_DEVICE_CHECK:
548 acpi_bus_check_device(device);
550 * TBD: We'll need to outsource certain events to non-ACPI
551 * drivers via the device manager (device.c).
553 break;
555 case ACPI_NOTIFY_DEVICE_WAKE:
556 /* TBD */
557 break;
559 case ACPI_NOTIFY_EJECT_REQUEST:
560 /* TBD */
561 break;
563 case ACPI_NOTIFY_DEVICE_CHECK_LIGHT:
564 /* TBD: Exactly what does 'light' mean? */
565 break;
567 case ACPI_NOTIFY_FREQUENCY_MISMATCH:
568 /* TBD */
569 break;
571 case ACPI_NOTIFY_BUS_MODE_MISMATCH:
572 /* TBD */
573 break;
575 case ACPI_NOTIFY_POWER_FAULT:
576 /* TBD */
577 break;
579 default:
580 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
581 "Received unknown/unsupported notification [%08x]\n",
582 type));
583 break;
586 driver = device->driver;
587 if (driver && driver->ops.notify &&
588 (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
589 driver->ops.notify(device, type);
592 /* --------------------------------------------------------------------------
593 Initialization/Cleanup
594 -------------------------------------------------------------------------- */
596 static int __init acpi_bus_init_irq(void)
598 acpi_status status = AE_OK;
599 union acpi_object arg = { ACPI_TYPE_INTEGER };
600 struct acpi_object_list arg_list = { 1, &arg };
601 char *message = NULL;
605 * Let the system know what interrupt model we are using by
606 * evaluating the \_PIC object, if exists.
609 switch (acpi_irq_model) {
610 case ACPI_IRQ_MODEL_PIC:
611 message = "PIC";
612 break;
613 case ACPI_IRQ_MODEL_IOAPIC:
614 message = "IOAPIC";
615 break;
616 case ACPI_IRQ_MODEL_IOSAPIC:
617 message = "IOSAPIC";
618 break;
619 case ACPI_IRQ_MODEL_PLATFORM:
620 message = "platform specific model";
621 break;
622 default:
623 printk(KERN_WARNING PREFIX "Unknown interrupt routing model\n");
624 return -ENODEV;
627 printk(KERN_INFO PREFIX "Using %s for interrupt routing\n", message);
629 arg.integer.value = acpi_irq_model;
631 status = acpi_evaluate_object(NULL, "\\_PIC", &arg_list, NULL);
632 if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
633 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PIC"));
634 return -ENODEV;
637 return 0;
640 u8 acpi_gbl_permanent_mmap;
643 void __init acpi_early_init(void)
645 acpi_status status = AE_OK;
647 if (acpi_disabled)
648 return;
650 printk(KERN_INFO PREFIX "Core revision %08x\n", ACPI_CA_VERSION);
652 /* enable workarounds, unless strict ACPI spec. compliance */
653 if (!acpi_strict)
654 acpi_gbl_enable_interpreter_slack = TRUE;
656 acpi_gbl_permanent_mmap = 1;
658 status = acpi_reallocate_root_table();
659 if (ACPI_FAILURE(status)) {
660 printk(KERN_ERR PREFIX
661 "Unable to reallocate ACPI tables\n");
662 goto error0;
665 status = acpi_initialize_subsystem();
666 if (ACPI_FAILURE(status)) {
667 printk(KERN_ERR PREFIX
668 "Unable to initialize the ACPI Interpreter\n");
669 goto error0;
672 status = acpi_load_tables();
673 if (ACPI_FAILURE(status)) {
674 printk(KERN_ERR PREFIX
675 "Unable to load the System Description Tables\n");
676 goto error0;
679 #ifdef CONFIG_X86
680 if (!acpi_ioapic) {
681 /* compatible (0) means level (3) */
682 if (!(acpi_sci_flags & ACPI_MADT_TRIGGER_MASK)) {
683 acpi_sci_flags &= ~ACPI_MADT_TRIGGER_MASK;
684 acpi_sci_flags |= ACPI_MADT_TRIGGER_LEVEL;
686 /* Set PIC-mode SCI trigger type */
687 acpi_pic_sci_set_trigger(acpi_gbl_FADT.sci_interrupt,
688 (acpi_sci_flags & ACPI_MADT_TRIGGER_MASK) >> 2);
689 } else {
691 * now that acpi_gbl_FADT is initialized,
692 * update it with result from INT_SRC_OVR parsing
694 acpi_gbl_FADT.sci_interrupt = acpi_sci_override_gsi;
696 #endif
698 status =
699 acpi_enable_subsystem(~
700 (ACPI_NO_HARDWARE_INIT |
701 ACPI_NO_ACPI_ENABLE));
702 if (ACPI_FAILURE(status)) {
703 printk(KERN_ERR PREFIX "Unable to enable ACPI\n");
704 goto error0;
707 return;
709 error0:
710 disable_acpi();
711 return;
714 static int __init acpi_bus_init(void)
716 int result = 0;
717 acpi_status status = AE_OK;
718 extern acpi_status acpi_os_initialize1(void);
720 acpi_os_initialize1();
722 status =
723 acpi_enable_subsystem(ACPI_NO_HARDWARE_INIT | ACPI_NO_ACPI_ENABLE);
724 if (ACPI_FAILURE(status)) {
725 printk(KERN_ERR PREFIX
726 "Unable to start the ACPI Interpreter\n");
727 goto error1;
731 * ACPI 2.0 requires the EC driver to be loaded and work before
732 * the EC device is found in the namespace (i.e. before acpi_initialize_objects()
733 * is called).
735 * This is accomplished by looking for the ECDT table, and getting
736 * the EC parameters out of that.
738 status = acpi_ec_ecdt_probe();
739 /* Ignore result. Not having an ECDT is not fatal. */
741 status = acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
742 if (ACPI_FAILURE(status)) {
743 printk(KERN_ERR PREFIX "Unable to initialize ACPI objects\n");
744 goto error1;
748 * Maybe EC region is required at bus_scan/acpi_get_devices. So it
749 * is necessary to enable it as early as possible.
751 acpi_boot_ec_enable();
753 printk(KERN_INFO PREFIX "Interpreter enabled\n");
755 /* Initialize sleep structures */
756 acpi_sleep_init();
759 * Get the system interrupt model and evaluate \_PIC.
761 result = acpi_bus_init_irq();
762 if (result)
763 goto error1;
766 * Register the for all standard device notifications.
768 status =
769 acpi_install_notify_handler(ACPI_ROOT_OBJECT, ACPI_SYSTEM_NOTIFY,
770 &acpi_bus_notify, NULL);
771 if (ACPI_FAILURE(status)) {
772 printk(KERN_ERR PREFIX
773 "Unable to register for device notifications\n");
774 goto error1;
778 * Create the top ACPI proc directory
780 acpi_root_dir = proc_mkdir(ACPI_BUS_FILE_ROOT, NULL);
782 return 0;
784 /* Mimic structured exception handling */
785 error1:
786 acpi_terminate();
787 return -ENODEV;
790 struct kobject *acpi_kobj;
792 static int __init acpi_init(void)
794 int result = 0;
797 if (acpi_disabled) {
798 printk(KERN_INFO PREFIX "Interpreter disabled.\n");
799 return -ENODEV;
802 acpi_kobj = kobject_create_and_add("acpi", firmware_kobj);
803 if (!acpi_kobj) {
804 printk(KERN_WARNING "%s: kset create error\n", __func__);
805 acpi_kobj = NULL;
808 init_acpi_device_notify();
809 result = acpi_bus_init();
811 if (!result) {
812 pci_mmcfg_late_init();
813 if (!(pm_flags & PM_APM))
814 pm_flags |= PM_ACPI;
815 else {
816 printk(KERN_INFO PREFIX
817 "APM is already active, exiting\n");
818 disable_acpi();
819 result = -ENODEV;
821 } else
822 disable_acpi();
824 if (acpi_disabled)
825 return result;
828 * If the laptop falls into the DMI check table, the power state check
829 * will be disabled in the course of device power transistion.
831 dmi_check_system(power_nocheck_dmi_table);
833 acpi_scan_init();
834 acpi_ec_init();
835 acpi_power_init();
836 acpi_system_init();
837 acpi_debug_init();
838 acpi_sleep_proc_init();
839 acpi_wakeup_device_init();
840 return result;
843 subsys_initcall(acpi_init);