added 2.6.29.6 aldebaran kernel

[nao-ulib.git] / kernel / 2.6.29.6-aldebaran-rt / drivers / acpi / bus.c

/*
 *  acpi_bus.c - ACPI Bus Driver ($Revision: 80 $)
 *
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/proc_fs.h>
#include <linux/acpi.h>
#ifdef CONFIG_X86
#include <asm/mpspec.h>
#endif
#include <linux/pci.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>

#define _COMPONENT              ACPI_BUS_COMPONENT
ACPI_MODULE_NAME("bus");

struct acpi_device *acpi_root;
struct proc_dir_entry *acpi_root_dir;
EXPORT_SYMBOL(acpi_root_dir);

#define STRUCT_TO_INT(s)        (*((int*)&s))

static int set_power_nocheck(const struct dmi_system_id *id)
{
        printk(KERN_NOTICE PREFIX "%s detected - "
                "disable power check in power transistion\n", id->ident);
        acpi_power_nocheck = 1;
        return 0;
}
static struct dmi_system_id __cpuinitdata power_nocheck_dmi_table[] = {
        {
        set_power_nocheck, "HP Pavilion 05", {
        DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
        DMI_MATCH(DMI_SYS_VENDOR, "HP Pavilion 05"),
        DMI_MATCH(DMI_PRODUCT_VERSION, "2001211RE101GLEND") }, NULL},
        {},
};


/* --------------------------------------------------------------------------
                                Device Management
   -------------------------------------------------------------------------- */

int acpi_bus_get_device(acpi_handle handle, struct acpi_device **device)
{
        acpi_status status = AE_OK;


        if (!device)
                return -EINVAL;

        /* TBD: Support fixed-feature devices */

        status = acpi_get_data(handle, acpi_bus_data_handler, (void **)device);
        if (ACPI_FAILURE(status) || !*device) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
                                  handle));
                return -ENODEV;
        }

        return 0;
}

EXPORT_SYMBOL(acpi_bus_get_device);

int acpi_bus_get_status(struct acpi_device *device)
{
        acpi_status status = AE_OK;
        unsigned long long sta = 0;


        if (!device)
                return -EINVAL;

        /*
         * Evaluate _STA if present.
         */
        if (device->flags.dynamic_status) {
                status =
                    acpi_evaluate_integer(device->handle, "_STA", NULL, &sta);
                if (ACPI_FAILURE(status))
                        return -ENODEV;
                STRUCT_TO_INT(device->status) = (int)sta;
        }

        /*
         * According to ACPI spec some device can be present and functional
         * even if the parent is not present but functional.
         * In such conditions the child device should not inherit the status
         * from the parent.
         */
        else
                STRUCT_TO_INT(device->status) =
                    ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
                    ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;

        if (device->status.functional && !device->status.present) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]: "
                       "functional but not present;\n",
                        device->pnp.bus_id,
                        (u32) STRUCT_TO_INT(device->status)));
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
                          device->pnp.bus_id,
                          (u32) STRUCT_TO_INT(device->status)));

        return 0;
}

EXPORT_SYMBOL(acpi_bus_get_status);

void acpi_bus_private_data_handler(acpi_handle handle,
                                   u32 function, void *context)
{
        return;
}
EXPORT_SYMBOL(acpi_bus_private_data_handler);

int acpi_bus_get_private_data(acpi_handle handle, void **data)
{
        acpi_status status = AE_OK;

        if (!*data)
                return -EINVAL;

        status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
        if (ACPI_FAILURE(status) || !*data) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",
                                handle));
                return -ENODEV;
        }

        return 0;
}
EXPORT_SYMBOL(acpi_bus_get_private_data);

/* --------------------------------------------------------------------------
                                 Power Management
   -------------------------------------------------------------------------- */

int acpi_bus_get_power(acpi_handle handle, int *state)
{
        int result = 0;
        acpi_status status = 0;
        struct acpi_device *device = NULL;
        unsigned long long psc = 0;


        result = acpi_bus_get_device(handle, &device);
        if (result)
                return result;

        *state = ACPI_STATE_UNKNOWN;

        if (!device->flags.power_manageable) {
                /* TBD: Non-recursive algorithm for walking up hierarchy */
                if (device->parent)
                        *state = device->parent->power.state;
                else
                        *state = ACPI_STATE_D0;
        } else {
                /*
                 * Get the device's power state either directly (via _PSC) or
                 * indirectly (via power resources).
                 */
                if (device->power.flags.explicit_get) {
                        status = acpi_evaluate_integer(device->handle, "_PSC",
                                                       NULL, &psc);
                        if (ACPI_FAILURE(status))
                                return -ENODEV;
                        device->power.state = (int)psc;
                } else if (device->power.flags.power_resources) {
                        result = acpi_power_get_inferred_state(device);
                        if (result)
                                return result;
                }

                *state = device->power.state;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is D%d\n",
                          device->pnp.bus_id, device->power.state));

        return 0;
}

EXPORT_SYMBOL(acpi_bus_get_power);

int acpi_bus_set_power(acpi_handle handle, int state)
{
        int result = 0;
        acpi_status status = AE_OK;
        struct acpi_device *device = NULL;
        char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };


        result = acpi_bus_get_device(handle, &device);
        if (result)
                return result;

        if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
                return -EINVAL;

        /* Make sure this is a valid target state */

        if (!device->flags.power_manageable) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",
                                kobject_name(&device->dev.kobj)));
                return -ENODEV;
        }
        /*
         * Get device's current power state
         */
        if (!acpi_power_nocheck) {
                /*
                 * Maybe the incorrect power state is returned on the bogus
                 * bios, which is different with the real power state.
                 * For example: the bios returns D0 state and the real power
                 * state is D3. OS expects to set the device to D0 state. In
                 * such case if OS uses the power state returned by the BIOS,
                 * the device can't be transisted to the correct power state.
                 * So if the acpi_power_nocheck is set, it is unnecessary to
                 * get the power state by calling acpi_bus_get_power.
                 */
                acpi_bus_get_power(device->handle, &device->power.state);
        }
        if ((state == device->power.state) && !device->flags.force_power_state) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",
                                  state));
                return 0;
        }

        if (!device->power.states[state].flags.valid) {
                printk(KERN_WARNING PREFIX "Device does not support D%d\n", state);
                return -ENODEV;
        }
        if (device->parent && (state < device->parent->power.state)) {
                printk(KERN_WARNING PREFIX
                              "Cannot set device to a higher-powered"
                              " state than parent\n");
                return -ENODEV;
        }

        /*
         * Transition Power
         * ----------------
         * On transitions to a high-powered state we first apply power (via
         * power resources) then evalute _PSx.  Conversly for transitions to
         * a lower-powered state.
         */
        if (state < device->power.state) {
                if (device->power.flags.power_resources) {
                        result = acpi_power_transition(device, state);
                        if (result)
                                goto end;
                }
                if (device->power.states[state].flags.explicit_set) {
                        status = acpi_evaluate_object(device->handle,
                                                      object_name, NULL, NULL);
                        if (ACPI_FAILURE(status)) {
                                result = -ENODEV;
                                goto end;
                        }
                }
        } else {
                if (device->power.states[state].flags.explicit_set) {
                        status = acpi_evaluate_object(device->handle,
                                                      object_name, NULL, NULL);
                        if (ACPI_FAILURE(status)) {
                                result = -ENODEV;
                                goto end;
                        }
                }
                if (device->power.flags.power_resources) {
                        result = acpi_power_transition(device, state);
                        if (result)
                                goto end;
                }
        }

      end:
        if (result)
                printk(KERN_WARNING PREFIX
                              "Transitioning device [%s] to D%d\n",
                              device->pnp.bus_id, state);
        else {
                device->power.state = state;
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Device [%s] transitioned to D%d\n",
                                  device->pnp.bus_id, state));
        }

        return result;
}

EXPORT_SYMBOL(acpi_bus_set_power);

bool acpi_bus_power_manageable(acpi_handle handle)
{
        struct acpi_device *device;
        int result;

        result = acpi_bus_get_device(handle, &device);
        return result ? false : device->flags.power_manageable;
}

EXPORT_SYMBOL(acpi_bus_power_manageable);

bool acpi_bus_can_wakeup(acpi_handle handle)
{
        struct acpi_device *device;
        int result;

        result = acpi_bus_get_device(handle, &device);
        return result ? false : device->wakeup.flags.valid;
}

EXPORT_SYMBOL(acpi_bus_can_wakeup);

/* --------------------------------------------------------------------------
                                Event Management
   -------------------------------------------------------------------------- */

#ifdef CONFIG_ACPI_PROC_EVENT
static DEFINE_SPINLOCK(acpi_bus_event_lock);

LIST_HEAD(acpi_bus_event_list);
DECLARE_WAIT_QUEUE_HEAD(acpi_bus_event_queue);

extern int event_is_open;

int acpi_bus_generate_proc_event4(const char *device_class, const char *bus_id, u8 type, int data)
{
        struct acpi_bus_event *event;
        unsigned long flags = 0;

        /* drop event on the floor if no one's listening */
        if (!event_is_open)
                return 0;

        event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC);
        if (!event)
                return -ENOMEM;

        strcpy(event->device_class, device_class);
        strcpy(event->bus_id, bus_id);
        event->type = type;
        event->data = data;

        spin_lock_irqsave(&acpi_bus_event_lock, flags);
        list_add_tail(&event->node, &acpi_bus_event_list);
        spin_unlock_irqrestore(&acpi_bus_event_lock, flags);

        wake_up_interruptible(&acpi_bus_event_queue);

        return 0;

}

EXPORT_SYMBOL_GPL(acpi_bus_generate_proc_event4);

int acpi_bus_generate_proc_event(struct acpi_device *device, u8 type, int data)
{
        if (!device)
                return -EINVAL;
        return acpi_bus_generate_proc_event4(device->pnp.device_class,
                                             device->pnp.bus_id, type, data);
}

EXPORT_SYMBOL(acpi_bus_generate_proc_event);

int acpi_bus_receive_event(struct acpi_bus_event *event)
{
        unsigned long flags = 0;
        struct acpi_bus_event *entry = NULL;

        DECLARE_WAITQUEUE(wait, current);


        if (!event)
                return -EINVAL;

        if (list_empty(&acpi_bus_event_list)) {

                set_current_state(TASK_INTERRUPTIBLE);
                add_wait_queue(&acpi_bus_event_queue, &wait);

                if (list_empty(&acpi_bus_event_list))
                        schedule();

                remove_wait_queue(&acpi_bus_event_queue, &wait);
                set_current_state(TASK_RUNNING);

                if (signal_pending(current))
                        return -ERESTARTSYS;
        }

        spin_lock_irqsave(&acpi_bus_event_lock, flags);
        if (!list_empty(&acpi_bus_event_list)) {
                entry = list_entry(acpi_bus_event_list.next,
                                   struct acpi_bus_event, node);
                list_del(&entry->node);
        }
        spin_unlock_irqrestore(&acpi_bus_event_lock, flags);

        if (!entry)
                return -ENODEV;

        memcpy(event, entry, sizeof(struct acpi_bus_event));

        kfree(entry);

        return 0;
}

#endif  /* CONFIG_ACPI_PROC_EVENT */

/* --------------------------------------------------------------------------
                             Notification Handling
   -------------------------------------------------------------------------- */

static int
acpi_bus_check_device(struct acpi_device *device, int *status_changed)
{
        acpi_status status = 0;
        struct acpi_device_status old_status;


        if (!device)
                return -EINVAL;

        if (status_changed)
                *status_changed = 0;

        old_status = device->status;

        /*
         * Make sure this device's parent is present before we go about
         * messing with the device.
         */
        if (device->parent && !device->parent->status.present) {
                device->status = device->parent->status;
                if (STRUCT_TO_INT(old_status) != STRUCT_TO_INT(device->status)) {
                        if (status_changed)
                                *status_changed = 1;
                }
                return 0;
        }

        status = acpi_bus_get_status(device);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        if (STRUCT_TO_INT(old_status) == STRUCT_TO_INT(device->status))
                return 0;

        if (status_changed)
                *status_changed = 1;

        /*
         * Device Insertion/Removal
         */
        if ((device->status.present) && !(old_status.present)) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n"));
                /* TBD: Handle device insertion */
        } else if (!(device->status.present) && (old_status.present)) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device removal detected\n"));
                /* TBD: Handle device removal */
        }

        return 0;
}

static int acpi_bus_check_scope(struct acpi_device *device)
{
        int result = 0;
        int status_changed = 0;


        if (!device)
                return -EINVAL;

        /* Status Change? */
        result = acpi_bus_check_device(device, &status_changed);
        if (result)
                return result;

        if (!status_changed)
                return 0;

        /*
         * TBD: Enumerate child devices within this device's scope and
         *       run acpi_bus_check_device()'s on them.
         */

        return 0;
}

static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
int register_acpi_bus_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
}
EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);

void unregister_acpi_bus_notifier(struct notifier_block *nb)
{
        blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
}
EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);

/**
 * acpi_bus_notify
 * ---------------
 * Callback for all 'system-level' device notifications (values 0x00-0x7F).
 */
static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
{
        int result = 0;
        struct acpi_device *device = NULL;

        blocking_notifier_call_chain(&acpi_bus_notify_list,
                type, (void *)handle);

        if (acpi_bus_get_device(handle, &device))
                return;

        switch (type) {

        case ACPI_NOTIFY_BUS_CHECK:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received BUS CHECK notification for device [%s]\n",
                                  device->pnp.bus_id));
                result = acpi_bus_check_scope(device);
                /*
                 * TBD: We'll need to outsource certain events to non-ACPI
                 *      drivers via the device manager (device.c).
                 */
                break;

        case ACPI_NOTIFY_DEVICE_CHECK:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received DEVICE CHECK notification for device [%s]\n",
                                  device->pnp.bus_id));
                result = acpi_bus_check_device(device, NULL);
                /*
                 * TBD: We'll need to outsource certain events to non-ACPI
                 *      drivers via the device manager (device.c).
                 */
                break;

        case ACPI_NOTIFY_DEVICE_WAKE:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received DEVICE WAKE notification for device [%s]\n",
                                  device->pnp.bus_id));
                /* TBD */
                break;

        case ACPI_NOTIFY_EJECT_REQUEST:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received EJECT REQUEST notification for device [%s]\n",
                                  device->pnp.bus_id));
                /* TBD */
                break;

        case ACPI_NOTIFY_DEVICE_CHECK_LIGHT:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received DEVICE CHECK LIGHT notification for device [%s]\n",
                                  device->pnp.bus_id));
                /* TBD: Exactly what does 'light' mean? */
                break;

        case ACPI_NOTIFY_FREQUENCY_MISMATCH:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received FREQUENCY MISMATCH notification for device [%s]\n",
                                  device->pnp.bus_id));
                /* TBD */
                break;

        case ACPI_NOTIFY_BUS_MODE_MISMATCH:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received BUS MODE MISMATCH notification for device [%s]\n",
                                  device->pnp.bus_id));
                /* TBD */
                break;

        case ACPI_NOTIFY_POWER_FAULT:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received POWER FAULT notification for device [%s]\n",
                                  device->pnp.bus_id));
                /* TBD */
                break;

        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Received unknown/unsupported notification [%08x]\n",
                                  type));
                break;
        }

        return;
}

/* --------------------------------------------------------------------------
                             Initialization/Cleanup
   -------------------------------------------------------------------------- */

static int __init acpi_bus_init_irq(void)
{
        acpi_status status = AE_OK;
        union acpi_object arg = { ACPI_TYPE_INTEGER };
        struct acpi_object_list arg_list = { 1, &arg };
        char *message = NULL;


        /*
         * Let the system know what interrupt model we are using by
         * evaluating the \_PIC object, if exists.
         */

        switch (acpi_irq_model) {
        case ACPI_IRQ_MODEL_PIC:
                message = "PIC";
                break;
        case ACPI_IRQ_MODEL_IOAPIC:
                message = "IOAPIC";
                break;
        case ACPI_IRQ_MODEL_IOSAPIC:
                message = "IOSAPIC";
                break;
        case ACPI_IRQ_MODEL_PLATFORM:
                message = "platform specific model";
                break;
        default:
                printk(KERN_WARNING PREFIX "Unknown interrupt routing model\n");
                return -ENODEV;
        }

        printk(KERN_INFO PREFIX "Using %s for interrupt routing\n", message);

        arg.integer.value = acpi_irq_model;

        status = acpi_evaluate_object(NULL, "\\_PIC", &arg_list, NULL);
        if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PIC"));
                return -ENODEV;
        }

        return 0;
}

u8 acpi_gbl_permanent_mmap;


void __init acpi_early_init(void)
{
        acpi_status status = AE_OK;

        if (acpi_disabled)
                return;

        printk(KERN_INFO PREFIX "Core revision %08x\n", ACPI_CA_VERSION);

        /* enable workarounds, unless strict ACPI spec. compliance */
        if (!acpi_strict)
                acpi_gbl_enable_interpreter_slack = TRUE;

        acpi_gbl_permanent_mmap = 1;

        status = acpi_reallocate_root_table();
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX
                       "Unable to reallocate ACPI tables\n");
                goto error0;
        }

        status = acpi_initialize_subsystem();
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX
                       "Unable to initialize the ACPI Interpreter\n");
                goto error0;
        }

        status = acpi_load_tables();
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX
                       "Unable to load the System Description Tables\n");
                goto error0;
        }

#ifdef CONFIG_X86
        if (!acpi_ioapic) {
                /* compatible (0) means level (3) */
                if (!(acpi_sci_flags & ACPI_MADT_TRIGGER_MASK)) {
                        acpi_sci_flags &= ~ACPI_MADT_TRIGGER_MASK;
                        acpi_sci_flags |= ACPI_MADT_TRIGGER_LEVEL;
                }
                /* Set PIC-mode SCI trigger type */
                acpi_pic_sci_set_trigger(acpi_gbl_FADT.sci_interrupt,
                                         (acpi_sci_flags & ACPI_MADT_TRIGGER_MASK) >> 2);
        } else {
                /*
                 * now that acpi_gbl_FADT is initialized,
                 * update it with result from INT_SRC_OVR parsing
                 */
                acpi_gbl_FADT.sci_interrupt = acpi_sci_override_gsi;
        }
#endif

        status =
            acpi_enable_subsystem(~
                                  (ACPI_NO_HARDWARE_INIT |
                                   ACPI_NO_ACPI_ENABLE));
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX "Unable to enable ACPI\n");
                goto error0;
        }

        return;

      error0:
        disable_acpi();
        return;
}

static int __init acpi_bus_init(void)
{
        int result = 0;
        acpi_status status = AE_OK;
        extern acpi_status acpi_os_initialize1(void);

        acpi_os_initialize1();

        status =
            acpi_enable_subsystem(ACPI_NO_HARDWARE_INIT | ACPI_NO_ACPI_ENABLE);
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX
                       "Unable to start the ACPI Interpreter\n");
                goto error1;
        }

        /*
         * ACPI 2.0 requires the EC driver to be loaded and work before
         * the EC device is found in the namespace (i.e. before acpi_initialize_objects()
         * is called).
         *
         * This is accomplished by looking for the ECDT table, and getting
         * the EC parameters out of that.
         */
        status = acpi_ec_ecdt_probe();
        /* Ignore result. Not having an ECDT is not fatal. */

        status = acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX "Unable to initialize ACPI objects\n");
                goto error1;
        }

        /*
         * Maybe EC region is required at bus_scan/acpi_get_devices. So it
         * is necessary to enable it as early as possible.
         */
        acpi_boot_ec_enable();

        printk(KERN_INFO PREFIX "Interpreter enabled\n");

        /* Initialize sleep structures */
        acpi_sleep_init();

        /*
         * Get the system interrupt model and evaluate \_PIC.
         */
        result = acpi_bus_init_irq();
        if (result)
                goto error1;

        /*
         * Register the for all standard device notifications.
         */
        status =
            acpi_install_notify_handler(ACPI_ROOT_OBJECT, ACPI_SYSTEM_NOTIFY,
                                        &acpi_bus_notify, NULL);
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX
                       "Unable to register for device notifications\n");
                goto error1;
        }

        /*
         * Create the top ACPI proc directory
         */
        acpi_root_dir = proc_mkdir(ACPI_BUS_FILE_ROOT, NULL);

        return 0;

        /* Mimic structured exception handling */
      error1:
        acpi_terminate();
        return -ENODEV;
}

struct kobject *acpi_kobj;

static int __init acpi_init(void)
{
        int result = 0;


        if (acpi_disabled) {
                printk(KERN_INFO PREFIX "Interpreter disabled.\n");
                return -ENODEV;
        }

        acpi_kobj = kobject_create_and_add("acpi", firmware_kobj);
        if (!acpi_kobj) {
                printk(KERN_WARNING "%s: kset create error\n", __func__);
                acpi_kobj = NULL;
        }

        result = acpi_bus_init();

        if (!result) {
                pci_mmcfg_late_init();
                if (!(pm_flags & PM_APM))
                        pm_flags |= PM_ACPI;
                else {
                        printk(KERN_INFO PREFIX
                               "APM is already active, exiting\n");
                        disable_acpi();
                        result = -ENODEV;
                }
        } else
                disable_acpi();
        /*
         * If the laptop falls into the DMI check table, the power state check
         * will be disabled in the course of device power transistion.
         */
        dmi_check_system(power_nocheck_dmi_table);
        return result;
}

subsys_initcall(acpi_init);