Merge branch 'master' into for-next
[safe/jmp/linux-2.6] / drivers / acpi / power.c
index fe67a8a..f74d3b3 100644 (file)
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/slab.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
+#include "sleep.h"
 
-#define _COMPONENT             ACPI_POWER_COMPONENT
-ACPI_MODULE_NAME("acpi_power")
-#define ACPI_POWER_COMPONENT           0x00800000
+#define PREFIX "ACPI: "
+
+#define _COMPONENT                     ACPI_POWER_COMPONENT
+ACPI_MODULE_NAME("power");
 #define ACPI_POWER_CLASS               "power_resource"
-#define ACPI_POWER_DRIVER_NAME         "ACPI Power Resource Driver"
 #define ACPI_POWER_DEVICE_NAME         "Power Resource"
 #define ACPI_POWER_FILE_INFO           "info"
 #define ACPI_POWER_FILE_STATUS         "state"
 #define ACPI_POWER_RESOURCE_STATE_OFF  0x00
 #define ACPI_POWER_RESOURCE_STATE_ON   0x01
 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
+
+int acpi_power_nocheck;
+module_param_named(power_nocheck, acpi_power_nocheck, bool, 000);
+
 static int acpi_power_add(struct acpi_device *device);
 static int acpi_power_remove(struct acpi_device *device, int type);
+static int acpi_power_resume(struct acpi_device *device);
 static int acpi_power_open_fs(struct inode *inode, struct file *file);
 
+static const struct acpi_device_id power_device_ids[] = {
+       {ACPI_POWER_HID, 0},
+       {"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, power_device_ids);
+
 static struct acpi_driver acpi_power_driver = {
-       .name = ACPI_POWER_DRIVER_NAME,
+       .name = "power",
        .class = ACPI_POWER_CLASS,
-       .ids = ACPI_POWER_HID,
+       .ids = power_device_ids,
        .ops = {
                .add = acpi_power_add,
                .remove = acpi_power_remove,
+               .resume = acpi_power_resume,
                },
 };
 
+struct acpi_power_reference {
+       struct list_head node;
+       struct acpi_device *device;
+};
+
 struct acpi_power_resource {
        struct acpi_device * device;
        acpi_bus_id name;
        u32 system_level;
        u32 order;
-       int state;
-       int references;
+       struct mutex resource_lock;
+       struct list_head reference;
 };
 
 static struct list_head acpi_power_resource_list;
 
 static const struct file_operations acpi_power_fops = {
+       .owner = THIS_MODULE,
        .open = acpi_power_open_fs,
        .read = seq_read,
        .llseek = seq_lseek,
@@ -108,41 +128,43 @@ acpi_power_get_context(acpi_handle handle,
                return result;
        }
 
-       *resource = (struct acpi_power_resource *)acpi_driver_data(device);
-       if (!resource)
+       *resource = acpi_driver_data(device);
+       if (!*resource)
                return -ENODEV;
 
        return 0;
 }
 
-static int acpi_power_get_state(struct acpi_power_resource *resource)
+static int acpi_power_get_state(acpi_handle handle, int *state)
 {
        acpi_status status = AE_OK;
-       unsigned long sta = 0;
+       unsigned long long sta = 0;
+       char node_name[5];
+       struct acpi_buffer buffer = { sizeof(node_name), node_name };
 
 
-       if (!resource)
+       if (!handle || !state)
                return -EINVAL;
 
-       status = acpi_evaluate_integer(resource->device->handle, "_STA", NULL, &sta);
+       status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
        if (ACPI_FAILURE(status))
                return -ENODEV;
 
-       if (sta & 0x01)
-               resource->state = ACPI_POWER_RESOURCE_STATE_ON;
-       else
-               resource->state = ACPI_POWER_RESOURCE_STATE_OFF;
+       *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
+                             ACPI_POWER_RESOURCE_STATE_OFF;
+
+       acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 
        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
-                         resource->name, resource->state ? "on" : "off"));
+                         node_name,
+                               *state ? "on" : "off"));
 
        return 0;
 }
 
 static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
 {
-       int result = 0;
-       struct acpi_power_resource *resource = NULL;
+       int result = 0, state1;
        u32 i = 0;
 
 
@@ -152,14 +174,16 @@ static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
        /* The state of the list is 'on' IFF all resources are 'on'. */
 
        for (i = 0; i < list->count; i++) {
-               result = acpi_power_get_context(list->handles[i], &resource);
-               if (result)
-                       return result;
-               result = acpi_power_get_state(resource);
+               /*
+                * The state of the power resource can be obtained by
+                * using the ACPI handle. In such case it is unnecessary to
+                * get the Power resource first and then get its state again.
+                */
+               result = acpi_power_get_state(list->handles[i], &state1);
                if (result)
                        return result;
 
-               *state = resource->state;
+               *state = state1;
 
                if (*state != ACPI_POWER_RESOURCE_STATE_ON)
                        break;
@@ -171,83 +195,95 @@ static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
        return result;
 }
 
-static int acpi_power_on(acpi_handle handle)
+static int acpi_power_on(acpi_handle handle, struct acpi_device *dev)
 {
        int result = 0;
+       int found = 0;
        acpi_status status = AE_OK;
-       struct acpi_device *device = NULL;
        struct acpi_power_resource *resource = NULL;
+       struct list_head *node, *next;
+       struct acpi_power_reference *ref;
 
 
        result = acpi_power_get_context(handle, &resource);
        if (result)
                return result;
 
-       resource->references++;
+       mutex_lock(&resource->resource_lock);
+       list_for_each_safe(node, next, &resource->reference) {
+               ref = container_of(node, struct acpi_power_reference, node);
+               if (dev->handle == ref->device->handle) {
+                       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already referenced by resource [%s]\n",
+                                 dev->pnp.bus_id, resource->name));
+                       found = 1;
+                       break;
+               }
+       }
 
-       if ((resource->references > 1)
-           || (resource->state == ACPI_POWER_RESOURCE_STATE_ON)) {
-               ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] already on\n",
-                                 resource->name));
-               return 0;
+       if (!found) {
+               ref = kmalloc(sizeof (struct acpi_power_reference),
+                   irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL);
+               if (!ref) {
+                       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "kmalloc() failed\n"));
+                       mutex_unlock(&resource->resource_lock);
+                       return -ENOMEM;
+               }
+               list_add_tail(&ref->node, &resource->reference);
+               ref->device = dev;
+               ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] added to resource [%s] references\n",
+                         dev->pnp.bus_id, resource->name));
        }
+       mutex_unlock(&resource->resource_lock);
 
        status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
        if (ACPI_FAILURE(status))
                return -ENODEV;
 
-       result = acpi_power_get_state(resource);
-       if (result)
-               return result;
-       if (resource->state != ACPI_POWER_RESOURCE_STATE_ON)
-               return -ENOEXEC;
-
        /* Update the power resource's _device_ power state */
-       device = resource->device;
        resource->device->power.state = ACPI_STATE_D0;
 
        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned on\n",
                          resource->name));
-
        return 0;
 }
 
-static int acpi_power_off_device(acpi_handle handle)
+static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev)
 {
        int result = 0;
        acpi_status status = AE_OK;
        struct acpi_power_resource *resource = NULL;
+       struct list_head *node, *next;
+       struct acpi_power_reference *ref;
+
 
        result = acpi_power_get_context(handle, &resource);
        if (result)
                return result;
 
-       if (resource->references)
-               resource->references--;
-
-       if (resource->references) {
-               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-                                 "Resource [%s] is still in use, dereferencing\n",
-                                 resource->device->pnp.bus_id));
-               return 0;
+       mutex_lock(&resource->resource_lock);
+       list_for_each_safe(node, next, &resource->reference) {
+               ref = container_of(node, struct acpi_power_reference, node);
+               if (dev->handle == ref->device->handle) {
+                       list_del(&ref->node);
+                       kfree(ref);
+                       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] removed from resource [%s] references\n",
+                           dev->pnp.bus_id, resource->name));
+                       break;
+               }
        }
 
-       if (resource->state == ACPI_POWER_RESOURCE_STATE_OFF) {
-               ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] already off\n",
-                                 resource->device->pnp.bus_id));
+       if (!list_empty(&resource->reference)) {
+               ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cannot turn resource [%s] off - resource is in use\n",
+                   resource->name));
+               mutex_unlock(&resource->resource_lock);
                return 0;
        }
+       mutex_unlock(&resource->resource_lock);
 
        status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
        if (ACPI_FAILURE(status))
                return -ENODEV;
 
-       result = acpi_power_get_state(resource);
-       if (result)
-               return result;
-       if (resource->state != ACPI_POWER_RESOURCE_STATE_OFF)
-               return -ENOEXEC;
-
        /* Update the power resource's _device_ power state */
        resource->device->power.state = ACPI_STATE_D3;
 
@@ -257,81 +293,157 @@ static int acpi_power_off_device(acpi_handle handle)
        return 0;
 }
 
+/**
+ * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
+ *                          ACPI 3.0) _PSW (Power State Wake)
+ * @dev: Device to handle.
+ * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
+ * @sleep_state: Target sleep state of the system.
+ * @dev_state: Target power state of the device.
+ *
+ * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
+ * State Wake) for the device, if present.  On failure reset the device's
+ * wakeup.flags.valid flag.
+ *
+ * RETURN VALUE:
+ * 0 if either _DSW or _PSW has been successfully executed
+ * 0 if neither _DSW nor _PSW has been found
+ * -ENODEV if the execution of either _DSW or _PSW has failed
+ */
+int acpi_device_sleep_wake(struct acpi_device *dev,
+                           int enable, int sleep_state, int dev_state)
+{
+       union acpi_object in_arg[3];
+       struct acpi_object_list arg_list = { 3, in_arg };
+       acpi_status status = AE_OK;
+
+       /*
+        * Try to execute _DSW first.
+        *
+        * Three agruments are needed for the _DSW object:
+        * Argument 0: enable/disable the wake capabilities
+        * Argument 1: target system state
+        * Argument 2: target device state
+        * When _DSW object is called to disable the wake capabilities, maybe
+        * the first argument is filled. The values of the other two agruments
+        * are meaningless.
+        */
+       in_arg[0].type = ACPI_TYPE_INTEGER;
+       in_arg[0].integer.value = enable;
+       in_arg[1].type = ACPI_TYPE_INTEGER;
+       in_arg[1].integer.value = sleep_state;
+       in_arg[2].type = ACPI_TYPE_INTEGER;
+       in_arg[2].integer.value = dev_state;
+       status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
+       if (ACPI_SUCCESS(status)) {
+               return 0;
+       } else if (status != AE_NOT_FOUND) {
+               printk(KERN_ERR PREFIX "_DSW execution failed\n");
+               dev->wakeup.flags.valid = 0;
+               return -ENODEV;
+       }
+
+       /* Execute _PSW */
+       arg_list.count = 1;
+       in_arg[0].integer.value = enable;
+       status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
+       if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
+               printk(KERN_ERR PREFIX "_PSW execution failed\n");
+               dev->wakeup.flags.valid = 0;
+               return -ENODEV;
+       }
+
+       return 0;
+}
+
 /*
  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
  * 1. Power on the power resources required for the wakeup device 
- * 2. Enable _PSW (power state wake) for the device if present
+ * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
+ *    State Wake) for the device, if present
  */
-int acpi_enable_wakeup_device_power(struct acpi_device *dev)
+int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 {
-       union acpi_object arg = { ACPI_TYPE_INTEGER };
-       struct acpi_object_list arg_list = { 1, &arg };
-       acpi_status status = AE_OK;
-       int i;
-       int ret = 0;
+       int i, err = 0;
 
        if (!dev || !dev->wakeup.flags.valid)
-               return -1;
+               return -EINVAL;
+
+       mutex_lock(&acpi_device_lock);
+
+       if (dev->wakeup.prepare_count++)
+               goto out;
 
-       arg.integer.value = 1;
        /* Open power resource */
        for (i = 0; i < dev->wakeup.resources.count; i++) {
-               ret = acpi_power_on(dev->wakeup.resources.handles[i]);
+               int ret = acpi_power_on(dev->wakeup.resources.handles[i], dev);
                if (ret) {
                        printk(KERN_ERR PREFIX "Transition power state\n");
                        dev->wakeup.flags.valid = 0;
-                       return -1;
+                       err = -ENODEV;
+                       goto err_out;
                }
        }
 
-       /* Execute PSW */
-       status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
-       if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
-               printk(KERN_ERR PREFIX "Evaluate _PSW\n");
-               dev->wakeup.flags.valid = 0;
-               ret = -1;
-       }
+       /*
+        * Passing 3 as the third argument below means the device may be placed
+        * in arbitrary power state afterwards.
+        */
+       err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
+
+ err_out:
+       if (err)
+               dev->wakeup.prepare_count = 0;
 
-       return ret;
+ out:
+       mutex_unlock(&acpi_device_lock);
+       return err;
 }
 
 /*
  * Shutdown a wakeup device, counterpart of above method
- * 1. Disable _PSW (power state wake)
+ * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
+ *    State Wake) for the device, if present
  * 2. Shutdown down the power resources
  */
 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 {
-       union acpi_object arg = { ACPI_TYPE_INTEGER };
-       struct acpi_object_list arg_list = { 1, &arg };
-       acpi_status status = AE_OK;
-       int i;
-       int ret = 0;
-
+       int i, err = 0;
 
        if (!dev || !dev->wakeup.flags.valid)
-               return -1;
+               return -EINVAL;
 
-       arg.integer.value = 0;
-       /* Execute PSW */
-       status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
-       if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
-               printk(KERN_ERR PREFIX "Evaluate _PSW\n");
-               dev->wakeup.flags.valid = 0;
-               return -1;
-       }
+       mutex_lock(&acpi_device_lock);
+
+       if (--dev->wakeup.prepare_count > 0)
+               goto out;
+
+       /*
+        * Executing the code below even if prepare_count is already zero when
+        * the function is called may be useful, for example for initialisation.
+        */
+       if (dev->wakeup.prepare_count < 0)
+               dev->wakeup.prepare_count = 0;
+
+       err = acpi_device_sleep_wake(dev, 0, 0, 0);
+       if (err)
+               goto out;
 
        /* Close power resource */
        for (i = 0; i < dev->wakeup.resources.count; i++) {
-               ret = acpi_power_off_device(dev->wakeup.resources.handles[i]);
+               int ret = acpi_power_off_device(
+                               dev->wakeup.resources.handles[i], dev);
                if (ret) {
                        printk(KERN_ERR PREFIX "Transition power state\n");
                        dev->wakeup.flags.valid = 0;
-                       return -1;
+                       err = -ENODEV;
+                       goto out;
                }
        }
 
-       return ret;
+ out:
+       mutex_unlock(&acpi_device_lock);
+       return err;
 }
 
 /* --------------------------------------------------------------------------
@@ -393,13 +505,6 @@ int acpi_power_transition(struct acpi_device *device, int state)
        cl = &device->power.states[device->power.state].resources;
        tl = &device->power.states[state].resources;
 
-       device->power.state = ACPI_STATE_UNKNOWN;
-
-       if (!cl->count && !tl->count) {
-               result = -ENODEV;
-               goto end;
-       }
-
        /* TBD: Resources must be ordered. */
 
        /*
@@ -407,26 +512,31 @@ int acpi_power_transition(struct acpi_device *device, int state)
         * (e.g. so the device doesn't lose power while transitioning).
         */
        for (i = 0; i < tl->count; i++) {
-               result = acpi_power_on(tl->handles[i]);
+               result = acpi_power_on(tl->handles[i], device);
                if (result)
                        goto end;
        }
 
+       if (device->power.state == state) {
+               goto end;
+       }
+
        /*
         * Then we dereference all power resources used in the current list.
         */
        for (i = 0; i < cl->count; i++) {
-               result = acpi_power_off_device(cl->handles[i]);
+               result = acpi_power_off_device(cl->handles[i], device);
                if (result)
                        goto end;
        }
 
-       /* We shouldn't change the state till all above operations succeed */
-       device->power.state = state;
-      end:
+     end:
        if (result)
-               printk(KERN_WARNING PREFIX "Transitioning device [%s] to D%d\n",
-                             device->pnp.bus_id, state);
+               device->power.state = ACPI_STATE_UNKNOWN;
+       else {
+       /* We shouldn't change the state till all above operations succeed */
+               device->power.state = state;
+       }
 
        return result;
 }
@@ -439,16 +549,24 @@ static struct proc_dir_entry *acpi_power_dir;
 
 static int acpi_power_seq_show(struct seq_file *seq, void *offset)
 {
+       int count = 0;
+       int result = 0, state;
        struct acpi_power_resource *resource = NULL;
+       struct list_head *node, *next;
+       struct acpi_power_reference *ref;
 
 
-       resource = (struct acpi_power_resource *)seq->private;
+       resource = seq->private;
 
        if (!resource)
                goto end;
 
+       result = acpi_power_get_state(resource->device->handle, &state);
+       if (result)
+               goto end;
+
        seq_puts(seq, "state:                   ");
-       switch (resource->state) {
+       switch (state) {
        case ACPI_POWER_RESOURCE_STATE_ON:
                seq_puts(seq, "on\n");
                break;
@@ -460,11 +578,18 @@ static int acpi_power_seq_show(struct seq_file *seq, void *offset)
                break;
        }
 
+       mutex_lock(&resource->resource_lock);
+       list_for_each_safe(node, next, &resource->reference) {
+               ref = container_of(node, struct acpi_power_reference, node);
+               count++;
+       }
+       mutex_unlock(&resource->resource_lock);
+
        seq_printf(seq, "system level:            S%d\n"
                   "order:                   %d\n"
                   "reference count:         %d\n",
                   resource->system_level,
-                  resource->order, resource->references);
+                  resource->order, count);
 
       end:
        return 0;
@@ -491,15 +616,11 @@ static int acpi_power_add_fs(struct acpi_device *device)
        }
 
        /* 'status' [R] */
-       entry = create_proc_entry(ACPI_POWER_FILE_STATUS,
-                                 S_IRUGO, acpi_device_dir(device));
+       entry = proc_create_data(ACPI_POWER_FILE_STATUS,
+                                S_IRUGO, acpi_device_dir(device),
+                                &acpi_power_fops, acpi_driver_data(device));
        if (!entry)
                return -EIO;
-       else {
-               entry->proc_fops = &acpi_power_fops;
-               entry->data = acpi_driver_data(device);
-       }
-
        return 0;
 }
 
@@ -522,7 +643,7 @@ static int acpi_power_remove_fs(struct acpi_device *device)
 
 static int acpi_power_add(struct acpi_device *device)
 {
-       int result = 0;
+       int result = 0, state;
        acpi_status status = AE_OK;
        struct acpi_power_resource *resource = NULL;
        union acpi_object acpi_object;
@@ -532,16 +653,17 @@ static int acpi_power_add(struct acpi_device *device)
        if (!device)
                return -EINVAL;
 
-       resource = kmalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
+       resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
        if (!resource)
                return -ENOMEM;
-       memset(resource, 0, sizeof(struct acpi_power_resource));
 
        resource->device = device;
+       mutex_init(&resource->resource_lock);
+       INIT_LIST_HEAD(&resource->reference);
        strcpy(resource->name, device->pnp.bus_id);
        strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
        strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
-       acpi_driver_data(device) = resource;
+       device->driver_data = resource;
 
        /* Evalute the object to get the system level and resource order. */
        status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
@@ -552,11 +674,11 @@ static int acpi_power_add(struct acpi_device *device)
        resource->system_level = acpi_object.power_resource.system_level;
        resource->order = acpi_object.power_resource.resource_order;
 
-       result = acpi_power_get_state(resource);
+       result = acpi_power_get_state(device->handle, &state);
        if (result)
                goto end;
 
-       switch (resource->state) {
+       switch (state) {
        case ACPI_POWER_RESOURCE_STATE_ON:
                device->power.state = ACPI_STATE_D0;
                break;
@@ -573,7 +695,7 @@ static int acpi_power_add(struct acpi_device *device)
                goto end;
 
        printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
-              acpi_device_bid(device), resource->state ? "on" : "off");
+              acpi_device_bid(device), state ? "on" : "off");
 
       end:
        if (result)
@@ -585,27 +707,60 @@ static int acpi_power_add(struct acpi_device *device)
 static int acpi_power_remove(struct acpi_device *device, int type)
 {
        struct acpi_power_resource *resource = NULL;
+       struct list_head *node, *next;
 
 
        if (!device || !acpi_driver_data(device))
                return -EINVAL;
 
-       resource = (struct acpi_power_resource *)acpi_driver_data(device);
+       resource = acpi_driver_data(device);
 
        acpi_power_remove_fs(device);
 
+       mutex_lock(&resource->resource_lock);
+       list_for_each_safe(node, next, &resource->reference) {
+               struct acpi_power_reference *ref = container_of(node, struct acpi_power_reference, node);
+               list_del(&ref->node);
+               kfree(ref);
+       }
+       mutex_unlock(&resource->resource_lock);
+
        kfree(resource);
 
        return 0;
 }
 
-static int __init acpi_power_init(void)
+static int acpi_power_resume(struct acpi_device *device)
 {
-       int result = 0;
+       int result = 0, state;
+       struct acpi_power_resource *resource = NULL;
+       struct acpi_power_reference *ref;
+
+       if (!device || !acpi_driver_data(device))
+               return -EINVAL;
 
+       resource = acpi_driver_data(device);
 
-       if (acpi_disabled)
-               return 0;
+       result = acpi_power_get_state(device->handle, &state);
+       if (result)
+               return result;
+
+       mutex_lock(&resource->resource_lock);
+       if (state == ACPI_POWER_RESOURCE_STATE_OFF &&
+           !list_empty(&resource->reference)) {
+               ref = container_of(resource->reference.next, struct acpi_power_reference, node);
+               mutex_unlock(&resource->resource_lock);
+               result = acpi_power_on(device->handle, ref->device);
+               return result;
+       }
+
+       mutex_unlock(&resource->resource_lock);
+       return 0;
+}
+
+int __init acpi_power_init(void)
+{
+       int result = 0;
 
        INIT_LIST_HEAD(&acpi_power_resource_list);
 
@@ -621,5 +776,3 @@ static int __init acpi_power_init(void)
 
        return 0;
 }
-
-subsys_initcall(acpi_power_init);