1 /* 2 * acpi_power.c - ACPI Bus Power Management ($Revision: 39 $) 3 * 4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> 5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> 6 * 7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or (at 12 * your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; if not, write to the Free Software Foundation, Inc., 21 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. 22 * 23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 24 */ 25 26 /* 27 * ACPI power-managed devices may be controlled in two ways: 28 * 1. via "Device Specific (D-State) Control" 29 * 2. via "Power Resource Control". 30 * This module is used to manage devices relying on Power Resource Control. 31 * 32 * An ACPI "power resource object" describes a software controllable power 33 * plane, clock plane, or other resource used by a power managed device. 34 * A device may rely on multiple power resources, and a power resource 35 * may be shared by multiple devices. 36 */ 37 38 #include <linux/kernel.h> 39 #include <linux/module.h> 40 #include <linux/init.h> 41 #include <linux/types.h> 42 #include <linux/proc_fs.h> 43 #include <linux/seq_file.h> 44 #include <acpi/acpi_bus.h> 45 #include <acpi/acpi_drivers.h> 46 #include "sleep.h" 47 48 #define PREFIX "ACPI: " 49 50 #define _COMPONENT ACPI_POWER_COMPONENT 51 ACPI_MODULE_NAME("power"); 52 #define ACPI_POWER_CLASS "power_resource" 53 #define ACPI_POWER_DEVICE_NAME "Power Resource" 54 #define ACPI_POWER_FILE_INFO "info" 55 #define ACPI_POWER_FILE_STATUS "state" 56 #define ACPI_POWER_RESOURCE_STATE_OFF 0x00 57 #define ACPI_POWER_RESOURCE_STATE_ON 0x01 58 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF 59 60 int acpi_power_nocheck; 61 module_param_named(power_nocheck, acpi_power_nocheck, bool, 000); 62 63 static int acpi_power_add(struct acpi_device *device); 64 static int acpi_power_remove(struct acpi_device *device, int type); 65 static int acpi_power_resume(struct acpi_device *device); 66 static int acpi_power_open_fs(struct inode *inode, struct file *file); 67 68 static struct acpi_device_id power_device_ids[] = { 69 {ACPI_POWER_HID, 0}, 70 {"", 0}, 71 }; 72 MODULE_DEVICE_TABLE(acpi, power_device_ids); 73 74 static struct acpi_driver acpi_power_driver = { 75 .name = "power", 76 .class = ACPI_POWER_CLASS, 77 .ids = power_device_ids, 78 .ops = { 79 .add = acpi_power_add, 80 .remove = acpi_power_remove, 81 .resume = acpi_power_resume, 82 }, 83 }; 84 85 struct acpi_power_reference { 86 struct list_head node; 87 struct acpi_device *device; 88 }; 89 90 struct acpi_power_resource { 91 struct acpi_device * device; 92 acpi_bus_id name; 93 u32 system_level; 94 u32 order; 95 struct mutex resource_lock; 96 struct list_head reference; 97 }; 98 99 static struct list_head acpi_power_resource_list; 100 101 static const struct file_operations acpi_power_fops = { 102 .owner = THIS_MODULE, 103 .open = acpi_power_open_fs, 104 .read = seq_read, 105 .llseek = seq_lseek, 106 .release = single_release, 107 }; 108 109 /* -------------------------------------------------------------------------- 110 Power Resource Management 111 -------------------------------------------------------------------------- */ 112 113 static int 114 acpi_power_get_context(acpi_handle handle, 115 struct acpi_power_resource **resource) 116 { 117 int result = 0; 118 struct acpi_device *device = NULL; 119 120 121 if (!resource) 122 return -ENODEV; 123 124 result = acpi_bus_get_device(handle, &device); 125 if (result) { 126 printk(KERN_WARNING PREFIX "Getting context [%p]\n", handle); 127 return result; 128 } 129 130 *resource = acpi_driver_data(device); 131 if (!*resource) 132 return -ENODEV; 133 134 return 0; 135 } 136 137 static int acpi_power_get_state(acpi_handle handle, int *state) 138 { 139 acpi_status status = AE_OK; 140 unsigned long long sta = 0; 141 char node_name[5]; 142 struct acpi_buffer buffer = { sizeof(node_name), node_name }; 143 144 145 if (!handle || !state) 146 return -EINVAL; 147 148 status = acpi_evaluate_integer(handle, "_STA", NULL, &sta); 149 if (ACPI_FAILURE(status)) 150 return -ENODEV; 151 152 *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON: 153 ACPI_POWER_RESOURCE_STATE_OFF; 154 155 acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer); 156 157 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n", 158 node_name, 159 *state ? "on" : "off")); 160 161 return 0; 162 } 163 164 static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state) 165 { 166 int result = 0, state1; 167 u32 i = 0; 168 169 170 if (!list || !state) 171 return -EINVAL; 172 173 /* The state of the list is 'on' IFF all resources are 'on'. */ 174 /* */ 175 176 for (i = 0; i < list->count; i++) { 177 /* 178 * The state of the power resource can be obtained by 179 * using the ACPI handle. In such case it is unnecessary to 180 * get the Power resource first and then get its state again. 181 */ 182 result = acpi_power_get_state(list->handles[i], &state1); 183 if (result) 184 return result; 185 186 *state = state1; 187 188 if (*state != ACPI_POWER_RESOURCE_STATE_ON) 189 break; 190 } 191 192 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n", 193 *state ? "on" : "off")); 194 195 return result; 196 } 197 198 static int acpi_power_on(acpi_handle handle, struct acpi_device *dev) 199 { 200 int result = 0; 201 int found = 0; 202 acpi_status status = AE_OK; 203 struct acpi_power_resource *resource = NULL; 204 struct list_head *node, *next; 205 struct acpi_power_reference *ref; 206 207 208 result = acpi_power_get_context(handle, &resource); 209 if (result) 210 return result; 211 212 mutex_lock(&resource->resource_lock); 213 list_for_each_safe(node, next, &resource->reference) { 214 ref = container_of(node, struct acpi_power_reference, node); 215 if (dev->handle == ref->device->handle) { 216 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already referenced by resource [%s]\n", 217 dev->pnp.bus_id, resource->name)); 218 found = 1; 219 break; 220 } 221 } 222 223 if (!found) { 224 ref = kmalloc(sizeof (struct acpi_power_reference), 225 irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL); 226 if (!ref) { 227 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "kmalloc() failed\n")); 228 mutex_unlock(&resource->resource_lock); 229 return -ENOMEM; 230 } 231 list_add_tail(&ref->node, &resource->reference); 232 ref->device = dev; 233 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] added to resource [%s] references\n", 234 dev->pnp.bus_id, resource->name)); 235 } 236 mutex_unlock(&resource->resource_lock); 237 238 status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL); 239 if (ACPI_FAILURE(status)) 240 return -ENODEV; 241 242 /* Update the power resource's _device_ power state */ 243 resource->device->power.state = ACPI_STATE_D0; 244 245 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned on\n", 246 resource->name)); 247 return 0; 248 } 249 250 static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev) 251 { 252 int result = 0; 253 acpi_status status = AE_OK; 254 struct acpi_power_resource *resource = NULL; 255 struct list_head *node, *next; 256 struct acpi_power_reference *ref; 257 258 259 result = acpi_power_get_context(handle, &resource); 260 if (result) 261 return result; 262 263 mutex_lock(&resource->resource_lock); 264 list_for_each_safe(node, next, &resource->reference) { 265 ref = container_of(node, struct acpi_power_reference, node); 266 if (dev->handle == ref->device->handle) { 267 list_del(&ref->node); 268 kfree(ref); 269 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] removed from resource [%s] references\n", 270 dev->pnp.bus_id, resource->name)); 271 break; 272 } 273 } 274 275 if (!list_empty(&resource->reference)) { 276 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cannot turn resource [%s] off - resource is in use\n", 277 resource->name)); 278 mutex_unlock(&resource->resource_lock); 279 return 0; 280 } 281 mutex_unlock(&resource->resource_lock); 282 283 status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL); 284 if (ACPI_FAILURE(status)) 285 return -ENODEV; 286 287 /* Update the power resource's _device_ power state */ 288 resource->device->power.state = ACPI_STATE_D3; 289 290 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned off\n", 291 resource->name)); 292 293 return 0; 294 } 295 296 /** 297 * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in 298 * ACPI 3.0) _PSW (Power State Wake) 299 * @dev: Device to handle. 300 * @enable: 0 - disable, 1 - enable the wake capabilities of the device. 301 * @sleep_state: Target sleep state of the system. 302 * @dev_state: Target power state of the device. 303 * 304 * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power 305 * State Wake) for the device, if present. On failure reset the device's 306 * wakeup.flags.valid flag. 307 * 308 * RETURN VALUE: 309 * 0 if either _DSW or _PSW has been successfully executed 310 * 0 if neither _DSW nor _PSW has been found 311 * -ENODEV if the execution of either _DSW or _PSW has failed 312 */ 313 int acpi_device_sleep_wake(struct acpi_device *dev, 314 int enable, int sleep_state, int dev_state) 315 { 316 union acpi_object in_arg[3]; 317 struct acpi_object_list arg_list = { 3, in_arg }; 318 acpi_status status = AE_OK; 319 320 /* 321 * Try to execute _DSW first. 322 * 323 * Three agruments are needed for the _DSW object: 324 * Argument 0: enable/disable the wake capabilities 325 * Argument 1: target system state 326 * Argument 2: target device state 327 * When _DSW object is called to disable the wake capabilities, maybe 328 * the first argument is filled. The values of the other two agruments 329 * are meaningless. 330 */ 331 in_arg[0].type = ACPI_TYPE_INTEGER; 332 in_arg[0].integer.value = enable; 333 in_arg[1].type = ACPI_TYPE_INTEGER; 334 in_arg[1].integer.value = sleep_state; 335 in_arg[2].type = ACPI_TYPE_INTEGER; 336 in_arg[2].integer.value = dev_state; 337 status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL); 338 if (ACPI_SUCCESS(status)) { 339 return 0; 340 } else if (status != AE_NOT_FOUND) { 341 printk(KERN_ERR PREFIX "_DSW execution failed\n"); 342 dev->wakeup.flags.valid = 0; 343 return -ENODEV; 344 } 345 346 /* Execute _PSW */ 347 arg_list.count = 1; 348 in_arg[0].integer.value = enable; 349 status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL); 350 if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) { 351 printk(KERN_ERR PREFIX "_PSW execution failed\n"); 352 dev->wakeup.flags.valid = 0; 353 return -ENODEV; 354 } 355 356 return 0; 357 } 358 359 /* 360 * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229): 361 * 1. Power on the power resources required for the wakeup device 362 * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power 363 * State Wake) for the device, if present 364 */ 365 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state) 366 { 367 int i, err = 0; 368 369 if (!dev || !dev->wakeup.flags.valid) 370 return -EINVAL; 371 372 mutex_lock(&acpi_device_lock); 373 374 if (dev->wakeup.prepare_count++) 375 goto out; 376 377 /* Open power resource */ 378 for (i = 0; i < dev->wakeup.resources.count; i++) { 379 int ret = acpi_power_on(dev->wakeup.resources.handles[i], dev); 380 if (ret) { 381 printk(KERN_ERR PREFIX "Transition power state\n"); 382 dev->wakeup.flags.valid = 0; 383 err = -ENODEV; 384 goto err_out; 385 } 386 } 387 388 /* 389 * Passing 3 as the third argument below means the device may be placed 390 * in arbitrary power state afterwards. 391 */ 392 err = acpi_device_sleep_wake(dev, 1, sleep_state, 3); 393 394 err_out: 395 if (err) 396 dev->wakeup.prepare_count = 0; 397 398 out: 399 mutex_unlock(&acpi_device_lock); 400 return err; 401 } 402 403 /* 404 * Shutdown a wakeup device, counterpart of above method 405 * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power 406 * State Wake) for the device, if present 407 * 2. Shutdown down the power resources 408 */ 409 int acpi_disable_wakeup_device_power(struct acpi_device *dev) 410 { 411 int i, err = 0; 412 413 if (!dev || !dev->wakeup.flags.valid) 414 return -EINVAL; 415 416 mutex_lock(&acpi_device_lock); 417 418 if (--dev->wakeup.prepare_count > 0) 419 goto out; 420 421 /* 422 * Executing the code below even if prepare_count is already zero when 423 * the function is called may be useful, for example for initialisation. 424 */ 425 if (dev->wakeup.prepare_count < 0) 426 dev->wakeup.prepare_count = 0; 427 428 err = acpi_device_sleep_wake(dev, 0, 0, 0); 429 if (err) 430 goto out; 431 432 /* Close power resource */ 433 for (i = 0; i < dev->wakeup.resources.count; i++) { 434 int ret = acpi_power_off_device( 435 dev->wakeup.resources.handles[i], dev); 436 if (ret) { 437 printk(KERN_ERR PREFIX "Transition power state\n"); 438 dev->wakeup.flags.valid = 0; 439 err = -ENODEV; 440 goto out; 441 } 442 } 443 444 out: 445 mutex_unlock(&acpi_device_lock); 446 return err; 447 } 448 449 /* -------------------------------------------------------------------------- 450 Device Power Management 451 -------------------------------------------------------------------------- */ 452 453 int acpi_power_get_inferred_state(struct acpi_device *device) 454 { 455 int result = 0; 456 struct acpi_handle_list *list = NULL; 457 int list_state = 0; 458 int i = 0; 459 460 461 if (!device) 462 return -EINVAL; 463 464 device->power.state = ACPI_STATE_UNKNOWN; 465 466 /* 467 * We know a device's inferred power state when all the resources 468 * required for a given D-state are 'on'. 469 */ 470 for (i = ACPI_STATE_D0; i < ACPI_STATE_D3; i++) { 471 list = &device->power.states[i].resources; 472 if (list->count < 1) 473 continue; 474 475 result = acpi_power_get_list_state(list, &list_state); 476 if (result) 477 return result; 478 479 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) { 480 device->power.state = i; 481 return 0; 482 } 483 } 484 485 device->power.state = ACPI_STATE_D3; 486 487 return 0; 488 } 489 490 int acpi_power_transition(struct acpi_device *device, int state) 491 { 492 int result = 0; 493 struct acpi_handle_list *cl = NULL; /* Current Resources */ 494 struct acpi_handle_list *tl = NULL; /* Target Resources */ 495 int i = 0; 496 497 498 if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3)) 499 return -EINVAL; 500 501 if ((device->power.state < ACPI_STATE_D0) 502 || (device->power.state > ACPI_STATE_D3)) 503 return -ENODEV; 504 505 cl = &device->power.states[device->power.state].resources; 506 tl = &device->power.states[state].resources; 507 508 /* TBD: Resources must be ordered. */ 509 510 /* 511 * First we reference all power resources required in the target list 512 * (e.g. so the device doesn't lose power while transitioning). 513 */ 514 for (i = 0; i < tl->count; i++) { 515 result = acpi_power_on(tl->handles[i], device); 516 if (result) 517 goto end; 518 } 519 520 if (device->power.state == state) { 521 goto end; 522 } 523 524 /* 525 * Then we dereference all power resources used in the current list. 526 */ 527 for (i = 0; i < cl->count; i++) { 528 result = acpi_power_off_device(cl->handles[i], device); 529 if (result) 530 goto end; 531 } 532 533 end: 534 if (result) 535 device->power.state = ACPI_STATE_UNKNOWN; 536 else { 537 /* We shouldn't change the state till all above operations succeed */ 538 device->power.state = state; 539 } 540 541 return result; 542 } 543 544 /* -------------------------------------------------------------------------- 545 FS Interface (/proc) 546 -------------------------------------------------------------------------- */ 547 548 static struct proc_dir_entry *acpi_power_dir; 549 550 static int acpi_power_seq_show(struct seq_file *seq, void *offset) 551 { 552 int count = 0; 553 int result = 0, state; 554 struct acpi_power_resource *resource = NULL; 555 struct list_head *node, *next; 556 struct acpi_power_reference *ref; 557 558 559 resource = seq->private; 560 561 if (!resource) 562 goto end; 563 564 result = acpi_power_get_state(resource->device->handle, &state); 565 if (result) 566 goto end; 567 568 seq_puts(seq, "state: "); 569 switch (state) { 570 case ACPI_POWER_RESOURCE_STATE_ON: 571 seq_puts(seq, "on\n"); 572 break; 573 case ACPI_POWER_RESOURCE_STATE_OFF: 574 seq_puts(seq, "off\n"); 575 break; 576 default: 577 seq_puts(seq, "unknown\n"); 578 break; 579 } 580 581 mutex_lock(&resource->resource_lock); 582 list_for_each_safe(node, next, &resource->reference) { 583 ref = container_of(node, struct acpi_power_reference, node); 584 count++; 585 } 586 mutex_unlock(&resource->resource_lock); 587 588 seq_printf(seq, "system level: S%d\n" 589 "order: %d\n" 590 "reference count: %d\n", 591 resource->system_level, 592 resource->order, count); 593 594 end: 595 return 0; 596 } 597 598 static int acpi_power_open_fs(struct inode *inode, struct file *file) 599 { 600 return single_open(file, acpi_power_seq_show, PDE(inode)->data); 601 } 602 603 static int acpi_power_add_fs(struct acpi_device *device) 604 { 605 struct proc_dir_entry *entry = NULL; 606 607 608 if (!device) 609 return -EINVAL; 610 611 if (!acpi_device_dir(device)) { 612 acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), 613 acpi_power_dir); 614 if (!acpi_device_dir(device)) 615 return -ENODEV; 616 } 617 618 /* 'status' [R] */ 619 entry = proc_create_data(ACPI_POWER_FILE_STATUS, 620 S_IRUGO, acpi_device_dir(device), 621 &acpi_power_fops, acpi_driver_data(device)); 622 if (!entry) 623 return -EIO; 624 return 0; 625 } 626 627 static int acpi_power_remove_fs(struct acpi_device *device) 628 { 629 630 if (acpi_device_dir(device)) { 631 remove_proc_entry(ACPI_POWER_FILE_STATUS, 632 acpi_device_dir(device)); 633 remove_proc_entry(acpi_device_bid(device), acpi_power_dir); 634 acpi_device_dir(device) = NULL; 635 } 636 637 return 0; 638 } 639 640 /* -------------------------------------------------------------------------- 641 Driver Interface 642 -------------------------------------------------------------------------- */ 643 644 static int acpi_power_add(struct acpi_device *device) 645 { 646 int result = 0, state; 647 acpi_status status = AE_OK; 648 struct acpi_power_resource *resource = NULL; 649 union acpi_object acpi_object; 650 struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object }; 651 652 653 if (!device) 654 return -EINVAL; 655 656 resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL); 657 if (!resource) 658 return -ENOMEM; 659 660 resource->device = device; 661 mutex_init(&resource->resource_lock); 662 INIT_LIST_HEAD(&resource->reference); 663 strcpy(resource->name, device->pnp.bus_id); 664 strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME); 665 strcpy(acpi_device_class(device), ACPI_POWER_CLASS); 666 device->driver_data = resource; 667 668 /* Evalute the object to get the system level and resource order. */ 669 status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer); 670 if (ACPI_FAILURE(status)) { 671 result = -ENODEV; 672 goto end; 673 } 674 resource->system_level = acpi_object.power_resource.system_level; 675 resource->order = acpi_object.power_resource.resource_order; 676 677 result = acpi_power_get_state(device->handle, &state); 678 if (result) 679 goto end; 680 681 switch (state) { 682 case ACPI_POWER_RESOURCE_STATE_ON: 683 device->power.state = ACPI_STATE_D0; 684 break; 685 case ACPI_POWER_RESOURCE_STATE_OFF: 686 device->power.state = ACPI_STATE_D3; 687 break; 688 default: 689 device->power.state = ACPI_STATE_UNKNOWN; 690 break; 691 } 692 693 result = acpi_power_add_fs(device); 694 if (result) 695 goto end; 696 697 printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device), 698 acpi_device_bid(device), state ? "on" : "off"); 699 700 end: 701 if (result) 702 kfree(resource); 703 704 return result; 705 } 706 707 static int acpi_power_remove(struct acpi_device *device, int type) 708 { 709 struct acpi_power_resource *resource = NULL; 710 struct list_head *node, *next; 711 712 713 if (!device || !acpi_driver_data(device)) 714 return -EINVAL; 715 716 resource = acpi_driver_data(device); 717 718 acpi_power_remove_fs(device); 719 720 mutex_lock(&resource->resource_lock); 721 list_for_each_safe(node, next, &resource->reference) { 722 struct acpi_power_reference *ref = container_of(node, struct acpi_power_reference, node); 723 list_del(&ref->node); 724 kfree(ref); 725 } 726 mutex_unlock(&resource->resource_lock); 727 728 kfree(resource); 729 730 return 0; 731 } 732 733 static int acpi_power_resume(struct acpi_device *device) 734 { 735 int result = 0, state; 736 struct acpi_power_resource *resource = NULL; 737 struct acpi_power_reference *ref; 738 739 if (!device || !acpi_driver_data(device)) 740 return -EINVAL; 741 742 resource = acpi_driver_data(device); 743 744 result = acpi_power_get_state(device->handle, &state); 745 if (result) 746 return result; 747 748 mutex_lock(&resource->resource_lock); 749 if (state == ACPI_POWER_RESOURCE_STATE_OFF && 750 !list_empty(&resource->reference)) { 751 ref = container_of(resource->reference.next, struct acpi_power_reference, node); 752 mutex_unlock(&resource->resource_lock); 753 result = acpi_power_on(device->handle, ref->device); 754 return result; 755 } 756 757 mutex_unlock(&resource->resource_lock); 758 return 0; 759 } 760 761 int __init acpi_power_init(void) 762 { 763 int result = 0; 764 765 INIT_LIST_HEAD(&acpi_power_resource_list); 766 767 acpi_power_dir = proc_mkdir(ACPI_POWER_CLASS, acpi_root_dir); 768 if (!acpi_power_dir) 769 return -ENODEV; 770 771 result = acpi_bus_register_driver(&acpi_power_driver); 772 if (result < 0) { 773 remove_proc_entry(ACPI_POWER_CLASS, acpi_root_dir); 774 return -ENODEV; 775 } 776 777 return 0; 778 } 779