1 /* 2 * kernel/power/main.c - PM subsystem core functionality. 3 * 4 * Copyright (c) 2003 Patrick Mochel 5 * Copyright (c) 2003 Open Source Development Lab 6 * 7 * This file is released under the GPLv2 8 * 9 */ 10 11 #include <linux/export.h> 12 #include <linux/kobject.h> 13 #include <linux/string.h> 14 #include <linux/pm-trace.h> 15 #include <linux/workqueue.h> 16 #include <linux/debugfs.h> 17 #include <linux/seq_file.h> 18 19 #include "power.h" 20 21 DEFINE_MUTEX(pm_mutex); 22 23 #ifdef CONFIG_PM_SLEEP 24 25 /* Routines for PM-transition notifications */ 26 27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head); 28 29 int register_pm_notifier(struct notifier_block *nb) 30 { 31 return blocking_notifier_chain_register(&pm_chain_head, nb); 32 } 33 EXPORT_SYMBOL_GPL(register_pm_notifier); 34 35 int unregister_pm_notifier(struct notifier_block *nb) 36 { 37 return blocking_notifier_chain_unregister(&pm_chain_head, nb); 38 } 39 EXPORT_SYMBOL_GPL(unregister_pm_notifier); 40 41 int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls) 42 { 43 int ret; 44 45 ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL, 46 nr_to_call, nr_calls); 47 48 return notifier_to_errno(ret); 49 } 50 int pm_notifier_call_chain(unsigned long val) 51 { 52 return __pm_notifier_call_chain(val, -1, NULL); 53 } 54 55 /* If set, devices may be suspended and resumed asynchronously. */ 56 int pm_async_enabled = 1; 57 58 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, 59 char *buf) 60 { 61 return sprintf(buf, "%d\n", pm_async_enabled); 62 } 63 64 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, 65 const char *buf, size_t n) 66 { 67 unsigned long val; 68 69 if (kstrtoul(buf, 10, &val)) 70 return -EINVAL; 71 72 if (val > 1) 73 return -EINVAL; 74 75 pm_async_enabled = val; 76 return n; 77 } 78 79 power_attr(pm_async); 80 81 #ifdef CONFIG_SUSPEND 82 static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr, 83 char *buf) 84 { 85 char *s = buf; 86 suspend_state_t i; 87 88 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++) 89 if (mem_sleep_states[i]) { 90 const char *label = mem_sleep_states[i]; 91 92 if (mem_sleep_current == i) 93 s += sprintf(s, "[%s] ", label); 94 else 95 s += sprintf(s, "%s ", label); 96 } 97 98 /* Convert the last space to a newline if needed. */ 99 if (s != buf) 100 *(s-1) = '\n'; 101 102 return (s - buf); 103 } 104 105 static suspend_state_t decode_suspend_state(const char *buf, size_t n) 106 { 107 suspend_state_t state; 108 char *p; 109 int len; 110 111 p = memchr(buf, '\n', n); 112 len = p ? p - buf : n; 113 114 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) { 115 const char *label = mem_sleep_states[state]; 116 117 if (label && len == strlen(label) && !strncmp(buf, label, len)) 118 return state; 119 } 120 121 return PM_SUSPEND_ON; 122 } 123 124 static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr, 125 const char *buf, size_t n) 126 { 127 suspend_state_t state; 128 int error; 129 130 error = pm_autosleep_lock(); 131 if (error) 132 return error; 133 134 if (pm_autosleep_state() > PM_SUSPEND_ON) { 135 error = -EBUSY; 136 goto out; 137 } 138 139 state = decode_suspend_state(buf, n); 140 if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON) 141 mem_sleep_current = state; 142 else 143 error = -EINVAL; 144 145 out: 146 pm_autosleep_unlock(); 147 return error ? error : n; 148 } 149 150 power_attr(mem_sleep); 151 #endif /* CONFIG_SUSPEND */ 152 153 #ifdef CONFIG_PM_SLEEP_DEBUG 154 int pm_test_level = TEST_NONE; 155 156 static const char * const pm_tests[__TEST_AFTER_LAST] = { 157 [TEST_NONE] = "none", 158 [TEST_CORE] = "core", 159 [TEST_CPUS] = "processors", 160 [TEST_PLATFORM] = "platform", 161 [TEST_DEVICES] = "devices", 162 [TEST_FREEZER] = "freezer", 163 }; 164 165 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr, 166 char *buf) 167 { 168 char *s = buf; 169 int level; 170 171 for (level = TEST_FIRST; level <= TEST_MAX; level++) 172 if (pm_tests[level]) { 173 if (level == pm_test_level) 174 s += sprintf(s, "[%s] ", pm_tests[level]); 175 else 176 s += sprintf(s, "%s ", pm_tests[level]); 177 } 178 179 if (s != buf) 180 /* convert the last space to a newline */ 181 *(s-1) = '\n'; 182 183 return (s - buf); 184 } 185 186 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, 187 const char *buf, size_t n) 188 { 189 const char * const *s; 190 int level; 191 char *p; 192 int len; 193 int error = -EINVAL; 194 195 p = memchr(buf, '\n', n); 196 len = p ? p - buf : n; 197 198 lock_system_sleep(); 199 200 level = TEST_FIRST; 201 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++) 202 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) { 203 pm_test_level = level; 204 error = 0; 205 break; 206 } 207 208 unlock_system_sleep(); 209 210 return error ? error : n; 211 } 212 213 power_attr(pm_test); 214 #endif /* CONFIG_PM_SLEEP_DEBUG */ 215 216 #ifdef CONFIG_DEBUG_FS 217 static char *suspend_step_name(enum suspend_stat_step step) 218 { 219 switch (step) { 220 case SUSPEND_FREEZE: 221 return "freeze"; 222 case SUSPEND_PREPARE: 223 return "prepare"; 224 case SUSPEND_SUSPEND: 225 return "suspend"; 226 case SUSPEND_SUSPEND_NOIRQ: 227 return "suspend_noirq"; 228 case SUSPEND_RESUME_NOIRQ: 229 return "resume_noirq"; 230 case SUSPEND_RESUME: 231 return "resume"; 232 default: 233 return ""; 234 } 235 } 236 237 static int suspend_stats_show(struct seq_file *s, void *unused) 238 { 239 int i, index, last_dev, last_errno, last_step; 240 241 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1; 242 last_dev %= REC_FAILED_NUM; 243 last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1; 244 last_errno %= REC_FAILED_NUM; 245 last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1; 246 last_step %= REC_FAILED_NUM; 247 seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n" 248 "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n", 249 "success", suspend_stats.success, 250 "fail", suspend_stats.fail, 251 "failed_freeze", suspend_stats.failed_freeze, 252 "failed_prepare", suspend_stats.failed_prepare, 253 "failed_suspend", suspend_stats.failed_suspend, 254 "failed_suspend_late", 255 suspend_stats.failed_suspend_late, 256 "failed_suspend_noirq", 257 suspend_stats.failed_suspend_noirq, 258 "failed_resume", suspend_stats.failed_resume, 259 "failed_resume_early", 260 suspend_stats.failed_resume_early, 261 "failed_resume_noirq", 262 suspend_stats.failed_resume_noirq); 263 seq_printf(s, "failures:\n last_failed_dev:\t%-s\n", 264 suspend_stats.failed_devs[last_dev]); 265 for (i = 1; i < REC_FAILED_NUM; i++) { 266 index = last_dev + REC_FAILED_NUM - i; 267 index %= REC_FAILED_NUM; 268 seq_printf(s, "\t\t\t%-s\n", 269 suspend_stats.failed_devs[index]); 270 } 271 seq_printf(s, " last_failed_errno:\t%-d\n", 272 suspend_stats.errno[last_errno]); 273 for (i = 1; i < REC_FAILED_NUM; i++) { 274 index = last_errno + REC_FAILED_NUM - i; 275 index %= REC_FAILED_NUM; 276 seq_printf(s, "\t\t\t%-d\n", 277 suspend_stats.errno[index]); 278 } 279 seq_printf(s, " last_failed_step:\t%-s\n", 280 suspend_step_name( 281 suspend_stats.failed_steps[last_step])); 282 for (i = 1; i < REC_FAILED_NUM; i++) { 283 index = last_step + REC_FAILED_NUM - i; 284 index %= REC_FAILED_NUM; 285 seq_printf(s, "\t\t\t%-s\n", 286 suspend_step_name( 287 suspend_stats.failed_steps[index])); 288 } 289 290 return 0; 291 } 292 293 static int suspend_stats_open(struct inode *inode, struct file *file) 294 { 295 return single_open(file, suspend_stats_show, NULL); 296 } 297 298 static const struct file_operations suspend_stats_operations = { 299 .open = suspend_stats_open, 300 .read = seq_read, 301 .llseek = seq_lseek, 302 .release = single_release, 303 }; 304 305 static int __init pm_debugfs_init(void) 306 { 307 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO, 308 NULL, NULL, &suspend_stats_operations); 309 return 0; 310 } 311 312 late_initcall(pm_debugfs_init); 313 #endif /* CONFIG_DEBUG_FS */ 314 315 #endif /* CONFIG_PM_SLEEP */ 316 317 #ifdef CONFIG_PM_SLEEP_DEBUG 318 /* 319 * pm_print_times: print time taken by devices to suspend and resume. 320 * 321 * show() returns whether printing of suspend and resume times is enabled. 322 * store() accepts 0 or 1. 0 disables printing and 1 enables it. 323 */ 324 bool pm_print_times_enabled; 325 326 static ssize_t pm_print_times_show(struct kobject *kobj, 327 struct kobj_attribute *attr, char *buf) 328 { 329 return sprintf(buf, "%d\n", pm_print_times_enabled); 330 } 331 332 static ssize_t pm_print_times_store(struct kobject *kobj, 333 struct kobj_attribute *attr, 334 const char *buf, size_t n) 335 { 336 unsigned long val; 337 338 if (kstrtoul(buf, 10, &val)) 339 return -EINVAL; 340 341 if (val > 1) 342 return -EINVAL; 343 344 pm_print_times_enabled = !!val; 345 return n; 346 } 347 348 power_attr(pm_print_times); 349 350 static inline void pm_print_times_init(void) 351 { 352 pm_print_times_enabled = !!initcall_debug; 353 } 354 355 static ssize_t pm_wakeup_irq_show(struct kobject *kobj, 356 struct kobj_attribute *attr, 357 char *buf) 358 { 359 return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA; 360 } 361 362 power_attr_ro(pm_wakeup_irq); 363 364 bool pm_debug_messages_on __read_mostly; 365 366 static ssize_t pm_debug_messages_show(struct kobject *kobj, 367 struct kobj_attribute *attr, char *buf) 368 { 369 return sprintf(buf, "%d\n", pm_debug_messages_on); 370 } 371 372 static ssize_t pm_debug_messages_store(struct kobject *kobj, 373 struct kobj_attribute *attr, 374 const char *buf, size_t n) 375 { 376 unsigned long val; 377 378 if (kstrtoul(buf, 10, &val)) 379 return -EINVAL; 380 381 if (val > 1) 382 return -EINVAL; 383 384 pm_debug_messages_on = !!val; 385 return n; 386 } 387 388 power_attr(pm_debug_messages); 389 390 /** 391 * __pm_pr_dbg - Print a suspend debug message to the kernel log. 392 * @defer: Whether or not to use printk_deferred() to print the message. 393 * @fmt: Message format. 394 * 395 * The message will be emitted if enabled through the pm_debug_messages 396 * sysfs attribute. 397 */ 398 void __pm_pr_dbg(bool defer, const char *fmt, ...) 399 { 400 struct va_format vaf; 401 va_list args; 402 403 if (!pm_debug_messages_on) 404 return; 405 406 va_start(args, fmt); 407 408 vaf.fmt = fmt; 409 vaf.va = &args; 410 411 if (defer) 412 printk_deferred(KERN_DEBUG "PM: %pV", &vaf); 413 else 414 printk(KERN_DEBUG "PM: %pV", &vaf); 415 416 va_end(args); 417 } 418 419 #else /* !CONFIG_PM_SLEEP_DEBUG */ 420 static inline void pm_print_times_init(void) {} 421 #endif /* CONFIG_PM_SLEEP_DEBUG */ 422 423 struct kobject *power_kobj; 424 425 /** 426 * state - control system sleep states. 427 * 428 * show() returns available sleep state labels, which may be "mem", "standby", 429 * "freeze" and "disk" (hibernation). See Documentation/power/states.txt for a 430 * description of what they mean. 431 * 432 * store() accepts one of those strings, translates it into the proper 433 * enumerated value, and initiates a suspend transition. 434 */ 435 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr, 436 char *buf) 437 { 438 char *s = buf; 439 #ifdef CONFIG_SUSPEND 440 suspend_state_t i; 441 442 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++) 443 if (pm_states[i]) 444 s += sprintf(s,"%s ", pm_states[i]); 445 446 #endif 447 if (hibernation_available()) 448 s += sprintf(s, "disk "); 449 if (s != buf) 450 /* convert the last space to a newline */ 451 *(s-1) = '\n'; 452 return (s - buf); 453 } 454 455 static suspend_state_t decode_state(const char *buf, size_t n) 456 { 457 #ifdef CONFIG_SUSPEND 458 suspend_state_t state; 459 #endif 460 char *p; 461 int len; 462 463 p = memchr(buf, '\n', n); 464 len = p ? p - buf : n; 465 466 /* Check hibernation first. */ 467 if (len == 4 && !strncmp(buf, "disk", len)) 468 return PM_SUSPEND_MAX; 469 470 #ifdef CONFIG_SUSPEND 471 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) { 472 const char *label = pm_states[state]; 473 474 if (label && len == strlen(label) && !strncmp(buf, label, len)) 475 return state; 476 } 477 #endif 478 479 return PM_SUSPEND_ON; 480 } 481 482 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr, 483 const char *buf, size_t n) 484 { 485 suspend_state_t state; 486 int error; 487 488 error = pm_autosleep_lock(); 489 if (error) 490 return error; 491 492 if (pm_autosleep_state() > PM_SUSPEND_ON) { 493 error = -EBUSY; 494 goto out; 495 } 496 497 state = decode_state(buf, n); 498 if (state < PM_SUSPEND_MAX) { 499 if (state == PM_SUSPEND_MEM) 500 state = mem_sleep_current; 501 502 error = pm_suspend(state); 503 } else if (state == PM_SUSPEND_MAX) { 504 error = hibernate(); 505 } else { 506 error = -EINVAL; 507 } 508 509 out: 510 pm_autosleep_unlock(); 511 return error ? error : n; 512 } 513 514 power_attr(state); 515 516 #ifdef CONFIG_PM_SLEEP 517 /* 518 * The 'wakeup_count' attribute, along with the functions defined in 519 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be 520 * handled in a non-racy way. 521 * 522 * If a wakeup event occurs when the system is in a sleep state, it simply is 523 * woken up. In turn, if an event that would wake the system up from a sleep 524 * state occurs when it is undergoing a transition to that sleep state, the 525 * transition should be aborted. Moreover, if such an event occurs when the 526 * system is in the working state, an attempt to start a transition to the 527 * given sleep state should fail during certain period after the detection of 528 * the event. Using the 'state' attribute alone is not sufficient to satisfy 529 * these requirements, because a wakeup event may occur exactly when 'state' 530 * is being written to and may be delivered to user space right before it is 531 * frozen, so the event will remain only partially processed until the system is 532 * woken up by another event. In particular, it won't cause the transition to 533 * a sleep state to be aborted. 534 * 535 * This difficulty may be overcome if user space uses 'wakeup_count' before 536 * writing to 'state'. It first should read from 'wakeup_count' and store 537 * the read value. Then, after carrying out its own preparations for the system 538 * transition to a sleep state, it should write the stored value to 539 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since 540 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it 541 * is allowed to write to 'state', but the transition will be aborted if there 542 * are any wakeup events detected after 'wakeup_count' was written to. 543 */ 544 545 static ssize_t wakeup_count_show(struct kobject *kobj, 546 struct kobj_attribute *attr, 547 char *buf) 548 { 549 unsigned int val; 550 551 return pm_get_wakeup_count(&val, true) ? 552 sprintf(buf, "%u\n", val) : -EINTR; 553 } 554 555 static ssize_t wakeup_count_store(struct kobject *kobj, 556 struct kobj_attribute *attr, 557 const char *buf, size_t n) 558 { 559 unsigned int val; 560 int error; 561 562 error = pm_autosleep_lock(); 563 if (error) 564 return error; 565 566 if (pm_autosleep_state() > PM_SUSPEND_ON) { 567 error = -EBUSY; 568 goto out; 569 } 570 571 error = -EINVAL; 572 if (sscanf(buf, "%u", &val) == 1) { 573 if (pm_save_wakeup_count(val)) 574 error = n; 575 else 576 pm_print_active_wakeup_sources(); 577 } 578 579 out: 580 pm_autosleep_unlock(); 581 return error; 582 } 583 584 power_attr(wakeup_count); 585 586 #ifdef CONFIG_PM_AUTOSLEEP 587 static ssize_t autosleep_show(struct kobject *kobj, 588 struct kobj_attribute *attr, 589 char *buf) 590 { 591 suspend_state_t state = pm_autosleep_state(); 592 593 if (state == PM_SUSPEND_ON) 594 return sprintf(buf, "off\n"); 595 596 #ifdef CONFIG_SUSPEND 597 if (state < PM_SUSPEND_MAX) 598 return sprintf(buf, "%s\n", pm_states[state] ? 599 pm_states[state] : "error"); 600 #endif 601 #ifdef CONFIG_HIBERNATION 602 return sprintf(buf, "disk\n"); 603 #else 604 return sprintf(buf, "error"); 605 #endif 606 } 607 608 static ssize_t autosleep_store(struct kobject *kobj, 609 struct kobj_attribute *attr, 610 const char *buf, size_t n) 611 { 612 suspend_state_t state = decode_state(buf, n); 613 int error; 614 615 if (state == PM_SUSPEND_ON 616 && strcmp(buf, "off") && strcmp(buf, "off\n")) 617 return -EINVAL; 618 619 if (state == PM_SUSPEND_MEM) 620 state = mem_sleep_current; 621 622 error = pm_autosleep_set_state(state); 623 return error ? error : n; 624 } 625 626 power_attr(autosleep); 627 #endif /* CONFIG_PM_AUTOSLEEP */ 628 629 #ifdef CONFIG_PM_WAKELOCKS 630 static ssize_t wake_lock_show(struct kobject *kobj, 631 struct kobj_attribute *attr, 632 char *buf) 633 { 634 return pm_show_wakelocks(buf, true); 635 } 636 637 static ssize_t wake_lock_store(struct kobject *kobj, 638 struct kobj_attribute *attr, 639 const char *buf, size_t n) 640 { 641 int error = pm_wake_lock(buf); 642 return error ? error : n; 643 } 644 645 power_attr(wake_lock); 646 647 static ssize_t wake_unlock_show(struct kobject *kobj, 648 struct kobj_attribute *attr, 649 char *buf) 650 { 651 return pm_show_wakelocks(buf, false); 652 } 653 654 static ssize_t wake_unlock_store(struct kobject *kobj, 655 struct kobj_attribute *attr, 656 const char *buf, size_t n) 657 { 658 int error = pm_wake_unlock(buf); 659 return error ? error : n; 660 } 661 662 power_attr(wake_unlock); 663 664 #endif /* CONFIG_PM_WAKELOCKS */ 665 #endif /* CONFIG_PM_SLEEP */ 666 667 #ifdef CONFIG_PM_TRACE 668 int pm_trace_enabled; 669 670 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr, 671 char *buf) 672 { 673 return sprintf(buf, "%d\n", pm_trace_enabled); 674 } 675 676 static ssize_t 677 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 678 const char *buf, size_t n) 679 { 680 int val; 681 682 if (sscanf(buf, "%d", &val) == 1) { 683 pm_trace_enabled = !!val; 684 if (pm_trace_enabled) { 685 pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n" 686 "PM: Correct system time has to be restored manually after resume.\n"); 687 } 688 return n; 689 } 690 return -EINVAL; 691 } 692 693 power_attr(pm_trace); 694 695 static ssize_t pm_trace_dev_match_show(struct kobject *kobj, 696 struct kobj_attribute *attr, 697 char *buf) 698 { 699 return show_trace_dev_match(buf, PAGE_SIZE); 700 } 701 702 power_attr_ro(pm_trace_dev_match); 703 704 #endif /* CONFIG_PM_TRACE */ 705 706 #ifdef CONFIG_FREEZER 707 static ssize_t pm_freeze_timeout_show(struct kobject *kobj, 708 struct kobj_attribute *attr, char *buf) 709 { 710 return sprintf(buf, "%u\n", freeze_timeout_msecs); 711 } 712 713 static ssize_t pm_freeze_timeout_store(struct kobject *kobj, 714 struct kobj_attribute *attr, 715 const char *buf, size_t n) 716 { 717 unsigned long val; 718 719 if (kstrtoul(buf, 10, &val)) 720 return -EINVAL; 721 722 freeze_timeout_msecs = val; 723 return n; 724 } 725 726 power_attr(pm_freeze_timeout); 727 728 #endif /* CONFIG_FREEZER*/ 729 730 static struct attribute * g[] = { 731 &state_attr.attr, 732 #ifdef CONFIG_PM_TRACE 733 &pm_trace_attr.attr, 734 &pm_trace_dev_match_attr.attr, 735 #endif 736 #ifdef CONFIG_PM_SLEEP 737 &pm_async_attr.attr, 738 &wakeup_count_attr.attr, 739 #ifdef CONFIG_SUSPEND 740 &mem_sleep_attr.attr, 741 #endif 742 #ifdef CONFIG_PM_AUTOSLEEP 743 &autosleep_attr.attr, 744 #endif 745 #ifdef CONFIG_PM_WAKELOCKS 746 &wake_lock_attr.attr, 747 &wake_unlock_attr.attr, 748 #endif 749 #ifdef CONFIG_PM_SLEEP_DEBUG 750 &pm_test_attr.attr, 751 &pm_print_times_attr.attr, 752 &pm_wakeup_irq_attr.attr, 753 &pm_debug_messages_attr.attr, 754 #endif 755 #endif 756 #ifdef CONFIG_FREEZER 757 &pm_freeze_timeout_attr.attr, 758 #endif 759 NULL, 760 }; 761 762 static const struct attribute_group attr_group = { 763 .attrs = g, 764 }; 765 766 struct workqueue_struct *pm_wq; 767 EXPORT_SYMBOL_GPL(pm_wq); 768 769 static int __init pm_start_workqueue(void) 770 { 771 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0); 772 773 return pm_wq ? 0 : -ENOMEM; 774 } 775 776 static int __init pm_init(void) 777 { 778 int error = pm_start_workqueue(); 779 if (error) 780 return error; 781 hibernate_image_size_init(); 782 hibernate_reserved_size_init(); 783 pm_states_init(); 784 power_kobj = kobject_create_and_add("power", NULL); 785 if (!power_kobj) 786 return -ENOMEM; 787 error = sysfs_create_group(power_kobj, &attr_group); 788 if (error) 789 return error; 790 pm_print_times_init(); 791 return pm_autosleep_init(); 792 } 793 794 core_initcall(pm_init); 795