drivers/acpi/sleep/main.c

   1 /*
   2  * sleep.c - ACPI sleep support.
   3  *
   4  * Copyright (c) 2005 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   5  * Copyright (c) 2004 David Shaohua Li <shaohua.li@intel.com>
   6  * Copyright (c) 2000-2003 Patrick Mochel
   7  * Copyright (c) 2003 Open Source Development Lab
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/irq.h>
  15 #include <linux/dmi.h>
  16 #include <linux/device.h>
  17 #include <linux/suspend.h>
  18 #include <linux/reboot.h>
  19
  20 #include <asm/io.h>
  21
  22 #include <acpi/acpi_bus.h>
  23 #include <acpi/acpi_drivers.h>
  24 #include "sleep.h"
  25
  26 u8 sleep_states[ACPI_S_STATE_COUNT];
  27
  28 static void acpi_sleep_tts_switch(u32 acpi_state)
  29 {
  30         union acpi_object in_arg = { ACPI_TYPE_INTEGER };
  31         struct acpi_object_list arg_list = { 1, &in_arg };
  32         acpi_status status = AE_OK;
  33
  34         in_arg.integer.value = acpi_state;
  35         status = acpi_evaluate_object(NULL, "\\_TTS", &arg_list, NULL);
  36         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
  37                 /*
  38                  * OS can't evaluate the _TTS object correctly. Some warning
  39                  * message will be printed. But it won't break anything.
  40                  */
  41                 printk(KERN_NOTICE "Failure in evaluating _TTS object\n");
  42         }
  43 }
  44
  45 static int tts_notify_reboot(struct notifier_block *this,
  46                         unsigned long code, void *x)
  47 {
  48         acpi_sleep_tts_switch(ACPI_STATE_S5);
  49         return NOTIFY_DONE;
  50 }
  51
  52 static struct notifier_block tts_notifier = {
  53         .notifier_call  = tts_notify_reboot,
  54         .next           = NULL,
  55         .priority       = 0,
  56 };
  57
  58 static int acpi_sleep_prepare(u32 acpi_state)
  59 {
  60 #ifdef CONFIG_ACPI_SLEEP
  61         /* do we have a wakeup address for S2 and S3? */
  62         if (acpi_state == ACPI_STATE_S3) {
  63                 if (!acpi_wakeup_address) {
  64                         return -EFAULT;
  65                 }
  66                 acpi_set_firmware_waking_vector(
  67                                 (acpi_physical_address)acpi_wakeup_address);
  68
  69         }
  70         ACPI_FLUSH_CPU_CACHE();
  71         acpi_enable_wakeup_device_prep(acpi_state);
  72 #endif
  73         printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
  74                 acpi_state);
  75         acpi_enter_sleep_state_prep(acpi_state);
  76         return 0;
  77 }
  78
  79 #ifdef CONFIG_ACPI_SLEEP
  80 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
  81 /*
  82  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
  83  * user to request that behavior by using the 'acpi_old_suspend_ordering'
  84  * kernel command line option that causes the following variable to be set.
  85  */
  86 static bool old_suspend_ordering;
  87
  88 void __init acpi_old_suspend_ordering(void)
  89 {
  90         old_suspend_ordering = true;
  91 }
  92
  93 /**
  94  *      acpi_pm_disable_gpes - Disable the GPEs.
  95  */
  96 static int acpi_pm_disable_gpes(void)
  97 {
  98         acpi_hw_disable_all_gpes();
  99         return 0;
 100 }
 101
 102 /**
 103  *      __acpi_pm_prepare - Prepare the platform to enter the target state.
 104  *
 105  *      If necessary, set the firmware waking vector and do arch-specific
 106  *      nastiness to get the wakeup code to the waking vector.
 107  */
 108 static int __acpi_pm_prepare(void)
 109 {
 110         int error = acpi_sleep_prepare(acpi_target_sleep_state);
 111
 112         if (error)
 113                 acpi_target_sleep_state = ACPI_STATE_S0;
 114         return error;
 115 }
 116
 117 /**
 118  *      acpi_pm_prepare - Prepare the platform to enter the target sleep
 119  *              state and disable the GPEs.
 120  */
 121 static int acpi_pm_prepare(void)
 122 {
 123         int error = __acpi_pm_prepare();
 124
 125         if (!error)
 126                 acpi_hw_disable_all_gpes();
 127         return error;
 128 }
 129
 130 /**
 131  *      acpi_pm_finish - Instruct the platform to leave a sleep state.
 132  *
 133  *      This is called after we wake back up (or if entering the sleep state
 134  *      failed).
 135  */
 136 static void acpi_pm_finish(void)
 137 {
 138         u32 acpi_state = acpi_target_sleep_state;
 139
 140         if (acpi_state == ACPI_STATE_S0)
 141                 return;
 142
 143         printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
 144                 acpi_state);
 145         acpi_disable_wakeup_device(acpi_state);
 146         acpi_leave_sleep_state(acpi_state);
 147
 148         /* reset firmware waking vector */
 149         acpi_set_firmware_waking_vector((acpi_physical_address) 0);
 150
 151         acpi_target_sleep_state = ACPI_STATE_S0;
 152 }
 153
 154 /**
 155  *      acpi_pm_end - Finish up suspend sequence.
 156  */
 157 static void acpi_pm_end(void)
 158 {
 159         /*
 160          * This is necessary in case acpi_pm_finish() is not called during a
 161          * failing transition to a sleep state.
 162          */
 163         acpi_target_sleep_state = ACPI_STATE_S0;
 164         acpi_sleep_tts_switch(acpi_target_sleep_state);
 165 }
 166 #endif /* CONFIG_ACPI_SLEEP */
 167
 168 #ifdef CONFIG_SUSPEND
 169 extern void do_suspend_lowlevel(void);
 170
 171 static u32 acpi_suspend_states[] = {
 172         [PM_SUSPEND_ON] = ACPI_STATE_S0,
 173         [PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
 174         [PM_SUSPEND_MEM] = ACPI_STATE_S3,
 175         [PM_SUSPEND_MAX] = ACPI_STATE_S5
 176 };
 177
 178 /**
 179  *      acpi_suspend_begin - Set the target system sleep state to the state
 180  *              associated with given @pm_state, if supported.
 181  */
 182 static int acpi_suspend_begin(suspend_state_t pm_state)
 183 {
 184         u32 acpi_state = acpi_suspend_states[pm_state];
 185         int error = 0;
 186
 187         if (sleep_states[acpi_state]) {
 188                 acpi_target_sleep_state = acpi_state;
 189                 acpi_sleep_tts_switch(acpi_target_sleep_state);
 190         } else {
 191                 printk(KERN_ERR "ACPI does not support this state: %d\n",
 192                         pm_state);
 193                 error = -ENOSYS;
 194         }
 195         return error;
 196 }
 197
 198 /**
 199  *      acpi_suspend_enter - Actually enter a sleep state.
 200  *      @pm_state: ignored
 201  *
 202  *      Flush caches and go to sleep. For STR we have to call arch-specific
 203  *      assembly, which in turn call acpi_enter_sleep_state().
 204  *      It's unfortunate, but it works. Please fix if you're feeling frisky.
 205  */
 206 static int acpi_suspend_enter(suspend_state_t pm_state)
 207 {
 208         acpi_status status = AE_OK;
 209         unsigned long flags = 0;
 210         u32 acpi_state = acpi_target_sleep_state;
 211
 212         ACPI_FLUSH_CPU_CACHE();
 213
 214         /* Do arch specific saving of state. */
 215         if (acpi_state == ACPI_STATE_S3) {
 216                 int error = acpi_save_state_mem();
 217
 218                 if (error)
 219                         return error;
 220         }
 221
 222         local_irq_save(flags);
 223         acpi_enable_wakeup_device(acpi_state);
 224         switch (acpi_state) {
 225         case ACPI_STATE_S1:
 226                 barrier();
 227                 status = acpi_enter_sleep_state(acpi_state);
 228                 break;
 229
 230         case ACPI_STATE_S3:
 231                 do_suspend_lowlevel();
 232                 break;
 233         }
 234
 235         /* If ACPI is not enabled by the BIOS, we need to enable it here. */
 236         acpi_enable();
 237         /* Reprogram control registers and execute _BFS */
 238         acpi_leave_sleep_state_prep(acpi_state);
 239
 240         /* ACPI 3.0 specs (P62) says that it's the responsibility
 241          * of the OSPM to clear the status bit [ implying that the
 242          * POWER_BUTTON event should not reach userspace ]
 243          */
 244         if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3))
 245                 acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
 246
 247         /*
 248          * Disable and clear GPE status before interrupt is enabled. Some GPEs
 249          * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
 250          * acpi_leave_sleep_state will reenable specific GPEs later
 251          */
 252         acpi_hw_disable_all_gpes();
 253
 254         local_irq_restore(flags);
 255         printk(KERN_DEBUG "Back to C!\n");
 256
 257         /* restore processor state */
 258         if (acpi_state == ACPI_STATE_S3)
 259                 acpi_restore_state_mem();
 260
 261         return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 262 }
 263
 264 static int acpi_suspend_state_valid(suspend_state_t pm_state)
 265 {
 266         u32 acpi_state;
 267
 268         switch (pm_state) {
 269         case PM_SUSPEND_ON:
 270         case PM_SUSPEND_STANDBY:
 271         case PM_SUSPEND_MEM:
 272                 acpi_state = acpi_suspend_states[pm_state];
 273
 274                 return sleep_states[acpi_state];
 275         default:
 276                 return 0;
 277         }
 278 }
 279
 280 static struct platform_suspend_ops acpi_suspend_ops = {
 281         .valid = acpi_suspend_state_valid,
 282         .begin = acpi_suspend_begin,
 283         .prepare = acpi_pm_prepare,
 284         .enter = acpi_suspend_enter,
 285         .finish = acpi_pm_finish,
 286         .end = acpi_pm_end,
 287 };
 288
 289 /**
 290  *      acpi_suspend_begin_old - Set the target system sleep state to the
 291  *              state associated with given @pm_state, if supported, and
 292  *              execute the _PTS control method.  This function is used if the
 293  *              pre-ACPI 2.0 suspend ordering has been requested.
 294  */
 295 static int acpi_suspend_begin_old(suspend_state_t pm_state)
 296 {
 297         int error = acpi_suspend_begin(pm_state);
 298
 299         if (!error)
 300                 error = __acpi_pm_prepare();
 301         return error;
 302 }
 303
 304 /*
 305  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
 306  * been requested.
 307  */
 308 static struct platform_suspend_ops acpi_suspend_ops_old = {
 309         .valid = acpi_suspend_state_valid,
 310         .begin = acpi_suspend_begin_old,
 311         .prepare = acpi_pm_disable_gpes,
 312         .enter = acpi_suspend_enter,
 313         .finish = acpi_pm_finish,
 314         .end = acpi_pm_end,
 315         .recover = acpi_pm_finish,
 316 };
 317
 318 static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
 319 {
 320         old_suspend_ordering = true;
 321         return 0;
 322 }
 323
 324 static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 325         {
 326         .callback = init_old_suspend_ordering,
 327         .ident = "Abit KN9 (nForce4 variant)",
 328         .matches = {
 329                 DMI_MATCH(DMI_BOARD_VENDOR, "http://www.abit.com.tw/"),
 330                 DMI_MATCH(DMI_BOARD_NAME, "KN9 Series(NF-CK804)"),
 331                 },
 332         },
 333         {
 334         .callback = init_old_suspend_ordering,
 335         .ident = "HP xw4600 Workstation",
 336         .matches = {
 337                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 338                 DMI_MATCH(DMI_PRODUCT_NAME, "HP xw4600 Workstation"),
 339                 },
 340         },
 341         {},
 342 };
 343 #endif /* CONFIG_SUSPEND */
 344
 345 #ifdef CONFIG_HIBERNATION
 346 static unsigned long s4_hardware_signature;
 347 static struct acpi_table_facs *facs;
 348 static bool nosigcheck;
 349
 350 void __init acpi_no_s4_hw_signature(void)
 351 {
 352         nosigcheck = true;
 353 }
 354
 355 static int acpi_hibernation_begin(void)
 356 {
 357         acpi_target_sleep_state = ACPI_STATE_S4;
 358         acpi_sleep_tts_switch(acpi_target_sleep_state);
 359         return 0;
 360 }
 361
 362 static int acpi_hibernation_enter(void)
 363 {
 364         acpi_status status = AE_OK;
 365         unsigned long flags = 0;
 366
 367         ACPI_FLUSH_CPU_CACHE();
 368
 369         local_irq_save(flags);
 370         acpi_enable_wakeup_device(ACPI_STATE_S4);
 371         /* This shouldn't return.  If it returns, we have a problem */
 372         status = acpi_enter_sleep_state(ACPI_STATE_S4);
 373         /* Reprogram control registers and execute _BFS */
 374         acpi_leave_sleep_state_prep(ACPI_STATE_S4);
 375         local_irq_restore(flags);
 376
 377         return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 378 }
 379
 380 static void acpi_hibernation_leave(void)
 381 {
 382         /*
 383          * If ACPI is not enabled by the BIOS and the boot kernel, we need to
 384          * enable it here.
 385          */
 386         acpi_enable();
 387         /* Reprogram control registers and execute _BFS */
 388         acpi_leave_sleep_state_prep(ACPI_STATE_S4);
 389         /* Check the hardware signature */
 390         if (facs && s4_hardware_signature != facs->hardware_signature) {
 391                 printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
 392                         "cannot resume!\n");
 393                 panic("ACPI S4 hardware signature mismatch");
 394         }
 395 }
 396
 397 static void acpi_pm_enable_gpes(void)
 398 {
 399         acpi_hw_enable_all_runtime_gpes();
 400 }
 401
 402 static struct platform_hibernation_ops acpi_hibernation_ops = {
 403         .begin = acpi_hibernation_begin,
 404         .end = acpi_pm_end,
 405         .pre_snapshot = acpi_pm_prepare,
 406         .finish = acpi_pm_finish,
 407         .prepare = acpi_pm_prepare,
 408         .enter = acpi_hibernation_enter,
 409         .leave = acpi_hibernation_leave,
 410         .pre_restore = acpi_pm_disable_gpes,
 411         .restore_cleanup = acpi_pm_enable_gpes,
 412 };
 413
 414 /**
 415  *      acpi_hibernation_begin_old - Set the target system sleep state to
 416  *              ACPI_STATE_S4 and execute the _PTS control method.  This
 417  *              function is used if the pre-ACPI 2.0 suspend ordering has been
 418  *              requested.
 419  */
 420 static int acpi_hibernation_begin_old(void)
 421 {
 422         int error;
 423         /*
 424          * The _TTS object should always be evaluated before the _PTS object.
 425          * When the old_suspended_ordering is true, the _PTS object is
 426          * evaluated in the acpi_sleep_prepare.
 427          */
 428         acpi_sleep_tts_switch(ACPI_STATE_S4);
 429
 430         error = acpi_sleep_prepare(ACPI_STATE_S4);
 431
 432         if (!error)
 433                 acpi_target_sleep_state = ACPI_STATE_S4;
 434         return error;
 435 }
 436
 437 /*
 438  * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
 439  * been requested.
 440  */
 441 static struct platform_hibernation_ops acpi_hibernation_ops_old = {
 442         .begin = acpi_hibernation_begin_old,
 443         .end = acpi_pm_end,
 444         .pre_snapshot = acpi_pm_disable_gpes,
 445         .finish = acpi_pm_finish,
 446         .prepare = acpi_pm_disable_gpes,
 447         .enter = acpi_hibernation_enter,
 448         .leave = acpi_hibernation_leave,
 449         .pre_restore = acpi_pm_disable_gpes,
 450         .restore_cleanup = acpi_pm_enable_gpes,
 451         .recover = acpi_pm_finish,
 452 };
 453 #endif /* CONFIG_HIBERNATION */
 454
 455 int acpi_suspend(u32 acpi_state)
 456 {
 457         suspend_state_t states[] = {
 458                 [1] = PM_SUSPEND_STANDBY,
 459                 [3] = PM_SUSPEND_MEM,
 460                 [5] = PM_SUSPEND_MAX
 461         };
 462
 463         if (acpi_state < 6 && states[acpi_state])
 464                 return pm_suspend(states[acpi_state]);
 465         if (acpi_state == 4)
 466                 return hibernate();
 467         return -EINVAL;
 468 }
 469
 470 #ifdef CONFIG_PM_SLEEP
 471 /**
 472  *      acpi_pm_device_sleep_state - return preferred power state of ACPI device
 473  *              in the system sleep state given by %acpi_target_sleep_state
 474  *      @dev: device to examine; its driver model wakeup flags control
 475  *              whether it should be able to wake up the system
 476  *      @d_min_p: used to store the upper limit of allowed states range
 477  *      Return value: preferred power state of the device on success, -ENODEV on
 478  *              failure (ie. if there's no 'struct acpi_device' for @dev)
 479  *
 480  *      Find the lowest power (highest number) ACPI device power state that
 481  *      device @dev can be in while the system is in the sleep state represented
 482  *      by %acpi_target_sleep_state.  If @wake is nonzero, the device should be
 483  *      able to wake up the system from this sleep state.  If @d_min_p is set,
 484  *      the highest power (lowest number) device power state of @dev allowed
 485  *      in this system sleep state is stored at the location pointed to by it.
 486  *
 487  *      The caller must ensure that @dev is valid before using this function.
 488  *      The caller is also responsible for figuring out if the device is
 489  *      supposed to be able to wake up the system and passing this information
 490  *      via @wake.
 491  */
 492
 493 int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p)
 494 {
 495         acpi_handle handle = DEVICE_ACPI_HANDLE(dev);
 496         struct acpi_device *adev;
 497         char acpi_method[] = "_SxD";
 498         unsigned long long d_min, d_max;
 499
 500         if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
 501                 printk(KERN_DEBUG "ACPI handle has no context!\n");
 502                 return -ENODEV;
 503         }
 504
 505         acpi_method[2] = '0' + acpi_target_sleep_state;
 506         /*
 507          * If the sleep state is S0, we will return D3, but if the device has
 508          * _S0W, we will use the value from _S0W
 509          */
 510         d_min = ACPI_STATE_D0;
 511         d_max = ACPI_STATE_D3;
 512
 513         /*
 514          * If present, _SxD methods return the minimum D-state (highest power
 515          * state) we can use for the corresponding S-states.  Otherwise, the
 516          * minimum D-state is D0 (ACPI 3.x).
 517          *
 518          * NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
 519          * provided -- that's our fault recovery, we ignore retval.
 520          */
 521         if (acpi_target_sleep_state > ACPI_STATE_S0)
 522                 acpi_evaluate_integer(handle, acpi_method, NULL, &d_min);
 523
 524         /*
 525          * If _PRW says we can wake up the system from the target sleep state,
 526          * the D-state returned by _SxD is sufficient for that (we assume a
 527          * wakeup-aware driver if wake is set).  Still, if _SxW exists
 528          * (ACPI 3.x), it should return the maximum (lowest power) D-state that
 529          * can wake the system.  _S0W may be valid, too.
 530          */
 531         if (acpi_target_sleep_state == ACPI_STATE_S0 ||
 532             (device_may_wakeup(dev) && adev->wakeup.state.enabled &&
 533              adev->wakeup.sleep_state <= acpi_target_sleep_state)) {
 534                 acpi_status status;
 535
 536                 acpi_method[3] = 'W';
 537                 status = acpi_evaluate_integer(handle, acpi_method, NULL,
 538                                                 &d_max);
 539                 if (ACPI_FAILURE(status)) {
 540                         d_max = d_min;
 541                 } else if (d_max < d_min) {
 542                         /* Warn the user of the broken DSDT */
 543                         printk(KERN_WARNING "ACPI: Wrong value from %s\n",
 544                                 acpi_method);
 545                         /* Sanitize it */
 546                         d_min = d_max;
 547                 }
 548         }
 549
 550         if (d_min_p)
 551                 *d_min_p = d_min;
 552         return d_max;
 553 }
 554
 555 /**
 556  *      acpi_pm_device_sleep_wake - enable or disable the system wake-up
 557  *                                  capability of given device
 558  *      @dev: device to handle
 559  *      @enable: 'true' - enable, 'false' - disable the wake-up capability
 560  */
 561 int acpi_pm_device_sleep_wake(struct device *dev, bool enable)
 562 {
 563         acpi_handle handle;
 564         struct acpi_device *adev;
 565
 566         if (!device_may_wakeup(dev))
 567                 return -EINVAL;
 568
 569         handle = DEVICE_ACPI_HANDLE(dev);
 570         if (!handle || ACPI_FAILURE(acpi_bus_get_device(handle, &adev))) {
 571                 printk(KERN_DEBUG "ACPI handle has no context!\n");
 572                 return -ENODEV;
 573         }
 574
 575         return enable ?
 576                 acpi_enable_wakeup_device_power(adev, acpi_target_sleep_state) :
 577                 acpi_disable_wakeup_device_power(adev);
 578 }
 579 #endif
 580
 581 static void acpi_power_off_prepare(void)
 582 {
 583         /* Prepare to power off the system */
 584         acpi_sleep_prepare(ACPI_STATE_S5);
 585         acpi_hw_disable_all_gpes();
 586 }
 587
 588 static void acpi_power_off(void)
 589 {
 590         /* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 591         printk("%s called\n", __func__);
 592         local_irq_disable();
 593         acpi_enable_wakeup_device(ACPI_STATE_S5);
 594         acpi_enter_sleep_state(ACPI_STATE_S5);
 595 }
 596
 597 int __init acpi_sleep_init(void)
 598 {
 599         acpi_status status;
 600         u8 type_a, type_b;
 601 #ifdef CONFIG_SUSPEND
 602         int i = 0;
 603
 604         dmi_check_system(acpisleep_dmi_table);
 605 #endif
 606
 607         if (acpi_disabled)
 608                 return 0;
 609
 610         sleep_states[ACPI_STATE_S0] = 1;
 611         printk(KERN_INFO PREFIX "(supports S0");
 612
 613 #ifdef CONFIG_SUSPEND
 614         for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++) {
 615                 status = acpi_get_sleep_type_data(i, &type_a, &type_b);
 616                 if (ACPI_SUCCESS(status)) {
 617                         sleep_states[i] = 1;
 618                         printk(" S%d", i);
 619                 }
 620         }
 621
 622         suspend_set_ops(old_suspend_ordering ?
 623                 &acpi_suspend_ops_old : &acpi_suspend_ops);
 624 #endif
 625
 626 #ifdef CONFIG_HIBERNATION
 627         status = acpi_get_sleep_type_data(ACPI_STATE_S4, &type_a, &type_b);
 628         if (ACPI_SUCCESS(status)) {
 629                 hibernation_set_ops(old_suspend_ordering ?
 630                         &acpi_hibernation_ops_old : &acpi_hibernation_ops);
 631                 sleep_states[ACPI_STATE_S4] = 1;
 632                 printk(" S4");
 633                 if (!nosigcheck) {
 634                         acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 635                                 (struct acpi_table_header **)&facs);
 636                         if (facs)
 637                                 s4_hardware_signature =
 638                                         facs->hardware_signature;
 639                 }
 640         }
 641 #endif
 642         status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);
 643         if (ACPI_SUCCESS(status)) {
 644                 sleep_states[ACPI_STATE_S5] = 1;
 645                 printk(" S5");
 646                 pm_power_off_prepare = acpi_power_off_prepare;
 647                 pm_power_off = acpi_power_off;
 648         }
 649         printk(")\n");
 650         /*
 651          * Register the tts_notifier to reboot notifier list so that the _TTS
 652          * object can also be evaluated when the system enters S5.
 653          */
 654         register_reboot_notifier(&tts_notifier);
 655         return 0;
 656 }