drivers/acpi/acpica/hwsleep.c

   1
   2 /******************************************************************************
   3  *
   4  * Name: hwsleep.c - ACPI Hardware Sleep/Wake Interface
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2011, Intel Corp.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification.
  18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  19  *    substantially similar to the "NO WARRANTY" disclaimer below
  20  *    ("Disclaimer") and any redistribution must be conditioned upon
  21  *    including a substantially similar Disclaimer requirement for further
  22  *    binary redistribution.
  23  * 3. Neither the names of the above-listed copyright holders nor the names
  24  *    of any contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * Alternatively, this software may be distributed under the terms of the
  28  * GNU General Public License ("GPL") version 2 as published by the Free
  29  * Software Foundation.
  30  *
  31  * NO WARRANTY
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  42  * POSSIBILITY OF SUCH DAMAGES.
  43  */
  44
  45 #include <acpi/acpi.h>
  46 #include "accommon.h"
  47 #include "actables.h"
  48 #include <linux/tboot.h>
  49
  50 #define _COMPONENT          ACPI_HARDWARE
  51 ACPI_MODULE_NAME("hwsleep")
  52
  53 /*******************************************************************************
  54  *
  55  * FUNCTION:    acpi_set_firmware_waking_vector
  56  *
  57  * PARAMETERS:  physical_address    - 32-bit physical address of ACPI real mode
  58  *                                    entry point.
  59  *
  60  * RETURN:      Status
  61  *
  62  * DESCRIPTION: Sets the 32-bit firmware_waking_vector field of the FACS
  63  *
  64  ******************************************************************************/
  65 acpi_status
  66 acpi_set_firmware_waking_vector(u32 physical_address)
  67 {
  68         ACPI_FUNCTION_TRACE(acpi_set_firmware_waking_vector);
  69
  70
  71         /*
  72          * According to the ACPI specification 2.0c and later, the 64-bit
  73          * waking vector should be cleared and the 32-bit waking vector should
  74          * be used, unless we want the wake-up code to be called by the BIOS in
  75          * Protected Mode.  Some systems (for example HP dv5-1004nr) are known
  76          * to fail to resume if the 64-bit vector is used.
  77          */
  78
  79         /* Set the 32-bit vector */
  80
  81         acpi_gbl_FACS->firmware_waking_vector = physical_address;
  82
  83         /* Clear the 64-bit vector if it exists */
  84
  85         if ((acpi_gbl_FACS->length > 32) && (acpi_gbl_FACS->version >= 1)) {
  86                 acpi_gbl_FACS->xfirmware_waking_vector = 0;
  87         }
  88
  89         return_ACPI_STATUS(AE_OK);
  90 }
  91
  92 ACPI_EXPORT_SYMBOL(acpi_set_firmware_waking_vector)
  93
  94 #if ACPI_MACHINE_WIDTH == 64
  95 /*******************************************************************************
  96  *
  97  * FUNCTION:    acpi_set_firmware_waking_vector64
  98  *
  99  * PARAMETERS:  physical_address    - 64-bit physical address of ACPI protected
 100  *                                    mode entry point.
 101  *
 102  * RETURN:      Status
 103  *
 104  * DESCRIPTION: Sets the 64-bit X_firmware_waking_vector field of the FACS, if
 105  *              it exists in the table. This function is intended for use with
 106  *              64-bit host operating systems.
 107  *
 108  ******************************************************************************/
 109 acpi_status
 110 acpi_set_firmware_waking_vector64(u64 physical_address)
 111 {
 112         ACPI_FUNCTION_TRACE(acpi_set_firmware_waking_vector64);
 113
 114
 115         /* Determine if the 64-bit vector actually exists */
 116
 117         if ((acpi_gbl_FACS->length <= 32) || (acpi_gbl_FACS->version < 1)) {
 118                 return_ACPI_STATUS(AE_NOT_EXIST);
 119         }
 120
 121         /* Clear 32-bit vector, set the 64-bit X_ vector */
 122
 123         acpi_gbl_FACS->firmware_waking_vector = 0;
 124         acpi_gbl_FACS->xfirmware_waking_vector = physical_address;
 125
 126         return_ACPI_STATUS(AE_OK);
 127 }
 128
 129 ACPI_EXPORT_SYMBOL(acpi_set_firmware_waking_vector64)
 130 #endif
 131
 132 /*******************************************************************************
 133  *
 134  * FUNCTION:    acpi_enter_sleep_state_prep
 135  *
 136  * PARAMETERS:  sleep_state         - Which sleep state to enter
 137  *
 138  * RETURN:      Status
 139  *
 140  * DESCRIPTION: Prepare to enter a system sleep state (see ACPI 2.0 spec p 231)
 141  *              This function must execute with interrupts enabled.
 142  *              We break sleeping into 2 stages so that OSPM can handle
 143  *              various OS-specific tasks between the two steps.
 144  *
 145  ******************************************************************************/
 146 acpi_status acpi_enter_sleep_state_prep(u8 sleep_state)
 147 {
 148         acpi_status status;
 149         struct acpi_object_list arg_list;
 150         union acpi_object arg;
 151
 152         ACPI_FUNCTION_TRACE(acpi_enter_sleep_state_prep);
 153
 154         /* _PSW methods could be run here to enable wake-on keyboard, LAN, etc. */
 155
 156         status = acpi_get_sleep_type_data(sleep_state,
 157                                           &acpi_gbl_sleep_type_a,
 158                                           &acpi_gbl_sleep_type_b);
 159         if (ACPI_FAILURE(status)) {
 160                 return_ACPI_STATUS(status);
 161         }
 162
 163         /* Setup parameter object */
 164
 165         arg_list.count = 1;
 166         arg_list.pointer = &arg;
 167
 168         arg.type = ACPI_TYPE_INTEGER;
 169         arg.integer.value = sleep_state;
 170
 171         /* Run the _PTS method */
 172
 173         status = acpi_evaluate_object(NULL, METHOD_NAME__PTS, &arg_list, NULL);
 174         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 175                 return_ACPI_STATUS(status);
 176         }
 177
 178         /* Setup the argument to _SST */
 179
 180         switch (sleep_state) {
 181         case ACPI_STATE_S0:
 182                 arg.integer.value = ACPI_SST_WORKING;
 183                 break;
 184
 185         case ACPI_STATE_S1:
 186         case ACPI_STATE_S2:
 187         case ACPI_STATE_S3:
 188                 arg.integer.value = ACPI_SST_SLEEPING;
 189                 break;
 190
 191         case ACPI_STATE_S4:
 192                 arg.integer.value = ACPI_SST_SLEEP_CONTEXT;
 193                 break;
 194
 195         default:
 196                 arg.integer.value = ACPI_SST_INDICATOR_OFF;     /* Default is off */
 197                 break;
 198         }
 199
 200         /*
 201          * Set the system indicators to show the desired sleep state.
 202          * _SST is an optional method (return no error if not found)
 203          */
 204         status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
 205         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 206                 ACPI_EXCEPTION((AE_INFO, status,
 207                                 "While executing method _SST"));
 208         }
 209
 210         return_ACPI_STATUS(AE_OK);
 211 }
 212
 213 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_prep)
 214
 215 static unsigned int gts, bfs;
 216 module_param(gts, uint, 0644);
 217 module_param(bfs, uint, 0644);
 218 MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
 219 MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
 220
 221 /*******************************************************************************
 222  *
 223  * FUNCTION:    acpi_enter_sleep_state
 224  *
 225  * PARAMETERS:  sleep_state         - Which sleep state to enter
 226  *
 227  * RETURN:      Status
 228  *
 229  * DESCRIPTION: Enter a system sleep state (see ACPI 2.0 spec p 231)
 230  *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
 231  *
 232  ******************************************************************************/
 233 acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state)
 234 {
 235         u32 pm1a_control;
 236         u32 pm1b_control;
 237         struct acpi_bit_register_info *sleep_type_reg_info;
 238         struct acpi_bit_register_info *sleep_enable_reg_info;
 239         u32 in_value;
 240         struct acpi_object_list arg_list;
 241         union acpi_object arg;
 242         acpi_status status;
 243
 244         ACPI_FUNCTION_TRACE(acpi_enter_sleep_state);
 245
 246         if ((acpi_gbl_sleep_type_a > ACPI_SLEEP_TYPE_MAX) ||
 247             (acpi_gbl_sleep_type_b > ACPI_SLEEP_TYPE_MAX)) {
 248                 ACPI_ERROR((AE_INFO, "Sleep values out of range: A=0x%X B=0x%X",
 249                             acpi_gbl_sleep_type_a, acpi_gbl_sleep_type_b));
 250                 return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
 251         }
 252
 253         sleep_type_reg_info =
 254             acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
 255         sleep_enable_reg_info =
 256             acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);
 257
 258         /* Clear wake status */
 259
 260         status =
 261             acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
 262         if (ACPI_FAILURE(status)) {
 263                 return_ACPI_STATUS(status);
 264         }
 265
 266         /* Clear all fixed and general purpose status bits */
 267
 268         status = acpi_hw_clear_acpi_status();
 269         if (ACPI_FAILURE(status)) {
 270                 return_ACPI_STATUS(status);
 271         }
 272
 273         /*
 274          * 1) Disable/Clear all GPEs
 275          * 2) Enable all wakeup GPEs
 276          */
 277         status = acpi_hw_disable_all_gpes();
 278         if (ACPI_FAILURE(status)) {
 279                 return_ACPI_STATUS(status);
 280         }
 281         acpi_gbl_system_awake_and_running = FALSE;
 282
 283         status = acpi_hw_enable_all_wakeup_gpes();
 284         if (ACPI_FAILURE(status)) {
 285                 return_ACPI_STATUS(status);
 286         }
 287
 288         if (gts) {
 289                 /* Execute the _GTS method */
 290
 291                 arg_list.count = 1;
 292                 arg_list.pointer = &arg;
 293                 arg.type = ACPI_TYPE_INTEGER;
 294                 arg.integer.value = sleep_state;
 295
 296                 status = acpi_evaluate_object(NULL, METHOD_NAME__GTS, &arg_list, NULL);
 297                 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 298                         return_ACPI_STATUS(status);
 299                 }
 300         }
 301
 302         /* Get current value of PM1A control */
 303
 304         status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
 305                                        &pm1a_control);
 306         if (ACPI_FAILURE(status)) {
 307                 return_ACPI_STATUS(status);
 308         }
 309         ACPI_DEBUG_PRINT((ACPI_DB_INIT,
 310                           "Entering sleep state [S%u]\n", sleep_state));
 311
 312         /* Clear the SLP_EN and SLP_TYP fields */
 313
 314         pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
 315                           sleep_enable_reg_info->access_bit_mask);
 316         pm1b_control = pm1a_control;
 317
 318         /* Insert the SLP_TYP bits */
 319
 320         pm1a_control |=
 321             (acpi_gbl_sleep_type_a << sleep_type_reg_info->bit_position);
 322         pm1b_control |=
 323             (acpi_gbl_sleep_type_b << sleep_type_reg_info->bit_position);
 324
 325         /*
 326          * We split the writes of SLP_TYP and SLP_EN to workaround
 327          * poorly implemented hardware.
 328          */
 329
 330         /* Write #1: write the SLP_TYP data to the PM1 Control registers */
 331
 332         status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
 333         if (ACPI_FAILURE(status)) {
 334                 return_ACPI_STATUS(status);
 335         }
 336
 337         /* Insert the sleep enable (SLP_EN) bit */
 338
 339         pm1a_control |= sleep_enable_reg_info->access_bit_mask;
 340         pm1b_control |= sleep_enable_reg_info->access_bit_mask;
 341
 342         /* Flush caches, as per ACPI specification */
 343
 344         ACPI_FLUSH_CPU_CACHE();
 345
 346         tboot_sleep(sleep_state, pm1a_control, pm1b_control);
 347
 348         /* Write #2: Write both SLP_TYP + SLP_EN */
 349
 350         status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
 351         if (ACPI_FAILURE(status)) {
 352                 return_ACPI_STATUS(status);
 353         }
 354
 355         if (sleep_state > ACPI_STATE_S3) {
 356                 /*
 357                  * We wanted to sleep > S3, but it didn't happen (by virtue of the
 358                  * fact that we are still executing!)
 359                  *
 360                  * Wait ten seconds, then try again. This is to get S4/S5 to work on
 361                  * all machines.
 362                  *
 363                  * We wait so long to allow chipsets that poll this reg very slowly
 364                  * to still read the right value. Ideally, this block would go
 365                  * away entirely.
 366                  */
 367                 acpi_os_stall(10000000);
 368
 369                 status = acpi_hw_register_write(ACPI_REGISTER_PM1_CONTROL,
 370                                                 sleep_enable_reg_info->
 371                                                 access_bit_mask);
 372                 if (ACPI_FAILURE(status)) {
 373                         return_ACPI_STATUS(status);
 374                 }
 375         }
 376
 377         /* Wait until we enter sleep state */
 378
 379         do {
 380                 status = acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS,
 381                                                     &in_value);
 382                 if (ACPI_FAILURE(status)) {
 383                         return_ACPI_STATUS(status);
 384                 }
 385
 386                 /* Spin until we wake */
 387
 388         } while (!in_value);
 389
 390         return_ACPI_STATUS(AE_OK);
 391 }
 392
 393 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state)
 394
 395 /*******************************************************************************
 396  *
 397  * FUNCTION:    acpi_enter_sleep_state_s4bios
 398  *
 399  * PARAMETERS:  None
 400  *
 401  * RETURN:      Status
 402  *
 403  * DESCRIPTION: Perform a S4 bios request.
 404  *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
 405  *
 406  ******************************************************************************/
 407 acpi_status asmlinkage acpi_enter_sleep_state_s4bios(void)
 408 {
 409         u32 in_value;
 410         acpi_status status;
 411
 412         ACPI_FUNCTION_TRACE(acpi_enter_sleep_state_s4bios);
 413
 414         /* Clear the wake status bit (PM1) */
 415
 416         status =
 417             acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
 418         if (ACPI_FAILURE(status)) {
 419                 return_ACPI_STATUS(status);
 420         }
 421
 422         status = acpi_hw_clear_acpi_status();
 423         if (ACPI_FAILURE(status)) {
 424                 return_ACPI_STATUS(status);
 425         }
 426
 427         /*
 428          * 1) Disable/Clear all GPEs
 429          * 2) Enable all wakeup GPEs
 430          */
 431         status = acpi_hw_disable_all_gpes();
 432         if (ACPI_FAILURE(status)) {
 433                 return_ACPI_STATUS(status);
 434         }
 435         acpi_gbl_system_awake_and_running = FALSE;
 436
 437         status = acpi_hw_enable_all_wakeup_gpes();
 438         if (ACPI_FAILURE(status)) {
 439                 return_ACPI_STATUS(status);
 440         }
 441
 442         ACPI_FLUSH_CPU_CACHE();
 443
 444         status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 445                                     (u32) acpi_gbl_FADT.S4bios_request, 8);
 446
 447         do {
 448                 acpi_os_stall(1000);
 449                 status =
 450                     acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS, &in_value);
 451                 if (ACPI_FAILURE(status)) {
 452                         return_ACPI_STATUS(status);
 453                 }
 454         } while (!in_value);
 455
 456         return_ACPI_STATUS(AE_OK);
 457 }
 458
 459 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_s4bios)
 460
 461 /*******************************************************************************
 462  *
 463  * FUNCTION:    acpi_leave_sleep_state_prep
 464  *
 465  * PARAMETERS:  sleep_state         - Which sleep state we are exiting
 466  *
 467  * RETURN:      Status
 468  *
 469  * DESCRIPTION: Perform the first state of OS-independent ACPI cleanup after a
 470  *              sleep.
 471  *              Called with interrupts DISABLED.
 472  *
 473  ******************************************************************************/
 474 acpi_status acpi_leave_sleep_state_prep(u8 sleep_state)
 475 {
 476         struct acpi_object_list arg_list;
 477         union acpi_object arg;
 478         acpi_status status;
 479         struct acpi_bit_register_info *sleep_type_reg_info;
 480         struct acpi_bit_register_info *sleep_enable_reg_info;
 481         u32 pm1a_control;
 482         u32 pm1b_control;
 483
 484         ACPI_FUNCTION_TRACE(acpi_leave_sleep_state_prep);
 485
 486         /*
 487          * Set SLP_TYPE and SLP_EN to state S0.
 488          * This is unclear from the ACPI Spec, but it is required
 489          * by some machines.
 490          */
 491         status = acpi_get_sleep_type_data(ACPI_STATE_S0,
 492                                           &acpi_gbl_sleep_type_a,
 493                                           &acpi_gbl_sleep_type_b);
 494         if (ACPI_SUCCESS(status)) {
 495                 sleep_type_reg_info =
 496                     acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
 497                 sleep_enable_reg_info =
 498                     acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);
 499
 500                 /* Get current value of PM1A control */
 501
 502                 status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
 503                                                &pm1a_control);
 504                 if (ACPI_SUCCESS(status)) {
 505
 506                         /* Clear the SLP_EN and SLP_TYP fields */
 507
 508                         pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
 509                                           sleep_enable_reg_info->
 510                                           access_bit_mask);
 511                         pm1b_control = pm1a_control;
 512
 513                         /* Insert the SLP_TYP bits */
 514
 515                         pm1a_control |= (acpi_gbl_sleep_type_a <<
 516                                          sleep_type_reg_info->bit_position);
 517                         pm1b_control |= (acpi_gbl_sleep_type_b <<
 518                                          sleep_type_reg_info->bit_position);
 519
 520                         /* Write the control registers and ignore any errors */
 521
 522                         (void)acpi_hw_write_pm1_control(pm1a_control,
 523                                                         pm1b_control);
 524                 }
 525         }
 526
 527         if (bfs) {
 528                 /* Execute the _BFS method */
 529
 530                 arg_list.count = 1;
 531                 arg_list.pointer = &arg;
 532                 arg.type = ACPI_TYPE_INTEGER;
 533                 arg.integer.value = sleep_state;
 534
 535                 status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
 536                 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 537                         ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
 538                 }
 539         }
 540         return_ACPI_STATUS(status);
 541 }
 542
 543 /*******************************************************************************
 544  *
 545  * FUNCTION:    acpi_leave_sleep_state
 546  *
 547  * PARAMETERS:  sleep_state         - Which sleep state we just exited
 548  *
 549  * RETURN:      Status
 550  *
 551  * DESCRIPTION: Perform OS-independent ACPI cleanup after a sleep
 552  *              Called with interrupts ENABLED.
 553  *
 554  ******************************************************************************/
 555 acpi_status acpi_leave_sleep_state(u8 sleep_state)
 556 {
 557         struct acpi_object_list arg_list;
 558         union acpi_object arg;
 559         acpi_status status;
 560
 561         ACPI_FUNCTION_TRACE(acpi_leave_sleep_state);
 562
 563         /* Ensure enter_sleep_state_prep -> enter_sleep_state ordering */
 564
 565         acpi_gbl_sleep_type_a = ACPI_SLEEP_TYPE_INVALID;
 566
 567         /* Setup parameter object */
 568
 569         arg_list.count = 1;
 570         arg_list.pointer = &arg;
 571         arg.type = ACPI_TYPE_INTEGER;
 572
 573         /* Ignore any errors from these methods */
 574
 575         arg.integer.value = ACPI_SST_WAKING;
 576         status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
 577         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 578                 ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
 579         }
 580
 581         /*
 582          * GPEs must be enabled before _WAK is called as GPEs
 583          * might get fired there
 584          *
 585          * Restore the GPEs:
 586          * 1) Disable/Clear all GPEs
 587          * 2) Enable all runtime GPEs
 588          */
 589         status = acpi_hw_disable_all_gpes();
 590         if (ACPI_FAILURE(status)) {
 591                 return_ACPI_STATUS(status);
 592         }
 593         status = acpi_hw_enable_all_runtime_gpes();
 594         if (ACPI_FAILURE(status)) {
 595                 return_ACPI_STATUS(status);
 596         }
 597
 598         arg.integer.value = sleep_state;
 599         status = acpi_evaluate_object(NULL, METHOD_NAME__WAK, &arg_list, NULL);
 600         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 601                 ACPI_EXCEPTION((AE_INFO, status, "During Method _WAK"));
 602         }
 603         /* TBD: _WAK "sometimes" returns stuff - do we want to look at it? */
 604
 605         /*
 606          * Some BIOSes assume that WAK_STS will be cleared on resume and use
 607          * it to determine whether the system is rebooting or resuming. Clear
 608          * it for compatibility.
 609          */
 610         acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, 1);
 611
 612         acpi_gbl_system_awake_and_running = TRUE;
 613
 614         /* Enable power button */
 615
 616         (void)
 617             acpi_write_bit_register(acpi_gbl_fixed_event_info
 618                               [ACPI_EVENT_POWER_BUTTON].
 619                               enable_register_id, ACPI_ENABLE_EVENT);
 620
 621         (void)
 622             acpi_write_bit_register(acpi_gbl_fixed_event_info
 623                               [ACPI_EVENT_POWER_BUTTON].
 624                               status_register_id, ACPI_CLEAR_STATUS);
 625
 626         arg.integer.value = ACPI_SST_WORKING;
 627         status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
 628         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 629                 ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
 630         }
 631
 632         return_ACPI_STATUS(status);
 633 }
 634
 635 ACPI_EXPORT_SYMBOL(acpi_leave_sleep_state)