release/src-rt-6.x.4708/linux/linux-2.6.36/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 - 2010, 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         /* Write #1: write the SLP_TYP data to the PM1 Control registers */
 327
 328         status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
 329         if (ACPI_FAILURE(status)) {
 330                 return_ACPI_STATUS(status);
 331         }
 332
 333         /* Insert the sleep enable (SLP_EN) bit */
 334
 335         pm1a_control |= sleep_enable_reg_info->access_bit_mask;
 336         pm1b_control |= sleep_enable_reg_info->access_bit_mask;
 337
 338         /* Flush caches, as per ACPI specification */
 339
 340         ACPI_FLUSH_CPU_CACHE();
 341
 342         tboot_sleep(sleep_state, pm1a_control, pm1b_control);
 343
 344         /* Write #2: Write both SLP_TYP + SLP_EN */
 345
 346         status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
 347         if (ACPI_FAILURE(status)) {
 348                 return_ACPI_STATUS(status);
 349         }
 350
 351         if (sleep_state > ACPI_STATE_S3) {
 352                 /*
 353                  * We wanted to sleep > S3, but it didn't happen (by virtue of the
 354                  * fact that we are still executing!)
 355                  *
 356                  * Wait ten seconds, then try again. This is to get S4/S5 to work on
 357                  * all machines.
 358                  *
 359                  * We wait so long to allow chipsets that poll this reg very slowly
 360                  * to still read the right value. Ideally, this block would go
 361                  * away entirely.
 362                  */
 363                 acpi_os_stall(10000000);
 364
 365                 status = acpi_hw_register_write(ACPI_REGISTER_PM1_CONTROL,
 366                                                 sleep_enable_reg_info->
 367                                                 access_bit_mask);
 368                 if (ACPI_FAILURE(status)) {
 369                         return_ACPI_STATUS(status);
 370                 }
 371         }
 372
 373         /* Wait until we enter sleep state */
 374
 375         do {
 376                 status = acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS,
 377                                                     &in_value);
 378                 if (ACPI_FAILURE(status)) {
 379                         return_ACPI_STATUS(status);
 380                 }
 381
 382                 /* Spin until we wake */
 383
 384         } while (!in_value);
 385
 386         return_ACPI_STATUS(AE_OK);
 387 }
 388
 389 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state)
 390
 391 /*******************************************************************************
 392  *
 393  * FUNCTION:    acpi_enter_sleep_state_s4bios
 394  *
 395  * PARAMETERS:  None
 396  *
 397  * RETURN:      Status
 398  *
 399  * DESCRIPTION: Perform a S4 bios request.
 400  *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
 401  *
 402  ******************************************************************************/
 403 acpi_status asmlinkage acpi_enter_sleep_state_s4bios(void)
 404 {
 405         u32 in_value;
 406         acpi_status status;
 407
 408         ACPI_FUNCTION_TRACE(acpi_enter_sleep_state_s4bios);
 409
 410         /* Clear the wake status bit (PM1) */
 411
 412         status =
 413             acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
 414         if (ACPI_FAILURE(status)) {
 415                 return_ACPI_STATUS(status);
 416         }
 417
 418         status = acpi_hw_clear_acpi_status();
 419         if (ACPI_FAILURE(status)) {
 420                 return_ACPI_STATUS(status);
 421         }
 422
 423         /*
 424          * 1) Disable/Clear all GPEs
 425          * 2) Enable all wakeup GPEs
 426          */
 427         status = acpi_hw_disable_all_gpes();
 428         if (ACPI_FAILURE(status)) {
 429                 return_ACPI_STATUS(status);
 430         }
 431         acpi_gbl_system_awake_and_running = FALSE;
 432
 433         status = acpi_hw_enable_all_wakeup_gpes();
 434         if (ACPI_FAILURE(status)) {
 435                 return_ACPI_STATUS(status);
 436         }
 437
 438         ACPI_FLUSH_CPU_CACHE();
 439
 440         status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
 441                                     (u32) acpi_gbl_FADT.S4bios_request, 8);
 442
 443         do {
 444                 acpi_os_stall(1000);
 445                 status =
 446                     acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS, &in_value);
 447                 if (ACPI_FAILURE(status)) {
 448                         return_ACPI_STATUS(status);
 449                 }
 450         } while (!in_value);
 451
 452         return_ACPI_STATUS(AE_OK);
 453 }
 454
 455 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_s4bios)
 456
 457 /*******************************************************************************
 458  *
 459  * FUNCTION:    acpi_leave_sleep_state_prep
 460  *
 461  * PARAMETERS:  sleep_state         - Which sleep state we are exiting
 462  *
 463  * RETURN:      Status
 464  *
 465  * DESCRIPTION: Perform the first state of OS-independent ACPI cleanup after a
 466  *              sleep.
 467  *              Called with interrupts DISABLED.
 468  *
 469  ******************************************************************************/
 470 acpi_status acpi_leave_sleep_state_prep(u8 sleep_state)
 471 {
 472         struct acpi_object_list arg_list;
 473         union acpi_object arg;
 474         acpi_status status;
 475         struct acpi_bit_register_info *sleep_type_reg_info;
 476         struct acpi_bit_register_info *sleep_enable_reg_info;
 477         u32 pm1a_control;
 478         u32 pm1b_control;
 479
 480         ACPI_FUNCTION_TRACE(acpi_leave_sleep_state_prep);
 481
 482         /*
 483          * Set SLP_TYPE and SLP_EN to state S0.
 484          * This is unclear from the ACPI Spec, but it is required
 485          * by some machines.
 486          */
 487         status = acpi_get_sleep_type_data(ACPI_STATE_S0,
 488                                           &acpi_gbl_sleep_type_a,
 489                                           &acpi_gbl_sleep_type_b);
 490         if (ACPI_SUCCESS(status)) {
 491                 sleep_type_reg_info =
 492                     acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
 493                 sleep_enable_reg_info =
 494                     acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);
 495
 496                 /* Get current value of PM1A control */
 497
 498                 status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
 499                                                &pm1a_control);
 500                 if (ACPI_SUCCESS(status)) {
 501
 502                         /* Clear the SLP_EN and SLP_TYP fields */
 503
 504                         pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
 505                                           sleep_enable_reg_info->
 506                                           access_bit_mask);
 507                         pm1b_control = pm1a_control;
 508
 509                         /* Insert the SLP_TYP bits */
 510
 511                         pm1a_control |= (acpi_gbl_sleep_type_a <<
 512                                          sleep_type_reg_info->bit_position);
 513                         pm1b_control |= (acpi_gbl_sleep_type_b <<
 514                                          sleep_type_reg_info->bit_position);
 515
 516                         /* Write the control registers and ignore any errors */
 517
 518                         (void)acpi_hw_write_pm1_control(pm1a_control,
 519                                                         pm1b_control);
 520                 }
 521         }
 522
 523         if (bfs) {
 524                 /* Execute the _BFS method */
 525
 526                 arg_list.count = 1;
 527                 arg_list.pointer = &arg;
 528                 arg.type = ACPI_TYPE_INTEGER;
 529                 arg.integer.value = sleep_state;
 530
 531                 status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
 532                 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 533                         ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
 534                 }
 535         }
 536         return_ACPI_STATUS(status);
 537 }
 538
 539 /*******************************************************************************
 540  *
 541  * FUNCTION:    acpi_leave_sleep_state
 542  *
 543  * PARAMETERS:  sleep_state         - Which sleep state we just exited
 544  *
 545  * RETURN:      Status
 546  *
 547  * DESCRIPTION: Perform OS-independent ACPI cleanup after a sleep
 548  *              Called with interrupts ENABLED.
 549  *
 550  ******************************************************************************/
 551 acpi_status acpi_leave_sleep_state(u8 sleep_state)
 552 {
 553         struct acpi_object_list arg_list;
 554         union acpi_object arg;
 555         acpi_status status;
 556
 557         ACPI_FUNCTION_TRACE(acpi_leave_sleep_state);
 558
 559         /* Ensure enter_sleep_state_prep -> enter_sleep_state ordering */
 560
 561         acpi_gbl_sleep_type_a = ACPI_SLEEP_TYPE_INVALID;
 562
 563         /* Setup parameter object */
 564
 565         arg_list.count = 1;
 566         arg_list.pointer = &arg;
 567         arg.type = ACPI_TYPE_INTEGER;
 568
 569         /* Ignore any errors from these methods */
 570
 571         arg.integer.value = ACPI_SST_WAKING;
 572         status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
 573         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 574                 ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
 575         }
 576
 577         /*
 578          * GPEs must be enabled before _WAK is called as GPEs
 579          * might get fired there
 580          *
 581          * Restore the GPEs:
 582          * 1) Disable/Clear all GPEs
 583          * 2) Enable all runtime GPEs
 584          */
 585         status = acpi_hw_disable_all_gpes();
 586         if (ACPI_FAILURE(status)) {
 587                 return_ACPI_STATUS(status);
 588         }
 589         status = acpi_hw_enable_all_runtime_gpes();
 590         if (ACPI_FAILURE(status)) {
 591                 return_ACPI_STATUS(status);
 592         }
 593
 594         arg.integer.value = sleep_state;
 595         status = acpi_evaluate_object(NULL, METHOD_NAME__WAK, &arg_list, NULL);
 596         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 597                 ACPI_EXCEPTION((AE_INFO, status, "During Method _WAK"));
 598         }
 599         /* TBD: _WAK "sometimes" returns stuff - do we want to look at it? */
 600
 601         /*
 602          * Some BIOSes assume that WAK_STS will be cleared on resume and use
 603          * it to determine whether the system is rebooting or resuming. Clear
 604          * it for compatibility.
 605          */
 606         acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, 1);
 607
 608         acpi_gbl_system_awake_and_running = TRUE;
 609
 610         /* Enable power button */
 611
 612         (void)
 613             acpi_write_bit_register(acpi_gbl_fixed_event_info
 614                               [ACPI_EVENT_POWER_BUTTON].
 615                               enable_register_id, ACPI_ENABLE_EVENT);
 616
 617         (void)
 618             acpi_write_bit_register(acpi_gbl_fixed_event_info
 619                               [ACPI_EVENT_POWER_BUTTON].
 620                               status_register_id, ACPI_CLEAR_STATUS);
 621
 622         arg.integer.value = ACPI_SST_WORKING;
 623         status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
 624         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 625                 ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
 626         }
 627
 628         return_ACPI_STATUS(status);
 629 }
 630
 631 ACPI_EXPORT_SYMBOL(acpi_leave_sleep_state)