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