drivers/acpi/events/evgpe.c

   1 /******************************************************************************
   2  *
   3  * Module Name: evgpe - General Purpose Event handling and dispatch
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2008, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include <acpi/accommon.h>
  46 #include <acpi/acevents.h>
  47 #include <acpi/acnamesp.h>
  48
  49 #define _COMPONENT          ACPI_EVENTS
  50 ACPI_MODULE_NAME("evgpe")
  51
  52 /* Local prototypes */
  53 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context);
  54
  55 /*******************************************************************************
  56  *
  57  * FUNCTION:    acpi_ev_set_gpe_type
  58  *
  59  * PARAMETERS:  gpe_event_info          - GPE to set
  60  *              Type                    - New type
  61  *
  62  * RETURN:      Status
  63  *
  64  * DESCRIPTION: Sets the new type for the GPE (wake, run, or wake/run)
  65  *
  66  ******************************************************************************/
  67
  68 acpi_status
  69 acpi_ev_set_gpe_type(struct acpi_gpe_event_info *gpe_event_info, u8 type)
  70 {
  71         acpi_status status;
  72
  73         ACPI_FUNCTION_TRACE(ev_set_gpe_type);
  74
  75         /* Validate type and update register enable masks */
  76
  77         switch (type) {
  78         case ACPI_GPE_TYPE_WAKE:
  79         case ACPI_GPE_TYPE_RUNTIME:
  80         case ACPI_GPE_TYPE_WAKE_RUN:
  81                 break;
  82
  83         default:
  84                 return_ACPI_STATUS(AE_BAD_PARAMETER);
  85         }
  86
  87         /* Disable the GPE if currently enabled */
  88
  89         status = acpi_ev_disable_gpe(gpe_event_info);
  90
  91         /* Type was validated above */
  92
  93         gpe_event_info->flags &= ~ACPI_GPE_TYPE_MASK;   /* Clear type bits */
  94         gpe_event_info->flags |= type;  /* Insert type */
  95         return_ACPI_STATUS(status);
  96 }
  97
  98 /*******************************************************************************
  99  *
 100  * FUNCTION:    acpi_ev_update_gpe_enable_masks
 101  *
 102  * PARAMETERS:  gpe_event_info          - GPE to update
 103  *              Type                    - What to do: ACPI_GPE_DISABLE or
 104  *                                        ACPI_GPE_ENABLE
 105  *
 106  * RETURN:      Status
 107  *
 108  * DESCRIPTION: Updates GPE register enable masks based on the GPE type
 109  *
 110  ******************************************************************************/
 111
 112 acpi_status
 113 acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info,
 114                                 u8 type)
 115 {
 116         struct acpi_gpe_register_info *gpe_register_info;
 117         u8 register_bit;
 118
 119         ACPI_FUNCTION_TRACE(ev_update_gpe_enable_masks);
 120
 121         gpe_register_info = gpe_event_info->register_info;
 122         if (!gpe_register_info) {
 123                 return_ACPI_STATUS(AE_NOT_EXIST);
 124         }
 125         register_bit = (u8)
 126             (1 <<
 127              (gpe_event_info->gpe_number - gpe_register_info->base_gpe_number));
 128
 129         /* 1) Disable case. Simply clear all enable bits */
 130
 131         if (type == ACPI_GPE_DISABLE) {
 132                 ACPI_CLEAR_BIT(gpe_register_info->enable_for_wake,
 133                                register_bit);
 134                 ACPI_CLEAR_BIT(gpe_register_info->enable_for_run, register_bit);
 135                 return_ACPI_STATUS(AE_OK);
 136         }
 137
 138         /* 2) Enable case. Set/Clear the appropriate enable bits */
 139
 140         switch (gpe_event_info->flags & ACPI_GPE_TYPE_MASK) {
 141         case ACPI_GPE_TYPE_WAKE:
 142                 ACPI_SET_BIT(gpe_register_info->enable_for_wake, register_bit);
 143                 ACPI_CLEAR_BIT(gpe_register_info->enable_for_run, register_bit);
 144                 break;
 145
 146         case ACPI_GPE_TYPE_RUNTIME:
 147                 ACPI_CLEAR_BIT(gpe_register_info->enable_for_wake,
 148                                register_bit);
 149                 ACPI_SET_BIT(gpe_register_info->enable_for_run, register_bit);
 150                 break;
 151
 152         case ACPI_GPE_TYPE_WAKE_RUN:
 153                 ACPI_SET_BIT(gpe_register_info->enable_for_wake, register_bit);
 154                 ACPI_SET_BIT(gpe_register_info->enable_for_run, register_bit);
 155                 break;
 156
 157         default:
 158                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 159         }
 160
 161         return_ACPI_STATUS(AE_OK);
 162 }
 163
 164 /*******************************************************************************
 165  *
 166  * FUNCTION:    acpi_ev_enable_gpe
 167  *
 168  * PARAMETERS:  gpe_event_info          - GPE to enable
 169  *              write_to_hardware       - Enable now, or just mark data structs
 170  *                                        (WAKE GPEs should be deferred)
 171  *
 172  * RETURN:      Status
 173  *
 174  * DESCRIPTION: Enable a GPE based on the GPE type
 175  *
 176  ******************************************************************************/
 177
 178 acpi_status
 179 acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info,
 180                    u8 write_to_hardware)
 181 {
 182         acpi_status status;
 183
 184         ACPI_FUNCTION_TRACE(ev_enable_gpe);
 185
 186         /* Make sure HW enable masks are updated */
 187
 188         status =
 189             acpi_ev_update_gpe_enable_masks(gpe_event_info, ACPI_GPE_ENABLE);
 190         if (ACPI_FAILURE(status)) {
 191                 return_ACPI_STATUS(status);
 192         }
 193
 194         /* Mark wake-enabled or HW enable, or both */
 195
 196         switch (gpe_event_info->flags & ACPI_GPE_TYPE_MASK) {
 197         case ACPI_GPE_TYPE_WAKE:
 198
 199                 ACPI_SET_BIT(gpe_event_info->flags, ACPI_GPE_WAKE_ENABLED);
 200                 break;
 201
 202         case ACPI_GPE_TYPE_WAKE_RUN:
 203
 204                 ACPI_SET_BIT(gpe_event_info->flags, ACPI_GPE_WAKE_ENABLED);
 205
 206                 /*lint -fallthrough */
 207
 208         case ACPI_GPE_TYPE_RUNTIME:
 209
 210                 ACPI_SET_BIT(gpe_event_info->flags, ACPI_GPE_RUN_ENABLED);
 211
 212                 if (write_to_hardware) {
 213
 214                         /* Clear the GPE (of stale events), then enable it */
 215
 216                         status = acpi_hw_clear_gpe(gpe_event_info);
 217                         if (ACPI_FAILURE(status)) {
 218                                 return_ACPI_STATUS(status);
 219                         }
 220
 221                         /* Enable the requested runtime GPE */
 222
 223                         status = acpi_hw_write_gpe_enable_reg(gpe_event_info);
 224                 }
 225                 break;
 226
 227         default:
 228                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 229         }
 230
 231         return_ACPI_STATUS(AE_OK);
 232 }
 233
 234 /*******************************************************************************
 235  *
 236  * FUNCTION:    acpi_ev_disable_gpe
 237  *
 238  * PARAMETERS:  gpe_event_info          - GPE to disable
 239  *
 240  * RETURN:      Status
 241  *
 242  * DESCRIPTION: Disable a GPE based on the GPE type
 243  *
 244  ******************************************************************************/
 245
 246 acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 247 {
 248         acpi_status status;
 249
 250         ACPI_FUNCTION_TRACE(ev_disable_gpe);
 251
 252         /* Make sure HW enable masks are updated */
 253
 254         status =
 255             acpi_ev_update_gpe_enable_masks(gpe_event_info, ACPI_GPE_DISABLE);
 256         if (ACPI_FAILURE(status)) {
 257                 return_ACPI_STATUS(status);
 258         }
 259
 260         /* Clear the appropriate enabled flags for this GPE */
 261
 262         switch (gpe_event_info->flags & ACPI_GPE_TYPE_MASK) {
 263         case ACPI_GPE_TYPE_WAKE:
 264                 ACPI_CLEAR_BIT(gpe_event_info->flags, ACPI_GPE_WAKE_ENABLED);
 265                 break;
 266
 267         case ACPI_GPE_TYPE_WAKE_RUN:
 268                 ACPI_CLEAR_BIT(gpe_event_info->flags, ACPI_GPE_WAKE_ENABLED);
 269
 270                 /* fallthrough */
 271
 272         case ACPI_GPE_TYPE_RUNTIME:
 273
 274                 /* Disable the requested runtime GPE */
 275
 276                 ACPI_CLEAR_BIT(gpe_event_info->flags, ACPI_GPE_RUN_ENABLED);
 277                 break;
 278
 279         default:
 280                 break;
 281         }
 282
 283         /*
 284          * Even if we don't know the GPE type, make sure that we always
 285          * disable it. low_disable_gpe will just clear the enable bit for this
 286          * GPE and write it. It will not write out the current GPE enable mask,
 287          * since this may inadvertently enable GPEs too early, if a rogue GPE has
 288          * come in during ACPICA initialization - possibly as a result of AML or
 289          * other code that has enabled the GPE.
 290          */
 291         status = acpi_hw_low_disable_gpe(gpe_event_info);
 292         return_ACPI_STATUS(status);
 293 }
 294
 295 /*******************************************************************************
 296  *
 297  * FUNCTION:    acpi_ev_get_gpe_event_info
 298  *
 299  * PARAMETERS:  gpe_device          - Device node. NULL for GPE0/GPE1
 300  *              gpe_number          - Raw GPE number
 301  *
 302  * RETURN:      A GPE event_info struct. NULL if not a valid GPE
 303  *
 304  * DESCRIPTION: Returns the event_info struct associated with this GPE.
 305  *              Validates the gpe_block and the gpe_number
 306  *
 307  *              Should be called only when the GPE lists are semaphore locked
 308  *              and not subject to change.
 309  *
 310  ******************************************************************************/
 311
 312 struct acpi_gpe_event_info *acpi_ev_get_gpe_event_info(acpi_handle gpe_device,
 313                                                        u32 gpe_number)
 314 {
 315         union acpi_operand_object *obj_desc;
 316         struct acpi_gpe_block_info *gpe_block;
 317         u32 i;
 318
 319         ACPI_FUNCTION_ENTRY();
 320
 321         /* A NULL gpe_block means use the FADT-defined GPE block(s) */
 322
 323         if (!gpe_device) {
 324
 325                 /* Examine GPE Block 0 and 1 (These blocks are permanent) */
 326
 327                 for (i = 0; i < ACPI_MAX_GPE_BLOCKS; i++) {
 328                         gpe_block = acpi_gbl_gpe_fadt_blocks[i];
 329                         if (gpe_block) {
 330                                 if ((gpe_number >= gpe_block->block_base_number)
 331                                     && (gpe_number <
 332                                         gpe_block->block_base_number +
 333                                         (gpe_block->register_count * 8))) {
 334                                         return (&gpe_block->
 335                                                 event_info[gpe_number -
 336                                                            gpe_block->
 337                                                            block_base_number]);
 338                                 }
 339                         }
 340                 }
 341
 342                 /* The gpe_number was not in the range of either FADT GPE block */
 343
 344                 return (NULL);
 345         }
 346
 347         /* A Non-NULL gpe_device means this is a GPE Block Device */
 348
 349         obj_desc = acpi_ns_get_attached_object((struct acpi_namespace_node *)
 350                                                gpe_device);
 351         if (!obj_desc || !obj_desc->device.gpe_block) {
 352                 return (NULL);
 353         }
 354
 355         gpe_block = obj_desc->device.gpe_block;
 356
 357         if ((gpe_number >= gpe_block->block_base_number) &&
 358             (gpe_number <
 359              gpe_block->block_base_number + (gpe_block->register_count * 8))) {
 360                 return (&gpe_block->
 361                         event_info[gpe_number - gpe_block->block_base_number]);
 362         }
 363
 364         return (NULL);
 365 }
 366
 367 /*******************************************************************************
 368  *
 369  * FUNCTION:    acpi_ev_gpe_detect
 370  *
 371  * PARAMETERS:  gpe_xrupt_list      - Interrupt block for this interrupt.
 372  *                                    Can have multiple GPE blocks attached.
 373  *
 374  * RETURN:      INTERRUPT_HANDLED or INTERRUPT_NOT_HANDLED
 375  *
 376  * DESCRIPTION: Detect if any GP events have occurred. This function is
 377  *              executed at interrupt level.
 378  *
 379  ******************************************************************************/
 380
 381 u32 acpi_ev_gpe_detect(struct acpi_gpe_xrupt_info * gpe_xrupt_list)
 382 {
 383         acpi_status status;
 384         struct acpi_gpe_block_info *gpe_block;
 385         struct acpi_gpe_register_info *gpe_register_info;
 386         u32 int_status = ACPI_INTERRUPT_NOT_HANDLED;
 387         u8 enabled_status_byte;
 388         u32 status_reg;
 389         u32 enable_reg;
 390         acpi_cpu_flags flags;
 391         u32 i;
 392         u32 j;
 393
 394         ACPI_FUNCTION_NAME(ev_gpe_detect);
 395
 396         /* Check for the case where there are no GPEs */
 397
 398         if (!gpe_xrupt_list) {
 399                 return (int_status);
 400         }
 401
 402         /*
 403          * We need to obtain the GPE lock for both the data structs and registers
 404          * Note: Not necessary to obtain the hardware lock, since the GPE
 405          * registers are owned by the gpe_lock.
 406          */
 407         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 408
 409         /* Examine all GPE blocks attached to this interrupt level */
 410
 411         gpe_block = gpe_xrupt_list->gpe_block_list_head;
 412         while (gpe_block) {
 413                 /*
 414                  * Read all of the 8-bit GPE status and enable registers in this GPE
 415                  * block, saving all of them. Find all currently active GP events.
 416                  */
 417                 for (i = 0; i < gpe_block->register_count; i++) {
 418
 419                         /* Get the next status/enable pair */
 420
 421                         gpe_register_info = &gpe_block->register_info[i];
 422
 423                         /* Read the Status Register */
 424
 425                         status =
 426                             acpi_read(&status_reg,
 427                                       &gpe_register_info->status_address);
 428                         if (ACPI_FAILURE(status)) {
 429                                 goto unlock_and_exit;
 430                         }
 431
 432                         /* Read the Enable Register */
 433
 434                         status =
 435                             acpi_read(&enable_reg,
 436                                       &gpe_register_info->enable_address);
 437                         if (ACPI_FAILURE(status)) {
 438                                 goto unlock_and_exit;
 439                         }
 440
 441                         ACPI_DEBUG_PRINT((ACPI_DB_INTERRUPTS,
 442                                           "Read GPE Register at GPE%X: Status=%02X, Enable=%02X\n",
 443                                           gpe_register_info->base_gpe_number,
 444                                           status_reg, enable_reg));
 445
 446                         /* Check if there is anything active at all in this register */
 447
 448                         enabled_status_byte = (u8) (status_reg & enable_reg);
 449                         if (!enabled_status_byte) {
 450
 451                                 /* No active GPEs in this register, move on */
 452
 453                                 continue;
 454                         }
 455
 456                         /* Now look at the individual GPEs in this byte register */
 457
 458                         for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {
 459
 460                                 /* Examine one GPE bit */
 461
 462                                 if (enabled_status_byte & (1 << j)) {
 463                                         /*
 464                                          * Found an active GPE. Dispatch the event to a handler
 465                                          * or method.
 466                                          */
 467                                         int_status |=
 468                                             acpi_ev_gpe_dispatch(&gpe_block->
 469                                                 event_info[((acpi_size) i * ACPI_GPE_REGISTER_WIDTH) + j], j + gpe_register_info->base_gpe_number);
 470                                 }
 471                         }
 472                 }
 473
 474                 gpe_block = gpe_block->next;
 475         }
 476
 477       unlock_and_exit:
 478
 479         acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
 480         return (int_status);
 481 }
 482
 483 /*******************************************************************************
 484  *
 485  * FUNCTION:    acpi_ev_asynch_execute_gpe_method
 486  *
 487  * PARAMETERS:  Context (gpe_event_info) - Info for this GPE
 488  *
 489  * RETURN:      None
 490  *
 491  * DESCRIPTION: Perform the actual execution of a GPE control method. This
 492  *              function is called from an invocation of acpi_os_execute and
 493  *              therefore does NOT execute at interrupt level - so that
 494  *              the control method itself is not executed in the context of
 495  *              an interrupt handler.
 496  *
 497  ******************************************************************************/
 498 static void acpi_ev_asynch_enable_gpe(void *context);
 499
 500 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
 501 {
 502         struct acpi_gpe_event_info *gpe_event_info = (void *)context;
 503         acpi_status status;
 504         struct acpi_gpe_event_info local_gpe_event_info;
 505         struct acpi_evaluate_info *info;
 506
 507         ACPI_FUNCTION_TRACE(ev_asynch_execute_gpe_method);
 508
 509         status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
 510         if (ACPI_FAILURE(status)) {
 511                 return_VOID;
 512         }
 513
 514         /* Must revalidate the gpe_number/gpe_block */
 515
 516         if (!acpi_ev_valid_gpe_event(gpe_event_info)) {
 517                 status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
 518                 return_VOID;
 519         }
 520
 521         /* Set the GPE flags for return to enabled state */
 522
 523         (void)acpi_ev_enable_gpe(gpe_event_info, FALSE);
 524
 525         /*
 526          * Take a snapshot of the GPE info for this level - we copy the info to
 527          * prevent a race condition with remove_handler/remove_block.
 528          */
 529         ACPI_MEMCPY(&local_gpe_event_info, gpe_event_info,
 530                     sizeof(struct acpi_gpe_event_info));
 531
 532         status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
 533         if (ACPI_FAILURE(status)) {
 534                 return_VOID;
 535         }
 536
 537         /*
 538          * Must check for control method type dispatch one more time to avoid a
 539          * race with ev_gpe_install_handler
 540          */
 541         if ((local_gpe_event_info.flags & ACPI_GPE_DISPATCH_MASK) ==
 542             ACPI_GPE_DISPATCH_METHOD) {
 543
 544                 /* Allocate the evaluation information block */
 545
 546                 info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
 547                 if (!info) {
 548                         status = AE_NO_MEMORY;
 549                 } else {
 550                         /*
 551                          * Invoke the GPE Method (_Lxx, _Exx) i.e., evaluate the _Lxx/_Exx
 552                          * control method that corresponds to this GPE
 553                          */
 554                         info->prefix_node =
 555                             local_gpe_event_info.dispatch.method_node;
 556                         info->flags = ACPI_IGNORE_RETURN_VALUE;
 557
 558                         status = acpi_ns_evaluate(info);
 559                         ACPI_FREE(info);
 560                 }
 561
 562                 if (ACPI_FAILURE(status)) {
 563                         ACPI_EXCEPTION((AE_INFO, status,
 564                                         "while evaluating GPE method [%4.4s]",
 565                                         acpi_ut_get_node_name
 566                                         (local_gpe_event_info.dispatch.
 567                                          method_node)));
 568                 }
 569         }
 570         /* Defer enabling of GPE until all notify handlers are done */
 571         acpi_os_execute(OSL_NOTIFY_HANDLER, acpi_ev_asynch_enable_gpe,
 572                                 gpe_event_info);
 573         return_VOID;
 574 }
 575
 576 static void acpi_ev_asynch_enable_gpe(void *context)
 577 {
 578         struct acpi_gpe_event_info *gpe_event_info = context;
 579         acpi_status status;
 580         if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
 581             ACPI_GPE_LEVEL_TRIGGERED) {
 582                 /*
 583                  * GPE is level-triggered, we clear the GPE status bit after handling
 584                  * the event.
 585                  */
 586                 status = acpi_hw_clear_gpe(gpe_event_info);
 587                 if (ACPI_FAILURE(status)) {
 588                         return_VOID;
 589                 }
 590         }
 591
 592         /* Enable this GPE */
 593         (void)acpi_hw_write_gpe_enable_reg(gpe_event_info);
 594         return_VOID;
 595 }
 596
 597 /*******************************************************************************
 598  *
 599  * FUNCTION:    acpi_ev_gpe_dispatch
 600  *
 601  * PARAMETERS:  gpe_event_info  - Info for this GPE
 602  *              gpe_number      - Number relative to the parent GPE block
 603  *
 604  * RETURN:      INTERRUPT_HANDLED or INTERRUPT_NOT_HANDLED
 605  *
 606  * DESCRIPTION: Dispatch a General Purpose Event to either a function (e.g. EC)
 607  *              or method (e.g. _Lxx/_Exx) handler.
 608  *
 609  *              This function executes at interrupt level.
 610  *
 611  ******************************************************************************/
 612
 613 u32
 614 acpi_ev_gpe_dispatch(struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
 615 {
 616         acpi_status status;
 617
 618         ACPI_FUNCTION_TRACE(ev_gpe_dispatch);
 619
 620         acpi_os_gpe_count(gpe_number);
 621
 622         /*
 623          * If edge-triggered, clear the GPE status bit now. Note that
 624          * level-triggered events are cleared after the GPE is serviced.
 625          */
 626         if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
 627             ACPI_GPE_EDGE_TRIGGERED) {
 628                 status = acpi_hw_clear_gpe(gpe_event_info);
 629                 if (ACPI_FAILURE(status)) {
 630                         ACPI_EXCEPTION((AE_INFO, status,
 631                                         "Unable to clear GPE[%2X]",
 632                                         gpe_number));
 633                         return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
 634                 }
 635         }
 636
 637         /*
 638          * Dispatch the GPE to either an installed handler, or the control method
 639          * associated with this GPE (_Lxx or _Exx). If a handler exists, we invoke
 640          * it and do not attempt to run the method. If there is neither a handler
 641          * nor a method, we disable this GPE to prevent further such pointless
 642          * events from firing.
 643          */
 644         switch (gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
 645         case ACPI_GPE_DISPATCH_HANDLER:
 646
 647                 /*
 648                  * Invoke the installed handler (at interrupt level)
 649                  * Ignore return status for now.
 650                  * TBD: leave GPE disabled on error?
 651                  */
 652                 (void)gpe_event_info->dispatch.handler->address(gpe_event_info->
 653                                                                 dispatch.
 654                                                                 handler->
 655                                                                 context);
 656
 657                 /* It is now safe to clear level-triggered events. */
 658
 659                 if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
 660                     ACPI_GPE_LEVEL_TRIGGERED) {
 661                         status = acpi_hw_clear_gpe(gpe_event_info);
 662                         if (ACPI_FAILURE(status)) {
 663                                 ACPI_EXCEPTION((AE_INFO, status,
 664                                                 "Unable to clear GPE[%2X]",
 665                                                 gpe_number));
 666                                 return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
 667                         }
 668                 }
 669                 break;
 670
 671         case ACPI_GPE_DISPATCH_METHOD:
 672
 673                 /*
 674                  * Disable the GPE, so it doesn't keep firing before the method has a
 675                  * chance to run (it runs asynchronously with interrupts enabled).
 676                  */
 677                 status = acpi_ev_disable_gpe(gpe_event_info);
 678                 if (ACPI_FAILURE(status)) {
 679                         ACPI_EXCEPTION((AE_INFO, status,
 680                                         "Unable to disable GPE[%2X]",
 681                                         gpe_number));
 682                         return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
 683                 }
 684
 685                 /*
 686                  * Execute the method associated with the GPE
 687                  * NOTE: Level-triggered GPEs are cleared after the method completes.
 688                  */
 689                 status = acpi_os_execute(OSL_GPE_HANDLER,
 690                                          acpi_ev_asynch_execute_gpe_method,
 691                                          gpe_event_info);
 692                 if (ACPI_FAILURE(status)) {
 693                         ACPI_EXCEPTION((AE_INFO, status,
 694                                         "Unable to queue handler for GPE[%2X] - event disabled",
 695                                         gpe_number));
 696                 }
 697                 break;
 698
 699         default:
 700
 701                 /* No handler or method to run! */
 702
 703                 ACPI_ERROR((AE_INFO,
 704                             "No handler or method for GPE[%2X], disabling event",
 705                             gpe_number));
 706
 707                 /*
 708                  * Disable the GPE. The GPE will remain disabled until the ACPICA
 709                  * Core Subsystem is restarted, or a handler is installed.
 710                  */
 711                 status = acpi_ev_disable_gpe(gpe_event_info);
 712                 if (ACPI_FAILURE(status)) {
 713                         ACPI_EXCEPTION((AE_INFO, status,
 714                                         "Unable to disable GPE[%2X]",
 715                                         gpe_number));
 716                         return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
 717                 }
 718                 break;
 719         }
 720
 721         return_UINT32(ACPI_INTERRUPT_HANDLED);
 722 }