drivers/platform/x86/dell-wmi.c

   1 /*
   2  * Dell WMI hotkeys
   3  *
   4  * Copyright (C) 2008 Red Hat <mjg@redhat.com>
   5  * Copyright (C) 2014-2015 Pali Rohár <pali.rohar@gmail.com>
   6  *
   7  * Portions based on wistron_btns.c:
   8  * Copyright (C) 2005 Miloslav Trmac <mitr@volny.cz>
   9  * Copyright (C) 2005 Bernhard Rosenkraenzer <bero@arklinux.org>
  10  * Copyright (C) 2005 Dmitry Torokhov <dtor@mail.ru>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or
  15  *  (at your option) any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; if not, write to the Free Software
  24  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25  */
  26
  27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  28
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/slab.h>
  33 #include <linux/types.h>
  34 #include <linux/input.h>
  35 #include <linux/input/sparse-keymap.h>
  36 #include <linux/acpi.h>
  37 #include <linux/string.h>
  38 #include <linux/dmi.h>
  39 #include <acpi/video.h>
  40 #include "dell-smbios.h"
  41
  42 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
  43 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
  44 MODULE_DESCRIPTION("Dell laptop WMI hotkeys driver");
  45 MODULE_LICENSE("GPL");
  46
  47 #define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"
  48 #define DELL_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
  49
  50 static u32 dell_wmi_interface_version;
  51 static bool wmi_requires_smbios_request;
  52
  53 MODULE_ALIAS("wmi:"DELL_EVENT_GUID);
  54 MODULE_ALIAS("wmi:"DELL_DESCRIPTOR_GUID);
  55
  56 static int __init dmi_matched(const struct dmi_system_id *dmi)
  57 {
  58         wmi_requires_smbios_request = 1;
  59         return 1;
  60 }
  61
  62 static const struct dmi_system_id dell_wmi_smbios_list[] __initconst = {
  63         {
  64                 .callback = dmi_matched,
  65                 .ident = "Dell Vostro V131",
  66                 .matches = {
  67                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
  68                         DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
  69                 },
  70         },
  71         { }
  72 };
  73
  74 /*
  75  * Certain keys are flagged as KE_IGNORE. All of these are either
  76  * notifications (rather than requests for change) or are also sent
  77  * via the keyboard controller so should not be sent again.
  78  */
  79
  80 static const struct key_entry dell_wmi_legacy_keymap[] __initconst = {
  81         { KE_IGNORE, 0x003a, { KEY_CAPSLOCK } },
  82
  83         { KE_KEY, 0xe045, { KEY_PROG1 } },
  84         { KE_KEY, 0xe009, { KEY_EJECTCD } },
  85
  86         /* These also contain the brightness level at offset 6 */
  87         { KE_KEY, 0xe006, { KEY_BRIGHTNESSUP } },
  88         { KE_KEY, 0xe005, { KEY_BRIGHTNESSDOWN } },
  89
  90         /* Battery health status button */
  91         { KE_KEY, 0xe007, { KEY_BATTERY } },
  92
  93         /* Radio devices state change */
  94         { KE_IGNORE, 0xe008, { KEY_RFKILL } },
  95
  96         /* The next device is at offset 6, the active devices are at
  97            offset 8 and the attached devices at offset 10 */
  98         { KE_KEY, 0xe00b, { KEY_SWITCHVIDEOMODE } },
  99
 100         { KE_IGNORE, 0xe00c, { KEY_KBDILLUMTOGGLE } },
 101
 102         /* BIOS error detected */
 103         { KE_IGNORE, 0xe00d, { KEY_RESERVED } },
 104
 105         /* Wifi Catcher */
 106         { KE_KEY, 0xe011, {KEY_PROG2 } },
 107
 108         /* Ambient light sensor toggle */
 109         { KE_IGNORE, 0xe013, { KEY_RESERVED } },
 110
 111         { KE_IGNORE, 0xe020, { KEY_MUTE } },
 112
 113         /* Shortcut and audio panel keys */
 114         { KE_IGNORE, 0xe025, { KEY_RESERVED } },
 115         { KE_IGNORE, 0xe026, { KEY_RESERVED } },
 116
 117         { KE_IGNORE, 0xe02e, { KEY_VOLUMEDOWN } },
 118         { KE_IGNORE, 0xe030, { KEY_VOLUMEUP } },
 119         { KE_IGNORE, 0xe033, { KEY_KBDILLUMUP } },
 120         { KE_IGNORE, 0xe034, { KEY_KBDILLUMDOWN } },
 121         { KE_IGNORE, 0xe03a, { KEY_CAPSLOCK } },
 122         { KE_IGNORE, 0xe045, { KEY_NUMLOCK } },
 123         { KE_IGNORE, 0xe046, { KEY_SCROLLLOCK } },
 124         { KE_IGNORE, 0xe0f7, { KEY_MUTE } },
 125         { KE_IGNORE, 0xe0f8, { KEY_VOLUMEDOWN } },
 126         { KE_IGNORE, 0xe0f9, { KEY_VOLUMEUP } },
 127         { KE_END, 0 }
 128 };
 129
 130 static bool dell_new_hk_type;
 131
 132 struct dell_bios_keymap_entry {
 133         u16 scancode;
 134         u16 keycode;
 135 };
 136
 137 struct dell_bios_hotkey_table {
 138         struct dmi_header header;
 139         struct dell_bios_keymap_entry keymap[];
 140
 141 };
 142
 143 struct dell_dmi_results {
 144         int err;
 145         struct key_entry *keymap;
 146 };
 147
 148 /* Uninitialized entries here are KEY_RESERVED == 0. */
 149 static const u16 bios_to_linux_keycode[256] __initconst = {
 150         [0]     = KEY_MEDIA,
 151         [1]     = KEY_NEXTSONG,
 152         [2]     = KEY_PLAYPAUSE,
 153         [3]     = KEY_PREVIOUSSONG,
 154         [4]     = KEY_STOPCD,
 155         [5]     = KEY_UNKNOWN,
 156         [6]     = KEY_UNKNOWN,
 157         [7]     = KEY_UNKNOWN,
 158         [8]     = KEY_WWW,
 159         [9]     = KEY_UNKNOWN,
 160         [10]    = KEY_VOLUMEDOWN,
 161         [11]    = KEY_MUTE,
 162         [12]    = KEY_VOLUMEUP,
 163         [13]    = KEY_UNKNOWN,
 164         [14]    = KEY_BATTERY,
 165         [15]    = KEY_EJECTCD,
 166         [16]    = KEY_UNKNOWN,
 167         [17]    = KEY_SLEEP,
 168         [18]    = KEY_PROG1,
 169         [19]    = KEY_BRIGHTNESSDOWN,
 170         [20]    = KEY_BRIGHTNESSUP,
 171         [21]    = KEY_UNKNOWN,
 172         [22]    = KEY_KBDILLUMTOGGLE,
 173         [23]    = KEY_UNKNOWN,
 174         [24]    = KEY_SWITCHVIDEOMODE,
 175         [25]    = KEY_UNKNOWN,
 176         [26]    = KEY_UNKNOWN,
 177         [27]    = KEY_SWITCHVIDEOMODE,
 178         [28]    = KEY_UNKNOWN,
 179         [29]    = KEY_UNKNOWN,
 180         [30]    = KEY_PROG2,
 181         [31]    = KEY_UNKNOWN,
 182         [32]    = KEY_UNKNOWN,
 183         [33]    = KEY_UNKNOWN,
 184         [34]    = KEY_UNKNOWN,
 185         [35]    = KEY_UNKNOWN,
 186         [36]    = KEY_UNKNOWN,
 187         [37]    = KEY_UNKNOWN,
 188         [38]    = KEY_MICMUTE,
 189         [255]   = KEY_PROG3,
 190 };
 191
 192 /*
 193  * These are applied if the 0xB2 DMI hotkey table is present and doesn't
 194  * override them.
 195  */
 196 static const struct key_entry dell_wmi_extra_keymap[] __initconst = {
 197         /* Fn-lock */
 198         { KE_IGNORE, 0x151, { KEY_RESERVED } },
 199
 200         /* Change keyboard illumination */
 201         { KE_IGNORE, 0x152, { KEY_KBDILLUMTOGGLE } },
 202
 203         /*
 204          * Radio disable (notify only -- there is no model for which the
 205          * WMI event is supposed to trigger an action).
 206          */
 207         { KE_IGNORE, 0x153, { KEY_RFKILL } },
 208
 209         /* RGB keyboard backlight control */
 210         { KE_IGNORE, 0x154, { KEY_RESERVED } },
 211
 212         /* Stealth mode toggle */
 213         { KE_IGNORE, 0x155, { KEY_RESERVED } },
 214 };
 215
 216 static struct input_dev *dell_wmi_input_dev;
 217
 218 static void dell_wmi_process_key(int reported_key)
 219 {
 220         const struct key_entry *key;
 221
 222         key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
 223                                                 reported_key);
 224         if (!key) {
 225                 pr_info("Unknown key with scancode 0x%x pressed\n",
 226                         reported_key);
 227                 return;
 228         }
 229
 230         pr_debug("Key %x pressed\n", reported_key);
 231
 232         /* Don't report brightness notifications that will also come via ACPI */
 233         if ((key->keycode == KEY_BRIGHTNESSUP ||
 234              key->keycode == KEY_BRIGHTNESSDOWN) &&
 235             acpi_video_handles_brightness_key_presses())
 236                 return;
 237
 238         sparse_keymap_report_entry(dell_wmi_input_dev, key, 1, true);
 239 }
 240
 241 static void dell_wmi_notify(u32 value, void *context)
 242 {
 243         struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
 244         union acpi_object *obj;
 245         acpi_status status;
 246         acpi_size buffer_size;
 247         u16 *buffer_entry, *buffer_end;
 248         int len, i;
 249
 250         status = wmi_get_event_data(value, &response);
 251         if (status != AE_OK) {
 252                 pr_warn("bad event status 0x%x\n", status);
 253                 return;
 254         }
 255
 256         obj = (union acpi_object *)response.pointer;
 257         if (!obj) {
 258                 pr_warn("no response\n");
 259                 return;
 260         }
 261
 262         if (obj->type != ACPI_TYPE_BUFFER) {
 263                 pr_warn("bad response type %x\n", obj->type);
 264                 kfree(obj);
 265                 return;
 266         }
 267
 268         pr_debug("Received WMI event (%*ph)\n",
 269                 obj->buffer.length, obj->buffer.pointer);
 270
 271         buffer_entry = (u16 *)obj->buffer.pointer;
 272         buffer_size = obj->buffer.length/2;
 273
 274         if (!dell_new_hk_type) {
 275                 if (buffer_size >= 3 && buffer_entry[1] == 0x0)
 276                         dell_wmi_process_key(buffer_entry[2]);
 277                 else if (buffer_size >= 2)
 278                         dell_wmi_process_key(buffer_entry[1]);
 279                 else
 280                         pr_info("Received unknown WMI event\n");
 281                 kfree(obj);
 282                 return;
 283         }
 284
 285         buffer_end = buffer_entry + buffer_size;
 286
 287         /*
 288          * BIOS/ACPI on devices with WMI interface version 0 does not clear
 289          * buffer before filling it. So next time when BIOS/ACPI send WMI event
 290          * which is smaller as previous then it contains garbage in buffer from
 291          * previous event.
 292          *
 293          * BIOS/ACPI on devices with WMI interface version 1 clears buffer and
 294          * sometimes send more events in buffer at one call.
 295          *
 296          * So to prevent reading garbage from buffer we will process only first
 297          * one event on devices with WMI interface version 0.
 298          */
 299         if (dell_wmi_interface_version == 0 && buffer_entry < buffer_end)
 300                 if (buffer_end > buffer_entry + buffer_entry[0] + 1)
 301                         buffer_end = buffer_entry + buffer_entry[0] + 1;
 302
 303         while (buffer_entry < buffer_end) {
 304
 305                 len = buffer_entry[0];
 306                 if (len == 0)
 307                         break;
 308
 309                 len++;
 310
 311                 if (buffer_entry + len > buffer_end) {
 312                         pr_warn("Invalid length of WMI event\n");
 313                         break;
 314                 }
 315
 316                 pr_debug("Process buffer (%*ph)\n", len*2, buffer_entry);
 317
 318                 switch (buffer_entry[1]) {
 319                 case 0x00:
 320                         for (i = 2; i < len; ++i) {
 321                                 switch (buffer_entry[i]) {
 322                                 case 0xe043:
 323                                         /* NIC Link is Up */
 324                                         pr_debug("NIC Link is Up\n");
 325                                         break;
 326                                 case 0xe044:
 327                                         /* NIC Link is Down */
 328                                         pr_debug("NIC Link is Down\n");
 329                                         break;
 330                                 case 0xe045:
 331                                         /* Unknown event but defined in DSDT */
 332                                 default:
 333                                         /* Unknown event */
 334                                         pr_info("Unknown WMI event type 0x00: "
 335                                                 "0x%x\n", (int)buffer_entry[i]);
 336                                         break;
 337                                 }
 338                         }
 339                         break;
 340                 case 0x10:
 341                         /* Keys pressed */
 342                         for (i = 2; i < len; ++i)
 343                                 dell_wmi_process_key(buffer_entry[i]);
 344                         break;
 345                 case 0x11:
 346                         for (i = 2; i < len; ++i) {
 347                                 switch (buffer_entry[i]) {
 348                                 case 0xfff0:
 349                                         /* Battery unplugged */
 350                                         pr_debug("Battery unplugged\n");
 351                                         break;
 352                                 case 0xfff1:
 353                                         /* Battery inserted */
 354                                         pr_debug("Battery inserted\n");
 355                                         break;
 356                                 case 0x01e1:
 357                                 case 0x02ea:
 358                                 case 0x02eb:
 359                                 case 0x02ec:
 360                                 case 0x02f6:
 361                                         /* Keyboard backlight level changed */
 362                                         pr_debug("Keyboard backlight level "
 363                                                  "changed\n");
 364                                         break;
 365                                 default:
 366                                         /* Unknown event */
 367                                         pr_info("Unknown WMI event type 0x11: "
 368                                                 "0x%x\n", (int)buffer_entry[i]);
 369                                         break;
 370                                 }
 371                         }
 372                         break;
 373                 default:
 374                         /* Unknown event */
 375                         pr_info("Unknown WMI event type 0x%x\n",
 376                                 (int)buffer_entry[1]);
 377                         break;
 378                 }
 379
 380                 buffer_entry += len;
 381
 382         }
 383
 384         kfree(obj);
 385 }
 386
 387 static bool have_scancode(u32 scancode, const struct key_entry *keymap, int len)
 388 {
 389         int i;
 390
 391         for (i = 0; i < len; i++)
 392                 if (keymap[i].code == scancode)
 393                         return true;
 394
 395         return false;
 396 }
 397
 398 static void __init handle_dmi_entry(const struct dmi_header *dm,
 399
 400                                     void *opaque)
 401
 402 {
 403         struct dell_dmi_results *results = opaque;
 404         struct dell_bios_hotkey_table *table;
 405         int hotkey_num, i, pos = 0;
 406         struct key_entry *keymap;
 407         int num_bios_keys;
 408
 409         if (results->err || results->keymap)
 410                 return;         /* We already found the hotkey table. */
 411
 412         if (dm->type != 0xb2)
 413                 return;
 414
 415         table = container_of(dm, struct dell_bios_hotkey_table, header);
 416
 417         hotkey_num = (table->header.length -
 418                       sizeof(struct dell_bios_hotkey_table)) /
 419                                 sizeof(struct dell_bios_keymap_entry);
 420         if (hotkey_num < 1) {
 421                 /*
 422                  * Historically, dell-wmi would ignore a DMI entry of
 423                  * fewer than 7 bytes.  Sizes between 4 and 8 bytes are
 424                  * nonsensical (both the header and all entries are 4
 425                  * bytes), so we approximate the old behavior by
 426                  * ignoring tables with fewer than one entry.
 427                  */
 428                 return;
 429         }
 430
 431         keymap = kcalloc(hotkey_num + ARRAY_SIZE(dell_wmi_extra_keymap) + 1,
 432                          sizeof(struct key_entry), GFP_KERNEL);
 433         if (!keymap) {
 434                 results->err = -ENOMEM;
 435                 return;
 436         }
 437
 438         for (i = 0; i < hotkey_num; i++) {
 439                 const struct dell_bios_keymap_entry *bios_entry =
 440                                         &table->keymap[i];
 441
 442                 /* Uninitialized entries are 0 aka KEY_RESERVED. */
 443                 u16 keycode = (bios_entry->keycode <
 444                                ARRAY_SIZE(bios_to_linux_keycode)) ?
 445                         bios_to_linux_keycode[bios_entry->keycode] :
 446                         KEY_RESERVED;
 447
 448                 /*
 449                  * Log if we find an entry in the DMI table that we don't
 450                  * understand.  If this happens, we should figure out what
 451                  * the entry means and add it to bios_to_linux_keycode.
 452                  */
 453                 if (keycode == KEY_RESERVED) {
 454                         pr_info("firmware scancode 0x%x maps to unrecognized keycode 0x%x\n",
 455                                 bios_entry->scancode, bios_entry->keycode);
 456                         continue;
 457                 }
 458
 459                 if (keycode == KEY_KBDILLUMTOGGLE)
 460                         keymap[pos].type = KE_IGNORE;
 461                 else
 462                         keymap[pos].type = KE_KEY;
 463                 keymap[pos].code = bios_entry->scancode;
 464                 keymap[pos].keycode = keycode;
 465
 466                 pos++;
 467         }
 468
 469         num_bios_keys = pos;
 470
 471         for (i = 0; i < ARRAY_SIZE(dell_wmi_extra_keymap); i++) {
 472                 const struct key_entry *entry = &dell_wmi_extra_keymap[i];
 473
 474                 /*
 475                  * Check if we've already found this scancode.  This takes
 476                  * quadratic time, but it doesn't matter unless the list
 477                  * of extra keys gets very long.
 478                  */
 479                 if (!have_scancode(entry->code, keymap, num_bios_keys)) {
 480                         keymap[pos] = *entry;
 481                         pos++;
 482                 }
 483         }
 484
 485         keymap[pos].type = KE_END;
 486
 487         results->keymap = keymap;
 488 }
 489
 490 static int __init dell_wmi_input_setup(void)
 491 {
 492         struct dell_dmi_results dmi_results = {};
 493         int err;
 494
 495         dell_wmi_input_dev = input_allocate_device();
 496         if (!dell_wmi_input_dev)
 497                 return -ENOMEM;
 498
 499         dell_wmi_input_dev->name = "Dell WMI hotkeys";
 500         dell_wmi_input_dev->phys = "wmi/input0";
 501         dell_wmi_input_dev->id.bustype = BUS_HOST;
 502
 503         if (dmi_walk(handle_dmi_entry, &dmi_results)) {
 504                 /*
 505                  * Historically, dell-wmi ignored dmi_walk errors.  A failure
 506                  * is certainly surprising, but it probably just indicates
 507                  * a very old laptop.
 508                  */
 509                 pr_warn("no DMI; using the old-style hotkey interface\n");
 510         }
 511
 512         if (dmi_results.err) {
 513                 err = dmi_results.err;
 514                 goto err_free_dev;
 515         }
 516
 517         if (dmi_results.keymap) {
 518                 dell_new_hk_type = true;
 519
 520                 err = sparse_keymap_setup(dell_wmi_input_dev,
 521                                           dmi_results.keymap, NULL);
 522
 523                 /*
 524                  * Sparse keymap library makes a copy of keymap so we
 525                  * don't need the original one that was allocated.
 526                  */
 527                 kfree(dmi_results.keymap);
 528         } else {
 529                 err = sparse_keymap_setup(dell_wmi_input_dev,
 530                                           dell_wmi_legacy_keymap, NULL);
 531         }
 532         if (err)
 533                 goto err_free_dev;
 534
 535         err = input_register_device(dell_wmi_input_dev);
 536         if (err)
 537                 goto err_free_keymap;
 538
 539         return 0;
 540
 541  err_free_keymap:
 542         sparse_keymap_free(dell_wmi_input_dev);
 543  err_free_dev:
 544         input_free_device(dell_wmi_input_dev);
 545         return err;
 546 }
 547
 548 static void dell_wmi_input_destroy(void)
 549 {
 550         sparse_keymap_free(dell_wmi_input_dev);
 551         input_unregister_device(dell_wmi_input_dev);
 552 }
 553
 554 /*
 555  * Descriptor buffer is 128 byte long and contains:
 556  *
 557  *       Name             Offset  Length  Value
 558  * Vendor Signature          0       4    "DELL"
 559  * Object Signature          4       4    " WMI"
 560  * WMI Interface Version     8       4    <version>
 561  * WMI buffer length        12       4    4096
 562  */
 563 static int __init dell_wmi_check_descriptor_buffer(void)
 564 {
 565         struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
 566         union acpi_object *obj;
 567         acpi_status status;
 568         u32 *buffer;
 569
 570         status = wmi_query_block(DELL_DESCRIPTOR_GUID, 0, &out);
 571         if (ACPI_FAILURE(status)) {
 572                 pr_err("Cannot read Dell descriptor buffer - %d\n", status);
 573                 return status;
 574         }
 575
 576         obj = (union acpi_object *)out.pointer;
 577         if (!obj) {
 578                 pr_err("Dell descriptor buffer is empty\n");
 579                 return -EINVAL;
 580         }
 581
 582         if (obj->type != ACPI_TYPE_BUFFER) {
 583                 pr_err("Cannot read Dell descriptor buffer\n");
 584                 kfree(obj);
 585                 return -EINVAL;
 586         }
 587
 588         if (obj->buffer.length != 128) {
 589                 pr_err("Dell descriptor buffer has invalid length (%d)\n",
 590                         obj->buffer.length);
 591                 if (obj->buffer.length < 16) {
 592                         kfree(obj);
 593                         return -EINVAL;
 594                 }
 595         }
 596
 597         buffer = (u32 *)obj->buffer.pointer;
 598
 599         if (buffer[0] != 0x4C4C4544 && buffer[1] != 0x494D5720)
 600                 pr_warn("Dell descriptor buffer has invalid signature (%*ph)\n",
 601                         8, buffer);
 602
 603         if (buffer[2] != 0 && buffer[2] != 1)
 604                 pr_warn("Dell descriptor buffer has unknown version (%d)\n",
 605                         buffer[2]);
 606
 607         if (buffer[3] != 4096)
 608                 pr_warn("Dell descriptor buffer has invalid buffer length (%d)\n",
 609                         buffer[3]);
 610
 611         dell_wmi_interface_version = buffer[2];
 612
 613         pr_info("Detected Dell WMI interface version %u\n",
 614                 dell_wmi_interface_version);
 615
 616         kfree(obj);
 617         return 0;
 618 }
 619
 620 /*
 621  * According to Dell SMBIOS documentation:
 622  *
 623  * 17  3  Application Program Registration
 624  *
 625  *     cbArg1 Application ID 1 = 0x00010000
 626  *     cbArg2 Application ID 2
 627  *            QUICKSET/DCP = 0x51534554 "QSET"
 628  *            ALS Driver   = 0x416c7353 "AlsS"
 629  *            Latitude ON  = 0x4c6f6e52 "LonR"
 630  *     cbArg3 Application version or revision number
 631  *     cbArg4 0 = Unregister application
 632  *            1 = Register application
 633  *     cbRes1 Standard return codes (0, -1, -2)
 634  */
 635
 636 static int dell_wmi_events_set_enabled(bool enable)
 637 {
 638         struct calling_interface_buffer *buffer;
 639         int ret;
 640
 641         buffer = dell_smbios_get_buffer();
 642         buffer->input[0] = 0x10000;
 643         buffer->input[1] = 0x51534554;
 644         buffer->input[3] = enable;
 645         dell_smbios_send_request(17, 3);
 646         ret = buffer->output[0];
 647         dell_smbios_release_buffer();
 648
 649         return dell_smbios_error(ret);
 650 }
 651
 652 static int __init dell_wmi_init(void)
 653 {
 654         int err;
 655         acpi_status status;
 656
 657         if (!wmi_has_guid(DELL_EVENT_GUID) ||
 658             !wmi_has_guid(DELL_DESCRIPTOR_GUID)) {
 659                 pr_warn("Dell WMI GUID were not found\n");
 660                 return -ENODEV;
 661         }
 662
 663         err = dell_wmi_check_descriptor_buffer();
 664         if (err)
 665                 return err;
 666
 667         err = dell_wmi_input_setup();
 668         if (err)
 669                 return err;
 670
 671         status = wmi_install_notify_handler(DELL_EVENT_GUID,
 672                                          dell_wmi_notify, NULL);
 673         if (ACPI_FAILURE(status)) {
 674                 dell_wmi_input_destroy();
 675                 pr_err("Unable to register notify handler - %d\n", status);
 676                 return -ENODEV;
 677         }
 678
 679         dmi_check_system(dell_wmi_smbios_list);
 680
 681         if (wmi_requires_smbios_request) {
 682                 err = dell_wmi_events_set_enabled(true);
 683                 if (err) {
 684                         pr_err("Failed to enable WMI events\n");
 685                         wmi_remove_notify_handler(DELL_EVENT_GUID);
 686                         dell_wmi_input_destroy();
 687                         return err;
 688                 }
 689         }
 690
 691         return 0;
 692 }
 693 module_init(dell_wmi_init);
 694
 695 static void __exit dell_wmi_exit(void)
 696 {
 697         if (wmi_requires_smbios_request)
 698                 dell_wmi_events_set_enabled(false);
 699         wmi_remove_notify_handler(DELL_EVENT_GUID);
 700         dell_wmi_input_destroy();
 701 }
 702 module_exit(dell_wmi_exit);