drivers/acpi/button.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  button.c - ACPI Button Driver
   4  *
   5  *  Copyright (C) 2001, 2002 Andy Grover <[email protected]>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[email protected]>
   7  */
   8
   9 #define pr_fmt(fmt) "ACPI: button: " fmt
  10
  11 #include <linux/compiler.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/input.h>
  19 #include <linux/slab.h>
  20 #include <linux/acpi.h>
  21 #include <linux/dmi.h>
  22 #include <acpi/button.h>
  23
  24 #define PREFIX "ACPI: "
  25
  26 #define ACPI_BUTTON_CLASS               "button"
  27 #define ACPI_BUTTON_FILE_INFO           "info"
  28 #define ACPI_BUTTON_FILE_STATE          "state"
  29 #define ACPI_BUTTON_TYPE_UNKNOWN        0x00
  30 #define ACPI_BUTTON_NOTIFY_STATUS       0x80
  31
  32 #define ACPI_BUTTON_SUBCLASS_POWER      "power"
  33 #define ACPI_BUTTON_HID_POWER           "PNP0C0C"
  34 #define ACPI_BUTTON_DEVICE_NAME_POWER   "Power Button"
  35 #define ACPI_BUTTON_TYPE_POWER          0x01
  36
  37 #define ACPI_BUTTON_SUBCLASS_SLEEP      "sleep"
  38 #define ACPI_BUTTON_HID_SLEEP           "PNP0C0E"
  39 #define ACPI_BUTTON_DEVICE_NAME_SLEEP   "Sleep Button"
  40 #define ACPI_BUTTON_TYPE_SLEEP          0x03
  41
  42 #define ACPI_BUTTON_SUBCLASS_LID        "lid"
  43 #define ACPI_BUTTON_HID_LID             "PNP0C0D"
  44 #define ACPI_BUTTON_DEVICE_NAME_LID     "Lid Switch"
  45 #define ACPI_BUTTON_TYPE_LID            0x05
  46
  47 enum {
  48         ACPI_BUTTON_LID_INIT_IGNORE,
  49         ACPI_BUTTON_LID_INIT_OPEN,
  50         ACPI_BUTTON_LID_INIT_METHOD,
  51         ACPI_BUTTON_LID_INIT_DISABLED,
  52 };
  53
  54 static const char * const lid_init_state_str[] = {
  55         [ACPI_BUTTON_LID_INIT_IGNORE]           = "ignore",
  56         [ACPI_BUTTON_LID_INIT_OPEN]             = "open",
  57         [ACPI_BUTTON_LID_INIT_METHOD]           = "method",
  58         [ACPI_BUTTON_LID_INIT_DISABLED]         = "disabled",
  59 };
  60
  61 #define _COMPONENT              ACPI_BUTTON_COMPONENT
  62 ACPI_MODULE_NAME("button");
  63
  64 MODULE_AUTHOR("Paul Diefenbaugh");
  65 MODULE_DESCRIPTION("ACPI Button Driver");
  66 MODULE_LICENSE("GPL");
  67
  68 static const struct acpi_device_id button_device_ids[] = {
  69         {ACPI_BUTTON_HID_LID,    0},
  70         {ACPI_BUTTON_HID_SLEEP,  0},
  71         {ACPI_BUTTON_HID_SLEEPF, 0},
  72         {ACPI_BUTTON_HID_POWER,  0},
  73         {ACPI_BUTTON_HID_POWERF, 0},
  74         {"", 0},
  75 };
  76 MODULE_DEVICE_TABLE(acpi, button_device_ids);
  77
  78 /* Please keep this list sorted alphabetically by vendor and model */
  79 static const struct dmi_system_id dmi_lid_quirks[] = {
  80         {
  81                 /*
  82                  * Acer Switch 10 SW5-012. _LID method messes with home and
  83                  * power button GPIO IRQ settings causing an interrupt storm on
  84                  * both GPIOs. This is unfixable without a DSDT override, so we
  85                  * have to disable the lid-switch functionality altogether :|
  86                  */
  87                 .matches = {
  88                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
  89                         DMI_MATCH(DMI_PRODUCT_NAME, "Aspire SW5-012"),
  90                 },
  91                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
  92         },
  93         {
  94                 /*
  95                  * Asus T200TA, _LID keeps reporting closed after every second
  96                  * openening of the lid. Causing immediate re-suspend after
  97                  * opening every other open. Using LID_INIT_OPEN fixes this.
  98                  */
  99                 .matches = {
 100                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
 101                         DMI_MATCH(DMI_PRODUCT_NAME, "T200TA"),
 102                 },
 103                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
 104         },
 105         {
 106                 /* GP-electronic T701, _LID method points to a floating GPIO */
 107                 .matches = {
 108                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
 109                         DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
 110                         DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
 111                 },
 112                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
 113         },
 114         {
 115                 /*
 116                  * Medion Akoya E2215T, notification of the LID device only
 117                  * happens on close, not on open and _LID always returns closed.
 118                  */
 119                 .matches = {
 120                         DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
 121                         DMI_MATCH(DMI_PRODUCT_NAME, "E2215T MD60198"),
 122                 },
 123                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
 124         },
 125         {}
 126 };
 127
 128 static int acpi_button_add(struct acpi_device *device);
 129 static int acpi_button_remove(struct acpi_device *device);
 130 static void acpi_button_notify(struct acpi_device *device, u32 event);
 131
 132 #ifdef CONFIG_PM_SLEEP
 133 static int acpi_button_suspend(struct device *dev);
 134 static int acpi_button_resume(struct device *dev);
 135 #else
 136 #define acpi_button_suspend NULL
 137 #define acpi_button_resume NULL
 138 #endif
 139 static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
 140
 141 static struct acpi_driver acpi_button_driver = {
 142         .name = "button",
 143         .class = ACPI_BUTTON_CLASS,
 144         .ids = button_device_ids,
 145         .ops = {
 146                 .add = acpi_button_add,
 147                 .remove = acpi_button_remove,
 148                 .notify = acpi_button_notify,
 149         },
 150         .drv.pm = &acpi_button_pm,
 151 };
 152
 153 struct acpi_button {
 154         unsigned int type;
 155         struct input_dev *input;
 156         char phys[32];                  /* for input device */
 157         unsigned long pushed;
 158         int last_state;
 159         ktime_t last_time;
 160         bool suspended;
 161 };
 162
 163 static struct acpi_device *lid_device;
 164 static long lid_init_state = -1;
 165
 166 static unsigned long lid_report_interval __read_mostly = 500;
 167 module_param(lid_report_interval, ulong, 0644);
 168 MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
 169
 170 /* --------------------------------------------------------------------------
 171                               FS Interface (/proc)
 172    -------------------------------------------------------------------------- */
 173
 174 static struct proc_dir_entry *acpi_button_dir;
 175 static struct proc_dir_entry *acpi_lid_dir;
 176
 177 static int acpi_lid_evaluate_state(struct acpi_device *device)
 178 {
 179         unsigned long long lid_state;
 180         acpi_status status;
 181
 182         status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
 183         if (ACPI_FAILURE(status))
 184                 return -ENODEV;
 185
 186         return lid_state ? 1 : 0;
 187 }
 188
 189 static int acpi_lid_notify_state(struct acpi_device *device, int state)
 190 {
 191         struct acpi_button *button = acpi_driver_data(device);
 192         ktime_t next_report;
 193         bool do_update;
 194
 195         /*
 196          * In lid_init_state=ignore mode, if user opens/closes lid
 197          * frequently with "open" missing, and "last_time" is also updated
 198          * frequently, "close" cannot be delivered to the userspace.
 199          * So "last_time" is only updated after a timeout or an actual
 200          * switch.
 201          */
 202         if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
 203             button->last_state != !!state)
 204                 do_update = true;
 205         else
 206                 do_update = false;
 207
 208         next_report = ktime_add(button->last_time,
 209                                 ms_to_ktime(lid_report_interval));
 210         if (button->last_state == !!state &&
 211             ktime_after(ktime_get(), next_report)) {
 212                 /* Complain the buggy firmware */
 213                 pr_warn_once("The lid device is not compliant to SW_LID.\n");
 214
 215                 /*
 216                  * Send the unreliable complement switch event:
 217                  *
 218                  * On most platforms, the lid device is reliable. However
 219                  * there are exceptions:
 220                  * 1. Platforms returning initial lid state as "close" by
 221                  *    default after booting/resuming:
 222                  *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
 223                  *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
 224                  * 2. Platforms never reporting "open" events:
 225                  *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
 226                  * On these buggy platforms, the usage model of the ACPI
 227                  * lid device actually is:
 228                  * 1. The initial returning value of _LID may not be
 229                  *    reliable.
 230                  * 2. The open event may not be reliable.
 231                  * 3. The close event is reliable.
 232                  *
 233                  * But SW_LID is typed as input switch event, the input
 234                  * layer checks if the event is redundant. Hence if the
 235                  * state is not switched, the userspace cannot see this
 236                  * platform triggered reliable event. By inserting a
 237                  * complement switch event, it then is guaranteed that the
 238                  * platform triggered reliable one can always be seen by
 239                  * the userspace.
 240                  */
 241                 if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
 242                         do_update = true;
 243                         /*
 244                          * Do generate complement switch event for "close"
 245                          * as "close" is reliable and wrong "open" won't
 246                          * trigger unexpected behaviors.
 247                          * Do not generate complement switch event for
 248                          * "open" as "open" is not reliable and wrong
 249                          * "close" will trigger unexpected behaviors.
 250                          */
 251                         if (!state) {
 252                                 input_report_switch(button->input,
 253                                                     SW_LID, state);
 254                                 input_sync(button->input);
 255                         }
 256                 }
 257         }
 258         /* Send the platform triggered reliable event */
 259         if (do_update) {
 260                 acpi_handle_debug(device->handle, "ACPI LID %s\n",
 261                                   state ? "open" : "closed");
 262                 input_report_switch(button->input, SW_LID, !state);
 263                 input_sync(button->input);
 264                 button->last_state = !!state;
 265                 button->last_time = ktime_get();
 266         }
 267
 268         return 0;
 269 }
 270
 271 static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
 272                                                      void *offset)
 273 {
 274         struct acpi_device *device = seq->private;
 275         int state;
 276
 277         state = acpi_lid_evaluate_state(device);
 278         seq_printf(seq, "state:      %s\n",
 279                    state < 0 ? "unsupported" : (state ? "open" : "closed"));
 280         return 0;
 281 }
 282
 283 static int acpi_button_add_fs(struct acpi_device *device)
 284 {
 285         struct acpi_button *button = acpi_driver_data(device);
 286         struct proc_dir_entry *entry = NULL;
 287         int ret = 0;
 288
 289         /* procfs I/F for ACPI lid device only */
 290         if (button->type != ACPI_BUTTON_TYPE_LID)
 291                 return 0;
 292
 293         if (acpi_button_dir || acpi_lid_dir) {
 294                 printk(KERN_ERR PREFIX "More than one Lid device found!\n");
 295                 return -EEXIST;
 296         }
 297
 298         /* create /proc/acpi/button */
 299         acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
 300         if (!acpi_button_dir)
 301                 return -ENODEV;
 302
 303         /* create /proc/acpi/button/lid */
 304         acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 305         if (!acpi_lid_dir) {
 306                 ret = -ENODEV;
 307                 goto remove_button_dir;
 308         }
 309
 310         /* create /proc/acpi/button/lid/LID/ */
 311         acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
 312         if (!acpi_device_dir(device)) {
 313                 ret = -ENODEV;
 314                 goto remove_lid_dir;
 315         }
 316
 317         /* create /proc/acpi/button/lid/LID/state */
 318         entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
 319                         acpi_device_dir(device), acpi_button_state_seq_show,
 320                         device);
 321         if (!entry) {
 322                 ret = -ENODEV;
 323                 goto remove_dev_dir;
 324         }
 325
 326 done:
 327         return ret;
 328
 329 remove_dev_dir:
 330         remove_proc_entry(acpi_device_bid(device),
 331                           acpi_lid_dir);
 332         acpi_device_dir(device) = NULL;
 333 remove_lid_dir:
 334         remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 335         acpi_lid_dir = NULL;
 336 remove_button_dir:
 337         remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
 338         acpi_button_dir = NULL;
 339         goto done;
 340 }
 341
 342 static int acpi_button_remove_fs(struct acpi_device *device)
 343 {
 344         struct acpi_button *button = acpi_driver_data(device);
 345
 346         if (button->type != ACPI_BUTTON_TYPE_LID)
 347                 return 0;
 348
 349         remove_proc_entry(ACPI_BUTTON_FILE_STATE,
 350                           acpi_device_dir(device));
 351         remove_proc_entry(acpi_device_bid(device),
 352                           acpi_lid_dir);
 353         acpi_device_dir(device) = NULL;
 354         remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 355         acpi_lid_dir = NULL;
 356         remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
 357         acpi_button_dir = NULL;
 358
 359         return 0;
 360 }
 361
 362 /* --------------------------------------------------------------------------
 363                                 Driver Interface
 364    -------------------------------------------------------------------------- */
 365 int acpi_lid_open(void)
 366 {
 367         if (!lid_device)
 368                 return -ENODEV;
 369
 370         return acpi_lid_evaluate_state(lid_device);
 371 }
 372 EXPORT_SYMBOL(acpi_lid_open);
 373
 374 static int acpi_lid_update_state(struct acpi_device *device,
 375                                  bool signal_wakeup)
 376 {
 377         int state;
 378
 379         state = acpi_lid_evaluate_state(device);
 380         if (state < 0)
 381                 return state;
 382
 383         if (state && signal_wakeup)
 384                 acpi_pm_wakeup_event(&device->dev);
 385
 386         return acpi_lid_notify_state(device, state);
 387 }
 388
 389 static void acpi_lid_initialize_state(struct acpi_device *device)
 390 {
 391         switch (lid_init_state) {
 392         case ACPI_BUTTON_LID_INIT_OPEN:
 393                 (void)acpi_lid_notify_state(device, 1);
 394                 break;
 395         case ACPI_BUTTON_LID_INIT_METHOD:
 396                 (void)acpi_lid_update_state(device, false);
 397                 break;
 398         case ACPI_BUTTON_LID_INIT_IGNORE:
 399         default:
 400                 break;
 401         }
 402 }
 403
 404 static void acpi_button_notify(struct acpi_device *device, u32 event)
 405 {
 406         struct acpi_button *button = acpi_driver_data(device);
 407         struct input_dev *input;
 408         int users;
 409
 410         switch (event) {
 411         case ACPI_FIXED_HARDWARE_EVENT:
 412                 event = ACPI_BUTTON_NOTIFY_STATUS;
 413                 /* fall through */
 414         case ACPI_BUTTON_NOTIFY_STATUS:
 415                 input = button->input;
 416                 if (button->type == ACPI_BUTTON_TYPE_LID) {
 417                         mutex_lock(&button->input->mutex);
 418                         users = button->input->users;
 419                         mutex_unlock(&button->input->mutex);
 420                         if (users)
 421                                 acpi_lid_update_state(device, true);
 422                 } else {
 423                         int keycode;
 424
 425                         acpi_pm_wakeup_event(&device->dev);
 426                         if (button->suspended)
 427                                 break;
 428
 429                         keycode = test_bit(KEY_SLEEP, input->keybit) ?
 430                                                 KEY_SLEEP : KEY_POWER;
 431                         input_report_key(input, keycode, 1);
 432                         input_sync(input);
 433                         input_report_key(input, keycode, 0);
 434                         input_sync(input);
 435
 436                         acpi_bus_generate_netlink_event(
 437                                         device->pnp.device_class,
 438                                         dev_name(&device->dev),
 439                                         event, ++button->pushed);
 440                 }
 441                 break;
 442         default:
 443                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 444                                   "Unsupported event [0x%x]\n", event));
 445                 break;
 446         }
 447 }
 448
 449 #ifdef CONFIG_PM_SLEEP
 450 static int acpi_button_suspend(struct device *dev)
 451 {
 452         struct acpi_device *device = to_acpi_device(dev);
 453         struct acpi_button *button = acpi_driver_data(device);
 454
 455         button->suspended = true;
 456         return 0;
 457 }
 458
 459 static int acpi_button_resume(struct device *dev)
 460 {
 461         struct acpi_device *device = to_acpi_device(dev);
 462         struct acpi_button *button = acpi_driver_data(device);
 463
 464         button->suspended = false;
 465         if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users) {
 466                 button->last_state = !!acpi_lid_evaluate_state(device);
 467                 button->last_time = ktime_get();
 468                 acpi_lid_initialize_state(device);
 469         }
 470         return 0;
 471 }
 472 #endif
 473
 474 static int acpi_lid_input_open(struct input_dev *input)
 475 {
 476         struct acpi_device *device = input_get_drvdata(input);
 477         struct acpi_button *button = acpi_driver_data(device);
 478
 479         button->last_state = !!acpi_lid_evaluate_state(device);
 480         button->last_time = ktime_get();
 481         acpi_lid_initialize_state(device);
 482
 483         return 0;
 484 }
 485
 486 static int acpi_button_add(struct acpi_device *device)
 487 {
 488         struct acpi_button *button;
 489         struct input_dev *input;
 490         const char *hid = acpi_device_hid(device);
 491         char *name, *class;
 492         int error;
 493
 494         if (!strcmp(hid, ACPI_BUTTON_HID_LID) &&
 495              lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
 496                 return -ENODEV;
 497
 498         button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
 499         if (!button)
 500                 return -ENOMEM;
 501
 502         device->driver_data = button;
 503
 504         button->input = input = input_allocate_device();
 505         if (!input) {
 506                 error = -ENOMEM;
 507                 goto err_free_button;
 508         }
 509
 510         name = acpi_device_name(device);
 511         class = acpi_device_class(device);
 512
 513         if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
 514             !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
 515                 button->type = ACPI_BUTTON_TYPE_POWER;
 516                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
 517                 sprintf(class, "%s/%s",
 518                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
 519         } else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
 520                    !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
 521                 button->type = ACPI_BUTTON_TYPE_SLEEP;
 522                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
 523                 sprintf(class, "%s/%s",
 524                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
 525         } else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
 526                 button->type = ACPI_BUTTON_TYPE_LID;
 527                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
 528                 sprintf(class, "%s/%s",
 529                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
 530                 input->open = acpi_lid_input_open;
 531         } else {
 532                 printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
 533                 error = -ENODEV;
 534                 goto err_free_input;
 535         }
 536
 537         error = acpi_button_add_fs(device);
 538         if (error)
 539                 goto err_free_input;
 540
 541         snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
 542
 543         input->name = name;
 544         input->phys = button->phys;
 545         input->id.bustype = BUS_HOST;
 546         input->id.product = button->type;
 547         input->dev.parent = &device->dev;
 548
 549         switch (button->type) {
 550         case ACPI_BUTTON_TYPE_POWER:
 551                 input_set_capability(input, EV_KEY, KEY_POWER);
 552                 break;
 553
 554         case ACPI_BUTTON_TYPE_SLEEP:
 555                 input_set_capability(input, EV_KEY, KEY_SLEEP);
 556                 break;
 557
 558         case ACPI_BUTTON_TYPE_LID:
 559                 input_set_capability(input, EV_SW, SW_LID);
 560                 break;
 561         }
 562
 563         input_set_drvdata(input, device);
 564         error = input_register_device(input);
 565         if (error)
 566                 goto err_remove_fs;
 567         if (button->type == ACPI_BUTTON_TYPE_LID) {
 568                 /*
 569                  * This assumes there's only one lid device, or if there are
 570                  * more we only care about the last one...
 571                  */
 572                 lid_device = device;
 573         }
 574
 575         device_init_wakeup(&device->dev, true);
 576         printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
 577         return 0;
 578
 579  err_remove_fs:
 580         acpi_button_remove_fs(device);
 581  err_free_input:
 582         input_free_device(input);
 583  err_free_button:
 584         kfree(button);
 585         return error;
 586 }
 587
 588 static int acpi_button_remove(struct acpi_device *device)
 589 {
 590         struct acpi_button *button = acpi_driver_data(device);
 591
 592         acpi_button_remove_fs(device);
 593         input_unregister_device(button->input);
 594         kfree(button);
 595         return 0;
 596 }
 597
 598 static int param_set_lid_init_state(const char *val,
 599                                     const struct kernel_param *kp)
 600 {
 601         int i;
 602
 603         i = sysfs_match_string(lid_init_state_str, val);
 604         if (i < 0)
 605                 return i;
 606
 607         lid_init_state = i;
 608         pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
 609         return 0;
 610 }
 611
 612 static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
 613 {
 614         int i, c = 0;
 615
 616         for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
 617                 if (i == lid_init_state)
 618                         c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
 619                 else
 620                         c += sprintf(buf + c, "%s ", lid_init_state_str[i]);
 621
 622         buf[c - 1] = '\n'; /* Replace the final space with a newline */
 623
 624         return c;
 625 }
 626
 627 module_param_call(lid_init_state,
 628                   param_set_lid_init_state, param_get_lid_init_state,
 629                   NULL, 0644);
 630 MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
 631
 632 static int acpi_button_register_driver(struct acpi_driver *driver)
 633 {
 634         const struct dmi_system_id *dmi_id;
 635
 636         if (lid_init_state == -1) {
 637                 dmi_id = dmi_first_match(dmi_lid_quirks);
 638                 if (dmi_id)
 639                         lid_init_state = (long)dmi_id->driver_data;
 640                 else
 641                         lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
 642         }
 643
 644         /*
 645          * Modules such as nouveau.ko and i915.ko have a link time dependency
 646          * on acpi_lid_open(), and would therefore not be loadable on ACPI
 647          * capable kernels booted in non-ACPI mode if the return value of
 648          * acpi_bus_register_driver() is returned from here with ACPI disabled
 649          * when this driver is built as a module.
 650          */
 651         if (acpi_disabled)
 652                 return 0;
 653
 654         return acpi_bus_register_driver(driver);
 655 }
 656
 657 static void acpi_button_unregister_driver(struct acpi_driver *driver)
 658 {
 659         if (!acpi_disabled)
 660                 acpi_bus_unregister_driver(driver);
 661 }
 662
 663 module_driver(acpi_button_driver, acpi_button_register_driver,
 664                acpi_button_unregister_driver);