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 <andrew.grover@intel.com>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   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_DEVICE_NAME_POWER   "Power Button"
  34 #define ACPI_BUTTON_TYPE_POWER          0x01
  35
  36 #define ACPI_BUTTON_SUBCLASS_SLEEP      "sleep"
  37 #define ACPI_BUTTON_DEVICE_NAME_SLEEP   "Sleep Button"
  38 #define ACPI_BUTTON_TYPE_SLEEP          0x03
  39
  40 #define ACPI_BUTTON_SUBCLASS_LID        "lid"
  41 #define ACPI_BUTTON_DEVICE_NAME_LID     "Lid Switch"
  42 #define ACPI_BUTTON_TYPE_LID            0x05
  43
  44 enum {
  45         ACPI_BUTTON_LID_INIT_IGNORE,
  46         ACPI_BUTTON_LID_INIT_OPEN,
  47         ACPI_BUTTON_LID_INIT_METHOD,
  48         ACPI_BUTTON_LID_INIT_DISABLED,
  49 };
  50
  51 static const char * const lid_init_state_str[] = {
  52         [ACPI_BUTTON_LID_INIT_IGNORE]           = "ignore",
  53         [ACPI_BUTTON_LID_INIT_OPEN]             = "open",
  54         [ACPI_BUTTON_LID_INIT_METHOD]           = "method",
  55         [ACPI_BUTTON_LID_INIT_DISABLED]         = "disabled",
  56 };
  57
  58 #define _COMPONENT              ACPI_BUTTON_COMPONENT
  59 ACPI_MODULE_NAME("button");
  60
  61 MODULE_AUTHOR("Paul Diefenbaugh");
  62 MODULE_DESCRIPTION("ACPI Button Driver");
  63 MODULE_LICENSE("GPL");
  64
  65 static const struct acpi_device_id button_device_ids[] = {
  66         {ACPI_BUTTON_HID_LID,    0},
  67         {ACPI_BUTTON_HID_SLEEP,  0},
  68         {ACPI_BUTTON_HID_SLEEPF, 0},
  69         {ACPI_BUTTON_HID_POWER,  0},
  70         {ACPI_BUTTON_HID_POWERF, 0},
  71         {"", 0},
  72 };
  73 MODULE_DEVICE_TABLE(acpi, button_device_ids);
  74
  75 /* Please keep this list sorted alphabetically by vendor and model */
  76 static const struct dmi_system_id dmi_lid_quirks[] = {
  77         {
  78                 /*
  79                  * Acer Switch 10 SW5-012. _LID method messes with home and
  80                  * power button GPIO IRQ settings causing an interrupt storm on
  81                  * both GPIOs. This is unfixable without a DSDT override, so we
  82                  * have to disable the lid-switch functionality altogether :|
  83                  */
  84                 .matches = {
  85                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
  86                         DMI_MATCH(DMI_PRODUCT_NAME, "Aspire SW5-012"),
  87                 },
  88                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
  89         },
  90         {
  91                 /*
  92                  * Asus T200TA, _LID keeps reporting closed after every second
  93                  * openening of the lid. Causing immediate re-suspend after
  94                  * opening every other open. Using LID_INIT_OPEN fixes this.
  95                  */
  96                 .matches = {
  97                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
  98                         DMI_MATCH(DMI_PRODUCT_NAME, "T200TA"),
  99                 },
 100                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
 101         },
 102         {
 103                 /* GP-electronic T701, _LID method points to a floating GPIO */
 104                 .matches = {
 105                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
 106                         DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
 107                         DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
 108                 },
 109                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
 110         },
 111         {
 112                 /*
 113                  * Medion Akoya E2215T, notification of the LID device only
 114                  * happens on close, not on open and _LID always returns closed.
 115                  */
 116                 .matches = {
 117                         DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
 118                         DMI_MATCH(DMI_PRODUCT_NAME, "E2215T MD60198"),
 119                 },
 120                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
 121         },
 122         {
 123                 /*
 124                  * Razer Blade Stealth 13 late 2019, notification of the LID device
 125                  * only happens on close, not on open and _LID always returns closed.
 126                  */
 127                 .matches = {
 128                         DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
 129                         DMI_MATCH(DMI_PRODUCT_NAME, "Razer Blade Stealth 13 Late 2019"),
 130                 },
 131                 .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
 132         },
 133         {}
 134 };
 135
 136 static int acpi_button_add(struct acpi_device *device);
 137 static int acpi_button_remove(struct acpi_device *device);
 138 static void acpi_button_notify(struct acpi_device *device, u32 event);
 139
 140 #ifdef CONFIG_PM_SLEEP
 141 static int acpi_button_suspend(struct device *dev);
 142 static int acpi_button_resume(struct device *dev);
 143 #else
 144 #define acpi_button_suspend NULL
 145 #define acpi_button_resume NULL
 146 #endif
 147 static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
 148
 149 static struct acpi_driver acpi_button_driver = {
 150         .name = "button",
 151         .class = ACPI_BUTTON_CLASS,
 152         .ids = button_device_ids,
 153         .ops = {
 154                 .add = acpi_button_add,
 155                 .remove = acpi_button_remove,
 156                 .notify = acpi_button_notify,
 157         },
 158         .drv.pm = &acpi_button_pm,
 159 };
 160
 161 struct acpi_button {
 162         unsigned int type;
 163         struct input_dev *input;
 164         char phys[32];                  /* for input device */
 165         unsigned long pushed;
 166         int last_state;
 167         ktime_t last_time;
 168         bool suspended;
 169 };
 170
 171 static struct acpi_device *lid_device;
 172 static long lid_init_state = -1;
 173
 174 static unsigned long lid_report_interval __read_mostly = 500;
 175 module_param(lid_report_interval, ulong, 0644);
 176 MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
 177
 178 /* --------------------------------------------------------------------------
 179                               FS Interface (/proc)
 180    -------------------------------------------------------------------------- */
 181
 182 static struct proc_dir_entry *acpi_button_dir;
 183 static struct proc_dir_entry *acpi_lid_dir;
 184
 185 static int acpi_lid_evaluate_state(struct acpi_device *device)
 186 {
 187         unsigned long long lid_state;
 188         acpi_status status;
 189
 190         status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
 191         if (ACPI_FAILURE(status))
 192                 return -ENODEV;
 193
 194         return lid_state ? 1 : 0;
 195 }
 196
 197 static int acpi_lid_notify_state(struct acpi_device *device, int state)
 198 {
 199         struct acpi_button *button = acpi_driver_data(device);
 200         ktime_t next_report;
 201         bool do_update;
 202
 203         /*
 204          * In lid_init_state=ignore mode, if user opens/closes lid
 205          * frequently with "open" missing, and "last_time" is also updated
 206          * frequently, "close" cannot be delivered to the userspace.
 207          * So "last_time" is only updated after a timeout or an actual
 208          * switch.
 209          */
 210         if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
 211             button->last_state != !!state)
 212                 do_update = true;
 213         else
 214                 do_update = false;
 215
 216         next_report = ktime_add(button->last_time,
 217                                 ms_to_ktime(lid_report_interval));
 218         if (button->last_state == !!state &&
 219             ktime_after(ktime_get(), next_report)) {
 220                 /* Complain the buggy firmware */
 221                 pr_warn_once("The lid device is not compliant to SW_LID.\n");
 222
 223                 /*
 224                  * Send the unreliable complement switch event:
 225                  *
 226                  * On most platforms, the lid device is reliable. However
 227                  * there are exceptions:
 228                  * 1. Platforms returning initial lid state as "close" by
 229                  *    default after booting/resuming:
 230                  *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
 231                  *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
 232                  * 2. Platforms never reporting "open" events:
 233                  *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
 234                  * On these buggy platforms, the usage model of the ACPI
 235                  * lid device actually is:
 236                  * 1. The initial returning value of _LID may not be
 237                  *    reliable.
 238                  * 2. The open event may not be reliable.
 239                  * 3. The close event is reliable.
 240                  *
 241                  * But SW_LID is typed as input switch event, the input
 242                  * layer checks if the event is redundant. Hence if the
 243                  * state is not switched, the userspace cannot see this
 244                  * platform triggered reliable event. By inserting a
 245                  * complement switch event, it then is guaranteed that the
 246                  * platform triggered reliable one can always be seen by
 247                  * the userspace.
 248                  */
 249                 if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
 250                         do_update = true;
 251                         /*
 252                          * Do generate complement switch event for "close"
 253                          * as "close" is reliable and wrong "open" won't
 254                          * trigger unexpected behaviors.
 255                          * Do not generate complement switch event for
 256                          * "open" as "open" is not reliable and wrong
 257                          * "close" will trigger unexpected behaviors.
 258                          */
 259                         if (!state) {
 260                                 input_report_switch(button->input,
 261                                                     SW_LID, state);
 262                                 input_sync(button->input);
 263                         }
 264                 }
 265         }
 266         /* Send the platform triggered reliable event */
 267         if (do_update) {
 268                 acpi_handle_debug(device->handle, "ACPI LID %s\n",
 269                                   state ? "open" : "closed");
 270                 input_report_switch(button->input, SW_LID, !state);
 271                 input_sync(button->input);
 272                 button->last_state = !!state;
 273                 button->last_time = ktime_get();
 274         }
 275
 276         return 0;
 277 }
 278
 279 static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
 280                                                      void *offset)
 281 {
 282         struct acpi_device *device = seq->private;
 283         int state;
 284
 285         state = acpi_lid_evaluate_state(device);
 286         seq_printf(seq, "state:      %s\n",
 287                    state < 0 ? "unsupported" : (state ? "open" : "closed"));
 288         return 0;
 289 }
 290
 291 static int acpi_button_add_fs(struct acpi_device *device)
 292 {
 293         struct acpi_button *button = acpi_driver_data(device);
 294         struct proc_dir_entry *entry = NULL;
 295         int ret = 0;
 296
 297         /* procfs I/F for ACPI lid device only */
 298         if (button->type != ACPI_BUTTON_TYPE_LID)
 299                 return 0;
 300
 301         if (acpi_button_dir || acpi_lid_dir) {
 302                 printk(KERN_ERR PREFIX "More than one Lid device found!\n");
 303                 return -EEXIST;
 304         }
 305
 306         /* create /proc/acpi/button */
 307         acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
 308         if (!acpi_button_dir)
 309                 return -ENODEV;
 310
 311         /* create /proc/acpi/button/lid */
 312         acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 313         if (!acpi_lid_dir) {
 314                 ret = -ENODEV;
 315                 goto remove_button_dir;
 316         }
 317
 318         /* create /proc/acpi/button/lid/LID/ */
 319         acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
 320         if (!acpi_device_dir(device)) {
 321                 ret = -ENODEV;
 322                 goto remove_lid_dir;
 323         }
 324
 325         /* create /proc/acpi/button/lid/LID/state */
 326         entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
 327                         acpi_device_dir(device), acpi_button_state_seq_show,
 328                         device);
 329         if (!entry) {
 330                 ret = -ENODEV;
 331                 goto remove_dev_dir;
 332         }
 333
 334 done:
 335         return ret;
 336
 337 remove_dev_dir:
 338         remove_proc_entry(acpi_device_bid(device),
 339                           acpi_lid_dir);
 340         acpi_device_dir(device) = NULL;
 341 remove_lid_dir:
 342         remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 343         acpi_lid_dir = NULL;
 344 remove_button_dir:
 345         remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
 346         acpi_button_dir = NULL;
 347         goto done;
 348 }
 349
 350 static int acpi_button_remove_fs(struct acpi_device *device)
 351 {
 352         struct acpi_button *button = acpi_driver_data(device);
 353
 354         if (button->type != ACPI_BUTTON_TYPE_LID)
 355                 return 0;
 356
 357         remove_proc_entry(ACPI_BUTTON_FILE_STATE,
 358                           acpi_device_dir(device));
 359         remove_proc_entry(acpi_device_bid(device),
 360                           acpi_lid_dir);
 361         acpi_device_dir(device) = NULL;
 362         remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 363         acpi_lid_dir = NULL;
 364         remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
 365         acpi_button_dir = NULL;
 366
 367         return 0;
 368 }
 369
 370 /* --------------------------------------------------------------------------
 371                                 Driver Interface
 372    -------------------------------------------------------------------------- */
 373 int acpi_lid_open(void)
 374 {
 375         if (!lid_device)
 376                 return -ENODEV;
 377
 378         return acpi_lid_evaluate_state(lid_device);
 379 }
 380 EXPORT_SYMBOL(acpi_lid_open);
 381
 382 static int acpi_lid_update_state(struct acpi_device *device,
 383                                  bool signal_wakeup)
 384 {
 385         int state;
 386
 387         state = acpi_lid_evaluate_state(device);
 388         if (state < 0)
 389                 return state;
 390
 391         if (state && signal_wakeup)
 392                 acpi_pm_wakeup_event(&device->dev);
 393
 394         return acpi_lid_notify_state(device, state);
 395 }
 396
 397 static void acpi_lid_initialize_state(struct acpi_device *device)
 398 {
 399         switch (lid_init_state) {
 400         case ACPI_BUTTON_LID_INIT_OPEN:
 401                 (void)acpi_lid_notify_state(device, 1);
 402                 break;
 403         case ACPI_BUTTON_LID_INIT_METHOD:
 404                 (void)acpi_lid_update_state(device, false);
 405                 break;
 406         case ACPI_BUTTON_LID_INIT_IGNORE:
 407         default:
 408                 break;
 409         }
 410 }
 411
 412 static void acpi_button_notify(struct acpi_device *device, u32 event)
 413 {
 414         struct acpi_button *button = acpi_driver_data(device);
 415         struct input_dev *input;
 416         int users;
 417
 418         switch (event) {
 419         case ACPI_FIXED_HARDWARE_EVENT:
 420                 event = ACPI_BUTTON_NOTIFY_STATUS;
 421                 /* fall through */
 422         case ACPI_BUTTON_NOTIFY_STATUS:
 423                 input = button->input;
 424                 if (button->type == ACPI_BUTTON_TYPE_LID) {
 425                         mutex_lock(&button->input->mutex);
 426                         users = button->input->users;
 427                         mutex_unlock(&button->input->mutex);
 428                         if (users)
 429                                 acpi_lid_update_state(device, true);
 430                 } else {
 431                         int keycode;
 432
 433                         acpi_pm_wakeup_event(&device->dev);
 434                         if (button->suspended)
 435                                 break;
 436
 437                         keycode = test_bit(KEY_SLEEP, input->keybit) ?
 438                                                 KEY_SLEEP : KEY_POWER;
 439                         input_report_key(input, keycode, 1);
 440                         input_sync(input);
 441                         input_report_key(input, keycode, 0);
 442                         input_sync(input);
 443
 444                         acpi_bus_generate_netlink_event(
 445                                         device->pnp.device_class,
 446                                         dev_name(&device->dev),
 447                                         event, ++button->pushed);
 448                 }
 449                 break;
 450         default:
 451                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 452                                   "Unsupported event [0x%x]\n", event));
 453                 break;
 454         }
 455 }
 456
 457 #ifdef CONFIG_PM_SLEEP
 458 static int acpi_button_suspend(struct device *dev)
 459 {
 460         struct acpi_device *device = to_acpi_device(dev);
 461         struct acpi_button *button = acpi_driver_data(device);
 462
 463         button->suspended = true;
 464         return 0;
 465 }
 466
 467 static int acpi_button_resume(struct device *dev)
 468 {
 469         struct acpi_device *device = to_acpi_device(dev);
 470         struct acpi_button *button = acpi_driver_data(device);
 471
 472         button->suspended = false;
 473         if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users) {
 474                 button->last_state = !!acpi_lid_evaluate_state(device);
 475                 button->last_time = ktime_get();
 476                 acpi_lid_initialize_state(device);
 477         }
 478         return 0;
 479 }
 480 #endif
 481
 482 static int acpi_lid_input_open(struct input_dev *input)
 483 {
 484         struct acpi_device *device = input_get_drvdata(input);
 485         struct acpi_button *button = acpi_driver_data(device);
 486
 487         button->last_state = !!acpi_lid_evaluate_state(device);
 488         button->last_time = ktime_get();
 489         acpi_lid_initialize_state(device);
 490
 491         return 0;
 492 }
 493
 494 static int acpi_button_add(struct acpi_device *device)
 495 {
 496         struct acpi_button *button;
 497         struct input_dev *input;
 498         const char *hid = acpi_device_hid(device);
 499         char *name, *class;
 500         int error;
 501
 502         if (!strcmp(hid, ACPI_BUTTON_HID_LID) &&
 503              lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
 504                 return -ENODEV;
 505
 506         button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
 507         if (!button)
 508                 return -ENOMEM;
 509
 510         device->driver_data = button;
 511
 512         button->input = input = input_allocate_device();
 513         if (!input) {
 514                 error = -ENOMEM;
 515                 goto err_free_button;
 516         }
 517
 518         name = acpi_device_name(device);
 519         class = acpi_device_class(device);
 520
 521         if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
 522             !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
 523                 button->type = ACPI_BUTTON_TYPE_POWER;
 524                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
 525                 sprintf(class, "%s/%s",
 526                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
 527         } else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
 528                    !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
 529                 button->type = ACPI_BUTTON_TYPE_SLEEP;
 530                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
 531                 sprintf(class, "%s/%s",
 532                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
 533         } else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
 534                 button->type = ACPI_BUTTON_TYPE_LID;
 535                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
 536                 sprintf(class, "%s/%s",
 537                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
 538                 input->open = acpi_lid_input_open;
 539         } else {
 540                 printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
 541                 error = -ENODEV;
 542                 goto err_free_input;
 543         }
 544
 545         error = acpi_button_add_fs(device);
 546         if (error)
 547                 goto err_free_input;
 548
 549         snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
 550
 551         input->name = name;
 552         input->phys = button->phys;
 553         input->id.bustype = BUS_HOST;
 554         input->id.product = button->type;
 555         input->dev.parent = &device->dev;
 556
 557         switch (button->type) {
 558         case ACPI_BUTTON_TYPE_POWER:
 559                 input_set_capability(input, EV_KEY, KEY_POWER);
 560                 break;
 561
 562         case ACPI_BUTTON_TYPE_SLEEP:
 563                 input_set_capability(input, EV_KEY, KEY_SLEEP);
 564                 break;
 565
 566         case ACPI_BUTTON_TYPE_LID:
 567                 input_set_capability(input, EV_SW, SW_LID);
 568                 break;
 569         }
 570
 571         input_set_drvdata(input, device);
 572         error = input_register_device(input);
 573         if (error)
 574                 goto err_remove_fs;
 575         if (button->type == ACPI_BUTTON_TYPE_LID) {
 576                 /*
 577                  * This assumes there's only one lid device, or if there are
 578                  * more we only care about the last one...
 579                  */
 580                 lid_device = device;
 581         }
 582
 583         device_init_wakeup(&device->dev, true);
 584         printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
 585         return 0;
 586
 587  err_remove_fs:
 588         acpi_button_remove_fs(device);
 589  err_free_input:
 590         input_free_device(input);
 591  err_free_button:
 592         kfree(button);
 593         return error;
 594 }
 595
 596 static int acpi_button_remove(struct acpi_device *device)
 597 {
 598         struct acpi_button *button = acpi_driver_data(device);
 599
 600         acpi_button_remove_fs(device);
 601         input_unregister_device(button->input);
 602         kfree(button);
 603         return 0;
 604 }
 605
 606 static int param_set_lid_init_state(const char *val,
 607                                     const struct kernel_param *kp)
 608 {
 609         int i;
 610
 611         i = sysfs_match_string(lid_init_state_str, val);
 612         if (i < 0)
 613                 return i;
 614
 615         lid_init_state = i;
 616         pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
 617         return 0;
 618 }
 619
 620 static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
 621 {
 622         int i, c = 0;
 623
 624         for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
 625                 if (i == lid_init_state)
 626                         c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
 627                 else
 628                         c += sprintf(buf + c, "%s ", lid_init_state_str[i]);
 629
 630         buf[c - 1] = '\n'; /* Replace the final space with a newline */
 631
 632         return c;
 633 }
 634
 635 module_param_call(lid_init_state,
 636                   param_set_lid_init_state, param_get_lid_init_state,
 637                   NULL, 0644);
 638 MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
 639
 640 static int acpi_button_register_driver(struct acpi_driver *driver)
 641 {
 642         const struct dmi_system_id *dmi_id;
 643
 644         if (lid_init_state == -1) {
 645                 dmi_id = dmi_first_match(dmi_lid_quirks);
 646                 if (dmi_id)
 647                         lid_init_state = (long)dmi_id->driver_data;
 648                 else
 649                         lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
 650         }
 651
 652         /*
 653          * Modules such as nouveau.ko and i915.ko have a link time dependency
 654          * on acpi_lid_open(), and would therefore not be loadable on ACPI
 655          * capable kernels booted in non-ACPI mode if the return value of
 656          * acpi_bus_register_driver() is returned from here with ACPI disabled
 657          * when this driver is built as a module.
 658          */
 659         if (acpi_disabled)
 660                 return 0;
 661
 662         return acpi_bus_register_driver(driver);
 663 }
 664
 665 static void acpi_button_unregister_driver(struct acpi_driver *driver)
 666 {
 667         if (!acpi_disabled)
 668                 acpi_bus_unregister_driver(driver);
 669 }
 670
 671 module_driver(acpi_button_driver, acpi_button_register_driver,
 672                acpi_button_unregister_driver);