drivers/acpi/acpi_video.c

   1 /*
   2  *  video.c - ACPI Video Driver
   3  *
   4  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
   5  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
   6  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/types.h>
  27 #include <linux/list.h>
  28 #include <linux/mutex.h>
  29 #include <linux/input.h>
  30 #include <linux/backlight.h>
  31 #include <linux/thermal.h>
  32 #include <linux/sort.h>
  33 #include <linux/pci.h>
  34 #include <linux/pci_ids.h>
  35 #include <linux/slab.h>
  36 #include <linux/dmi.h>
  37 #include <linux/suspend.h>
  38 #include <linux/acpi.h>
  39 #include <acpi/video.h>
  40 #include <asm/uaccess.h>
  41
  42 #define PREFIX "ACPI: "
  43
  44 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
  45 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
  46 #define ACPI_VIDEO_NOTIFY_SWITCH        0x80
  47 #define ACPI_VIDEO_NOTIFY_PROBE         0x81
  48 #define ACPI_VIDEO_NOTIFY_CYCLE         0x82
  49 #define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT   0x83
  50 #define ACPI_VIDEO_NOTIFY_PREV_OUTPUT   0x84
  51
  52 #define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS      0x85
  53 #define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS        0x86
  54 #define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS        0x87
  55 #define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS       0x88
  56 #define ACPI_VIDEO_NOTIFY_DISPLAY_OFF           0x89
  57
  58 #define MAX_NAME_LEN    20
  59
  60 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  61 ACPI_MODULE_NAME("video");
  62
  63 MODULE_AUTHOR("Bruno Ducrot");
  64 MODULE_DESCRIPTION("ACPI Video Driver");
  65 MODULE_LICENSE("GPL");
  66
  67 static bool brightness_switch_enabled = 1;
  68 module_param(brightness_switch_enabled, bool, 0644);
  69
  70 /*
  71  * By default, we don't allow duplicate ACPI video bus devices
  72  * under the same VGA controller
  73  */
  74 static bool allow_duplicates;
  75 module_param(allow_duplicates, bool, 0644);
  76
  77 static int disable_backlight_sysfs_if = -1;
  78 module_param(disable_backlight_sysfs_if, int, 0444);
  79
  80 static bool device_id_scheme = false;
  81 module_param(device_id_scheme, bool, 0444);
  82
  83 static bool only_lcd = false;
  84 module_param(only_lcd, bool, 0444);
  85
  86 static int register_count;
  87 static DEFINE_MUTEX(register_count_mutex);
  88 static struct mutex video_list_lock;
  89 static struct list_head video_bus_head;
  90 static int acpi_video_bus_add(struct acpi_device *device);
  91 static int acpi_video_bus_remove(struct acpi_device *device);
  92 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
  93 void acpi_video_detect_exit(void);
  94
  95 static const struct acpi_device_id video_device_ids[] = {
  96         {ACPI_VIDEO_HID, 0},
  97         {"", 0},
  98 };
  99 MODULE_DEVICE_TABLE(acpi, video_device_ids);
 100
 101 static struct acpi_driver acpi_video_bus = {
 102         .name = "video",
 103         .class = ACPI_VIDEO_CLASS,
 104         .ids = video_device_ids,
 105         .ops = {
 106                 .add = acpi_video_bus_add,
 107                 .remove = acpi_video_bus_remove,
 108                 .notify = acpi_video_bus_notify,
 109                 },
 110 };
 111
 112 struct acpi_video_bus_flags {
 113         u8 multihead:1;         /* can switch video heads */
 114         u8 rom:1;               /* can retrieve a video rom */
 115         u8 post:1;              /* can configure the head to */
 116         u8 reserved:5;
 117 };
 118
 119 struct acpi_video_bus_cap {
 120         u8 _DOS:1;              /* Enable/Disable output switching */
 121         u8 _DOD:1;              /* Enumerate all devices attached to display adapter */
 122         u8 _ROM:1;              /* Get ROM Data */
 123         u8 _GPD:1;              /* Get POST Device */
 124         u8 _SPD:1;              /* Set POST Device */
 125         u8 _VPO:1;              /* Video POST Options */
 126         u8 reserved:2;
 127 };
 128
 129 struct acpi_video_device_attrib {
 130         u32 display_index:4;    /* A zero-based instance of the Display */
 131         u32 display_port_attachment:4;  /* This field differentiates the display type */
 132         u32 display_type:4;     /* Describe the specific type in use */
 133         u32 vendor_specific:4;  /* Chipset Vendor Specific */
 134         u32 bios_can_detect:1;  /* BIOS can detect the device */
 135         u32 depend_on_vga:1;    /* Non-VGA output device whose power is related to
 136                                    the VGA device. */
 137         u32 pipe_id:3;          /* For VGA multiple-head devices. */
 138         u32 reserved:10;        /* Must be 0 */
 139         u32 device_id_scheme:1; /* Device ID Scheme */
 140 };
 141
 142 struct acpi_video_enumerated_device {
 143         union {
 144                 u32 int_val;
 145                 struct acpi_video_device_attrib attrib;
 146         } value;
 147         struct acpi_video_device *bind_info;
 148 };
 149
 150 struct acpi_video_bus {
 151         struct acpi_device *device;
 152         bool backlight_registered;
 153         u8 dos_setting;
 154         struct acpi_video_enumerated_device *attached_array;
 155         u8 attached_count;
 156         u8 child_count;
 157         struct acpi_video_bus_cap cap;
 158         struct acpi_video_bus_flags flags;
 159         struct list_head video_device_list;
 160         struct mutex device_list_lock;  /* protects video_device_list */
 161         struct list_head entry;
 162         struct input_dev *input;
 163         char phys[32];  /* for input device */
 164         struct notifier_block pm_nb;
 165 };
 166
 167 struct acpi_video_device_flags {
 168         u8 crt:1;
 169         u8 lcd:1;
 170         u8 tvout:1;
 171         u8 dvi:1;
 172         u8 bios:1;
 173         u8 unknown:1;
 174         u8 notify:1;
 175         u8 reserved:1;
 176 };
 177
 178 struct acpi_video_device_cap {
 179         u8 _ADR:1;              /* Return the unique ID */
 180         u8 _BCL:1;              /* Query list of brightness control levels supported */
 181         u8 _BCM:1;              /* Set the brightness level */
 182         u8 _BQC:1;              /* Get current brightness level */
 183         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
 184         u8 _DDC:1;              /* Return the EDID for this device */
 185 };
 186
 187 struct acpi_video_brightness_flags {
 188         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
 189         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
 190         u8 _BQC_use_index:1;            /* _BQC returns an index value */
 191 };
 192
 193 struct acpi_video_device_brightness {
 194         int curr;
 195         int count;
 196         int *levels;
 197         struct acpi_video_brightness_flags flags;
 198 };
 199
 200 struct acpi_video_device {
 201         unsigned long device_id;
 202         struct acpi_video_device_flags flags;
 203         struct acpi_video_device_cap cap;
 204         struct list_head entry;
 205         struct delayed_work switch_brightness_work;
 206         int switch_brightness_event;
 207         struct acpi_video_bus *video;
 208         struct acpi_device *dev;
 209         struct acpi_video_device_brightness *brightness;
 210         struct backlight_device *backlight;
 211         struct thermal_cooling_device *cooling_dev;
 212 };
 213
 214 static const char device_decode[][30] = {
 215         "motherboard VGA device",
 216         "PCI VGA device",
 217         "AGP VGA device",
 218         "UNKNOWN",
 219 };
 220
 221 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 222 static void acpi_video_device_rebind(struct acpi_video_bus *video);
 223 static void acpi_video_device_bind(struct acpi_video_bus *video,
 224                                    struct acpi_video_device *device);
 225 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 226 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 227                         int level);
 228 static int acpi_video_device_lcd_get_level_current(
 229                         struct acpi_video_device *device,
 230                         unsigned long long *level, bool raw);
 231 static int acpi_video_get_next_level(struct acpi_video_device *device,
 232                                      u32 level_current, u32 event);
 233 static void acpi_video_switch_brightness(struct work_struct *work);
 234
 235 /* backlight device sysfs support */
 236 static int acpi_video_get_brightness(struct backlight_device *bd)
 237 {
 238         unsigned long long cur_level;
 239         int i;
 240         struct acpi_video_device *vd = bl_get_data(bd);
 241
 242         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 243                 return -EINVAL;
 244         for (i = 2; i < vd->brightness->count; i++) {
 245                 if (vd->brightness->levels[i] == cur_level)
 246                         /*
 247                          * The first two entries are special - see page 575
 248                          * of the ACPI spec 3.0
 249                          */
 250                         return i - 2;
 251         }
 252         return 0;
 253 }
 254
 255 static int acpi_video_set_brightness(struct backlight_device *bd)
 256 {
 257         int request_level = bd->props.brightness + 2;
 258         struct acpi_video_device *vd = bl_get_data(bd);
 259
 260         cancel_delayed_work(&vd->switch_brightness_work);
 261         return acpi_video_device_lcd_set_level(vd,
 262                                 vd->brightness->levels[request_level]);
 263 }
 264
 265 static const struct backlight_ops acpi_backlight_ops = {
 266         .get_brightness = acpi_video_get_brightness,
 267         .update_status  = acpi_video_set_brightness,
 268 };
 269
 270 /* thermal cooling device callbacks */
 271 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
 272                                long *state)
 273 {
 274         struct acpi_device *device = cooling_dev->devdata;
 275         struct acpi_video_device *video = acpi_driver_data(device);
 276
 277         *state = video->brightness->count - 3;
 278         return 0;
 279 }
 280
 281 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
 282                                long *state)
 283 {
 284         struct acpi_device *device = cooling_dev->devdata;
 285         struct acpi_video_device *video = acpi_driver_data(device);
 286         unsigned long long level;
 287         int offset;
 288
 289         if (acpi_video_device_lcd_get_level_current(video, &level, false))
 290                 return -EINVAL;
 291         for (offset = 2; offset < video->brightness->count; offset++)
 292                 if (level == video->brightness->levels[offset]) {
 293                         *state = video->brightness->count - offset - 1;
 294                         return 0;
 295                 }
 296
 297         return -EINVAL;
 298 }
 299
 300 static int
 301 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 302 {
 303         struct acpi_device *device = cooling_dev->devdata;
 304         struct acpi_video_device *video = acpi_driver_data(device);
 305         int level;
 306
 307         if (state >= video->brightness->count - 2)
 308                 return -EINVAL;
 309
 310         state = video->brightness->count - state;
 311         level = video->brightness->levels[state - 1];
 312         return acpi_video_device_lcd_set_level(video, level);
 313 }
 314
 315 static const struct thermal_cooling_device_ops video_cooling_ops = {
 316         .get_max_state = video_get_max_state,
 317         .get_cur_state = video_get_cur_state,
 318         .set_cur_state = video_set_cur_state,
 319 };
 320
 321 /*
 322  * --------------------------------------------------------------------------
 323  *                             Video Management
 324  * --------------------------------------------------------------------------
 325  */
 326
 327 static int
 328 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
 329                                    union acpi_object **levels)
 330 {
 331         int status;
 332         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 333         union acpi_object *obj;
 334
 335
 336         *levels = NULL;
 337
 338         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
 339         if (!ACPI_SUCCESS(status))
 340                 return status;
 341         obj = (union acpi_object *)buffer.pointer;
 342         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 343                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
 344                 status = -EFAULT;
 345                 goto err;
 346         }
 347
 348         *levels = obj;
 349
 350         return 0;
 351
 352 err:
 353         kfree(buffer.pointer);
 354
 355         return status;
 356 }
 357
 358 static int
 359 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 360 {
 361         int status;
 362         int state;
 363
 364         status = acpi_execute_simple_method(device->dev->handle,
 365                                             "_BCM", level);
 366         if (ACPI_FAILURE(status)) {
 367                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
 368                 return -EIO;
 369         }
 370
 371         device->brightness->curr = level;
 372         for (state = 2; state < device->brightness->count; state++)
 373                 if (level == device->brightness->levels[state]) {
 374                         if (device->backlight)
 375                                 device->backlight->props.brightness = state - 2;
 376                         return 0;
 377                 }
 378
 379         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
 380         return -EINVAL;
 381 }
 382
 383 /*
 384  * For some buggy _BQC methods, we need to add a constant value to
 385  * the _BQC return value to get the actual current brightness level
 386  */
 387
 388 static int bqc_offset_aml_bug_workaround;
 389 static int video_set_bqc_offset(const struct dmi_system_id *d)
 390 {
 391         bqc_offset_aml_bug_workaround = 9;
 392         return 0;
 393 }
 394
 395 static int video_disable_backlight_sysfs_if(
 396         const struct dmi_system_id *d)
 397 {
 398         if (disable_backlight_sysfs_if == -1)
 399                 disable_backlight_sysfs_if = 1;
 400         return 0;
 401 }
 402
 403 static int video_set_device_id_scheme(const struct dmi_system_id *d)
 404 {
 405         device_id_scheme = true;
 406         return 0;
 407 }
 408
 409 static int video_enable_only_lcd(const struct dmi_system_id *d)
 410 {
 411         only_lcd = true;
 412         return 0;
 413 }
 414
 415 static struct dmi_system_id video_dmi_table[] = {
 416         /*
 417          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 418          */
 419         {
 420          .callback = video_set_bqc_offset,
 421          .ident = "Acer Aspire 5720",
 422          .matches = {
 423                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 424                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 425                 },
 426         },
 427         {
 428          .callback = video_set_bqc_offset,
 429          .ident = "Acer Aspire 5710Z",
 430          .matches = {
 431                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 432                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 433                 },
 434         },
 435         {
 436          .callback = video_set_bqc_offset,
 437          .ident = "eMachines E510",
 438          .matches = {
 439                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 440                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 441                 },
 442         },
 443         {
 444          .callback = video_set_bqc_offset,
 445          .ident = "Acer Aspire 5315",
 446          .matches = {
 447                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 448                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 449                 },
 450         },
 451         {
 452          .callback = video_set_bqc_offset,
 453          .ident = "Acer Aspire 7720",
 454          .matches = {
 455                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 456                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 457                 },
 458         },
 459
 460         /*
 461          * Some machines have a broken acpi-video interface for brightness
 462          * control, but still need an acpi_video_device_lcd_set_level() call
 463          * on resume to turn the backlight power on.  We Enable backlight
 464          * control on these systems, but do not register a backlight sysfs
 465          * as brightness control does not work.
 466          */
 467         {
 468          /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
 469          .callback = video_disable_backlight_sysfs_if,
 470          .ident = "Toshiba Portege R830",
 471          .matches = {
 472                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 473                 DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
 474                 },
 475         },
 476         /*
 477          * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
 478          * but the IDs actually follow the Device ID Scheme.
 479          */
 480         {
 481          /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 482          .callback = video_set_device_id_scheme,
 483          .ident = "ESPRIMO Mobile M9410",
 484          .matches = {
 485                 DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 486                 DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 487                 },
 488         },
 489         /*
 490          * Some machines have multiple video output devices, but only the one
 491          * that is the type of LCD can do the backlight control so we should not
 492          * register backlight interface for other video output devices.
 493          */
 494         {
 495          /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 496          .callback = video_enable_only_lcd,
 497          .ident = "ESPRIMO Mobile M9410",
 498          .matches = {
 499                 DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 500                 DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 501                 },
 502         },
 503         {}
 504 };
 505
 506 static unsigned long long
 507 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 508                               unsigned long long bqc_value)
 509 {
 510         unsigned long long level;
 511
 512         if (device->brightness->flags._BQC_use_index) {
 513                 /*
 514                  * _BQC returns an index that doesn't account for
 515                  * the first 2 items with special meaning, so we need
 516                  * to compensate for that by offsetting ourselves
 517                  */
 518                 if (device->brightness->flags._BCL_reversed)
 519                         bqc_value = device->brightness->count - 3 - bqc_value;
 520
 521                 level = device->brightness->levels[bqc_value + 2];
 522         } else {
 523                 level = bqc_value;
 524         }
 525
 526         level += bqc_offset_aml_bug_workaround;
 527
 528         return level;
 529 }
 530
 531 static int
 532 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 533                                         unsigned long long *level, bool raw)
 534 {
 535         acpi_status status = AE_OK;
 536         int i;
 537
 538         if (device->cap._BQC || device->cap._BCQ) {
 539                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 540
 541                 status = acpi_evaluate_integer(device->dev->handle, buf,
 542                                                 NULL, level);
 543                 if (ACPI_SUCCESS(status)) {
 544                         if (raw) {
 545                                 /*
 546                                  * Caller has indicated he wants the raw
 547                                  * value returned by _BQC, so don't furtherly
 548                                  * mess with the value.
 549                                  */
 550                                 return 0;
 551                         }
 552
 553                         *level = acpi_video_bqc_value_to_level(device, *level);
 554
 555                         for (i = 2; i < device->brightness->count; i++)
 556                                 if (device->brightness->levels[i] == *level) {
 557                                         device->brightness->curr = *level;
 558                                         return 0;
 559                                 }
 560                         /*
 561                          * BQC returned an invalid level.
 562                          * Stop using it.
 563                          */
 564                         ACPI_WARNING((AE_INFO,
 565                                       "%s returned an invalid level",
 566                                       buf));
 567                         device->cap._BQC = device->cap._BCQ = 0;
 568                 } else {
 569                         /*
 570                          * Fixme:
 571                          * should we return an error or ignore this failure?
 572                          * dev->brightness->curr is a cached value which stores
 573                          * the correct current backlight level in most cases.
 574                          * ACPI video backlight still works w/ buggy _BQC.
 575                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 576                          */
 577                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
 578                         device->cap._BQC = device->cap._BCQ = 0;
 579                 }
 580         }
 581
 582         *level = device->brightness->curr;
 583         return 0;
 584 }
 585
 586 static int
 587 acpi_video_device_EDID(struct acpi_video_device *device,
 588                        union acpi_object **edid, ssize_t length)
 589 {
 590         int status;
 591         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 592         union acpi_object *obj;
 593         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 594         struct acpi_object_list args = { 1, &arg0 };
 595
 596
 597         *edid = NULL;
 598
 599         if (!device)
 600                 return -ENODEV;
 601         if (length == 128)
 602                 arg0.integer.value = 1;
 603         else if (length == 256)
 604                 arg0.integer.value = 2;
 605         else
 606                 return -EINVAL;
 607
 608         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 609         if (ACPI_FAILURE(status))
 610                 return -ENODEV;
 611
 612         obj = buffer.pointer;
 613
 614         if (obj && obj->type == ACPI_TYPE_BUFFER)
 615                 *edid = obj;
 616         else {
 617                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
 618                 status = -EFAULT;
 619                 kfree(obj);
 620         }
 621
 622         return status;
 623 }
 624
 625 /* bus */
 626
 627 /*
 628  *  Arg:
 629  *      video           : video bus device pointer
 630  *      bios_flag       :
 631  *              0.      The system BIOS should NOT automatically switch(toggle)
 632  *                      the active display output.
 633  *              1.      The system BIOS should automatically switch (toggle) the
 634  *                      active display output. No switch event.
 635  *              2.      The _DGS value should be locked.
 636  *              3.      The system BIOS should not automatically switch (toggle) the
 637  *                      active display output, but instead generate the display switch
 638  *                      event notify code.
 639  *      lcd_flag        :
 640  *              0.      The system BIOS should automatically control the brightness level
 641  *                      of the LCD when the power changes from AC to DC
 642  *              1.      The system BIOS should NOT automatically control the brightness
 643  *                      level of the LCD when the power changes from AC to DC.
 644  *  Return Value:
 645  *              -EINVAL wrong arg.
 646  */
 647
 648 static int
 649 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 650 {
 651         acpi_status status;
 652
 653         if (!video->cap._DOS)
 654                 return 0;
 655
 656         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 657                 return -EINVAL;
 658         video->dos_setting = (lcd_flag << 2) | bios_flag;
 659         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 660                                             (lcd_flag << 2) | bios_flag);
 661         if (ACPI_FAILURE(status))
 662                 return -EIO;
 663
 664         return 0;
 665 }
 666
 667 /*
 668  * Simple comparison function used to sort backlight levels.
 669  */
 670
 671 static int
 672 acpi_video_cmp_level(const void *a, const void *b)
 673 {
 674         return *(int *)a - *(int *)b;
 675 }
 676
 677 /*
 678  * Decides if _BQC/_BCQ for this system is usable
 679  *
 680  * We do this by changing the level first and then read out the current
 681  * brightness level, if the value does not match, find out if it is using
 682  * index. If not, clear the _BQC/_BCQ capability.
 683  */
 684 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 685                                 int max_level, int current_level)
 686 {
 687         struct acpi_video_device_brightness *br = device->brightness;
 688         int result;
 689         unsigned long long level;
 690         int test_level;
 691
 692         /* don't mess with existing known broken systems */
 693         if (bqc_offset_aml_bug_workaround)
 694                 return 0;
 695
 696         /*
 697          * Some systems always report current brightness level as maximum
 698          * through _BQC, we need to test another value for them.
 699          */
 700         test_level = current_level == max_level ? br->levels[3] : max_level;
 701
 702         result = acpi_video_device_lcd_set_level(device, test_level);
 703         if (result)
 704                 return result;
 705
 706         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 707         if (result)
 708                 return result;
 709
 710         if (level != test_level) {
 711                 /* buggy _BQC found, need to find out if it uses index */
 712                 if (level < br->count) {
 713                         if (br->flags._BCL_reversed)
 714                                 level = br->count - 3 - level;
 715                         if (br->levels[level + 2] == test_level)
 716                                 br->flags._BQC_use_index = 1;
 717                 }
 718
 719                 if (!br->flags._BQC_use_index)
 720                         device->cap._BQC = device->cap._BCQ = 0;
 721         }
 722
 723         return 0;
 724 }
 725
 726
 727 /*
 728  *  Arg:
 729  *      device  : video output device (LCD, CRT, ..)
 730  *
 731  *  Return Value:
 732  *      Maximum brightness level
 733  *
 734  *  Allocate and initialize device->brightness.
 735  */
 736
 737 static int
 738 acpi_video_init_brightness(struct acpi_video_device *device)
 739 {
 740         union acpi_object *obj = NULL;
 741         int i, max_level = 0, count = 0, level_ac_battery = 0;
 742         unsigned long long level, level_old;
 743         union acpi_object *o;
 744         struct acpi_video_device_brightness *br = NULL;
 745         int result = -EINVAL;
 746         u32 value;
 747
 748         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
 749                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
 750                                                 "LCD brightness level\n"));
 751                 goto out;
 752         }
 753
 754         if (obj->package.count < 2)
 755                 goto out;
 756
 757         br = kzalloc(sizeof(*br), GFP_KERNEL);
 758         if (!br) {
 759                 printk(KERN_ERR "can't allocate memory\n");
 760                 result = -ENOMEM;
 761                 goto out;
 762         }
 763
 764         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
 765                                 GFP_KERNEL);
 766         if (!br->levels) {
 767                 result = -ENOMEM;
 768                 goto out_free;
 769         }
 770
 771         for (i = 0; i < obj->package.count; i++) {
 772                 o = (union acpi_object *)&obj->package.elements[i];
 773                 if (o->type != ACPI_TYPE_INTEGER) {
 774                         printk(KERN_ERR PREFIX "Invalid data\n");
 775                         continue;
 776                 }
 777                 value = (u32) o->integer.value;
 778                 /* Skip duplicate entries */
 779                 if (count > 2 && br->levels[count - 1] == value)
 780                         continue;
 781
 782                 br->levels[count] = value;
 783
 784                 if (br->levels[count] > max_level)
 785                         max_level = br->levels[count];
 786                 count++;
 787         }
 788
 789         /*
 790          * some buggy BIOS don't export the levels
 791          * when machine is on AC/Battery in _BCL package.
 792          * In this case, the first two elements in _BCL packages
 793          * are also supported brightness levels that OS should take care of.
 794          */
 795         for (i = 2; i < count; i++) {
 796                 if (br->levels[i] == br->levels[0])
 797                         level_ac_battery++;
 798                 if (br->levels[i] == br->levels[1])
 799                         level_ac_battery++;
 800         }
 801
 802         if (level_ac_battery < 2) {
 803                 level_ac_battery = 2 - level_ac_battery;
 804                 br->flags._BCL_no_ac_battery_levels = 1;
 805                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
 806                         br->levels[i] = br->levels[i - level_ac_battery];
 807                 count += level_ac_battery;
 808         } else if (level_ac_battery > 2)
 809                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
 810
 811         /* Check if the _BCL package is in a reversed order */
 812         if (max_level == br->levels[2]) {
 813                 br->flags._BCL_reversed = 1;
 814                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
 815                         acpi_video_cmp_level, NULL);
 816         } else if (max_level != br->levels[count - 1])
 817                 ACPI_ERROR((AE_INFO,
 818                             "Found unordered _BCL package"));
 819
 820         br->count = count;
 821         device->brightness = br;
 822
 823         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 824         br->curr = level = max_level;
 825
 826         if (!device->cap._BQC)
 827                 goto set_level;
 828
 829         result = acpi_video_device_lcd_get_level_current(device,
 830                                                          &level_old, true);
 831         if (result)
 832                 goto out_free_levels;
 833
 834         result = acpi_video_bqc_quirk(device, max_level, level_old);
 835         if (result)
 836                 goto out_free_levels;
 837         /*
 838          * cap._BQC may get cleared due to _BQC is found to be broken
 839          * in acpi_video_bqc_quirk, so check again here.
 840          */
 841         if (!device->cap._BQC)
 842                 goto set_level;
 843
 844         level = acpi_video_bqc_value_to_level(device, level_old);
 845         /*
 846          * On some buggy laptops, _BQC returns an uninitialized
 847          * value when invoked for the first time, i.e.
 848          * level_old is invalid (no matter whether it's a level
 849          * or an index). Set the backlight to max_level in this case.
 850          */
 851         for (i = 2; i < br->count; i++)
 852                 if (level == br->levels[i])
 853                         break;
 854         if (i == br->count || !level)
 855                 level = max_level;
 856
 857 set_level:
 858         result = acpi_video_device_lcd_set_level(device, level);
 859         if (result)
 860                 goto out_free_levels;
 861
 862         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 863                           "found %d brightness levels\n", count - 2));
 864         kfree(obj);
 865         return result;
 866
 867 out_free_levels:
 868         kfree(br->levels);
 869 out_free:
 870         kfree(br);
 871 out:
 872         device->brightness = NULL;
 873         kfree(obj);
 874         return result;
 875 }
 876
 877 /*
 878  *  Arg:
 879  *      device  : video output device (LCD, CRT, ..)
 880  *
 881  *  Return Value:
 882  *      None
 883  *
 884  *  Find out all required AML methods defined under the output
 885  *  device.
 886  */
 887
 888 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 889 {
 890         if (acpi_has_method(device->dev->handle, "_ADR"))
 891                 device->cap._ADR = 1;
 892         if (acpi_has_method(device->dev->handle, "_BCL"))
 893                 device->cap._BCL = 1;
 894         if (acpi_has_method(device->dev->handle, "_BCM"))
 895                 device->cap._BCM = 1;
 896         if (acpi_has_method(device->dev->handle, "_BQC")) {
 897                 device->cap._BQC = 1;
 898         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 899                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
 900                 device->cap._BCQ = 1;
 901         }
 902
 903         if (acpi_has_method(device->dev->handle, "_DDC"))
 904                 device->cap._DDC = 1;
 905 }
 906
 907 /*
 908  *  Arg:
 909  *      device  : video output device (VGA)
 910  *
 911  *  Return Value:
 912  *      None
 913  *
 914  *  Find out all required AML methods defined under the video bus device.
 915  */
 916
 917 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
 918 {
 919         if (acpi_has_method(video->device->handle, "_DOS"))
 920                 video->cap._DOS = 1;
 921         if (acpi_has_method(video->device->handle, "_DOD"))
 922                 video->cap._DOD = 1;
 923         if (acpi_has_method(video->device->handle, "_ROM"))
 924                 video->cap._ROM = 1;
 925         if (acpi_has_method(video->device->handle, "_GPD"))
 926                 video->cap._GPD = 1;
 927         if (acpi_has_method(video->device->handle, "_SPD"))
 928                 video->cap._SPD = 1;
 929         if (acpi_has_method(video->device->handle, "_VPO"))
 930                 video->cap._VPO = 1;
 931 }
 932
 933 /*
 934  * Check whether the video bus device has required AML method to
 935  * support the desired features
 936  */
 937
 938 static int acpi_video_bus_check(struct acpi_video_bus *video)
 939 {
 940         acpi_status status = -ENOENT;
 941         struct pci_dev *dev;
 942
 943         if (!video)
 944                 return -EINVAL;
 945
 946         dev = acpi_get_pci_dev(video->device->handle);
 947         if (!dev)
 948                 return -ENODEV;
 949         pci_dev_put(dev);
 950
 951         /*
 952          * Since there is no HID, CID and so on for VGA driver, we have
 953          * to check well known required nodes.
 954          */
 955
 956         /* Does this device support video switching? */
 957         if (video->cap._DOS || video->cap._DOD) {
 958                 if (!video->cap._DOS) {
 959                         printk(KERN_WARNING FW_BUG
 960                                 "ACPI(%s) defines _DOD but not _DOS\n",
 961                                 acpi_device_bid(video->device));
 962                 }
 963                 video->flags.multihead = 1;
 964                 status = 0;
 965         }
 966
 967         /* Does this device support retrieving a video ROM? */
 968         if (video->cap._ROM) {
 969                 video->flags.rom = 1;
 970                 status = 0;
 971         }
 972
 973         /* Does this device support configuring which video device to POST? */
 974         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
 975                 video->flags.post = 1;
 976                 status = 0;
 977         }
 978
 979         return status;
 980 }
 981
 982 /*
 983  * --------------------------------------------------------------------------
 984  *                               Driver Interface
 985  * --------------------------------------------------------------------------
 986  */
 987
 988 /* device interface */
 989 static struct acpi_video_device_attrib *
 990 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
 991 {
 992         struct acpi_video_enumerated_device *ids;
 993         int i;
 994
 995         for (i = 0; i < video->attached_count; i++) {
 996                 ids = &video->attached_array[i];
 997                 if ((ids->value.int_val & 0xffff) == device_id)
 998                         return &ids->value.attrib;
 999         }
1000
1001         return NULL;
1002 }
1003
1004 static int
1005 acpi_video_get_device_type(struct acpi_video_bus *video,
1006                            unsigned long device_id)
1007 {
1008         struct acpi_video_enumerated_device *ids;
1009         int i;
1010
1011         for (i = 0; i < video->attached_count; i++) {
1012                 ids = &video->attached_array[i];
1013                 if ((ids->value.int_val & 0xffff) == device_id)
1014                         return ids->value.int_val;
1015         }
1016
1017         return 0;
1018 }
1019
1020 static int
1021 acpi_video_bus_get_one_device(struct acpi_device *device,
1022                               struct acpi_video_bus *video)
1023 {
1024         unsigned long long device_id;
1025         int status, device_type;
1026         struct acpi_video_device *data;
1027         struct acpi_video_device_attrib *attribute;
1028
1029         status =
1030             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1031         /* Some device omits _ADR, we skip them instead of fail */
1032         if (ACPI_FAILURE(status))
1033                 return 0;
1034
1035         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1036         if (!data)
1037                 return -ENOMEM;
1038
1039         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1040         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1041         device->driver_data = data;
1042
1043         data->device_id = device_id;
1044         data->video = video;
1045         data->dev = device;
1046         INIT_DELAYED_WORK(&data->switch_brightness_work,
1047                           acpi_video_switch_brightness);
1048
1049         attribute = acpi_video_get_device_attr(video, device_id);
1050
1051         if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1052                 switch (attribute->display_type) {
1053                 case ACPI_VIDEO_DISPLAY_CRT:
1054                         data->flags.crt = 1;
1055                         break;
1056                 case ACPI_VIDEO_DISPLAY_TV:
1057                         data->flags.tvout = 1;
1058                         break;
1059                 case ACPI_VIDEO_DISPLAY_DVI:
1060                         data->flags.dvi = 1;
1061                         break;
1062                 case ACPI_VIDEO_DISPLAY_LCD:
1063                         data->flags.lcd = 1;
1064                         break;
1065                 default:
1066                         data->flags.unknown = 1;
1067                         break;
1068                 }
1069                 if (attribute->bios_can_detect)
1070                         data->flags.bios = 1;
1071         } else {
1072                 /* Check for legacy IDs */
1073                 device_type = acpi_video_get_device_type(video, device_id);
1074                 /* Ignore bits 16 and 18-20 */
1075                 switch (device_type & 0xffe2ffff) {
1076                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1077                         data->flags.crt = 1;
1078                         break;
1079                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1080                         data->flags.lcd = 1;
1081                         break;
1082                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1083                         data->flags.tvout = 1;
1084                         break;
1085                 default:
1086                         data->flags.unknown = 1;
1087                 }
1088         }
1089
1090         acpi_video_device_bind(video, data);
1091         acpi_video_device_find_cap(data);
1092
1093         mutex_lock(&video->device_list_lock);
1094         list_add_tail(&data->entry, &video->video_device_list);
1095         mutex_unlock(&video->device_list_lock);
1096
1097         return status;
1098 }
1099
1100 /*
1101  *  Arg:
1102  *      video   : video bus device
1103  *
1104  *  Return:
1105  *      none
1106  *
1107  *  Enumerate the video device list of the video bus,
1108  *  bind the ids with the corresponding video devices
1109  *  under the video bus.
1110  */
1111
1112 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1113 {
1114         struct acpi_video_device *dev;
1115
1116         mutex_lock(&video->device_list_lock);
1117
1118         list_for_each_entry(dev, &video->video_device_list, entry)
1119                 acpi_video_device_bind(video, dev);
1120
1121         mutex_unlock(&video->device_list_lock);
1122 }
1123
1124 /*
1125  *  Arg:
1126  *      video   : video bus device
1127  *      device  : video output device under the video
1128  *              bus
1129  *
1130  *  Return:
1131  *      none
1132  *
1133  *  Bind the ids with the corresponding video devices
1134  *  under the video bus.
1135  */
1136
1137 static void
1138 acpi_video_device_bind(struct acpi_video_bus *video,
1139                        struct acpi_video_device *device)
1140 {
1141         struct acpi_video_enumerated_device *ids;
1142         int i;
1143
1144         for (i = 0; i < video->attached_count; i++) {
1145                 ids = &video->attached_array[i];
1146                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1147                         ids->bind_info = device;
1148                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1149                 }
1150         }
1151 }
1152
1153 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1154 {
1155         struct acpi_video_bus *video = device->video;
1156         int i;
1157
1158         /*
1159          * If we have a broken _DOD or we have more than 8 output devices
1160          * under the graphics controller node that we can't proper deal with
1161          * in the operation region code currently, no need to test.
1162          */
1163         if (!video->attached_count || video->child_count > 8)
1164                 return true;
1165
1166         for (i = 0; i < video->attached_count; i++) {
1167                 if ((video->attached_array[i].value.int_val & 0xfff) ==
1168                     (device->device_id & 0xfff))
1169                         return true;
1170         }
1171
1172         return false;
1173 }
1174
1175 /*
1176  *  Arg:
1177  *      video   : video bus device
1178  *
1179  *  Return:
1180  *      < 0     : error
1181  *
1182  *  Call _DOD to enumerate all devices attached to display adapter
1183  *
1184  */
1185
1186 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1187 {
1188         int status;
1189         int count;
1190         int i;
1191         struct acpi_video_enumerated_device *active_list;
1192         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1193         union acpi_object *dod = NULL;
1194         union acpi_object *obj;
1195
1196         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1197         if (!ACPI_SUCCESS(status)) {
1198                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1199                 return status;
1200         }
1201
1202         dod = buffer.pointer;
1203         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1204                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1205                 status = -EFAULT;
1206                 goto out;
1207         }
1208
1209         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1210                           dod->package.count));
1211
1212         active_list = kcalloc(1 + dod->package.count,
1213                               sizeof(struct acpi_video_enumerated_device),
1214                               GFP_KERNEL);
1215         if (!active_list) {
1216                 status = -ENOMEM;
1217                 goto out;
1218         }
1219
1220         count = 0;
1221         for (i = 0; i < dod->package.count; i++) {
1222                 obj = &dod->package.elements[i];
1223
1224                 if (obj->type != ACPI_TYPE_INTEGER) {
1225                         printk(KERN_ERR PREFIX
1226                                 "Invalid _DOD data in element %d\n", i);
1227                         continue;
1228                 }
1229
1230                 active_list[count].value.int_val = obj->integer.value;
1231                 active_list[count].bind_info = NULL;
1232                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1233                                   (int)obj->integer.value));
1234                 count++;
1235         }
1236
1237         kfree(video->attached_array);
1238
1239         video->attached_array = active_list;
1240         video->attached_count = count;
1241
1242 out:
1243         kfree(buffer.pointer);
1244         return status;
1245 }
1246
1247 static int
1248 acpi_video_get_next_level(struct acpi_video_device *device,
1249                           u32 level_current, u32 event)
1250 {
1251         int min, max, min_above, max_below, i, l, delta = 255;
1252         max = max_below = 0;
1253         min = min_above = 255;
1254         /* Find closest level to level_current */
1255         for (i = 2; i < device->brightness->count; i++) {
1256                 l = device->brightness->levels[i];
1257                 if (abs(l - level_current) < abs(delta)) {
1258                         delta = l - level_current;
1259                         if (!delta)
1260                                 break;
1261                 }
1262         }
1263         /* Ajust level_current to closest available level */
1264         level_current += delta;
1265         for (i = 2; i < device->brightness->count; i++) {
1266                 l = device->brightness->levels[i];
1267                 if (l < min)
1268                         min = l;
1269                 if (l > max)
1270                         max = l;
1271                 if (l < min_above && l > level_current)
1272                         min_above = l;
1273                 if (l > max_below && l < level_current)
1274                         max_below = l;
1275         }
1276
1277         switch (event) {
1278         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1279                 return (level_current < max) ? min_above : min;
1280         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1281                 return (level_current < max) ? min_above : max;
1282         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1283                 return (level_current > min) ? max_below : min;
1284         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1285         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1286                 return 0;
1287         default:
1288                 return level_current;
1289         }
1290 }
1291
1292 static void
1293 acpi_video_switch_brightness(struct work_struct *work)
1294 {
1295         struct acpi_video_device *device = container_of(to_delayed_work(work),
1296                              struct acpi_video_device, switch_brightness_work);
1297         unsigned long long level_current, level_next;
1298         int event = device->switch_brightness_event;
1299         int result = -EINVAL;
1300
1301         /* no warning message if acpi_backlight=vendor or a quirk is used */
1302         if (!device->backlight)
1303                 return;
1304
1305         if (!device->brightness)
1306                 goto out;
1307
1308         result = acpi_video_device_lcd_get_level_current(device,
1309                                                          &level_current,
1310                                                          false);
1311         if (result)
1312                 goto out;
1313
1314         level_next = acpi_video_get_next_level(device, level_current, event);
1315
1316         result = acpi_video_device_lcd_set_level(device, level_next);
1317
1318         if (!result)
1319                 backlight_force_update(device->backlight,
1320                                        BACKLIGHT_UPDATE_HOTKEY);
1321
1322 out:
1323         if (result)
1324                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1325 }
1326
1327 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1328                         void **edid)
1329 {
1330         struct acpi_video_bus *video;
1331         struct acpi_video_device *video_device;
1332         union acpi_object *buffer = NULL;
1333         acpi_status status;
1334         int i, length;
1335
1336         if (!device || !acpi_driver_data(device))
1337                 return -EINVAL;
1338
1339         video = acpi_driver_data(device);
1340
1341         for (i = 0; i < video->attached_count; i++) {
1342                 video_device = video->attached_array[i].bind_info;
1343                 length = 256;
1344
1345                 if (!video_device)
1346                         continue;
1347
1348                 if (!video_device->cap._DDC)
1349                         continue;
1350
1351                 if (type) {
1352                         switch (type) {
1353                         case ACPI_VIDEO_DISPLAY_CRT:
1354                                 if (!video_device->flags.crt)
1355                                         continue;
1356                                 break;
1357                         case ACPI_VIDEO_DISPLAY_TV:
1358                                 if (!video_device->flags.tvout)
1359                                         continue;
1360                                 break;
1361                         case ACPI_VIDEO_DISPLAY_DVI:
1362                                 if (!video_device->flags.dvi)
1363                                         continue;
1364                                 break;
1365                         case ACPI_VIDEO_DISPLAY_LCD:
1366                                 if (!video_device->flags.lcd)
1367                                         continue;
1368                                 break;
1369                         }
1370                 } else if (video_device->device_id != device_id) {
1371                         continue;
1372                 }
1373
1374                 status = acpi_video_device_EDID(video_device, &buffer, length);
1375
1376                 if (ACPI_FAILURE(status) || !buffer ||
1377                     buffer->type != ACPI_TYPE_BUFFER) {
1378                         length = 128;
1379                         status = acpi_video_device_EDID(video_device, &buffer,
1380                                                         length);
1381                         if (ACPI_FAILURE(status) || !buffer ||
1382                             buffer->type != ACPI_TYPE_BUFFER) {
1383                                 continue;
1384                         }
1385                 }
1386
1387                 *edid = buffer->buffer.pointer;
1388                 return length;
1389         }
1390
1391         return -ENODEV;
1392 }
1393 EXPORT_SYMBOL(acpi_video_get_edid);
1394
1395 static int
1396 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1397                            struct acpi_device *device)
1398 {
1399         int status = 0;
1400         struct acpi_device *dev;
1401
1402         /*
1403          * There are systems where video module known to work fine regardless
1404          * of broken _DOD and ignoring returned value here doesn't cause
1405          * any issues later.
1406          */
1407         acpi_video_device_enumerate(video);
1408
1409         list_for_each_entry(dev, &device->children, node) {
1410
1411                 status = acpi_video_bus_get_one_device(dev, video);
1412                 if (status) {
1413                         dev_err(&dev->dev, "Can't attach device\n");
1414                         break;
1415                 }
1416                 video->child_count++;
1417         }
1418         return status;
1419 }
1420
1421 /* acpi_video interface */
1422
1423 /*
1424  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1425  * preform any automatic brightness change on receiving a notification.
1426  */
1427 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1428 {
1429         return acpi_video_bus_DOS(video, 0,
1430                                   acpi_osi_is_win8() ? 1 : 0);
1431 }
1432
1433 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1434 {
1435         return acpi_video_bus_DOS(video, 0,
1436                                   acpi_osi_is_win8() ? 0 : 1);
1437 }
1438
1439 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1440 {
1441         struct acpi_video_bus *video = acpi_driver_data(device);
1442         struct input_dev *input;
1443         int keycode = 0;
1444
1445         if (!video || !video->input)
1446                 return;
1447
1448         input = video->input;
1449
1450         switch (event) {
1451         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1452                                          * most likely via hotkey. */
1453                 keycode = KEY_SWITCHVIDEOMODE;
1454                 break;
1455
1456         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1457                                          * connector. */
1458                 acpi_video_device_enumerate(video);
1459                 acpi_video_device_rebind(video);
1460                 keycode = KEY_SWITCHVIDEOMODE;
1461                 break;
1462
1463         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1464                 keycode = KEY_SWITCHVIDEOMODE;
1465                 break;
1466         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1467                 keycode = KEY_VIDEO_NEXT;
1468                 break;
1469         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1470                 keycode = KEY_VIDEO_PREV;
1471                 break;
1472
1473         default:
1474                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1475                                   "Unsupported event [0x%x]\n", event));
1476                 break;
1477         }
1478
1479         if (acpi_notifier_call_chain(device, event, 0))
1480                 /* Something vetoed the keypress. */
1481                 keycode = 0;
1482
1483         if (keycode) {
1484                 input_report_key(input, keycode, 1);
1485                 input_sync(input);
1486                 input_report_key(input, keycode, 0);
1487                 input_sync(input);
1488         }
1489
1490         return;
1491 }
1492
1493 static void brightness_switch_event(struct acpi_video_device *video_device,
1494                                     u32 event)
1495 {
1496         if (!brightness_switch_enabled)
1497                 return;
1498
1499         video_device->switch_brightness_event = event;
1500         schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1501 }
1502
1503 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1504 {
1505         struct acpi_video_device *video_device = data;
1506         struct acpi_device *device = NULL;
1507         struct acpi_video_bus *bus;
1508         struct input_dev *input;
1509         int keycode = 0;
1510
1511         if (!video_device)
1512                 return;
1513
1514         device = video_device->dev;
1515         bus = video_device->video;
1516         input = bus->input;
1517
1518         switch (event) {
1519         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1520                 brightness_switch_event(video_device, event);
1521                 keycode = KEY_BRIGHTNESS_CYCLE;
1522                 break;
1523         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1524                 brightness_switch_event(video_device, event);
1525                 keycode = KEY_BRIGHTNESSUP;
1526                 break;
1527         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1528                 brightness_switch_event(video_device, event);
1529                 keycode = KEY_BRIGHTNESSDOWN;
1530                 break;
1531         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1532                 brightness_switch_event(video_device, event);
1533                 keycode = KEY_BRIGHTNESS_ZERO;
1534                 break;
1535         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1536                 brightness_switch_event(video_device, event);
1537                 keycode = KEY_DISPLAY_OFF;
1538                 break;
1539         default:
1540                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1541                                   "Unsupported event [0x%x]\n", event));
1542                 break;
1543         }
1544
1545         acpi_notifier_call_chain(device, event, 0);
1546
1547         if (keycode) {
1548                 input_report_key(input, keycode, 1);
1549                 input_sync(input);
1550                 input_report_key(input, keycode, 0);
1551                 input_sync(input);
1552         }
1553
1554         return;
1555 }
1556
1557 static int acpi_video_resume(struct notifier_block *nb,
1558                                 unsigned long val, void *ign)
1559 {
1560         struct acpi_video_bus *video;
1561         struct acpi_video_device *video_device;
1562         int i;
1563
1564         switch (val) {
1565         case PM_HIBERNATION_PREPARE:
1566         case PM_SUSPEND_PREPARE:
1567         case PM_RESTORE_PREPARE:
1568                 return NOTIFY_DONE;
1569         }
1570
1571         video = container_of(nb, struct acpi_video_bus, pm_nb);
1572
1573         dev_info(&video->device->dev, "Restoring backlight state\n");
1574
1575         for (i = 0; i < video->attached_count; i++) {
1576                 video_device = video->attached_array[i].bind_info;
1577                 if (video_device && video_device->brightness)
1578                         acpi_video_device_lcd_set_level(video_device,
1579                                         video_device->brightness->curr);
1580         }
1581
1582         return NOTIFY_OK;
1583 }
1584
1585 static acpi_status
1586 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1587                         void **return_value)
1588 {
1589         struct acpi_device *device = context;
1590         struct acpi_device *sibling;
1591         int result;
1592
1593         if (handle == device->handle)
1594                 return AE_CTRL_TERMINATE;
1595
1596         result = acpi_bus_get_device(handle, &sibling);
1597         if (result)
1598                 return AE_OK;
1599
1600         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1601                         return AE_ALREADY_EXISTS;
1602
1603         return AE_OK;
1604 }
1605
1606 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1607 {
1608         struct backlight_properties props;
1609         struct pci_dev *pdev;
1610         acpi_handle acpi_parent;
1611         struct device *parent = NULL;
1612         int result;
1613         static int count;
1614         char *name;
1615
1616         result = acpi_video_init_brightness(device);
1617         if (result)
1618                 return;
1619
1620         if (disable_backlight_sysfs_if > 0)
1621                 return;
1622
1623         name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1624         if (!name)
1625                 return;
1626         count++;
1627
1628         acpi_get_parent(device->dev->handle, &acpi_parent);
1629
1630         pdev = acpi_get_pci_dev(acpi_parent);
1631         if (pdev) {
1632                 parent = &pdev->dev;
1633                 pci_dev_put(pdev);
1634         }
1635
1636         memset(&props, 0, sizeof(struct backlight_properties));
1637         props.type = BACKLIGHT_FIRMWARE;
1638         props.max_brightness = device->brightness->count - 3;
1639         device->backlight = backlight_device_register(name,
1640                                                       parent,
1641                                                       device,
1642                                                       &acpi_backlight_ops,
1643                                                       &props);
1644         kfree(name);
1645         if (IS_ERR(device->backlight)) {
1646                 device->backlight = NULL;
1647                 return;
1648         }
1649
1650         /*
1651          * Save current brightness level in case we have to restore it
1652          * before acpi_video_device_lcd_set_level() is called next time.
1653          */
1654         device->backlight->props.brightness =
1655                         acpi_video_get_brightness(device->backlight);
1656
1657         device->cooling_dev = thermal_cooling_device_register("LCD",
1658                                 device->dev, &video_cooling_ops);
1659         if (IS_ERR(device->cooling_dev)) {
1660                 /*
1661                  * Set cooling_dev to NULL so we don't crash trying to free it.
1662                  * Also, why the hell we are returning early and not attempt to
1663                  * register video output if cooling device registration failed?
1664                  * -- dtor
1665                  */
1666                 device->cooling_dev = NULL;
1667                 return;
1668         }
1669
1670         dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1671                  device->cooling_dev->id);
1672         result = sysfs_create_link(&device->dev->dev.kobj,
1673                         &device->cooling_dev->device.kobj,
1674                         "thermal_cooling");
1675         if (result)
1676                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1677         result = sysfs_create_link(&device->cooling_dev->device.kobj,
1678                         &device->dev->dev.kobj, "device");
1679         if (result)
1680                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1681 }
1682
1683 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1684 {
1685         struct acpi_video_device *dev;
1686         union acpi_object *levels;
1687
1688         mutex_lock(&video->device_list_lock);
1689         list_for_each_entry(dev, &video->video_device_list, entry) {
1690                 if (!acpi_video_device_lcd_query_levels(dev, &levels))
1691                         kfree(levels);
1692         }
1693         mutex_unlock(&video->device_list_lock);
1694 }
1695
1696 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1697 {
1698         /*
1699          * Do not create backlight device for video output
1700          * device that is not in the enumerated list.
1701          */
1702         if (!acpi_video_device_in_dod(dev)) {
1703                 dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1704                 return false;
1705         }
1706
1707         if (only_lcd)
1708                 return dev->flags.lcd;
1709         return true;
1710 }
1711
1712 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1713 {
1714         struct acpi_video_device *dev;
1715
1716         if (video->backlight_registered)
1717                 return 0;
1718
1719         acpi_video_run_bcl_for_osi(video);
1720
1721         if (acpi_video_get_backlight_type() != acpi_backlight_video)
1722                 return 0;
1723
1724         mutex_lock(&video->device_list_lock);
1725         list_for_each_entry(dev, &video->video_device_list, entry) {
1726                 if (acpi_video_should_register_backlight(dev))
1727                         acpi_video_dev_register_backlight(dev);
1728         }
1729         mutex_unlock(&video->device_list_lock);
1730
1731         video->backlight_registered = true;
1732
1733         video->pm_nb.notifier_call = acpi_video_resume;
1734         video->pm_nb.priority = 0;
1735         return register_pm_notifier(&video->pm_nb);
1736 }
1737
1738 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1739 {
1740         if (device->backlight) {
1741                 backlight_device_unregister(device->backlight);
1742                 device->backlight = NULL;
1743         }
1744         if (device->brightness) {
1745                 kfree(device->brightness->levels);
1746                 kfree(device->brightness);
1747                 device->brightness = NULL;
1748         }
1749         if (device->cooling_dev) {
1750                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1751                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1752                 thermal_cooling_device_unregister(device->cooling_dev);
1753                 device->cooling_dev = NULL;
1754         }
1755 }
1756
1757 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1758 {
1759         struct acpi_video_device *dev;
1760         int error;
1761
1762         if (!video->backlight_registered)
1763                 return 0;
1764
1765         error = unregister_pm_notifier(&video->pm_nb);
1766
1767         mutex_lock(&video->device_list_lock);
1768         list_for_each_entry(dev, &video->video_device_list, entry)
1769                 acpi_video_dev_unregister_backlight(dev);
1770         mutex_unlock(&video->device_list_lock);
1771
1772         video->backlight_registered = false;
1773
1774         return error;
1775 }
1776
1777 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1778 {
1779         acpi_status status;
1780         struct acpi_device *adev = device->dev;
1781
1782         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1783                                              acpi_video_device_notify, device);
1784         if (ACPI_FAILURE(status))
1785                 dev_err(&adev->dev, "Error installing notify handler\n");
1786         else
1787                 device->flags.notify = 1;
1788 }
1789
1790 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1791 {
1792         struct input_dev *input;
1793         struct acpi_video_device *dev;
1794         int error;
1795
1796         video->input = input = input_allocate_device();
1797         if (!input) {
1798                 error = -ENOMEM;
1799                 goto out;
1800         }
1801
1802         error = acpi_video_bus_start_devices(video);
1803         if (error)
1804                 goto err_free_input;
1805
1806         snprintf(video->phys, sizeof(video->phys),
1807                         "%s/video/input0", acpi_device_hid(video->device));
1808
1809         input->name = acpi_device_name(video->device);
1810         input->phys = video->phys;
1811         input->id.bustype = BUS_HOST;
1812         input->id.product = 0x06;
1813         input->dev.parent = &video->device->dev;
1814         input->evbit[0] = BIT(EV_KEY);
1815         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1816         set_bit(KEY_VIDEO_NEXT, input->keybit);
1817         set_bit(KEY_VIDEO_PREV, input->keybit);
1818         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1819         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1820         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1821         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1822         set_bit(KEY_DISPLAY_OFF, input->keybit);
1823
1824         error = input_register_device(input);
1825         if (error)
1826                 goto err_stop_dev;
1827
1828         mutex_lock(&video->device_list_lock);
1829         list_for_each_entry(dev, &video->video_device_list, entry)
1830                 acpi_video_dev_add_notify_handler(dev);
1831         mutex_unlock(&video->device_list_lock);
1832
1833         return 0;
1834
1835 err_stop_dev:
1836         acpi_video_bus_stop_devices(video);
1837 err_free_input:
1838         input_free_device(input);
1839         video->input = NULL;
1840 out:
1841         return error;
1842 }
1843
1844 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1845 {
1846         if (dev->flags.notify) {
1847                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1848                                            acpi_video_device_notify);
1849                 dev->flags.notify = 0;
1850         }
1851 }
1852
1853 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1854 {
1855         struct acpi_video_device *dev;
1856
1857         mutex_lock(&video->device_list_lock);
1858         list_for_each_entry(dev, &video->video_device_list, entry)
1859                 acpi_video_dev_remove_notify_handler(dev);
1860         mutex_unlock(&video->device_list_lock);
1861
1862         acpi_video_bus_stop_devices(video);
1863         input_unregister_device(video->input);
1864         video->input = NULL;
1865 }
1866
1867 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1868 {
1869         struct acpi_video_device *dev, *next;
1870
1871         mutex_lock(&video->device_list_lock);
1872         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1873                 list_del(&dev->entry);
1874                 kfree(dev);
1875         }
1876         mutex_unlock(&video->device_list_lock);
1877
1878         return 0;
1879 }
1880
1881 static int instance;
1882
1883 static int acpi_video_bus_add(struct acpi_device *device)
1884 {
1885         struct acpi_video_bus *video;
1886         int error;
1887         acpi_status status;
1888
1889         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1890                                 device->parent->handle, 1,
1891                                 acpi_video_bus_match, NULL,
1892                                 device, NULL);
1893         if (status == AE_ALREADY_EXISTS) {
1894                 printk(KERN_WARNING FW_BUG
1895                         "Duplicate ACPI video bus devices for the"
1896                         " same VGA controller, please try module "
1897                         "parameter \"video.allow_duplicates=1\""
1898                         "if the current driver doesn't work.\n");
1899                 if (!allow_duplicates)
1900                         return -ENODEV;
1901         }
1902
1903         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1904         if (!video)
1905                 return -ENOMEM;
1906
1907         /* a hack to fix the duplicate name "VID" problem on T61 */
1908         if (!strcmp(device->pnp.bus_id, "VID")) {
1909                 if (instance)
1910                         device->pnp.bus_id[3] = '0' + instance;
1911                 instance++;
1912         }
1913         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1914         if (!strcmp(device->pnp.bus_id, "VGA")) {
1915                 if (instance)
1916                         device->pnp.bus_id[3] = '0' + instance;
1917                 instance++;
1918         }
1919
1920         video->device = device;
1921         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1922         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1923         device->driver_data = video;
1924
1925         acpi_video_bus_find_cap(video);
1926         error = acpi_video_bus_check(video);
1927         if (error)
1928                 goto err_free_video;
1929
1930         mutex_init(&video->device_list_lock);
1931         INIT_LIST_HEAD(&video->video_device_list);
1932
1933         error = acpi_video_bus_get_devices(video, device);
1934         if (error)
1935                 goto err_put_video;
1936
1937         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1938                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1939                video->flags.multihead ? "yes" : "no",
1940                video->flags.rom ? "yes" : "no",
1941                video->flags.post ? "yes" : "no");
1942         mutex_lock(&video_list_lock);
1943         list_add_tail(&video->entry, &video_bus_head);
1944         mutex_unlock(&video_list_lock);
1945
1946         acpi_video_bus_register_backlight(video);
1947         acpi_video_bus_add_notify_handler(video);
1948
1949         return 0;
1950
1951 err_put_video:
1952         acpi_video_bus_put_devices(video);
1953         kfree(video->attached_array);
1954 err_free_video:
1955         kfree(video);
1956         device->driver_data = NULL;
1957
1958         return error;
1959 }
1960
1961 static int acpi_video_bus_remove(struct acpi_device *device)
1962 {
1963         struct acpi_video_bus *video = NULL;
1964
1965
1966         if (!device || !acpi_driver_data(device))
1967                 return -EINVAL;
1968
1969         video = acpi_driver_data(device);
1970
1971         acpi_video_bus_remove_notify_handler(video);
1972         acpi_video_bus_unregister_backlight(video);
1973         acpi_video_bus_put_devices(video);
1974
1975         mutex_lock(&video_list_lock);
1976         list_del(&video->entry);
1977         mutex_unlock(&video_list_lock);
1978
1979         kfree(video->attached_array);
1980         kfree(video);
1981
1982         return 0;
1983 }
1984
1985 static int __init is_i740(struct pci_dev *dev)
1986 {
1987         if (dev->device == 0x00D1)
1988                 return 1;
1989         if (dev->device == 0x7000)
1990                 return 1;
1991         return 0;
1992 }
1993
1994 static int __init intel_opregion_present(void)
1995 {
1996         int opregion = 0;
1997         struct pci_dev *dev = NULL;
1998         u32 address;
1999
2000         for_each_pci_dev(dev) {
2001                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2002                         continue;
2003                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2004                         continue;
2005                 /* We don't want to poke around undefined i740 registers */
2006                 if (is_i740(dev))
2007                         continue;
2008                 pci_read_config_dword(dev, 0xfc, &address);
2009                 if (!address)
2010                         continue;
2011                 opregion = 1;
2012         }
2013         return opregion;
2014 }
2015
2016 int acpi_video_register(void)
2017 {
2018         int ret = 0;
2019
2020         mutex_lock(&register_count_mutex);
2021         if (register_count) {
2022                 /*
2023                  * if the function of acpi_video_register is already called,
2024                  * don't register the acpi_vide_bus again and return no error.
2025                  */
2026                 goto leave;
2027         }
2028
2029         mutex_init(&video_list_lock);
2030         INIT_LIST_HEAD(&video_bus_head);
2031
2032         dmi_check_system(video_dmi_table);
2033
2034         ret = acpi_bus_register_driver(&acpi_video_bus);
2035         if (ret)
2036                 goto leave;
2037
2038         /*
2039          * When the acpi_video_bus is loaded successfully, increase
2040          * the counter reference.
2041          */
2042         register_count = 1;
2043
2044 leave:
2045         mutex_unlock(&register_count_mutex);
2046         return ret;
2047 }
2048 EXPORT_SYMBOL(acpi_video_register);
2049
2050 void acpi_video_unregister(void)
2051 {
2052         mutex_lock(&register_count_mutex);
2053         if (register_count) {
2054                 acpi_bus_unregister_driver(&acpi_video_bus);
2055                 register_count = 0;
2056         }
2057         mutex_unlock(&register_count_mutex);
2058 }
2059 EXPORT_SYMBOL(acpi_video_unregister);
2060
2061 void acpi_video_unregister_backlight(void)
2062 {
2063         struct acpi_video_bus *video;
2064
2065         mutex_lock(&register_count_mutex);
2066         if (register_count) {
2067                 mutex_lock(&video_list_lock);
2068                 list_for_each_entry(video, &video_bus_head, entry)
2069                         acpi_video_bus_unregister_backlight(video);
2070                 mutex_unlock(&video_list_lock);
2071         }
2072         mutex_unlock(&register_count_mutex);
2073 }
2074
2075 /*
2076  * This is kind of nasty. Hardware using Intel chipsets may require
2077  * the video opregion code to be run first in order to initialise
2078  * state before any ACPI video calls are made. To handle this we defer
2079  * registration of the video class until the opregion code has run.
2080  */
2081
2082 static int __init acpi_video_init(void)
2083 {
2084         /*
2085          * Let the module load even if ACPI is disabled (e.g. due to
2086          * a broken BIOS) so that i915.ko can still be loaded on such
2087          * old systems without an AcpiOpRegion.
2088          *
2089          * acpi_video_register() will report -ENODEV later as well due
2090          * to acpi_disabled when i915.ko tries to register itself afterwards.
2091          */
2092         if (acpi_disabled)
2093                 return 0;
2094
2095         if (intel_opregion_present())
2096                 return 0;
2097
2098         return acpi_video_register();
2099 }
2100
2101 static void __exit acpi_video_exit(void)
2102 {
2103         acpi_video_detect_exit();
2104         acpi_video_unregister();
2105
2106         return;
2107 }
2108
2109 module_init(acpi_video_init);
2110 module_exit(acpi_video_exit);