drivers/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  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23  *
  24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25  */
  26
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/types.h>
  31 #include <linux/list.h>
  32 #include <linux/mutex.h>
  33 #include <linux/input.h>
  34 #include <linux/backlight.h>
  35 #include <linux/thermal.h>
  36 #include <linux/sort.h>
  37 #include <linux/pci.h>
  38 #include <linux/pci_ids.h>
  39 #include <linux/slab.h>
  40 #include <linux/dmi.h>
  41 #include <linux/suspend.h>
  42 #include <linux/acpi.h>
  43 #include <acpi/video.h>
  44 #include <asm/uaccess.h>
  45
  46 #include "internal.h"
  47
  48 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
  49 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
  50 #define ACPI_VIDEO_NOTIFY_SWITCH        0x80
  51 #define ACPI_VIDEO_NOTIFY_PROBE         0x81
  52 #define ACPI_VIDEO_NOTIFY_CYCLE         0x82
  53 #define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT   0x83
  54 #define ACPI_VIDEO_NOTIFY_PREV_OUTPUT   0x84
  55
  56 #define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS      0x85
  57 #define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS        0x86
  58 #define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS        0x87
  59 #define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS       0x88
  60 #define ACPI_VIDEO_NOTIFY_DISPLAY_OFF           0x89
  61
  62 #define MAX_NAME_LEN    20
  63
  64 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  65 ACPI_MODULE_NAME("video");
  66
  67 MODULE_AUTHOR("Bruno Ducrot");
  68 MODULE_DESCRIPTION("ACPI Video Driver");
  69 MODULE_LICENSE("GPL");
  70
  71 static bool brightness_switch_enabled = 1;
  72 module_param(brightness_switch_enabled, bool, 0644);
  73
  74 /*
  75  * By default, we don't allow duplicate ACPI video bus devices
  76  * under the same VGA controller
  77  */
  78 static bool allow_duplicates;
  79 module_param(allow_duplicates, bool, 0644);
  80
  81 /*
  82  * For Windows 8 systems: used to decide if video module
  83  * should skip registering backlight interface of its own.
  84  */
  85 static int use_native_backlight_param = -1;
  86 module_param_named(use_native_backlight, use_native_backlight_param, int, 0444);
  87 static bool use_native_backlight_dmi = false;
  88
  89 static int register_count;
  90 static struct mutex video_list_lock;
  91 static struct list_head video_bus_head;
  92 static int acpi_video_bus_add(struct acpi_device *device);
  93 static int acpi_video_bus_remove(struct acpi_device *device);
  94 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
  95
  96 static const struct acpi_device_id video_device_ids[] = {
  97         {ACPI_VIDEO_HID, 0},
  98         {"", 0},
  99 };
 100 MODULE_DEVICE_TABLE(acpi, video_device_ids);
 101
 102 static struct acpi_driver acpi_video_bus = {
 103         .name = "video",
 104         .class = ACPI_VIDEO_CLASS,
 105         .ids = video_device_ids,
 106         .ops = {
 107                 .add = acpi_video_bus_add,
 108                 .remove = acpi_video_bus_remove,
 109                 .notify = acpi_video_bus_notify,
 110                 },
 111 };
 112
 113 struct acpi_video_bus_flags {
 114         u8 multihead:1;         /* can switch video heads */
 115         u8 rom:1;               /* can retrieve a video rom */
 116         u8 post:1;              /* can configure the head to */
 117         u8 reserved:5;
 118 };
 119
 120 struct acpi_video_bus_cap {
 121         u8 _DOS:1;              /* Enable/Disable output switching */
 122         u8 _DOD:1;              /* Enumerate all devices attached to display adapter */
 123         u8 _ROM:1;              /* Get ROM Data */
 124         u8 _GPD:1;              /* Get POST Device */
 125         u8 _SPD:1;              /* Set POST Device */
 126         u8 _VPO:1;              /* Video POST Options */
 127         u8 reserved:2;
 128 };
 129
 130 struct acpi_video_device_attrib {
 131         u32 display_index:4;    /* A zero-based instance of the Display */
 132         u32 display_port_attachment:4;  /* This field differentiates the display type */
 133         u32 display_type:4;     /* Describe the specific type in use */
 134         u32 vendor_specific:4;  /* Chipset Vendor Specific */
 135         u32 bios_can_detect:1;  /* BIOS can detect the device */
 136         u32 depend_on_vga:1;    /* Non-VGA output device whose power is related to
 137                                    the VGA device. */
 138         u32 pipe_id:3;          /* For VGA multiple-head devices. */
 139         u32 reserved:10;        /* Must be 0 */
 140         u32 device_id_scheme:1; /* Device ID Scheme */
 141 };
 142
 143 struct acpi_video_enumerated_device {
 144         union {
 145                 u32 int_val;
 146                 struct acpi_video_device_attrib attrib;
 147         } value;
 148         struct acpi_video_device *bind_info;
 149 };
 150
 151 struct acpi_video_bus {
 152         struct acpi_device *device;
 153         u8 dos_setting;
 154         struct acpi_video_enumerated_device *attached_array;
 155         u8 attached_count;
 156         struct acpi_video_bus_cap cap;
 157         struct acpi_video_bus_flags flags;
 158         struct list_head video_device_list;
 159         struct mutex device_list_lock;  /* protects video_device_list */
 160         struct list_head entry;
 161         struct input_dev *input;
 162         char phys[32];  /* for input device */
 163         struct notifier_block pm_nb;
 164 };
 165
 166 struct acpi_video_device_flags {
 167         u8 crt:1;
 168         u8 lcd:1;
 169         u8 tvout:1;
 170         u8 dvi:1;
 171         u8 bios:1;
 172         u8 unknown:1;
 173         u8 notify:1;
 174         u8 reserved:1;
 175 };
 176
 177 struct acpi_video_device_cap {
 178         u8 _ADR:1;              /* Return the unique ID */
 179         u8 _BCL:1;              /* Query list of brightness control levels supported */
 180         u8 _BCM:1;              /* Set the brightness level */
 181         u8 _BQC:1;              /* Get current brightness level */
 182         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
 183         u8 _DDC:1;              /* Return the EDID for this device */
 184 };
 185
 186 struct acpi_video_brightness_flags {
 187         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
 188         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
 189         u8 _BQC_use_index:1;            /* _BQC returns an index value */
 190 };
 191
 192 struct acpi_video_device_brightness {
 193         int curr;
 194         int count;
 195         int *levels;
 196         struct acpi_video_brightness_flags flags;
 197 };
 198
 199 struct acpi_video_device {
 200         unsigned long device_id;
 201         struct acpi_video_device_flags flags;
 202         struct acpi_video_device_cap cap;
 203         struct list_head entry;
 204         struct acpi_video_bus *video;
 205         struct acpi_device *dev;
 206         struct acpi_video_device_brightness *brightness;
 207         struct backlight_device *backlight;
 208         struct thermal_cooling_device *cooling_dev;
 209 };
 210
 211 static const char device_decode[][30] = {
 212         "motherboard VGA device",
 213         "PCI VGA device",
 214         "AGP VGA device",
 215         "UNKNOWN",
 216 };
 217
 218 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 219 static void acpi_video_device_rebind(struct acpi_video_bus *video);
 220 static void acpi_video_device_bind(struct acpi_video_bus *video,
 221                                    struct acpi_video_device *device);
 222 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 223 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 224                         int level);
 225 static int acpi_video_device_lcd_get_level_current(
 226                         struct acpi_video_device *device,
 227                         unsigned long long *level, bool raw);
 228 static int acpi_video_get_next_level(struct acpi_video_device *device,
 229                                      u32 level_current, u32 event);
 230 static int acpi_video_switch_brightness(struct acpi_video_device *device,
 231                                          int event);
 232
 233 static bool acpi_video_use_native_backlight(void)
 234 {
 235         if (use_native_backlight_param != -1)
 236                 return use_native_backlight_param;
 237         else
 238                 return use_native_backlight_dmi;
 239 }
 240
 241 static bool acpi_video_verify_backlight_support(void)
 242 {
 243         if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
 244             backlight_device_registered(BACKLIGHT_RAW))
 245                 return false;
 246         return acpi_video_backlight_support();
 247 }
 248
 249 /* backlight device sysfs support */
 250 static int acpi_video_get_brightness(struct backlight_device *bd)
 251 {
 252         unsigned long long cur_level;
 253         int i;
 254         struct acpi_video_device *vd = bl_get_data(bd);
 255
 256         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 257                 return -EINVAL;
 258         for (i = 2; i < vd->brightness->count; i++) {
 259                 if (vd->brightness->levels[i] == cur_level)
 260                         /*
 261                          * The first two entries are special - see page 575
 262                          * of the ACPI spec 3.0
 263                          */
 264                         return i - 2;
 265         }
 266         return 0;
 267 }
 268
 269 static int acpi_video_set_brightness(struct backlight_device *bd)
 270 {
 271         int request_level = bd->props.brightness + 2;
 272         struct acpi_video_device *vd = bl_get_data(bd);
 273
 274         return acpi_video_device_lcd_set_level(vd,
 275                                 vd->brightness->levels[request_level]);
 276 }
 277
 278 static const struct backlight_ops acpi_backlight_ops = {
 279         .get_brightness = acpi_video_get_brightness,
 280         .update_status  = acpi_video_set_brightness,
 281 };
 282
 283 /* thermal cooling device callbacks */
 284 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
 285                                long *state)
 286 {
 287         struct acpi_device *device = cooling_dev->devdata;
 288         struct acpi_video_device *video = acpi_driver_data(device);
 289
 290         *state = video->brightness->count - 3;
 291         return 0;
 292 }
 293
 294 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
 295                                long *state)
 296 {
 297         struct acpi_device *device = cooling_dev->devdata;
 298         struct acpi_video_device *video = acpi_driver_data(device);
 299         unsigned long long level;
 300         int offset;
 301
 302         if (acpi_video_device_lcd_get_level_current(video, &level, false))
 303                 return -EINVAL;
 304         for (offset = 2; offset < video->brightness->count; offset++)
 305                 if (level == video->brightness->levels[offset]) {
 306                         *state = video->brightness->count - offset - 1;
 307                         return 0;
 308                 }
 309
 310         return -EINVAL;
 311 }
 312
 313 static int
 314 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 315 {
 316         struct acpi_device *device = cooling_dev->devdata;
 317         struct acpi_video_device *video = acpi_driver_data(device);
 318         int level;
 319
 320         if (state >= video->brightness->count - 2)
 321                 return -EINVAL;
 322
 323         state = video->brightness->count - state;
 324         level = video->brightness->levels[state - 1];
 325         return acpi_video_device_lcd_set_level(video, level);
 326 }
 327
 328 static const struct thermal_cooling_device_ops video_cooling_ops = {
 329         .get_max_state = video_get_max_state,
 330         .get_cur_state = video_get_cur_state,
 331         .set_cur_state = video_set_cur_state,
 332 };
 333
 334 /*
 335  * --------------------------------------------------------------------------
 336  *                             Video Management
 337  * --------------------------------------------------------------------------
 338  */
 339
 340 static int
 341 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
 342                                    union acpi_object **levels)
 343 {
 344         int status;
 345         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 346         union acpi_object *obj;
 347
 348
 349         *levels = NULL;
 350
 351         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
 352         if (!ACPI_SUCCESS(status))
 353                 return status;
 354         obj = (union acpi_object *)buffer.pointer;
 355         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 356                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
 357                 status = -EFAULT;
 358                 goto err;
 359         }
 360
 361         *levels = obj;
 362
 363         return 0;
 364
 365 err:
 366         kfree(buffer.pointer);
 367
 368         return status;
 369 }
 370
 371 static int
 372 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 373 {
 374         int status;
 375         int state;
 376
 377         status = acpi_execute_simple_method(device->dev->handle,
 378                                             "_BCM", level);
 379         if (ACPI_FAILURE(status)) {
 380                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
 381                 return -EIO;
 382         }
 383
 384         device->brightness->curr = level;
 385         for (state = 2; state < device->brightness->count; state++)
 386                 if (level == device->brightness->levels[state]) {
 387                         if (device->backlight)
 388                                 device->backlight->props.brightness = state - 2;
 389                         return 0;
 390                 }
 391
 392         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
 393         return -EINVAL;
 394 }
 395
 396 /*
 397  * For some buggy _BQC methods, we need to add a constant value to
 398  * the _BQC return value to get the actual current brightness level
 399  */
 400
 401 static int bqc_offset_aml_bug_workaround;
 402 static int __init video_set_bqc_offset(const struct dmi_system_id *d)
 403 {
 404         bqc_offset_aml_bug_workaround = 9;
 405         return 0;
 406 }
 407
 408 static int __init video_set_use_native_backlight(const struct dmi_system_id *d)
 409 {
 410         use_native_backlight_dmi = true;
 411         return 0;
 412 }
 413
 414 static struct dmi_system_id video_dmi_table[] __initdata = {
 415         /*
 416          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 417          */
 418         {
 419          .callback = video_set_bqc_offset,
 420          .ident = "Acer Aspire 5720",
 421          .matches = {
 422                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 423                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 424                 },
 425         },
 426         {
 427          .callback = video_set_bqc_offset,
 428          .ident = "Acer Aspire 5710Z",
 429          .matches = {
 430                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 431                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 432                 },
 433         },
 434         {
 435          .callback = video_set_bqc_offset,
 436          .ident = "eMachines E510",
 437          .matches = {
 438                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 439                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 440                 },
 441         },
 442         {
 443          .callback = video_set_bqc_offset,
 444          .ident = "Acer Aspire 5315",
 445          .matches = {
 446                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 447                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 448                 },
 449         },
 450         {
 451          .callback = video_set_bqc_offset,
 452          .ident = "Acer Aspire 7720",
 453          .matches = {
 454                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 455                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 456                 },
 457         },
 458         {
 459          .callback = video_set_use_native_backlight,
 460          .ident = "ThinkPad T430 and T430s",
 461          .matches = {
 462                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 463                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T430"),
 464                 },
 465         },
 466         {
 467          .callback = video_set_use_native_backlight,
 468          .ident = "ThinkPad X230",
 469          .matches = {
 470                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 471                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X230"),
 472                 },
 473         },
 474         {
 475          .callback = video_set_use_native_backlight,
 476          .ident = "ThinkPad T530",
 477          .matches = {
 478                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 479                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T530"),
 480                 },
 481         },
 482         {
 483         .callback = video_set_use_native_backlight,
 484         .ident = "ThinkPad X1 Carbon",
 485         .matches = {
 486                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 487                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon"),
 488                 },
 489         },
 490         {
 491          .callback = video_set_use_native_backlight,
 492          .ident = "Lenovo Yoga 13",
 493          .matches = {
 494                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 495                 DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Yoga 13"),
 496                 },
 497         },
 498         {
 499         .callback = video_set_use_native_backlight,
 500         .ident = "Thinkpad Helix",
 501         .matches = {
 502                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 503                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad Helix"),
 504                 },
 505         },
 506         {
 507          .callback = video_set_use_native_backlight,
 508          .ident = "Dell Inspiron 7520",
 509          .matches = {
 510                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 511                 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7520"),
 512                 },
 513         },
 514         {
 515          .callback = video_set_use_native_backlight,
 516          .ident = "Acer Aspire 5733Z",
 517          .matches = {
 518                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 519                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5733Z"),
 520                 },
 521         },
 522         {
 523          .callback = video_set_use_native_backlight,
 524          .ident = "Acer Aspire 5742G",
 525          .matches = {
 526                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 527                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5742G"),
 528                 },
 529         },
 530         {
 531          .callback = video_set_use_native_backlight,
 532          .ident = "Acer Aspire V5-431",
 533          .matches = {
 534                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 535                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-431"),
 536                 },
 537         },
 538         {
 539         .callback = video_set_use_native_backlight,
 540         .ident = "HP ProBook 4340s",
 541         .matches = {
 542                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 543                 DMI_MATCH(DMI_PRODUCT_VERSION, "HP ProBook 4340s"),
 544                 },
 545         },
 546         {
 547         .callback = video_set_use_native_backlight,
 548         .ident = "HP ProBook 2013 models",
 549         .matches = {
 550                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 551                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ProBook "),
 552                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
 553                 },
 554         },
 555         {
 556         .callback = video_set_use_native_backlight,
 557         .ident = "HP EliteBook 2013 models",
 558         .matches = {
 559                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 560                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook "),
 561                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
 562                 },
 563         },
 564         {
 565         .callback = video_set_use_native_backlight,
 566         .ident = "HP ZBook 14",
 567         .matches = {
 568                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 569                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 14"),
 570                 },
 571         },
 572         {
 573         .callback = video_set_use_native_backlight,
 574         .ident = "HP ZBook 15",
 575         .matches = {
 576                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 577                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 15"),
 578                 },
 579         },
 580         {
 581         .callback = video_set_use_native_backlight,
 582         .ident = "HP ZBook 17",
 583         .matches = {
 584                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 585                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 17"),
 586                 },
 587         },
 588         {
 589         .callback = video_set_use_native_backlight,
 590         .ident = "HP EliteBook 8780w",
 591         .matches = {
 592                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 593                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
 594                 },
 595         },
 596         {}
 597 };
 598
 599 static unsigned long long
 600 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 601                               unsigned long long bqc_value)
 602 {
 603         unsigned long long level;
 604
 605         if (device->brightness->flags._BQC_use_index) {
 606                 /*
 607                  * _BQC returns an index that doesn't account for
 608                  * the first 2 items with special meaning, so we need
 609                  * to compensate for that by offsetting ourselves
 610                  */
 611                 if (device->brightness->flags._BCL_reversed)
 612                         bqc_value = device->brightness->count - 3 - bqc_value;
 613
 614                 level = device->brightness->levels[bqc_value + 2];
 615         } else {
 616                 level = bqc_value;
 617         }
 618
 619         level += bqc_offset_aml_bug_workaround;
 620
 621         return level;
 622 }
 623
 624 static int
 625 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 626                                         unsigned long long *level, bool raw)
 627 {
 628         acpi_status status = AE_OK;
 629         int i;
 630
 631         if (device->cap._BQC || device->cap._BCQ) {
 632                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 633
 634                 status = acpi_evaluate_integer(device->dev->handle, buf,
 635                                                 NULL, level);
 636                 if (ACPI_SUCCESS(status)) {
 637                         if (raw) {
 638                                 /*
 639                                  * Caller has indicated he wants the raw
 640                                  * value returned by _BQC, so don't furtherly
 641                                  * mess with the value.
 642                                  */
 643                                 return 0;
 644                         }
 645
 646                         *level = acpi_video_bqc_value_to_level(device, *level);
 647
 648                         for (i = 2; i < device->brightness->count; i++)
 649                                 if (device->brightness->levels[i] == *level) {
 650                                         device->brightness->curr = *level;
 651                                         return 0;
 652                                 }
 653                         /*
 654                          * BQC returned an invalid level.
 655                          * Stop using it.
 656                          */
 657                         ACPI_WARNING((AE_INFO,
 658                                       "%s returned an invalid level",
 659                                       buf));
 660                         device->cap._BQC = device->cap._BCQ = 0;
 661                 } else {
 662                         /*
 663                          * Fixme:
 664                          * should we return an error or ignore this failure?
 665                          * dev->brightness->curr is a cached value which stores
 666                          * the correct current backlight level in most cases.
 667                          * ACPI video backlight still works w/ buggy _BQC.
 668                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 669                          */
 670                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
 671                         device->cap._BQC = device->cap._BCQ = 0;
 672                 }
 673         }
 674
 675         *level = device->brightness->curr;
 676         return 0;
 677 }
 678
 679 static int
 680 acpi_video_device_EDID(struct acpi_video_device *device,
 681                        union acpi_object **edid, ssize_t length)
 682 {
 683         int status;
 684         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 685         union acpi_object *obj;
 686         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 687         struct acpi_object_list args = { 1, &arg0 };
 688
 689
 690         *edid = NULL;
 691
 692         if (!device)
 693                 return -ENODEV;
 694         if (length == 128)
 695                 arg0.integer.value = 1;
 696         else if (length == 256)
 697                 arg0.integer.value = 2;
 698         else
 699                 return -EINVAL;
 700
 701         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 702         if (ACPI_FAILURE(status))
 703                 return -ENODEV;
 704
 705         obj = buffer.pointer;
 706
 707         if (obj && obj->type == ACPI_TYPE_BUFFER)
 708                 *edid = obj;
 709         else {
 710                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
 711                 status = -EFAULT;
 712                 kfree(obj);
 713         }
 714
 715         return status;
 716 }
 717
 718 /* bus */
 719
 720 /*
 721  *  Arg:
 722  *      video           : video bus device pointer
 723  *      bios_flag       :
 724  *              0.      The system BIOS should NOT automatically switch(toggle)
 725  *                      the active display output.
 726  *              1.      The system BIOS should automatically switch (toggle) the
 727  *                      active display output. No switch event.
 728  *              2.      The _DGS value should be locked.
 729  *              3.      The system BIOS should not automatically switch (toggle) the
 730  *                      active display output, but instead generate the display switch
 731  *                      event notify code.
 732  *      lcd_flag        :
 733  *              0.      The system BIOS should automatically control the brightness level
 734  *                      of the LCD when the power changes from AC to DC
 735  *              1.      The system BIOS should NOT automatically control the brightness
 736  *                      level of the LCD when the power changes from AC to DC.
 737  *  Return Value:
 738  *              -EINVAL wrong arg.
 739  */
 740
 741 static int
 742 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 743 {
 744         acpi_status status;
 745
 746         if (!video->cap._DOS)
 747                 return 0;
 748
 749         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 750                 return -EINVAL;
 751         video->dos_setting = (lcd_flag << 2) | bios_flag;
 752         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 753                                             (lcd_flag << 2) | bios_flag);
 754         if (ACPI_FAILURE(status))
 755                 return -EIO;
 756
 757         return 0;
 758 }
 759
 760 /*
 761  * Simple comparison function used to sort backlight levels.
 762  */
 763
 764 static int
 765 acpi_video_cmp_level(const void *a, const void *b)
 766 {
 767         return *(int *)a - *(int *)b;
 768 }
 769
 770 /*
 771  * Decides if _BQC/_BCQ for this system is usable
 772  *
 773  * We do this by changing the level first and then read out the current
 774  * brightness level, if the value does not match, find out if it is using
 775  * index. If not, clear the _BQC/_BCQ capability.
 776  */
 777 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 778                                 int max_level, int current_level)
 779 {
 780         struct acpi_video_device_brightness *br = device->brightness;
 781         int result;
 782         unsigned long long level;
 783         int test_level;
 784
 785         /* don't mess with existing known broken systems */
 786         if (bqc_offset_aml_bug_workaround)
 787                 return 0;
 788
 789         /*
 790          * Some systems always report current brightness level as maximum
 791          * through _BQC, we need to test another value for them.
 792          */
 793         test_level = current_level == max_level ? br->levels[3] : max_level;
 794
 795         result = acpi_video_device_lcd_set_level(device, test_level);
 796         if (result)
 797                 return result;
 798
 799         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 800         if (result)
 801                 return result;
 802
 803         if (level != test_level) {
 804                 /* buggy _BQC found, need to find out if it uses index */
 805                 if (level < br->count) {
 806                         if (br->flags._BCL_reversed)
 807                                 level = br->count - 3 - level;
 808                         if (br->levels[level + 2] == test_level)
 809                                 br->flags._BQC_use_index = 1;
 810                 }
 811
 812                 if (!br->flags._BQC_use_index)
 813                         device->cap._BQC = device->cap._BCQ = 0;
 814         }
 815
 816         return 0;
 817 }
 818
 819
 820 /*
 821  *  Arg:
 822  *      device  : video output device (LCD, CRT, ..)
 823  *
 824  *  Return Value:
 825  *      Maximum brightness level
 826  *
 827  *  Allocate and initialize device->brightness.
 828  */
 829
 830 static int
 831 acpi_video_init_brightness(struct acpi_video_device *device)
 832 {
 833         union acpi_object *obj = NULL;
 834         int i, max_level = 0, count = 0, level_ac_battery = 0;
 835         unsigned long long level, level_old;
 836         union acpi_object *o;
 837         struct acpi_video_device_brightness *br = NULL;
 838         int result = -EINVAL;
 839         u32 value;
 840
 841         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
 842                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
 843                                                 "LCD brightness level\n"));
 844                 goto out;
 845         }
 846
 847         if (obj->package.count < 2)
 848                 goto out;
 849
 850         br = kzalloc(sizeof(*br), GFP_KERNEL);
 851         if (!br) {
 852                 printk(KERN_ERR "can't allocate memory\n");
 853                 result = -ENOMEM;
 854                 goto out;
 855         }
 856
 857         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
 858                                 GFP_KERNEL);
 859         if (!br->levels) {
 860                 result = -ENOMEM;
 861                 goto out_free;
 862         }
 863
 864         for (i = 0; i < obj->package.count; i++) {
 865                 o = (union acpi_object *)&obj->package.elements[i];
 866                 if (o->type != ACPI_TYPE_INTEGER) {
 867                         printk(KERN_ERR PREFIX "Invalid data\n");
 868                         continue;
 869                 }
 870                 value = (u32) o->integer.value;
 871                 /* Skip duplicate entries */
 872                 if (count > 2 && br->levels[count - 1] == value)
 873                         continue;
 874
 875                 br->levels[count] = value;
 876
 877                 if (br->levels[count] > max_level)
 878                         max_level = br->levels[count];
 879                 count++;
 880         }
 881
 882         /*
 883          * some buggy BIOS don't export the levels
 884          * when machine is on AC/Battery in _BCL package.
 885          * In this case, the first two elements in _BCL packages
 886          * are also supported brightness levels that OS should take care of.
 887          */
 888         for (i = 2; i < count; i++) {
 889                 if (br->levels[i] == br->levels[0])
 890                         level_ac_battery++;
 891                 if (br->levels[i] == br->levels[1])
 892                         level_ac_battery++;
 893         }
 894
 895         if (level_ac_battery < 2) {
 896                 level_ac_battery = 2 - level_ac_battery;
 897                 br->flags._BCL_no_ac_battery_levels = 1;
 898                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
 899                         br->levels[i] = br->levels[i - level_ac_battery];
 900                 count += level_ac_battery;
 901         } else if (level_ac_battery > 2)
 902                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
 903
 904         /* Check if the _BCL package is in a reversed order */
 905         if (max_level == br->levels[2]) {
 906                 br->flags._BCL_reversed = 1;
 907                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
 908                         acpi_video_cmp_level, NULL);
 909         } else if (max_level != br->levels[count - 1])
 910                 ACPI_ERROR((AE_INFO,
 911                             "Found unordered _BCL package"));
 912
 913         br->count = count;
 914         device->brightness = br;
 915
 916         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 917         br->curr = level = max_level;
 918
 919         if (!device->cap._BQC)
 920                 goto set_level;
 921
 922         result = acpi_video_device_lcd_get_level_current(device,
 923                                                          &level_old, true);
 924         if (result)
 925                 goto out_free_levels;
 926
 927         result = acpi_video_bqc_quirk(device, max_level, level_old);
 928         if (result)
 929                 goto out_free_levels;
 930         /*
 931          * cap._BQC may get cleared due to _BQC is found to be broken
 932          * in acpi_video_bqc_quirk, so check again here.
 933          */
 934         if (!device->cap._BQC)
 935                 goto set_level;
 936
 937         level = acpi_video_bqc_value_to_level(device, level_old);
 938         /*
 939          * On some buggy laptops, _BQC returns an uninitialized
 940          * value when invoked for the first time, i.e.
 941          * level_old is invalid (no matter whether it's a level
 942          * or an index). Set the backlight to max_level in this case.
 943          */
 944         for (i = 2; i < br->count; i++)
 945                 if (level == br->levels[i])
 946                         break;
 947         if (i == br->count || !level)
 948                 level = max_level;
 949
 950 set_level:
 951         result = acpi_video_device_lcd_set_level(device, level);
 952         if (result)
 953                 goto out_free_levels;
 954
 955         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 956                           "found %d brightness levels\n", count - 2));
 957         kfree(obj);
 958         return result;
 959
 960 out_free_levels:
 961         kfree(br->levels);
 962 out_free:
 963         kfree(br);
 964 out:
 965         device->brightness = NULL;
 966         kfree(obj);
 967         return result;
 968 }
 969
 970 /*
 971  *  Arg:
 972  *      device  : video output device (LCD, CRT, ..)
 973  *
 974  *  Return Value:
 975  *      None
 976  *
 977  *  Find out all required AML methods defined under the output
 978  *  device.
 979  */
 980
 981 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 982 {
 983         if (acpi_has_method(device->dev->handle, "_ADR"))
 984                 device->cap._ADR = 1;
 985         if (acpi_has_method(device->dev->handle, "_BCL"))
 986                 device->cap._BCL = 1;
 987         if (acpi_has_method(device->dev->handle, "_BCM"))
 988                 device->cap._BCM = 1;
 989         if (acpi_has_method(device->dev->handle, "_BQC")) {
 990                 device->cap._BQC = 1;
 991         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 992                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
 993                 device->cap._BCQ = 1;
 994         }
 995
 996         if (acpi_has_method(device->dev->handle, "_DDC"))
 997                 device->cap._DDC = 1;
 998 }
 999
1000 /*
1001  *  Arg:
1002  *      device  : video output device (VGA)
1003  *
1004  *  Return Value:
1005  *      None
1006  *
1007  *  Find out all required AML methods defined under the video bus device.
1008  */
1009
1010 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1011 {
1012         if (acpi_has_method(video->device->handle, "_DOS"))
1013                 video->cap._DOS = 1;
1014         if (acpi_has_method(video->device->handle, "_DOD"))
1015                 video->cap._DOD = 1;
1016         if (acpi_has_method(video->device->handle, "_ROM"))
1017                 video->cap._ROM = 1;
1018         if (acpi_has_method(video->device->handle, "_GPD"))
1019                 video->cap._GPD = 1;
1020         if (acpi_has_method(video->device->handle, "_SPD"))
1021                 video->cap._SPD = 1;
1022         if (acpi_has_method(video->device->handle, "_VPO"))
1023                 video->cap._VPO = 1;
1024 }
1025
1026 /*
1027  * Check whether the video bus device has required AML method to
1028  * support the desired features
1029  */
1030
1031 static int acpi_video_bus_check(struct acpi_video_bus *video)
1032 {
1033         acpi_status status = -ENOENT;
1034         struct pci_dev *dev;
1035
1036         if (!video)
1037                 return -EINVAL;
1038
1039         dev = acpi_get_pci_dev(video->device->handle);
1040         if (!dev)
1041                 return -ENODEV;
1042         pci_dev_put(dev);
1043
1044         /*
1045          * Since there is no HID, CID and so on for VGA driver, we have
1046          * to check well known required nodes.
1047          */
1048
1049         /* Does this device support video switching? */
1050         if (video->cap._DOS || video->cap._DOD) {
1051                 if (!video->cap._DOS) {
1052                         printk(KERN_WARNING FW_BUG
1053                                 "ACPI(%s) defines _DOD but not _DOS\n",
1054                                 acpi_device_bid(video->device));
1055                 }
1056                 video->flags.multihead = 1;
1057                 status = 0;
1058         }
1059
1060         /* Does this device support retrieving a video ROM? */
1061         if (video->cap._ROM) {
1062                 video->flags.rom = 1;
1063                 status = 0;
1064         }
1065
1066         /* Does this device support configuring which video device to POST? */
1067         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1068                 video->flags.post = 1;
1069                 status = 0;
1070         }
1071
1072         return status;
1073 }
1074
1075 /*
1076  * --------------------------------------------------------------------------
1077  *                               Driver Interface
1078  * --------------------------------------------------------------------------
1079  */
1080
1081 /* device interface */
1082 static struct acpi_video_device_attrib *
1083 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1084 {
1085         struct acpi_video_enumerated_device *ids;
1086         int i;
1087
1088         for (i = 0; i < video->attached_count; i++) {
1089                 ids = &video->attached_array[i];
1090                 if ((ids->value.int_val & 0xffff) == device_id)
1091                         return &ids->value.attrib;
1092         }
1093
1094         return NULL;
1095 }
1096
1097 static int
1098 acpi_video_get_device_type(struct acpi_video_bus *video,
1099                            unsigned long device_id)
1100 {
1101         struct acpi_video_enumerated_device *ids;
1102         int i;
1103
1104         for (i = 0; i < video->attached_count; i++) {
1105                 ids = &video->attached_array[i];
1106                 if ((ids->value.int_val & 0xffff) == device_id)
1107                         return ids->value.int_val;
1108         }
1109
1110         return 0;
1111 }
1112
1113 static int
1114 acpi_video_bus_get_one_device(struct acpi_device *device,
1115                               struct acpi_video_bus *video)
1116 {
1117         unsigned long long device_id;
1118         int status, device_type;
1119         struct acpi_video_device *data;
1120         struct acpi_video_device_attrib *attribute;
1121
1122         status =
1123             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1124         /* Some device omits _ADR, we skip them instead of fail */
1125         if (ACPI_FAILURE(status))
1126                 return 0;
1127
1128         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1129         if (!data)
1130                 return -ENOMEM;
1131
1132         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1133         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1134         device->driver_data = data;
1135
1136         data->device_id = device_id;
1137         data->video = video;
1138         data->dev = device;
1139
1140         attribute = acpi_video_get_device_attr(video, device_id);
1141
1142         if (attribute && attribute->device_id_scheme) {
1143                 switch (attribute->display_type) {
1144                 case ACPI_VIDEO_DISPLAY_CRT:
1145                         data->flags.crt = 1;
1146                         break;
1147                 case ACPI_VIDEO_DISPLAY_TV:
1148                         data->flags.tvout = 1;
1149                         break;
1150                 case ACPI_VIDEO_DISPLAY_DVI:
1151                         data->flags.dvi = 1;
1152                         break;
1153                 case ACPI_VIDEO_DISPLAY_LCD:
1154                         data->flags.lcd = 1;
1155                         break;
1156                 default:
1157                         data->flags.unknown = 1;
1158                         break;
1159                 }
1160                 if (attribute->bios_can_detect)
1161                         data->flags.bios = 1;
1162         } else {
1163                 /* Check for legacy IDs */
1164                 device_type = acpi_video_get_device_type(video, device_id);
1165                 /* Ignore bits 16 and 18-20 */
1166                 switch (device_type & 0xffe2ffff) {
1167                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1168                         data->flags.crt = 1;
1169                         break;
1170                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1171                         data->flags.lcd = 1;
1172                         break;
1173                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1174                         data->flags.tvout = 1;
1175                         break;
1176                 default:
1177                         data->flags.unknown = 1;
1178                 }
1179         }
1180
1181         acpi_video_device_bind(video, data);
1182         acpi_video_device_find_cap(data);
1183
1184         mutex_lock(&video->device_list_lock);
1185         list_add_tail(&data->entry, &video->video_device_list);
1186         mutex_unlock(&video->device_list_lock);
1187
1188         return status;
1189 }
1190
1191 /*
1192  *  Arg:
1193  *      video   : video bus device
1194  *
1195  *  Return:
1196  *      none
1197  *
1198  *  Enumerate the video device list of the video bus,
1199  *  bind the ids with the corresponding video devices
1200  *  under the video bus.
1201  */
1202
1203 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1204 {
1205         struct acpi_video_device *dev;
1206
1207         mutex_lock(&video->device_list_lock);
1208
1209         list_for_each_entry(dev, &video->video_device_list, entry)
1210                 acpi_video_device_bind(video, dev);
1211
1212         mutex_unlock(&video->device_list_lock);
1213 }
1214
1215 /*
1216  *  Arg:
1217  *      video   : video bus device
1218  *      device  : video output device under the video
1219  *              bus
1220  *
1221  *  Return:
1222  *      none
1223  *
1224  *  Bind the ids with the corresponding video devices
1225  *  under the video bus.
1226  */
1227
1228 static void
1229 acpi_video_device_bind(struct acpi_video_bus *video,
1230                        struct acpi_video_device *device)
1231 {
1232         struct acpi_video_enumerated_device *ids;
1233         int i;
1234
1235         for (i = 0; i < video->attached_count; i++) {
1236                 ids = &video->attached_array[i];
1237                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1238                         ids->bind_info = device;
1239                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1240                 }
1241         }
1242 }
1243
1244 /*
1245  *  Arg:
1246  *      video   : video bus device
1247  *
1248  *  Return:
1249  *      < 0     : error
1250  *
1251  *  Call _DOD to enumerate all devices attached to display adapter
1252  *
1253  */
1254
1255 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1256 {
1257         int status;
1258         int count;
1259         int i;
1260         struct acpi_video_enumerated_device *active_list;
1261         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1262         union acpi_object *dod = NULL;
1263         union acpi_object *obj;
1264
1265         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1266         if (!ACPI_SUCCESS(status)) {
1267                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1268                 return status;
1269         }
1270
1271         dod = buffer.pointer;
1272         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1273                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1274                 status = -EFAULT;
1275                 goto out;
1276         }
1277
1278         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1279                           dod->package.count));
1280
1281         active_list = kcalloc(1 + dod->package.count,
1282                               sizeof(struct acpi_video_enumerated_device),
1283                               GFP_KERNEL);
1284         if (!active_list) {
1285                 status = -ENOMEM;
1286                 goto out;
1287         }
1288
1289         count = 0;
1290         for (i = 0; i < dod->package.count; i++) {
1291                 obj = &dod->package.elements[i];
1292
1293                 if (obj->type != ACPI_TYPE_INTEGER) {
1294                         printk(KERN_ERR PREFIX
1295                                 "Invalid _DOD data in element %d\n", i);
1296                         continue;
1297                 }
1298
1299                 active_list[count].value.int_val = obj->integer.value;
1300                 active_list[count].bind_info = NULL;
1301                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1302                                   (int)obj->integer.value));
1303                 count++;
1304         }
1305
1306         kfree(video->attached_array);
1307
1308         video->attached_array = active_list;
1309         video->attached_count = count;
1310
1311 out:
1312         kfree(buffer.pointer);
1313         return status;
1314 }
1315
1316 static int
1317 acpi_video_get_next_level(struct acpi_video_device *device,
1318                           u32 level_current, u32 event)
1319 {
1320         int min, max, min_above, max_below, i, l, delta = 255;
1321         max = max_below = 0;
1322         min = min_above = 255;
1323         /* Find closest level to level_current */
1324         for (i = 2; i < device->brightness->count; i++) {
1325                 l = device->brightness->levels[i];
1326                 if (abs(l - level_current) < abs(delta)) {
1327                         delta = l - level_current;
1328                         if (!delta)
1329                                 break;
1330                 }
1331         }
1332         /* Ajust level_current to closest available level */
1333         level_current += delta;
1334         for (i = 2; i < device->brightness->count; i++) {
1335                 l = device->brightness->levels[i];
1336                 if (l < min)
1337                         min = l;
1338                 if (l > max)
1339                         max = l;
1340                 if (l < min_above && l > level_current)
1341                         min_above = l;
1342                 if (l > max_below && l < level_current)
1343                         max_below = l;
1344         }
1345
1346         switch (event) {
1347         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1348                 return (level_current < max) ? min_above : min;
1349         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1350                 return (level_current < max) ? min_above : max;
1351         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1352                 return (level_current > min) ? max_below : min;
1353         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1354         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1355                 return 0;
1356         default:
1357                 return level_current;
1358         }
1359 }
1360
1361 static int
1362 acpi_video_switch_brightness(struct acpi_video_device *device, int event)
1363 {
1364         unsigned long long level_current, level_next;
1365         int result = -EINVAL;
1366
1367         /* no warning message if acpi_backlight=vendor or a quirk is used */
1368         if (!acpi_video_verify_backlight_support())
1369                 return 0;
1370
1371         if (!device->brightness)
1372                 goto out;
1373
1374         result = acpi_video_device_lcd_get_level_current(device,
1375                                                          &level_current,
1376                                                          false);
1377         if (result)
1378                 goto out;
1379
1380         level_next = acpi_video_get_next_level(device, level_current, event);
1381
1382         result = acpi_video_device_lcd_set_level(device, level_next);
1383
1384         if (!result)
1385                 backlight_force_update(device->backlight,
1386                                        BACKLIGHT_UPDATE_HOTKEY);
1387
1388 out:
1389         if (result)
1390                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1391
1392         return result;
1393 }
1394
1395 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1396                         void **edid)
1397 {
1398         struct acpi_video_bus *video;
1399         struct acpi_video_device *video_device;
1400         union acpi_object *buffer = NULL;
1401         acpi_status status;
1402         int i, length;
1403
1404         if (!device || !acpi_driver_data(device))
1405                 return -EINVAL;
1406
1407         video = acpi_driver_data(device);
1408
1409         for (i = 0; i < video->attached_count; i++) {
1410                 video_device = video->attached_array[i].bind_info;
1411                 length = 256;
1412
1413                 if (!video_device)
1414                         continue;
1415
1416                 if (!video_device->cap._DDC)
1417                         continue;
1418
1419                 if (type) {
1420                         switch (type) {
1421                         case ACPI_VIDEO_DISPLAY_CRT:
1422                                 if (!video_device->flags.crt)
1423                                         continue;
1424                                 break;
1425                         case ACPI_VIDEO_DISPLAY_TV:
1426                                 if (!video_device->flags.tvout)
1427                                         continue;
1428                                 break;
1429                         case ACPI_VIDEO_DISPLAY_DVI:
1430                                 if (!video_device->flags.dvi)
1431                                         continue;
1432                                 break;
1433                         case ACPI_VIDEO_DISPLAY_LCD:
1434                                 if (!video_device->flags.lcd)
1435                                         continue;
1436                                 break;
1437                         }
1438                 } else if (video_device->device_id != device_id) {
1439                         continue;
1440                 }
1441
1442                 status = acpi_video_device_EDID(video_device, &buffer, length);
1443
1444                 if (ACPI_FAILURE(status) || !buffer ||
1445                     buffer->type != ACPI_TYPE_BUFFER) {
1446                         length = 128;
1447                         status = acpi_video_device_EDID(video_device, &buffer,
1448                                                         length);
1449                         if (ACPI_FAILURE(status) || !buffer ||
1450                             buffer->type != ACPI_TYPE_BUFFER) {
1451                                 continue;
1452                         }
1453                 }
1454
1455                 *edid = buffer->buffer.pointer;
1456                 return length;
1457         }
1458
1459         return -ENODEV;
1460 }
1461 EXPORT_SYMBOL(acpi_video_get_edid);
1462
1463 static int
1464 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1465                            struct acpi_device *device)
1466 {
1467         int status = 0;
1468         struct acpi_device *dev;
1469
1470         /*
1471          * There are systems where video module known to work fine regardless
1472          * of broken _DOD and ignoring returned value here doesn't cause
1473          * any issues later.
1474          */
1475         acpi_video_device_enumerate(video);
1476
1477         list_for_each_entry(dev, &device->children, node) {
1478
1479                 status = acpi_video_bus_get_one_device(dev, video);
1480                 if (status) {
1481                         dev_err(&dev->dev, "Can't attach device\n");
1482                         break;
1483                 }
1484         }
1485         return status;
1486 }
1487
1488 /* acpi_video interface */
1489
1490 /*
1491  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1492  * preform any automatic brightness change on receiving a notification.
1493  */
1494 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1495 {
1496         return acpi_video_bus_DOS(video, 0,
1497                                   acpi_osi_is_win8() ? 1 : 0);
1498 }
1499
1500 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1501 {
1502         return acpi_video_bus_DOS(video, 0,
1503                                   acpi_osi_is_win8() ? 0 : 1);
1504 }
1505
1506 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1507 {
1508         struct acpi_video_bus *video = acpi_driver_data(device);
1509         struct input_dev *input;
1510         int keycode = 0;
1511
1512         if (!video || !video->input)
1513                 return;
1514
1515         input = video->input;
1516
1517         switch (event) {
1518         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1519                                          * most likely via hotkey. */
1520                 keycode = KEY_SWITCHVIDEOMODE;
1521                 break;
1522
1523         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1524                                          * connector. */
1525                 acpi_video_device_enumerate(video);
1526                 acpi_video_device_rebind(video);
1527                 keycode = KEY_SWITCHVIDEOMODE;
1528                 break;
1529
1530         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1531                 keycode = KEY_SWITCHVIDEOMODE;
1532                 break;
1533         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1534                 keycode = KEY_VIDEO_NEXT;
1535                 break;
1536         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1537                 keycode = KEY_VIDEO_PREV;
1538                 break;
1539
1540         default:
1541                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1542                                   "Unsupported event [0x%x]\n", event));
1543                 break;
1544         }
1545
1546         if (acpi_notifier_call_chain(device, event, 0))
1547                 /* Something vetoed the keypress. */
1548                 keycode = 0;
1549
1550         if (keycode) {
1551                 input_report_key(input, keycode, 1);
1552                 input_sync(input);
1553                 input_report_key(input, keycode, 0);
1554                 input_sync(input);
1555         }
1556
1557         return;
1558 }
1559
1560 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1561 {
1562         struct acpi_video_device *video_device = data;
1563         struct acpi_device *device = NULL;
1564         struct acpi_video_bus *bus;
1565         struct input_dev *input;
1566         int keycode = 0;
1567
1568         if (!video_device)
1569                 return;
1570
1571         device = video_device->dev;
1572         bus = video_device->video;
1573         input = bus->input;
1574
1575         switch (event) {
1576         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1577                 if (brightness_switch_enabled)
1578                         acpi_video_switch_brightness(video_device, event);
1579                 keycode = KEY_BRIGHTNESS_CYCLE;
1580                 break;
1581         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1582                 if (brightness_switch_enabled)
1583                         acpi_video_switch_brightness(video_device, event);
1584                 keycode = KEY_BRIGHTNESSUP;
1585                 break;
1586         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1587                 if (brightness_switch_enabled)
1588                         acpi_video_switch_brightness(video_device, event);
1589                 keycode = KEY_BRIGHTNESSDOWN;
1590                 break;
1591         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1592                 if (brightness_switch_enabled)
1593                         acpi_video_switch_brightness(video_device, event);
1594                 keycode = KEY_BRIGHTNESS_ZERO;
1595                 break;
1596         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1597                 if (brightness_switch_enabled)
1598                         acpi_video_switch_brightness(video_device, event);
1599                 keycode = KEY_DISPLAY_OFF;
1600                 break;
1601         default:
1602                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1603                                   "Unsupported event [0x%x]\n", event));
1604                 break;
1605         }
1606
1607         acpi_notifier_call_chain(device, event, 0);
1608
1609         if (keycode) {
1610                 input_report_key(input, keycode, 1);
1611                 input_sync(input);
1612                 input_report_key(input, keycode, 0);
1613                 input_sync(input);
1614         }
1615
1616         return;
1617 }
1618
1619 static int acpi_video_resume(struct notifier_block *nb,
1620                                 unsigned long val, void *ign)
1621 {
1622         struct acpi_video_bus *video;
1623         struct acpi_video_device *video_device;
1624         int i;
1625
1626         switch (val) {
1627         case PM_HIBERNATION_PREPARE:
1628         case PM_SUSPEND_PREPARE:
1629         case PM_RESTORE_PREPARE:
1630                 return NOTIFY_DONE;
1631         }
1632
1633         video = container_of(nb, struct acpi_video_bus, pm_nb);
1634
1635         dev_info(&video->device->dev, "Restoring backlight state\n");
1636
1637         for (i = 0; i < video->attached_count; i++) {
1638                 video_device = video->attached_array[i].bind_info;
1639                 if (video_device && video_device->backlight)
1640                         acpi_video_set_brightness(video_device->backlight);
1641         }
1642
1643         return NOTIFY_OK;
1644 }
1645
1646 static acpi_status
1647 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1648                         void **return_value)
1649 {
1650         struct acpi_device *device = context;
1651         struct acpi_device *sibling;
1652         int result;
1653
1654         if (handle == device->handle)
1655                 return AE_CTRL_TERMINATE;
1656
1657         result = acpi_bus_get_device(handle, &sibling);
1658         if (result)
1659                 return AE_OK;
1660
1661         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1662                         return AE_ALREADY_EXISTS;
1663
1664         return AE_OK;
1665 }
1666
1667 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1668 {
1669         if (acpi_video_verify_backlight_support()) {
1670                 struct backlight_properties props;
1671                 struct pci_dev *pdev;
1672                 acpi_handle acpi_parent;
1673                 struct device *parent = NULL;
1674                 int result;
1675                 static int count;
1676                 char *name;
1677
1678                 result = acpi_video_init_brightness(device);
1679                 if (result)
1680                         return;
1681                 name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1682                 if (!name)
1683                         return;
1684                 count++;
1685
1686                 acpi_get_parent(device->dev->handle, &acpi_parent);
1687
1688                 pdev = acpi_get_pci_dev(acpi_parent);
1689                 if (pdev) {
1690                         parent = &pdev->dev;
1691                         pci_dev_put(pdev);
1692                 }
1693
1694                 memset(&props, 0, sizeof(struct backlight_properties));
1695                 props.type = BACKLIGHT_FIRMWARE;
1696                 props.max_brightness = device->brightness->count - 3;
1697                 device->backlight = backlight_device_register(name,
1698                                                               parent,
1699                                                               device,
1700                                                               &acpi_backlight_ops,
1701                                                               &props);
1702                 kfree(name);
1703                 if (IS_ERR(device->backlight))
1704                         return;
1705
1706                 /*
1707                  * Save current brightness level in case we have to restore it
1708                  * before acpi_video_device_lcd_set_level() is called next time.
1709                  */
1710                 device->backlight->props.brightness =
1711                                 acpi_video_get_brightness(device->backlight);
1712
1713                 device->cooling_dev = thermal_cooling_device_register("LCD",
1714                                         device->dev, &video_cooling_ops);
1715                 if (IS_ERR(device->cooling_dev)) {
1716                         /*
1717                          * Set cooling_dev to NULL so we don't crash trying to
1718                          * free it.
1719                          * Also, why the hell we are returning early and
1720                          * not attempt to register video output if cooling
1721                          * device registration failed?
1722                          * -- dtor
1723                          */
1724                         device->cooling_dev = NULL;
1725                         return;
1726                 }
1727
1728                 dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1729                          device->cooling_dev->id);
1730                 result = sysfs_create_link(&device->dev->dev.kobj,
1731                                 &device->cooling_dev->device.kobj,
1732                                 "thermal_cooling");
1733                 if (result)
1734                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1735                 result = sysfs_create_link(&device->cooling_dev->device.kobj,
1736                                 &device->dev->dev.kobj, "device");
1737                 if (result)
1738                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1739         }
1740 }
1741
1742 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1743 {
1744         struct acpi_video_device *dev;
1745
1746         mutex_lock(&video->device_list_lock);
1747         list_for_each_entry(dev, &video->video_device_list, entry)
1748                 acpi_video_dev_register_backlight(dev);
1749         mutex_unlock(&video->device_list_lock);
1750
1751         video->pm_nb.notifier_call = acpi_video_resume;
1752         video->pm_nb.priority = 0;
1753         return register_pm_notifier(&video->pm_nb);
1754 }
1755
1756 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1757 {
1758         if (device->backlight) {
1759                 backlight_device_unregister(device->backlight);
1760                 device->backlight = NULL;
1761         }
1762         if (device->brightness) {
1763                 kfree(device->brightness->levels);
1764                 kfree(device->brightness);
1765                 device->brightness = NULL;
1766         }
1767         if (device->cooling_dev) {
1768                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1769                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1770                 thermal_cooling_device_unregister(device->cooling_dev);
1771                 device->cooling_dev = NULL;
1772         }
1773 }
1774
1775 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1776 {
1777         struct acpi_video_device *dev;
1778         int error = unregister_pm_notifier(&video->pm_nb);
1779
1780         mutex_lock(&video->device_list_lock);
1781         list_for_each_entry(dev, &video->video_device_list, entry)
1782                 acpi_video_dev_unregister_backlight(dev);
1783         mutex_unlock(&video->device_list_lock);
1784
1785         return error;
1786 }
1787
1788 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1789 {
1790         acpi_status status;
1791         struct acpi_device *adev = device->dev;
1792
1793         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1794                                              acpi_video_device_notify, device);
1795         if (ACPI_FAILURE(status))
1796                 dev_err(&adev->dev, "Error installing notify handler\n");
1797         else
1798                 device->flags.notify = 1;
1799 }
1800
1801 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1802 {
1803         struct input_dev *input;
1804         struct acpi_video_device *dev;
1805         int error;
1806
1807         video->input = input = input_allocate_device();
1808         if (!input) {
1809                 error = -ENOMEM;
1810                 goto out;
1811         }
1812
1813         error = acpi_video_bus_start_devices(video);
1814         if (error)
1815                 goto err_free_input;
1816
1817         snprintf(video->phys, sizeof(video->phys),
1818                         "%s/video/input0", acpi_device_hid(video->device));
1819
1820         input->name = acpi_device_name(video->device);
1821         input->phys = video->phys;
1822         input->id.bustype = BUS_HOST;
1823         input->id.product = 0x06;
1824         input->dev.parent = &video->device->dev;
1825         input->evbit[0] = BIT(EV_KEY);
1826         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1827         set_bit(KEY_VIDEO_NEXT, input->keybit);
1828         set_bit(KEY_VIDEO_PREV, input->keybit);
1829         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1830         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1831         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1832         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1833         set_bit(KEY_DISPLAY_OFF, input->keybit);
1834
1835         error = input_register_device(input);
1836         if (error)
1837                 goto err_stop_dev;
1838
1839         mutex_lock(&video->device_list_lock);
1840         list_for_each_entry(dev, &video->video_device_list, entry)
1841                 acpi_video_dev_add_notify_handler(dev);
1842         mutex_unlock(&video->device_list_lock);
1843
1844         return 0;
1845
1846 err_stop_dev:
1847         acpi_video_bus_stop_devices(video);
1848 err_free_input:
1849         input_free_device(input);
1850         video->input = NULL;
1851 out:
1852         return error;
1853 }
1854
1855 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1856 {
1857         if (dev->flags.notify) {
1858                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1859                                            acpi_video_device_notify);
1860                 dev->flags.notify = 0;
1861         }
1862 }
1863
1864 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1865 {
1866         struct acpi_video_device *dev;
1867
1868         mutex_lock(&video->device_list_lock);
1869         list_for_each_entry(dev, &video->video_device_list, entry)
1870                 acpi_video_dev_remove_notify_handler(dev);
1871         mutex_unlock(&video->device_list_lock);
1872
1873         acpi_video_bus_stop_devices(video);
1874         input_unregister_device(video->input);
1875         video->input = NULL;
1876 }
1877
1878 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1879 {
1880         struct acpi_video_device *dev, *next;
1881
1882         mutex_lock(&video->device_list_lock);
1883         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1884                 list_del(&dev->entry);
1885                 kfree(dev);
1886         }
1887         mutex_unlock(&video->device_list_lock);
1888
1889         return 0;
1890 }
1891
1892 static int instance;
1893
1894 static int acpi_video_bus_add(struct acpi_device *device)
1895 {
1896         struct acpi_video_bus *video;
1897         int error;
1898         acpi_status status;
1899
1900         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1901                                 device->parent->handle, 1,
1902                                 acpi_video_bus_match, NULL,
1903                                 device, NULL);
1904         if (status == AE_ALREADY_EXISTS) {
1905                 printk(KERN_WARNING FW_BUG
1906                         "Duplicate ACPI video bus devices for the"
1907                         " same VGA controller, please try module "
1908                         "parameter \"video.allow_duplicates=1\""
1909                         "if the current driver doesn't work.\n");
1910                 if (!allow_duplicates)
1911                         return -ENODEV;
1912         }
1913
1914         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1915         if (!video)
1916                 return -ENOMEM;
1917
1918         /* a hack to fix the duplicate name "VID" problem on T61 */
1919         if (!strcmp(device->pnp.bus_id, "VID")) {
1920                 if (instance)
1921                         device->pnp.bus_id[3] = '0' + instance;
1922                 instance++;
1923         }
1924         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1925         if (!strcmp(device->pnp.bus_id, "VGA")) {
1926                 if (instance)
1927                         device->pnp.bus_id[3] = '0' + instance;
1928                 instance++;
1929         }
1930
1931         video->device = device;
1932         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1933         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1934         device->driver_data = video;
1935
1936         acpi_video_bus_find_cap(video);
1937         error = acpi_video_bus_check(video);
1938         if (error)
1939                 goto err_free_video;
1940
1941         mutex_init(&video->device_list_lock);
1942         INIT_LIST_HEAD(&video->video_device_list);
1943
1944         error = acpi_video_bus_get_devices(video, device);
1945         if (error)
1946                 goto err_put_video;
1947
1948         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1949                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1950                video->flags.multihead ? "yes" : "no",
1951                video->flags.rom ? "yes" : "no",
1952                video->flags.post ? "yes" : "no");
1953         mutex_lock(&video_list_lock);
1954         list_add_tail(&video->entry, &video_bus_head);
1955         mutex_unlock(&video_list_lock);
1956
1957         acpi_video_bus_register_backlight(video);
1958         acpi_video_bus_add_notify_handler(video);
1959
1960         return 0;
1961
1962 err_put_video:
1963         acpi_video_bus_put_devices(video);
1964         kfree(video->attached_array);
1965 err_free_video:
1966         kfree(video);
1967         device->driver_data = NULL;
1968
1969         return error;
1970 }
1971
1972 static int acpi_video_bus_remove(struct acpi_device *device)
1973 {
1974         struct acpi_video_bus *video = NULL;
1975
1976
1977         if (!device || !acpi_driver_data(device))
1978                 return -EINVAL;
1979
1980         video = acpi_driver_data(device);
1981
1982         acpi_video_bus_remove_notify_handler(video);
1983         acpi_video_bus_unregister_backlight(video);
1984         acpi_video_bus_put_devices(video);
1985
1986         mutex_lock(&video_list_lock);
1987         list_del(&video->entry);
1988         mutex_unlock(&video_list_lock);
1989
1990         kfree(video->attached_array);
1991         kfree(video);
1992
1993         return 0;
1994 }
1995
1996 static int __init is_i740(struct pci_dev *dev)
1997 {
1998         if (dev->device == 0x00D1)
1999                 return 1;
2000         if (dev->device == 0x7000)
2001                 return 1;
2002         return 0;
2003 }
2004
2005 static int __init intel_opregion_present(void)
2006 {
2007         int opregion = 0;
2008         struct pci_dev *dev = NULL;
2009         u32 address;
2010
2011         for_each_pci_dev(dev) {
2012                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2013                         continue;
2014                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2015                         continue;
2016                 /* We don't want to poke around undefined i740 registers */
2017                 if (is_i740(dev))
2018                         continue;
2019                 pci_read_config_dword(dev, 0xfc, &address);
2020                 if (!address)
2021                         continue;
2022                 opregion = 1;
2023         }
2024         return opregion;
2025 }
2026
2027 int acpi_video_register(void)
2028 {
2029         int result = 0;
2030         if (register_count) {
2031                 /*
2032                  * if the function of acpi_video_register is already called,
2033                  * don't register the acpi_vide_bus again and return no error.
2034                  */
2035                 return 0;
2036         }
2037
2038         mutex_init(&video_list_lock);
2039         INIT_LIST_HEAD(&video_bus_head);
2040
2041         result = acpi_bus_register_driver(&acpi_video_bus);
2042         if (result < 0)
2043                 return -ENODEV;
2044
2045         /*
2046          * When the acpi_video_bus is loaded successfully, increase
2047          * the counter reference.
2048          */
2049         register_count = 1;
2050
2051         return 0;
2052 }
2053 EXPORT_SYMBOL(acpi_video_register);
2054
2055 void acpi_video_unregister(void)
2056 {
2057         if (!register_count) {
2058                 /*
2059                  * If the acpi video bus is already unloaded, don't
2060                  * unload it again and return directly.
2061                  */
2062                 return;
2063         }
2064         acpi_bus_unregister_driver(&acpi_video_bus);
2065
2066         register_count = 0;
2067
2068         return;
2069 }
2070 EXPORT_SYMBOL(acpi_video_unregister);
2071
2072 /*
2073  * This is kind of nasty. Hardware using Intel chipsets may require
2074  * the video opregion code to be run first in order to initialise
2075  * state before any ACPI video calls are made. To handle this we defer
2076  * registration of the video class until the opregion code has run.
2077  */
2078
2079 static int __init acpi_video_init(void)
2080 {
2081         dmi_check_system(video_dmi_table);
2082
2083         if (intel_opregion_present())
2084                 return 0;
2085
2086         return acpi_video_register();
2087 }
2088
2089 static void __exit acpi_video_exit(void)
2090 {
2091         acpi_video_unregister();
2092
2093         return;
2094 }
2095
2096 module_init(acpi_video_init);
2097 module_exit(acpi_video_exit);