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 T430s",
 461          .matches = {
 462                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 463                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T430s"),
 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 X1 Carbon",
 477         .matches = {
 478                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 479                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon"),
 480                 },
 481         },
 482         {
 483          .callback = video_set_use_native_backlight,
 484          .ident = "Lenovo Yoga 13",
 485          .matches = {
 486                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 487                 DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Yoga 13"),
 488                 },
 489         },
 490         {
 491         .callback = video_set_use_native_backlight,
 492         .ident = "Thinkpad Helix",
 493         .matches = {
 494                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 495                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad Helix"),
 496                 },
 497         },
 498         {
 499          .callback = video_set_use_native_backlight,
 500          .ident = "Dell Inspiron 7520",
 501          .matches = {
 502                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 503                 DMI_MATCH(DMI_PRODUCT_VERSION, "Inspiron 7520"),
 504                 },
 505         },
 506         {
 507          .callback = video_set_use_native_backlight,
 508          .ident = "Acer Aspire 5733Z",
 509          .matches = {
 510                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 511                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5733Z"),
 512                 },
 513         },
 514         {
 515          .callback = video_set_use_native_backlight,
 516          .ident = "Acer Aspire V5-431",
 517          .matches = {
 518                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 519                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-431"),
 520                 },
 521         },
 522         {
 523         .callback = video_set_use_native_backlight,
 524         .ident = "HP ProBook 4340s",
 525         .matches = {
 526                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 527                 DMI_MATCH(DMI_PRODUCT_VERSION, "HP ProBook 4340s"),
 528                 },
 529         },
 530         {
 531         .callback = video_set_use_native_backlight,
 532         .ident = "HP ProBook 2013 models",
 533         .matches = {
 534                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 535                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ProBook "),
 536                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
 537                 },
 538         },
 539         {
 540         .callback = video_set_use_native_backlight,
 541         .ident = "HP EliteBook 2013 models",
 542         .matches = {
 543                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 544                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook "),
 545                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
 546                 },
 547         },
 548         {
 549         .callback = video_set_use_native_backlight,
 550         .ident = "HP ZBook 14",
 551         .matches = {
 552                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 553                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 14"),
 554                 },
 555         },
 556         {
 557         .callback = video_set_use_native_backlight,
 558         .ident = "HP ZBook 15",
 559         .matches = {
 560                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 561                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 15"),
 562                 },
 563         },
 564         {
 565         .callback = video_set_use_native_backlight,
 566         .ident = "HP ZBook 17",
 567         .matches = {
 568                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 569                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 17"),
 570                 },
 571         },
 572         {
 573         .callback = video_set_use_native_backlight,
 574         .ident = "HP EliteBook 8780w",
 575         .matches = {
 576                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 577                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
 578                 },
 579         },
 580         {}
 581 };
 582
 583 static unsigned long long
 584 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 585                               unsigned long long bqc_value)
 586 {
 587         unsigned long long level;
 588
 589         if (device->brightness->flags._BQC_use_index) {
 590                 /*
 591                  * _BQC returns an index that doesn't account for
 592                  * the first 2 items with special meaning, so we need
 593                  * to compensate for that by offsetting ourselves
 594                  */
 595                 if (device->brightness->flags._BCL_reversed)
 596                         bqc_value = device->brightness->count - 3 - bqc_value;
 597
 598                 level = device->brightness->levels[bqc_value + 2];
 599         } else {
 600                 level = bqc_value;
 601         }
 602
 603         level += bqc_offset_aml_bug_workaround;
 604
 605         return level;
 606 }
 607
 608 static int
 609 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 610                                         unsigned long long *level, bool raw)
 611 {
 612         acpi_status status = AE_OK;
 613         int i;
 614
 615         if (device->cap._BQC || device->cap._BCQ) {
 616                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 617
 618                 status = acpi_evaluate_integer(device->dev->handle, buf,
 619                                                 NULL, level);
 620                 if (ACPI_SUCCESS(status)) {
 621                         if (raw) {
 622                                 /*
 623                                  * Caller has indicated he wants the raw
 624                                  * value returned by _BQC, so don't furtherly
 625                                  * mess with the value.
 626                                  */
 627                                 return 0;
 628                         }
 629
 630                         *level = acpi_video_bqc_value_to_level(device, *level);
 631
 632                         for (i = 2; i < device->brightness->count; i++)
 633                                 if (device->brightness->levels[i] == *level) {
 634                                         device->brightness->curr = *level;
 635                                         return 0;
 636                                 }
 637                         /*
 638                          * BQC returned an invalid level.
 639                          * Stop using it.
 640                          */
 641                         ACPI_WARNING((AE_INFO,
 642                                       "%s returned an invalid level",
 643                                       buf));
 644                         device->cap._BQC = device->cap._BCQ = 0;
 645                 } else {
 646                         /*
 647                          * Fixme:
 648                          * should we return an error or ignore this failure?
 649                          * dev->brightness->curr is a cached value which stores
 650                          * the correct current backlight level in most cases.
 651                          * ACPI video backlight still works w/ buggy _BQC.
 652                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 653                          */
 654                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
 655                         device->cap._BQC = device->cap._BCQ = 0;
 656                 }
 657         }
 658
 659         *level = device->brightness->curr;
 660         return 0;
 661 }
 662
 663 static int
 664 acpi_video_device_EDID(struct acpi_video_device *device,
 665                        union acpi_object **edid, ssize_t length)
 666 {
 667         int status;
 668         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 669         union acpi_object *obj;
 670         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 671         struct acpi_object_list args = { 1, &arg0 };
 672
 673
 674         *edid = NULL;
 675
 676         if (!device)
 677                 return -ENODEV;
 678         if (length == 128)
 679                 arg0.integer.value = 1;
 680         else if (length == 256)
 681                 arg0.integer.value = 2;
 682         else
 683                 return -EINVAL;
 684
 685         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 686         if (ACPI_FAILURE(status))
 687                 return -ENODEV;
 688
 689         obj = buffer.pointer;
 690
 691         if (obj && obj->type == ACPI_TYPE_BUFFER)
 692                 *edid = obj;
 693         else {
 694                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
 695                 status = -EFAULT;
 696                 kfree(obj);
 697         }
 698
 699         return status;
 700 }
 701
 702 /* bus */
 703
 704 /*
 705  *  Arg:
 706  *      video           : video bus device pointer
 707  *      bios_flag       :
 708  *              0.      The system BIOS should NOT automatically switch(toggle)
 709  *                      the active display output.
 710  *              1.      The system BIOS should automatically switch (toggle) the
 711  *                      active display output. No switch event.
 712  *              2.      The _DGS value should be locked.
 713  *              3.      The system BIOS should not automatically switch (toggle) the
 714  *                      active display output, but instead generate the display switch
 715  *                      event notify code.
 716  *      lcd_flag        :
 717  *              0.      The system BIOS should automatically control the brightness level
 718  *                      of the LCD when the power changes from AC to DC
 719  *              1.      The system BIOS should NOT automatically control the brightness
 720  *                      level of the LCD when the power changes from AC to DC.
 721  *  Return Value:
 722  *              -EINVAL wrong arg.
 723  */
 724
 725 static int
 726 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 727 {
 728         acpi_status status;
 729
 730         if (!video->cap._DOS)
 731                 return 0;
 732
 733         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 734                 return -EINVAL;
 735         video->dos_setting = (lcd_flag << 2) | bios_flag;
 736         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 737                                             (lcd_flag << 2) | bios_flag);
 738         if (ACPI_FAILURE(status))
 739                 return -EIO;
 740
 741         return 0;
 742 }
 743
 744 /*
 745  * Simple comparison function used to sort backlight levels.
 746  */
 747
 748 static int
 749 acpi_video_cmp_level(const void *a, const void *b)
 750 {
 751         return *(int *)a - *(int *)b;
 752 }
 753
 754 /*
 755  * Decides if _BQC/_BCQ for this system is usable
 756  *
 757  * We do this by changing the level first and then read out the current
 758  * brightness level, if the value does not match, find out if it is using
 759  * index. If not, clear the _BQC/_BCQ capability.
 760  */
 761 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 762                                 int max_level, int current_level)
 763 {
 764         struct acpi_video_device_brightness *br = device->brightness;
 765         int result;
 766         unsigned long long level;
 767         int test_level;
 768
 769         /* don't mess with existing known broken systems */
 770         if (bqc_offset_aml_bug_workaround)
 771                 return 0;
 772
 773         /*
 774          * Some systems always report current brightness level as maximum
 775          * through _BQC, we need to test another value for them.
 776          */
 777         test_level = current_level == max_level ? br->levels[3] : max_level;
 778
 779         result = acpi_video_device_lcd_set_level(device, test_level);
 780         if (result)
 781                 return result;
 782
 783         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 784         if (result)
 785                 return result;
 786
 787         if (level != test_level) {
 788                 /* buggy _BQC found, need to find out if it uses index */
 789                 if (level < br->count) {
 790                         if (br->flags._BCL_reversed)
 791                                 level = br->count - 3 - level;
 792                         if (br->levels[level + 2] == test_level)
 793                                 br->flags._BQC_use_index = 1;
 794                 }
 795
 796                 if (!br->flags._BQC_use_index)
 797                         device->cap._BQC = device->cap._BCQ = 0;
 798         }
 799
 800         return 0;
 801 }
 802
 803
 804 /*
 805  *  Arg:
 806  *      device  : video output device (LCD, CRT, ..)
 807  *
 808  *  Return Value:
 809  *      Maximum brightness level
 810  *
 811  *  Allocate and initialize device->brightness.
 812  */
 813
 814 static int
 815 acpi_video_init_brightness(struct acpi_video_device *device)
 816 {
 817         union acpi_object *obj = NULL;
 818         int i, max_level = 0, count = 0, level_ac_battery = 0;
 819         unsigned long long level, level_old;
 820         union acpi_object *o;
 821         struct acpi_video_device_brightness *br = NULL;
 822         int result = -EINVAL;
 823         u32 value;
 824
 825         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
 826                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
 827                                                 "LCD brightness level\n"));
 828                 goto out;
 829         }
 830
 831         if (obj->package.count < 2)
 832                 goto out;
 833
 834         br = kzalloc(sizeof(*br), GFP_KERNEL);
 835         if (!br) {
 836                 printk(KERN_ERR "can't allocate memory\n");
 837                 result = -ENOMEM;
 838                 goto out;
 839         }
 840
 841         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
 842                                 GFP_KERNEL);
 843         if (!br->levels) {
 844                 result = -ENOMEM;
 845                 goto out_free;
 846         }
 847
 848         for (i = 0; i < obj->package.count; i++) {
 849                 o = (union acpi_object *)&obj->package.elements[i];
 850                 if (o->type != ACPI_TYPE_INTEGER) {
 851                         printk(KERN_ERR PREFIX "Invalid data\n");
 852                         continue;
 853                 }
 854                 value = (u32) o->integer.value;
 855                 /* Skip duplicate entries */
 856                 if (count > 2 && br->levels[count - 1] == value)
 857                         continue;
 858
 859                 br->levels[count] = value;
 860
 861                 if (br->levels[count] > max_level)
 862                         max_level = br->levels[count];
 863                 count++;
 864         }
 865
 866         /*
 867          * some buggy BIOS don't export the levels
 868          * when machine is on AC/Battery in _BCL package.
 869          * In this case, the first two elements in _BCL packages
 870          * are also supported brightness levels that OS should take care of.
 871          */
 872         for (i = 2; i < count; i++) {
 873                 if (br->levels[i] == br->levels[0])
 874                         level_ac_battery++;
 875                 if (br->levels[i] == br->levels[1])
 876                         level_ac_battery++;
 877         }
 878
 879         if (level_ac_battery < 2) {
 880                 level_ac_battery = 2 - level_ac_battery;
 881                 br->flags._BCL_no_ac_battery_levels = 1;
 882                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
 883                         br->levels[i] = br->levels[i - level_ac_battery];
 884                 count += level_ac_battery;
 885         } else if (level_ac_battery > 2)
 886                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
 887
 888         /* Check if the _BCL package is in a reversed order */
 889         if (max_level == br->levels[2]) {
 890                 br->flags._BCL_reversed = 1;
 891                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
 892                         acpi_video_cmp_level, NULL);
 893         } else if (max_level != br->levels[count - 1])
 894                 ACPI_ERROR((AE_INFO,
 895                             "Found unordered _BCL package"));
 896
 897         br->count = count;
 898         device->brightness = br;
 899
 900         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 901         br->curr = level = max_level;
 902
 903         if (!device->cap._BQC)
 904                 goto set_level;
 905
 906         result = acpi_video_device_lcd_get_level_current(device,
 907                                                          &level_old, true);
 908         if (result)
 909                 goto out_free_levels;
 910
 911         result = acpi_video_bqc_quirk(device, max_level, level_old);
 912         if (result)
 913                 goto out_free_levels;
 914         /*
 915          * cap._BQC may get cleared due to _BQC is found to be broken
 916          * in acpi_video_bqc_quirk, so check again here.
 917          */
 918         if (!device->cap._BQC)
 919                 goto set_level;
 920
 921         level = acpi_video_bqc_value_to_level(device, level_old);
 922         /*
 923          * On some buggy laptops, _BQC returns an uninitialized
 924          * value when invoked for the first time, i.e.
 925          * level_old is invalid (no matter whether it's a level
 926          * or an index). Set the backlight to max_level in this case.
 927          */
 928         for (i = 2; i < br->count; i++)
 929                 if (level == br->levels[i])
 930                         break;
 931         if (i == br->count || !level)
 932                 level = max_level;
 933
 934 set_level:
 935         result = acpi_video_device_lcd_set_level(device, level);
 936         if (result)
 937                 goto out_free_levels;
 938
 939         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 940                           "found %d brightness levels\n", count - 2));
 941         kfree(obj);
 942         return result;
 943
 944 out_free_levels:
 945         kfree(br->levels);
 946 out_free:
 947         kfree(br);
 948 out:
 949         device->brightness = NULL;
 950         kfree(obj);
 951         return result;
 952 }
 953
 954 /*
 955  *  Arg:
 956  *      device  : video output device (LCD, CRT, ..)
 957  *
 958  *  Return Value:
 959  *      None
 960  *
 961  *  Find out all required AML methods defined under the output
 962  *  device.
 963  */
 964
 965 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 966 {
 967         if (acpi_has_method(device->dev->handle, "_ADR"))
 968                 device->cap._ADR = 1;
 969         if (acpi_has_method(device->dev->handle, "_BCL"))
 970                 device->cap._BCL = 1;
 971         if (acpi_has_method(device->dev->handle, "_BCM"))
 972                 device->cap._BCM = 1;
 973         if (acpi_has_method(device->dev->handle, "_BQC")) {
 974                 device->cap._BQC = 1;
 975         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 976                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
 977                 device->cap._BCQ = 1;
 978         }
 979
 980         if (acpi_has_method(device->dev->handle, "_DDC"))
 981                 device->cap._DDC = 1;
 982 }
 983
 984 /*
 985  *  Arg:
 986  *      device  : video output device (VGA)
 987  *
 988  *  Return Value:
 989  *      None
 990  *
 991  *  Find out all required AML methods defined under the video bus device.
 992  */
 993
 994 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
 995 {
 996         if (acpi_has_method(video->device->handle, "_DOS"))
 997                 video->cap._DOS = 1;
 998         if (acpi_has_method(video->device->handle, "_DOD"))
 999                 video->cap._DOD = 1;
1000         if (acpi_has_method(video->device->handle, "_ROM"))
1001                 video->cap._ROM = 1;
1002         if (acpi_has_method(video->device->handle, "_GPD"))
1003                 video->cap._GPD = 1;
1004         if (acpi_has_method(video->device->handle, "_SPD"))
1005                 video->cap._SPD = 1;
1006         if (acpi_has_method(video->device->handle, "_VPO"))
1007                 video->cap._VPO = 1;
1008 }
1009
1010 /*
1011  * Check whether the video bus device has required AML method to
1012  * support the desired features
1013  */
1014
1015 static int acpi_video_bus_check(struct acpi_video_bus *video)
1016 {
1017         acpi_status status = -ENOENT;
1018         struct pci_dev *dev;
1019
1020         if (!video)
1021                 return -EINVAL;
1022
1023         dev = acpi_get_pci_dev(video->device->handle);
1024         if (!dev)
1025                 return -ENODEV;
1026         pci_dev_put(dev);
1027
1028         /*
1029          * Since there is no HID, CID and so on for VGA driver, we have
1030          * to check well known required nodes.
1031          */
1032
1033         /* Does this device support video switching? */
1034         if (video->cap._DOS || video->cap._DOD) {
1035                 if (!video->cap._DOS) {
1036                         printk(KERN_WARNING FW_BUG
1037                                 "ACPI(%s) defines _DOD but not _DOS\n",
1038                                 acpi_device_bid(video->device));
1039                 }
1040                 video->flags.multihead = 1;
1041                 status = 0;
1042         }
1043
1044         /* Does this device support retrieving a video ROM? */
1045         if (video->cap._ROM) {
1046                 video->flags.rom = 1;
1047                 status = 0;
1048         }
1049
1050         /* Does this device support configuring which video device to POST? */
1051         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1052                 video->flags.post = 1;
1053                 status = 0;
1054         }
1055
1056         return status;
1057 }
1058
1059 /*
1060  * --------------------------------------------------------------------------
1061  *                               Driver Interface
1062  * --------------------------------------------------------------------------
1063  */
1064
1065 /* device interface */
1066 static struct acpi_video_device_attrib *
1067 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1068 {
1069         struct acpi_video_enumerated_device *ids;
1070         int i;
1071
1072         for (i = 0; i < video->attached_count; i++) {
1073                 ids = &video->attached_array[i];
1074                 if ((ids->value.int_val & 0xffff) == device_id)
1075                         return &ids->value.attrib;
1076         }
1077
1078         return NULL;
1079 }
1080
1081 static int
1082 acpi_video_get_device_type(struct acpi_video_bus *video,
1083                            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.int_val;
1092         }
1093
1094         return 0;
1095 }
1096
1097 static int
1098 acpi_video_bus_get_one_device(struct acpi_device *device,
1099                               struct acpi_video_bus *video)
1100 {
1101         unsigned long long device_id;
1102         int status, device_type;
1103         struct acpi_video_device *data;
1104         struct acpi_video_device_attrib *attribute;
1105
1106         status =
1107             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1108         /* Some device omits _ADR, we skip them instead of fail */
1109         if (ACPI_FAILURE(status))
1110                 return 0;
1111
1112         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1113         if (!data)
1114                 return -ENOMEM;
1115
1116         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1117         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1118         device->driver_data = data;
1119
1120         data->device_id = device_id;
1121         data->video = video;
1122         data->dev = device;
1123
1124         attribute = acpi_video_get_device_attr(video, device_id);
1125
1126         if (attribute && attribute->device_id_scheme) {
1127                 switch (attribute->display_type) {
1128                 case ACPI_VIDEO_DISPLAY_CRT:
1129                         data->flags.crt = 1;
1130                         break;
1131                 case ACPI_VIDEO_DISPLAY_TV:
1132                         data->flags.tvout = 1;
1133                         break;
1134                 case ACPI_VIDEO_DISPLAY_DVI:
1135                         data->flags.dvi = 1;
1136                         break;
1137                 case ACPI_VIDEO_DISPLAY_LCD:
1138                         data->flags.lcd = 1;
1139                         break;
1140                 default:
1141                         data->flags.unknown = 1;
1142                         break;
1143                 }
1144                 if (attribute->bios_can_detect)
1145                         data->flags.bios = 1;
1146         } else {
1147                 /* Check for legacy IDs */
1148                 device_type = acpi_video_get_device_type(video, device_id);
1149                 /* Ignore bits 16 and 18-20 */
1150                 switch (device_type & 0xffe2ffff) {
1151                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1152                         data->flags.crt = 1;
1153                         break;
1154                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1155                         data->flags.lcd = 1;
1156                         break;
1157                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1158                         data->flags.tvout = 1;
1159                         break;
1160                 default:
1161                         data->flags.unknown = 1;
1162                 }
1163         }
1164
1165         acpi_video_device_bind(video, data);
1166         acpi_video_device_find_cap(data);
1167
1168         mutex_lock(&video->device_list_lock);
1169         list_add_tail(&data->entry, &video->video_device_list);
1170         mutex_unlock(&video->device_list_lock);
1171
1172         return status;
1173 }
1174
1175 /*
1176  *  Arg:
1177  *      video   : video bus device
1178  *
1179  *  Return:
1180  *      none
1181  *
1182  *  Enumerate the video device list of the video bus,
1183  *  bind the ids with the corresponding video devices
1184  *  under the video bus.
1185  */
1186
1187 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1188 {
1189         struct acpi_video_device *dev;
1190
1191         mutex_lock(&video->device_list_lock);
1192
1193         list_for_each_entry(dev, &video->video_device_list, entry)
1194                 acpi_video_device_bind(video, dev);
1195
1196         mutex_unlock(&video->device_list_lock);
1197 }
1198
1199 /*
1200  *  Arg:
1201  *      video   : video bus device
1202  *      device  : video output device under the video
1203  *              bus
1204  *
1205  *  Return:
1206  *      none
1207  *
1208  *  Bind the ids with the corresponding video devices
1209  *  under the video bus.
1210  */
1211
1212 static void
1213 acpi_video_device_bind(struct acpi_video_bus *video,
1214                        struct acpi_video_device *device)
1215 {
1216         struct acpi_video_enumerated_device *ids;
1217         int i;
1218
1219         for (i = 0; i < video->attached_count; i++) {
1220                 ids = &video->attached_array[i];
1221                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1222                         ids->bind_info = device;
1223                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1224                 }
1225         }
1226 }
1227
1228 /*
1229  *  Arg:
1230  *      video   : video bus device
1231  *
1232  *  Return:
1233  *      < 0     : error
1234  *
1235  *  Call _DOD to enumerate all devices attached to display adapter
1236  *
1237  */
1238
1239 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1240 {
1241         int status;
1242         int count;
1243         int i;
1244         struct acpi_video_enumerated_device *active_list;
1245         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1246         union acpi_object *dod = NULL;
1247         union acpi_object *obj;
1248
1249         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1250         if (!ACPI_SUCCESS(status)) {
1251                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1252                 return status;
1253         }
1254
1255         dod = buffer.pointer;
1256         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1257                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1258                 status = -EFAULT;
1259                 goto out;
1260         }
1261
1262         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1263                           dod->package.count));
1264
1265         active_list = kcalloc(1 + dod->package.count,
1266                               sizeof(struct acpi_video_enumerated_device),
1267                               GFP_KERNEL);
1268         if (!active_list) {
1269                 status = -ENOMEM;
1270                 goto out;
1271         }
1272
1273         count = 0;
1274         for (i = 0; i < dod->package.count; i++) {
1275                 obj = &dod->package.elements[i];
1276
1277                 if (obj->type != ACPI_TYPE_INTEGER) {
1278                         printk(KERN_ERR PREFIX
1279                                 "Invalid _DOD data in element %d\n", i);
1280                         continue;
1281                 }
1282
1283                 active_list[count].value.int_val = obj->integer.value;
1284                 active_list[count].bind_info = NULL;
1285                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1286                                   (int)obj->integer.value));
1287                 count++;
1288         }
1289
1290         kfree(video->attached_array);
1291
1292         video->attached_array = active_list;
1293         video->attached_count = count;
1294
1295 out:
1296         kfree(buffer.pointer);
1297         return status;
1298 }
1299
1300 static int
1301 acpi_video_get_next_level(struct acpi_video_device *device,
1302                           u32 level_current, u32 event)
1303 {
1304         int min, max, min_above, max_below, i, l, delta = 255;
1305         max = max_below = 0;
1306         min = min_above = 255;
1307         /* Find closest level to level_current */
1308         for (i = 2; i < device->brightness->count; i++) {
1309                 l = device->brightness->levels[i];
1310                 if (abs(l - level_current) < abs(delta)) {
1311                         delta = l - level_current;
1312                         if (!delta)
1313                                 break;
1314                 }
1315         }
1316         /* Ajust level_current to closest available level */
1317         level_current += delta;
1318         for (i = 2; i < device->brightness->count; i++) {
1319                 l = device->brightness->levels[i];
1320                 if (l < min)
1321                         min = l;
1322                 if (l > max)
1323                         max = l;
1324                 if (l < min_above && l > level_current)
1325                         min_above = l;
1326                 if (l > max_below && l < level_current)
1327                         max_below = l;
1328         }
1329
1330         switch (event) {
1331         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1332                 return (level_current < max) ? min_above : min;
1333         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1334                 return (level_current < max) ? min_above : max;
1335         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1336                 return (level_current > min) ? max_below : min;
1337         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1338         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1339                 return 0;
1340         default:
1341                 return level_current;
1342         }
1343 }
1344
1345 static int
1346 acpi_video_switch_brightness(struct acpi_video_device *device, int event)
1347 {
1348         unsigned long long level_current, level_next;
1349         int result = -EINVAL;
1350
1351         /* no warning message if acpi_backlight=vendor or a quirk is used */
1352         if (!acpi_video_verify_backlight_support())
1353                 return 0;
1354
1355         if (!device->brightness)
1356                 goto out;
1357
1358         result = acpi_video_device_lcd_get_level_current(device,
1359                                                          &level_current,
1360                                                          false);
1361         if (result)
1362                 goto out;
1363
1364         level_next = acpi_video_get_next_level(device, level_current, event);
1365
1366         result = acpi_video_device_lcd_set_level(device, level_next);
1367
1368         if (!result)
1369                 backlight_force_update(device->backlight,
1370                                        BACKLIGHT_UPDATE_HOTKEY);
1371
1372 out:
1373         if (result)
1374                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1375
1376         return result;
1377 }
1378
1379 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1380                         void **edid)
1381 {
1382         struct acpi_video_bus *video;
1383         struct acpi_video_device *video_device;
1384         union acpi_object *buffer = NULL;
1385         acpi_status status;
1386         int i, length;
1387
1388         if (!device || !acpi_driver_data(device))
1389                 return -EINVAL;
1390
1391         video = acpi_driver_data(device);
1392
1393         for (i = 0; i < video->attached_count; i++) {
1394                 video_device = video->attached_array[i].bind_info;
1395                 length = 256;
1396
1397                 if (!video_device)
1398                         continue;
1399
1400                 if (!video_device->cap._DDC)
1401                         continue;
1402
1403                 if (type) {
1404                         switch (type) {
1405                         case ACPI_VIDEO_DISPLAY_CRT:
1406                                 if (!video_device->flags.crt)
1407                                         continue;
1408                                 break;
1409                         case ACPI_VIDEO_DISPLAY_TV:
1410                                 if (!video_device->flags.tvout)
1411                                         continue;
1412                                 break;
1413                         case ACPI_VIDEO_DISPLAY_DVI:
1414                                 if (!video_device->flags.dvi)
1415                                         continue;
1416                                 break;
1417                         case ACPI_VIDEO_DISPLAY_LCD:
1418                                 if (!video_device->flags.lcd)
1419                                         continue;
1420                                 break;
1421                         }
1422                 } else if (video_device->device_id != device_id) {
1423                         continue;
1424                 }
1425
1426                 status = acpi_video_device_EDID(video_device, &buffer, length);
1427
1428                 if (ACPI_FAILURE(status) || !buffer ||
1429                     buffer->type != ACPI_TYPE_BUFFER) {
1430                         length = 128;
1431                         status = acpi_video_device_EDID(video_device, &buffer,
1432                                                         length);
1433                         if (ACPI_FAILURE(status) || !buffer ||
1434                             buffer->type != ACPI_TYPE_BUFFER) {
1435                                 continue;
1436                         }
1437                 }
1438
1439                 *edid = buffer->buffer.pointer;
1440                 return length;
1441         }
1442
1443         return -ENODEV;
1444 }
1445 EXPORT_SYMBOL(acpi_video_get_edid);
1446
1447 static int
1448 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1449                            struct acpi_device *device)
1450 {
1451         int status = 0;
1452         struct acpi_device *dev;
1453
1454         /*
1455          * There are systems where video module known to work fine regardless
1456          * of broken _DOD and ignoring returned value here doesn't cause
1457          * any issues later.
1458          */
1459         acpi_video_device_enumerate(video);
1460
1461         list_for_each_entry(dev, &device->children, node) {
1462
1463                 status = acpi_video_bus_get_one_device(dev, video);
1464                 if (status) {
1465                         dev_err(&dev->dev, "Can't attach device\n");
1466                         break;
1467                 }
1468         }
1469         return status;
1470 }
1471
1472 /* acpi_video interface */
1473
1474 /*
1475  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1476  * preform any automatic brightness change on receiving a notification.
1477  */
1478 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1479 {
1480         return acpi_video_bus_DOS(video, 0,
1481                                   acpi_osi_is_win8() ? 1 : 0);
1482 }
1483
1484 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1485 {
1486         return acpi_video_bus_DOS(video, 0,
1487                                   acpi_osi_is_win8() ? 0 : 1);
1488 }
1489
1490 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1491 {
1492         struct acpi_video_bus *video = acpi_driver_data(device);
1493         struct input_dev *input;
1494         int keycode = 0;
1495
1496         if (!video || !video->input)
1497                 return;
1498
1499         input = video->input;
1500
1501         switch (event) {
1502         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1503                                          * most likely via hotkey. */
1504                 keycode = KEY_SWITCHVIDEOMODE;
1505                 break;
1506
1507         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1508                                          * connector. */
1509                 acpi_video_device_enumerate(video);
1510                 acpi_video_device_rebind(video);
1511                 keycode = KEY_SWITCHVIDEOMODE;
1512                 break;
1513
1514         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1515                 keycode = KEY_SWITCHVIDEOMODE;
1516                 break;
1517         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1518                 keycode = KEY_VIDEO_NEXT;
1519                 break;
1520         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1521                 keycode = KEY_VIDEO_PREV;
1522                 break;
1523
1524         default:
1525                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1526                                   "Unsupported event [0x%x]\n", event));
1527                 break;
1528         }
1529
1530         if (acpi_notifier_call_chain(device, event, 0))
1531                 /* Something vetoed the keypress. */
1532                 keycode = 0;
1533
1534         if (keycode) {
1535                 input_report_key(input, keycode, 1);
1536                 input_sync(input);
1537                 input_report_key(input, keycode, 0);
1538                 input_sync(input);
1539         }
1540
1541         return;
1542 }
1543
1544 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1545 {
1546         struct acpi_video_device *video_device = data;
1547         struct acpi_device *device = NULL;
1548         struct acpi_video_bus *bus;
1549         struct input_dev *input;
1550         int keycode = 0;
1551
1552         if (!video_device)
1553                 return;
1554
1555         device = video_device->dev;
1556         bus = video_device->video;
1557         input = bus->input;
1558
1559         switch (event) {
1560         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1561                 if (brightness_switch_enabled)
1562                         acpi_video_switch_brightness(video_device, event);
1563                 keycode = KEY_BRIGHTNESS_CYCLE;
1564                 break;
1565         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1566                 if (brightness_switch_enabled)
1567                         acpi_video_switch_brightness(video_device, event);
1568                 keycode = KEY_BRIGHTNESSUP;
1569                 break;
1570         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1571                 if (brightness_switch_enabled)
1572                         acpi_video_switch_brightness(video_device, event);
1573                 keycode = KEY_BRIGHTNESSDOWN;
1574                 break;
1575         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1576                 if (brightness_switch_enabled)
1577                         acpi_video_switch_brightness(video_device, event);
1578                 keycode = KEY_BRIGHTNESS_ZERO;
1579                 break;
1580         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1581                 if (brightness_switch_enabled)
1582                         acpi_video_switch_brightness(video_device, event);
1583                 keycode = KEY_DISPLAY_OFF;
1584                 break;
1585         default:
1586                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1587                                   "Unsupported event [0x%x]\n", event));
1588                 break;
1589         }
1590
1591         acpi_notifier_call_chain(device, event, 0);
1592
1593         if (keycode) {
1594                 input_report_key(input, keycode, 1);
1595                 input_sync(input);
1596                 input_report_key(input, keycode, 0);
1597                 input_sync(input);
1598         }
1599
1600         return;
1601 }
1602
1603 static int acpi_video_resume(struct notifier_block *nb,
1604                                 unsigned long val, void *ign)
1605 {
1606         struct acpi_video_bus *video;
1607         struct acpi_video_device *video_device;
1608         int i;
1609
1610         switch (val) {
1611         case PM_HIBERNATION_PREPARE:
1612         case PM_SUSPEND_PREPARE:
1613         case PM_RESTORE_PREPARE:
1614                 return NOTIFY_DONE;
1615         }
1616
1617         video = container_of(nb, struct acpi_video_bus, pm_nb);
1618
1619         dev_info(&video->device->dev, "Restoring backlight state\n");
1620
1621         for (i = 0; i < video->attached_count; i++) {
1622                 video_device = video->attached_array[i].bind_info;
1623                 if (video_device && video_device->backlight)
1624                         acpi_video_set_brightness(video_device->backlight);
1625         }
1626
1627         return NOTIFY_OK;
1628 }
1629
1630 static acpi_status
1631 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1632                         void **return_value)
1633 {
1634         struct acpi_device *device = context;
1635         struct acpi_device *sibling;
1636         int result;
1637
1638         if (handle == device->handle)
1639                 return AE_CTRL_TERMINATE;
1640
1641         result = acpi_bus_get_device(handle, &sibling);
1642         if (result)
1643                 return AE_OK;
1644
1645         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1646                         return AE_ALREADY_EXISTS;
1647
1648         return AE_OK;
1649 }
1650
1651 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1652 {
1653         if (acpi_video_verify_backlight_support()) {
1654                 struct backlight_properties props;
1655                 struct pci_dev *pdev;
1656                 acpi_handle acpi_parent;
1657                 struct device *parent = NULL;
1658                 int result;
1659                 static int count;
1660                 char *name;
1661
1662                 result = acpi_video_init_brightness(device);
1663                 if (result)
1664                         return;
1665                 name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1666                 if (!name)
1667                         return;
1668                 count++;
1669
1670                 acpi_get_parent(device->dev->handle, &acpi_parent);
1671
1672                 pdev = acpi_get_pci_dev(acpi_parent);
1673                 if (pdev) {
1674                         parent = &pdev->dev;
1675                         pci_dev_put(pdev);
1676                 }
1677
1678                 memset(&props, 0, sizeof(struct backlight_properties));
1679                 props.type = BACKLIGHT_FIRMWARE;
1680                 props.max_brightness = device->brightness->count - 3;
1681                 device->backlight = backlight_device_register(name,
1682                                                               parent,
1683                                                               device,
1684                                                               &acpi_backlight_ops,
1685                                                               &props);
1686                 kfree(name);
1687                 if (IS_ERR(device->backlight))
1688                         return;
1689
1690                 /*
1691                  * Save current brightness level in case we have to restore it
1692                  * before acpi_video_device_lcd_set_level() is called next time.
1693                  */
1694                 device->backlight->props.brightness =
1695                                 acpi_video_get_brightness(device->backlight);
1696
1697                 device->cooling_dev = thermal_cooling_device_register("LCD",
1698                                         device->dev, &video_cooling_ops);
1699                 if (IS_ERR(device->cooling_dev)) {
1700                         /*
1701                          * Set cooling_dev to NULL so we don't crash trying to
1702                          * free it.
1703                          * Also, why the hell we are returning early and
1704                          * not attempt to register video output if cooling
1705                          * device registration failed?
1706                          * -- dtor
1707                          */
1708                         device->cooling_dev = NULL;
1709                         return;
1710                 }
1711
1712                 dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1713                          device->cooling_dev->id);
1714                 result = sysfs_create_link(&device->dev->dev.kobj,
1715                                 &device->cooling_dev->device.kobj,
1716                                 "thermal_cooling");
1717                 if (result)
1718                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1719                 result = sysfs_create_link(&device->cooling_dev->device.kobj,
1720                                 &device->dev->dev.kobj, "device");
1721                 if (result)
1722                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1723         }
1724 }
1725
1726 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1727 {
1728         struct acpi_video_device *dev;
1729
1730         mutex_lock(&video->device_list_lock);
1731         list_for_each_entry(dev, &video->video_device_list, entry)
1732                 acpi_video_dev_register_backlight(dev);
1733         mutex_unlock(&video->device_list_lock);
1734
1735         video->pm_nb.notifier_call = acpi_video_resume;
1736         video->pm_nb.priority = 0;
1737         return register_pm_notifier(&video->pm_nb);
1738 }
1739
1740 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1741 {
1742         if (device->backlight) {
1743                 backlight_device_unregister(device->backlight);
1744                 device->backlight = NULL;
1745         }
1746         if (device->brightness) {
1747                 kfree(device->brightness->levels);
1748                 kfree(device->brightness);
1749                 device->brightness = NULL;
1750         }
1751         if (device->cooling_dev) {
1752                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1753                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1754                 thermal_cooling_device_unregister(device->cooling_dev);
1755                 device->cooling_dev = NULL;
1756         }
1757 }
1758
1759 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1760 {
1761         struct acpi_video_device *dev;
1762         int error = unregister_pm_notifier(&video->pm_nb);
1763
1764         mutex_lock(&video->device_list_lock);
1765         list_for_each_entry(dev, &video->video_device_list, entry)
1766                 acpi_video_dev_unregister_backlight(dev);
1767         mutex_unlock(&video->device_list_lock);
1768
1769         return error;
1770 }
1771
1772 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1773 {
1774         acpi_status status;
1775         struct acpi_device *adev = device->dev;
1776
1777         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1778                                              acpi_video_device_notify, device);
1779         if (ACPI_FAILURE(status))
1780                 dev_err(&adev->dev, "Error installing notify handler\n");
1781         else
1782                 device->flags.notify = 1;
1783 }
1784
1785 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1786 {
1787         struct input_dev *input;
1788         struct acpi_video_device *dev;
1789         int error;
1790
1791         video->input = input = input_allocate_device();
1792         if (!input) {
1793                 error = -ENOMEM;
1794                 goto out;
1795         }
1796
1797         error = acpi_video_bus_start_devices(video);
1798         if (error)
1799                 goto err_free_input;
1800
1801         snprintf(video->phys, sizeof(video->phys),
1802                         "%s/video/input0", acpi_device_hid(video->device));
1803
1804         input->name = acpi_device_name(video->device);
1805         input->phys = video->phys;
1806         input->id.bustype = BUS_HOST;
1807         input->id.product = 0x06;
1808         input->dev.parent = &video->device->dev;
1809         input->evbit[0] = BIT(EV_KEY);
1810         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1811         set_bit(KEY_VIDEO_NEXT, input->keybit);
1812         set_bit(KEY_VIDEO_PREV, input->keybit);
1813         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1814         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1815         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1816         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1817         set_bit(KEY_DISPLAY_OFF, input->keybit);
1818
1819         error = input_register_device(input);
1820         if (error)
1821                 goto err_stop_dev;
1822
1823         mutex_lock(&video->device_list_lock);
1824         list_for_each_entry(dev, &video->video_device_list, entry)
1825                 acpi_video_dev_add_notify_handler(dev);
1826         mutex_unlock(&video->device_list_lock);
1827
1828         return 0;
1829
1830 err_stop_dev:
1831         acpi_video_bus_stop_devices(video);
1832 err_free_input:
1833         input_free_device(input);
1834         video->input = NULL;
1835 out:
1836         return error;
1837 }
1838
1839 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1840 {
1841         if (dev->flags.notify) {
1842                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1843                                            acpi_video_device_notify);
1844                 dev->flags.notify = 0;
1845         }
1846 }
1847
1848 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1849 {
1850         struct acpi_video_device *dev;
1851
1852         mutex_lock(&video->device_list_lock);
1853         list_for_each_entry(dev, &video->video_device_list, entry)
1854                 acpi_video_dev_remove_notify_handler(dev);
1855         mutex_unlock(&video->device_list_lock);
1856
1857         acpi_video_bus_stop_devices(video);
1858         input_unregister_device(video->input);
1859         video->input = NULL;
1860 }
1861
1862 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1863 {
1864         struct acpi_video_device *dev, *next;
1865
1866         mutex_lock(&video->device_list_lock);
1867         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1868                 list_del(&dev->entry);
1869                 kfree(dev);
1870         }
1871         mutex_unlock(&video->device_list_lock);
1872
1873         return 0;
1874 }
1875
1876 static int instance;
1877
1878 static int acpi_video_bus_add(struct acpi_device *device)
1879 {
1880         struct acpi_video_bus *video;
1881         int error;
1882         acpi_status status;
1883
1884         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1885                                 device->parent->handle, 1,
1886                                 acpi_video_bus_match, NULL,
1887                                 device, NULL);
1888         if (status == AE_ALREADY_EXISTS) {
1889                 printk(KERN_WARNING FW_BUG
1890                         "Duplicate ACPI video bus devices for the"
1891                         " same VGA controller, please try module "
1892                         "parameter \"video.allow_duplicates=1\""
1893                         "if the current driver doesn't work.\n");
1894                 if (!allow_duplicates)
1895                         return -ENODEV;
1896         }
1897
1898         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1899         if (!video)
1900                 return -ENOMEM;
1901
1902         /* a hack to fix the duplicate name "VID" problem on T61 */
1903         if (!strcmp(device->pnp.bus_id, "VID")) {
1904                 if (instance)
1905                         device->pnp.bus_id[3] = '0' + instance;
1906                 instance++;
1907         }
1908         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1909         if (!strcmp(device->pnp.bus_id, "VGA")) {
1910                 if (instance)
1911                         device->pnp.bus_id[3] = '0' + instance;
1912                 instance++;
1913         }
1914
1915         video->device = device;
1916         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1917         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1918         device->driver_data = video;
1919
1920         acpi_video_bus_find_cap(video);
1921         error = acpi_video_bus_check(video);
1922         if (error)
1923                 goto err_free_video;
1924
1925         mutex_init(&video->device_list_lock);
1926         INIT_LIST_HEAD(&video->video_device_list);
1927
1928         error = acpi_video_bus_get_devices(video, device);
1929         if (error)
1930                 goto err_put_video;
1931
1932         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1933                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1934                video->flags.multihead ? "yes" : "no",
1935                video->flags.rom ? "yes" : "no",
1936                video->flags.post ? "yes" : "no");
1937         mutex_lock(&video_list_lock);
1938         list_add_tail(&video->entry, &video_bus_head);
1939         mutex_unlock(&video_list_lock);
1940
1941         acpi_video_bus_register_backlight(video);
1942         acpi_video_bus_add_notify_handler(video);
1943
1944         return 0;
1945
1946 err_put_video:
1947         acpi_video_bus_put_devices(video);
1948         kfree(video->attached_array);
1949 err_free_video:
1950         kfree(video);
1951         device->driver_data = NULL;
1952
1953         return error;
1954 }
1955
1956 static int acpi_video_bus_remove(struct acpi_device *device)
1957 {
1958         struct acpi_video_bus *video = NULL;
1959
1960
1961         if (!device || !acpi_driver_data(device))
1962                 return -EINVAL;
1963
1964         video = acpi_driver_data(device);
1965
1966         acpi_video_bus_remove_notify_handler(video);
1967         acpi_video_bus_unregister_backlight(video);
1968         acpi_video_bus_put_devices(video);
1969
1970         mutex_lock(&video_list_lock);
1971         list_del(&video->entry);
1972         mutex_unlock(&video_list_lock);
1973
1974         kfree(video->attached_array);
1975         kfree(video);
1976
1977         return 0;
1978 }
1979
1980 static int __init is_i740(struct pci_dev *dev)
1981 {
1982         if (dev->device == 0x00D1)
1983                 return 1;
1984         if (dev->device == 0x7000)
1985                 return 1;
1986         return 0;
1987 }
1988
1989 static int __init intel_opregion_present(void)
1990 {
1991         int opregion = 0;
1992         struct pci_dev *dev = NULL;
1993         u32 address;
1994
1995         for_each_pci_dev(dev) {
1996                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
1997                         continue;
1998                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
1999                         continue;
2000                 /* We don't want to poke around undefined i740 registers */
2001                 if (is_i740(dev))
2002                         continue;
2003                 pci_read_config_dword(dev, 0xfc, &address);
2004                 if (!address)
2005                         continue;
2006                 opregion = 1;
2007         }
2008         return opregion;
2009 }
2010
2011 int acpi_video_register(void)
2012 {
2013         int result = 0;
2014         if (register_count) {
2015                 /*
2016                  * if the function of acpi_video_register is already called,
2017                  * don't register the acpi_vide_bus again and return no error.
2018                  */
2019                 return 0;
2020         }
2021
2022         mutex_init(&video_list_lock);
2023         INIT_LIST_HEAD(&video_bus_head);
2024
2025         result = acpi_bus_register_driver(&acpi_video_bus);
2026         if (result < 0)
2027                 return -ENODEV;
2028
2029         /*
2030          * When the acpi_video_bus is loaded successfully, increase
2031          * the counter reference.
2032          */
2033         register_count = 1;
2034
2035         return 0;
2036 }
2037 EXPORT_SYMBOL(acpi_video_register);
2038
2039 void acpi_video_unregister(void)
2040 {
2041         if (!register_count) {
2042                 /*
2043                  * If the acpi video bus is already unloaded, don't
2044                  * unload it again and return directly.
2045                  */
2046                 return;
2047         }
2048         acpi_bus_unregister_driver(&acpi_video_bus);
2049
2050         register_count = 0;
2051
2052         return;
2053 }
2054 EXPORT_SYMBOL(acpi_video_unregister);
2055
2056 /*
2057  * This is kind of nasty. Hardware using Intel chipsets may require
2058  * the video opregion code to be run first in order to initialise
2059  * state before any ACPI video calls are made. To handle this we defer
2060  * registration of the video class until the opregion code has run.
2061  */
2062
2063 static int __init acpi_video_init(void)
2064 {
2065         dmi_check_system(video_dmi_table);
2066
2067         if (intel_opregion_present())
2068                 return 0;
2069
2070         return acpi_video_register();
2071 }
2072
2073 static void __exit acpi_video_exit(void)
2074 {
2075         acpi_video_unregister();
2076
2077         return;
2078 }
2079
2080 module_init(acpi_video_init);
2081 module_exit(acpi_video_exit);