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 = true;
  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         bool backlight_registered;
 154         bool backlight_notifier_registered;
 155         u8 dos_setting;
 156         struct acpi_video_enumerated_device *attached_array;
 157         u8 attached_count;
 158         struct acpi_video_bus_cap cap;
 159         struct acpi_video_bus_flags flags;
 160         struct list_head video_device_list;
 161         struct mutex device_list_lock;  /* protects video_device_list */
 162         struct list_head entry;
 163         struct input_dev *input;
 164         char phys[32];  /* for input device */
 165         struct notifier_block pm_nb;
 166         struct notifier_block backlight_nb;
 167 };
 168
 169 struct acpi_video_device_flags {
 170         u8 crt:1;
 171         u8 lcd:1;
 172         u8 tvout:1;
 173         u8 dvi:1;
 174         u8 bios:1;
 175         u8 unknown:1;
 176         u8 notify:1;
 177         u8 reserved:1;
 178 };
 179
 180 struct acpi_video_device_cap {
 181         u8 _ADR:1;              /* Return the unique ID */
 182         u8 _BCL:1;              /* Query list of brightness control levels supported */
 183         u8 _BCM:1;              /* Set the brightness level */
 184         u8 _BQC:1;              /* Get current brightness level */
 185         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
 186         u8 _DDC:1;              /* Return the EDID for this device */
 187 };
 188
 189 struct acpi_video_brightness_flags {
 190         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
 191         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
 192         u8 _BQC_use_index:1;            /* _BQC returns an index value */
 193 };
 194
 195 struct acpi_video_device_brightness {
 196         int curr;
 197         int count;
 198         int *levels;
 199         struct acpi_video_brightness_flags flags;
 200 };
 201
 202 struct acpi_video_device {
 203         unsigned long device_id;
 204         struct acpi_video_device_flags flags;
 205         struct acpi_video_device_cap cap;
 206         struct list_head entry;
 207         struct delayed_work switch_brightness_work;
 208         int switch_brightness_event;
 209         struct acpi_video_bus *video;
 210         struct acpi_device *dev;
 211         struct acpi_video_device_brightness *brightness;
 212         struct backlight_device *backlight;
 213         struct thermal_cooling_device *cooling_dev;
 214 };
 215
 216 static const char device_decode[][30] = {
 217         "motherboard VGA device",
 218         "PCI VGA device",
 219         "AGP VGA device",
 220         "UNKNOWN",
 221 };
 222
 223 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 224 static void acpi_video_device_rebind(struct acpi_video_bus *video);
 225 static void acpi_video_device_bind(struct acpi_video_bus *video,
 226                                    struct acpi_video_device *device);
 227 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 228 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 229                         int level);
 230 static int acpi_video_device_lcd_get_level_current(
 231                         struct acpi_video_device *device,
 232                         unsigned long long *level, bool raw);
 233 static int acpi_video_get_next_level(struct acpi_video_device *device,
 234                                      u32 level_current, u32 event);
 235 static void acpi_video_switch_brightness(struct work_struct *work);
 236
 237 static bool acpi_video_use_native_backlight(void)
 238 {
 239         if (use_native_backlight_param != -1)
 240                 return use_native_backlight_param;
 241         else
 242                 return use_native_backlight_dmi;
 243 }
 244
 245 bool acpi_video_verify_backlight_support(void)
 246 {
 247         if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
 248             backlight_device_registered(BACKLIGHT_RAW))
 249                 return false;
 250         return acpi_video_backlight_support();
 251 }
 252 EXPORT_SYMBOL_GPL(acpi_video_verify_backlight_support);
 253
 254 /* backlight device sysfs support */
 255 static int acpi_video_get_brightness(struct backlight_device *bd)
 256 {
 257         unsigned long long cur_level;
 258         int i;
 259         struct acpi_video_device *vd = bl_get_data(bd);
 260
 261         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 262                 return -EINVAL;
 263         for (i = 2; i < vd->brightness->count; i++) {
 264                 if (vd->brightness->levels[i] == cur_level)
 265                         /*
 266                          * The first two entries are special - see page 575
 267                          * of the ACPI spec 3.0
 268                          */
 269                         return i - 2;
 270         }
 271         return 0;
 272 }
 273
 274 static int acpi_video_set_brightness(struct backlight_device *bd)
 275 {
 276         int request_level = bd->props.brightness + 2;
 277         struct acpi_video_device *vd = bl_get_data(bd);
 278
 279         cancel_delayed_work(&vd->switch_brightness_work);
 280         return acpi_video_device_lcd_set_level(vd,
 281                                 vd->brightness->levels[request_level]);
 282 }
 283
 284 static const struct backlight_ops acpi_backlight_ops = {
 285         .get_brightness = acpi_video_get_brightness,
 286         .update_status  = acpi_video_set_brightness,
 287 };
 288
 289 /* thermal cooling device callbacks */
 290 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
 291                                long *state)
 292 {
 293         struct acpi_device *device = cooling_dev->devdata;
 294         struct acpi_video_device *video = acpi_driver_data(device);
 295
 296         *state = video->brightness->count - 3;
 297         return 0;
 298 }
 299
 300 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
 301                                long *state)
 302 {
 303         struct acpi_device *device = cooling_dev->devdata;
 304         struct acpi_video_device *video = acpi_driver_data(device);
 305         unsigned long long level;
 306         int offset;
 307
 308         if (acpi_video_device_lcd_get_level_current(video, &level, false))
 309                 return -EINVAL;
 310         for (offset = 2; offset < video->brightness->count; offset++)
 311                 if (level == video->brightness->levels[offset]) {
 312                         *state = video->brightness->count - offset - 1;
 313                         return 0;
 314                 }
 315
 316         return -EINVAL;
 317 }
 318
 319 static int
 320 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 321 {
 322         struct acpi_device *device = cooling_dev->devdata;
 323         struct acpi_video_device *video = acpi_driver_data(device);
 324         int level;
 325
 326         if (state >= video->brightness->count - 2)
 327                 return -EINVAL;
 328
 329         state = video->brightness->count - state;
 330         level = video->brightness->levels[state - 1];
 331         return acpi_video_device_lcd_set_level(video, level);
 332 }
 333
 334 static const struct thermal_cooling_device_ops video_cooling_ops = {
 335         .get_max_state = video_get_max_state,
 336         .get_cur_state = video_get_cur_state,
 337         .set_cur_state = video_set_cur_state,
 338 };
 339
 340 /*
 341  * --------------------------------------------------------------------------
 342  *                             Video Management
 343  * --------------------------------------------------------------------------
 344  */
 345
 346 static int
 347 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
 348                                    union acpi_object **levels)
 349 {
 350         int status;
 351         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 352         union acpi_object *obj;
 353
 354
 355         *levels = NULL;
 356
 357         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
 358         if (!ACPI_SUCCESS(status))
 359                 return status;
 360         obj = (union acpi_object *)buffer.pointer;
 361         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 362                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
 363                 status = -EFAULT;
 364                 goto err;
 365         }
 366
 367         *levels = obj;
 368
 369         return 0;
 370
 371 err:
 372         kfree(buffer.pointer);
 373
 374         return status;
 375 }
 376
 377 static int
 378 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 379 {
 380         int status;
 381         int state;
 382
 383         status = acpi_execute_simple_method(device->dev->handle,
 384                                             "_BCM", level);
 385         if (ACPI_FAILURE(status)) {
 386                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
 387                 return -EIO;
 388         }
 389
 390         device->brightness->curr = level;
 391         for (state = 2; state < device->brightness->count; state++)
 392                 if (level == device->brightness->levels[state]) {
 393                         if (device->backlight)
 394                                 device->backlight->props.brightness = state - 2;
 395                         return 0;
 396                 }
 397
 398         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
 399         return -EINVAL;
 400 }
 401
 402 /*
 403  * For some buggy _BQC methods, we need to add a constant value to
 404  * the _BQC return value to get the actual current brightness level
 405  */
 406
 407 static int bqc_offset_aml_bug_workaround;
 408 static int __init video_set_bqc_offset(const struct dmi_system_id *d)
 409 {
 410         bqc_offset_aml_bug_workaround = 9;
 411         return 0;
 412 }
 413
 414 static int __init video_disable_native_backlight(const struct dmi_system_id *d)
 415 {
 416         use_native_backlight_dmi = false;
 417         return 0;
 418 }
 419
 420 static struct dmi_system_id video_dmi_table[] __initdata = {
 421         /*
 422          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 423          */
 424         {
 425          .callback = video_set_bqc_offset,
 426          .ident = "Acer Aspire 5720",
 427          .matches = {
 428                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 429                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 430                 },
 431         },
 432         {
 433          .callback = video_set_bqc_offset,
 434          .ident = "Acer Aspire 5710Z",
 435          .matches = {
 436                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 437                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 438                 },
 439         },
 440         {
 441          .callback = video_set_bqc_offset,
 442          .ident = "eMachines E510",
 443          .matches = {
 444                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 445                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 446                 },
 447         },
 448         {
 449          .callback = video_set_bqc_offset,
 450          .ident = "Acer Aspire 5315",
 451          .matches = {
 452                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 453                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 454                 },
 455         },
 456         {
 457          .callback = video_set_bqc_offset,
 458          .ident = "Acer Aspire 7720",
 459          .matches = {
 460                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 461                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 462                 },
 463         },
 464
 465         /*
 466          * These models have a working acpi_video backlight control, and using
 467          * native backlight causes a regression where backlight does not work
 468          * when userspace is not handling brightness key events. Disable
 469          * native_backlight on these to fix this:
 470          * https://bugzilla.kernel.org/show_bug.cgi?id=81691
 471          */
 472         {
 473          .callback = video_disable_native_backlight,
 474          .ident = "ThinkPad T420",
 475          .matches = {
 476                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 477                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
 478                 },
 479         },
 480         {
 481          .callback = video_disable_native_backlight,
 482          .ident = "ThinkPad T520",
 483          .matches = {
 484                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 485                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
 486                 },
 487         },
 488
 489         /* The native backlight controls do not work on some older machines */
 490         {
 491          /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
 492          .callback = video_disable_native_backlight,
 493          .ident = "HP ENVY 15 Notebook",
 494          .matches = {
 495                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 496                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
 497                 },
 498         },
 499         {}
 500 };
 501
 502 static unsigned long long
 503 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 504                               unsigned long long bqc_value)
 505 {
 506         unsigned long long level;
 507
 508         if (device->brightness->flags._BQC_use_index) {
 509                 /*
 510                  * _BQC returns an index that doesn't account for
 511                  * the first 2 items with special meaning, so we need
 512                  * to compensate for that by offsetting ourselves
 513                  */
 514                 if (device->brightness->flags._BCL_reversed)
 515                         bqc_value = device->brightness->count - 3 - bqc_value;
 516
 517                 level = device->brightness->levels[bqc_value + 2];
 518         } else {
 519                 level = bqc_value;
 520         }
 521
 522         level += bqc_offset_aml_bug_workaround;
 523
 524         return level;
 525 }
 526
 527 static int
 528 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 529                                         unsigned long long *level, bool raw)
 530 {
 531         acpi_status status = AE_OK;
 532         int i;
 533
 534         if (device->cap._BQC || device->cap._BCQ) {
 535                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 536
 537                 status = acpi_evaluate_integer(device->dev->handle, buf,
 538                                                 NULL, level);
 539                 if (ACPI_SUCCESS(status)) {
 540                         if (raw) {
 541                                 /*
 542                                  * Caller has indicated he wants the raw
 543                                  * value returned by _BQC, so don't furtherly
 544                                  * mess with the value.
 545                                  */
 546                                 return 0;
 547                         }
 548
 549                         *level = acpi_video_bqc_value_to_level(device, *level);
 550
 551                         for (i = 2; i < device->brightness->count; i++)
 552                                 if (device->brightness->levels[i] == *level) {
 553                                         device->brightness->curr = *level;
 554                                         return 0;
 555                                 }
 556                         /*
 557                          * BQC returned an invalid level.
 558                          * Stop using it.
 559                          */
 560                         ACPI_WARNING((AE_INFO,
 561                                       "%s returned an invalid level",
 562                                       buf));
 563                         device->cap._BQC = device->cap._BCQ = 0;
 564                 } else {
 565                         /*
 566                          * Fixme:
 567                          * should we return an error or ignore this failure?
 568                          * dev->brightness->curr is a cached value which stores
 569                          * the correct current backlight level in most cases.
 570                          * ACPI video backlight still works w/ buggy _BQC.
 571                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 572                          */
 573                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
 574                         device->cap._BQC = device->cap._BCQ = 0;
 575                 }
 576         }
 577
 578         *level = device->brightness->curr;
 579         return 0;
 580 }
 581
 582 static int
 583 acpi_video_device_EDID(struct acpi_video_device *device,
 584                        union acpi_object **edid, ssize_t length)
 585 {
 586         int status;
 587         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 588         union acpi_object *obj;
 589         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 590         struct acpi_object_list args = { 1, &arg0 };
 591
 592
 593         *edid = NULL;
 594
 595         if (!device)
 596                 return -ENODEV;
 597         if (length == 128)
 598                 arg0.integer.value = 1;
 599         else if (length == 256)
 600                 arg0.integer.value = 2;
 601         else
 602                 return -EINVAL;
 603
 604         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 605         if (ACPI_FAILURE(status))
 606                 return -ENODEV;
 607
 608         obj = buffer.pointer;
 609
 610         if (obj && obj->type == ACPI_TYPE_BUFFER)
 611                 *edid = obj;
 612         else {
 613                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
 614                 status = -EFAULT;
 615                 kfree(obj);
 616         }
 617
 618         return status;
 619 }
 620
 621 /* bus */
 622
 623 /*
 624  *  Arg:
 625  *      video           : video bus device pointer
 626  *      bios_flag       :
 627  *              0.      The system BIOS should NOT automatically switch(toggle)
 628  *                      the active display output.
 629  *              1.      The system BIOS should automatically switch (toggle) the
 630  *                      active display output. No switch event.
 631  *              2.      The _DGS value should be locked.
 632  *              3.      The system BIOS should not automatically switch (toggle) the
 633  *                      active display output, but instead generate the display switch
 634  *                      event notify code.
 635  *      lcd_flag        :
 636  *              0.      The system BIOS should automatically control the brightness level
 637  *                      of the LCD when the power changes from AC to DC
 638  *              1.      The system BIOS should NOT automatically control the brightness
 639  *                      level of the LCD when the power changes from AC to DC.
 640  *  Return Value:
 641  *              -EINVAL wrong arg.
 642  */
 643
 644 static int
 645 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 646 {
 647         acpi_status status;
 648
 649         if (!video->cap._DOS)
 650                 return 0;
 651
 652         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 653                 return -EINVAL;
 654         video->dos_setting = (lcd_flag << 2) | bios_flag;
 655         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 656                                             (lcd_flag << 2) | bios_flag);
 657         if (ACPI_FAILURE(status))
 658                 return -EIO;
 659
 660         return 0;
 661 }
 662
 663 /*
 664  * Simple comparison function used to sort backlight levels.
 665  */
 666
 667 static int
 668 acpi_video_cmp_level(const void *a, const void *b)
 669 {
 670         return *(int *)a - *(int *)b;
 671 }
 672
 673 /*
 674  * Decides if _BQC/_BCQ for this system is usable
 675  *
 676  * We do this by changing the level first and then read out the current
 677  * brightness level, if the value does not match, find out if it is using
 678  * index. If not, clear the _BQC/_BCQ capability.
 679  */
 680 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 681                                 int max_level, int current_level)
 682 {
 683         struct acpi_video_device_brightness *br = device->brightness;
 684         int result;
 685         unsigned long long level;
 686         int test_level;
 687
 688         /* don't mess with existing known broken systems */
 689         if (bqc_offset_aml_bug_workaround)
 690                 return 0;
 691
 692         /*
 693          * Some systems always report current brightness level as maximum
 694          * through _BQC, we need to test another value for them.
 695          */
 696         test_level = current_level == max_level ? br->levels[3] : max_level;
 697
 698         result = acpi_video_device_lcd_set_level(device, test_level);
 699         if (result)
 700                 return result;
 701
 702         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 703         if (result)
 704                 return result;
 705
 706         if (level != test_level) {
 707                 /* buggy _BQC found, need to find out if it uses index */
 708                 if (level < br->count) {
 709                         if (br->flags._BCL_reversed)
 710                                 level = br->count - 3 - level;
 711                         if (br->levels[level + 2] == test_level)
 712                                 br->flags._BQC_use_index = 1;
 713                 }
 714
 715                 if (!br->flags._BQC_use_index)
 716                         device->cap._BQC = device->cap._BCQ = 0;
 717         }
 718
 719         return 0;
 720 }
 721
 722
 723 /*
 724  *  Arg:
 725  *      device  : video output device (LCD, CRT, ..)
 726  *
 727  *  Return Value:
 728  *      Maximum brightness level
 729  *
 730  *  Allocate and initialize device->brightness.
 731  */
 732
 733 static int
 734 acpi_video_init_brightness(struct acpi_video_device *device)
 735 {
 736         union acpi_object *obj = NULL;
 737         int i, max_level = 0, count = 0, level_ac_battery = 0;
 738         unsigned long long level, level_old;
 739         union acpi_object *o;
 740         struct acpi_video_device_brightness *br = NULL;
 741         int result = -EINVAL;
 742         u32 value;
 743
 744         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
 745                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
 746                                                 "LCD brightness level\n"));
 747                 goto out;
 748         }
 749
 750         if (obj->package.count < 2)
 751                 goto out;
 752
 753         br = kzalloc(sizeof(*br), GFP_KERNEL);
 754         if (!br) {
 755                 printk(KERN_ERR "can't allocate memory\n");
 756                 result = -ENOMEM;
 757                 goto out;
 758         }
 759
 760         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
 761                                 GFP_KERNEL);
 762         if (!br->levels) {
 763                 result = -ENOMEM;
 764                 goto out_free;
 765         }
 766
 767         for (i = 0; i < obj->package.count; i++) {
 768                 o = (union acpi_object *)&obj->package.elements[i];
 769                 if (o->type != ACPI_TYPE_INTEGER) {
 770                         printk(KERN_ERR PREFIX "Invalid data\n");
 771                         continue;
 772                 }
 773                 value = (u32) o->integer.value;
 774                 /* Skip duplicate entries */
 775                 if (count > 2 && br->levels[count - 1] == value)
 776                         continue;
 777
 778                 br->levels[count] = value;
 779
 780                 if (br->levels[count] > max_level)
 781                         max_level = br->levels[count];
 782                 count++;
 783         }
 784
 785         /*
 786          * some buggy BIOS don't export the levels
 787          * when machine is on AC/Battery in _BCL package.
 788          * In this case, the first two elements in _BCL packages
 789          * are also supported brightness levels that OS should take care of.
 790          */
 791         for (i = 2; i < count; i++) {
 792                 if (br->levels[i] == br->levels[0])
 793                         level_ac_battery++;
 794                 if (br->levels[i] == br->levels[1])
 795                         level_ac_battery++;
 796         }
 797
 798         if (level_ac_battery < 2) {
 799                 level_ac_battery = 2 - level_ac_battery;
 800                 br->flags._BCL_no_ac_battery_levels = 1;
 801                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
 802                         br->levels[i] = br->levels[i - level_ac_battery];
 803                 count += level_ac_battery;
 804         } else if (level_ac_battery > 2)
 805                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
 806
 807         /* Check if the _BCL package is in a reversed order */
 808         if (max_level == br->levels[2]) {
 809                 br->flags._BCL_reversed = 1;
 810                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
 811                         acpi_video_cmp_level, NULL);
 812         } else if (max_level != br->levels[count - 1])
 813                 ACPI_ERROR((AE_INFO,
 814                             "Found unordered _BCL package"));
 815
 816         br->count = count;
 817         device->brightness = br;
 818
 819         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 820         br->curr = level = max_level;
 821
 822         if (!device->cap._BQC)
 823                 goto set_level;
 824
 825         result = acpi_video_device_lcd_get_level_current(device,
 826                                                          &level_old, true);
 827         if (result)
 828                 goto out_free_levels;
 829
 830         result = acpi_video_bqc_quirk(device, max_level, level_old);
 831         if (result)
 832                 goto out_free_levels;
 833         /*
 834          * cap._BQC may get cleared due to _BQC is found to be broken
 835          * in acpi_video_bqc_quirk, so check again here.
 836          */
 837         if (!device->cap._BQC)
 838                 goto set_level;
 839
 840         level = acpi_video_bqc_value_to_level(device, level_old);
 841         /*
 842          * On some buggy laptops, _BQC returns an uninitialized
 843          * value when invoked for the first time, i.e.
 844          * level_old is invalid (no matter whether it's a level
 845          * or an index). Set the backlight to max_level in this case.
 846          */
 847         for (i = 2; i < br->count; i++)
 848                 if (level == br->levels[i])
 849                         break;
 850         if (i == br->count || !level)
 851                 level = max_level;
 852
 853 set_level:
 854         result = acpi_video_device_lcd_set_level(device, level);
 855         if (result)
 856                 goto out_free_levels;
 857
 858         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 859                           "found %d brightness levels\n", count - 2));
 860         kfree(obj);
 861         return result;
 862
 863 out_free_levels:
 864         kfree(br->levels);
 865 out_free:
 866         kfree(br);
 867 out:
 868         device->brightness = NULL;
 869         kfree(obj);
 870         return result;
 871 }
 872
 873 /*
 874  *  Arg:
 875  *      device  : video output device (LCD, CRT, ..)
 876  *
 877  *  Return Value:
 878  *      None
 879  *
 880  *  Find out all required AML methods defined under the output
 881  *  device.
 882  */
 883
 884 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 885 {
 886         if (acpi_has_method(device->dev->handle, "_ADR"))
 887                 device->cap._ADR = 1;
 888         if (acpi_has_method(device->dev->handle, "_BCL"))
 889                 device->cap._BCL = 1;
 890         if (acpi_has_method(device->dev->handle, "_BCM"))
 891                 device->cap._BCM = 1;
 892         if (acpi_has_method(device->dev->handle, "_BQC")) {
 893                 device->cap._BQC = 1;
 894         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 895                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
 896                 device->cap._BCQ = 1;
 897         }
 898
 899         if (acpi_has_method(device->dev->handle, "_DDC"))
 900                 device->cap._DDC = 1;
 901 }
 902
 903 /*
 904  *  Arg:
 905  *      device  : video output device (VGA)
 906  *
 907  *  Return Value:
 908  *      None
 909  *
 910  *  Find out all required AML methods defined under the video bus device.
 911  */
 912
 913 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
 914 {
 915         if (acpi_has_method(video->device->handle, "_DOS"))
 916                 video->cap._DOS = 1;
 917         if (acpi_has_method(video->device->handle, "_DOD"))
 918                 video->cap._DOD = 1;
 919         if (acpi_has_method(video->device->handle, "_ROM"))
 920                 video->cap._ROM = 1;
 921         if (acpi_has_method(video->device->handle, "_GPD"))
 922                 video->cap._GPD = 1;
 923         if (acpi_has_method(video->device->handle, "_SPD"))
 924                 video->cap._SPD = 1;
 925         if (acpi_has_method(video->device->handle, "_VPO"))
 926                 video->cap._VPO = 1;
 927 }
 928
 929 /*
 930  * Check whether the video bus device has required AML method to
 931  * support the desired features
 932  */
 933
 934 static int acpi_video_bus_check(struct acpi_video_bus *video)
 935 {
 936         acpi_status status = -ENOENT;
 937         struct pci_dev *dev;
 938
 939         if (!video)
 940                 return -EINVAL;
 941
 942         dev = acpi_get_pci_dev(video->device->handle);
 943         if (!dev)
 944                 return -ENODEV;
 945         pci_dev_put(dev);
 946
 947         /*
 948          * Since there is no HID, CID and so on for VGA driver, we have
 949          * to check well known required nodes.
 950          */
 951
 952         /* Does this device support video switching? */
 953         if (video->cap._DOS || video->cap._DOD) {
 954                 if (!video->cap._DOS) {
 955                         printk(KERN_WARNING FW_BUG
 956                                 "ACPI(%s) defines _DOD but not _DOS\n",
 957                                 acpi_device_bid(video->device));
 958                 }
 959                 video->flags.multihead = 1;
 960                 status = 0;
 961         }
 962
 963         /* Does this device support retrieving a video ROM? */
 964         if (video->cap._ROM) {
 965                 video->flags.rom = 1;
 966                 status = 0;
 967         }
 968
 969         /* Does this device support configuring which video device to POST? */
 970         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
 971                 video->flags.post = 1;
 972                 status = 0;
 973         }
 974
 975         return status;
 976 }
 977
 978 /*
 979  * --------------------------------------------------------------------------
 980  *                               Driver Interface
 981  * --------------------------------------------------------------------------
 982  */
 983
 984 /* device interface */
 985 static struct acpi_video_device_attrib *
 986 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
 987 {
 988         struct acpi_video_enumerated_device *ids;
 989         int i;
 990
 991         for (i = 0; i < video->attached_count; i++) {
 992                 ids = &video->attached_array[i];
 993                 if ((ids->value.int_val & 0xffff) == device_id)
 994                         return &ids->value.attrib;
 995         }
 996
 997         return NULL;
 998 }
 999
1000 static int
1001 acpi_video_get_device_type(struct acpi_video_bus *video,
1002                            unsigned long device_id)
1003 {
1004         struct acpi_video_enumerated_device *ids;
1005         int i;
1006
1007         for (i = 0; i < video->attached_count; i++) {
1008                 ids = &video->attached_array[i];
1009                 if ((ids->value.int_val & 0xffff) == device_id)
1010                         return ids->value.int_val;
1011         }
1012
1013         return 0;
1014 }
1015
1016 static int
1017 acpi_video_bus_get_one_device(struct acpi_device *device,
1018                               struct acpi_video_bus *video)
1019 {
1020         unsigned long long device_id;
1021         int status, device_type;
1022         struct acpi_video_device *data;
1023         struct acpi_video_device_attrib *attribute;
1024
1025         status =
1026             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1027         /* Some device omits _ADR, we skip them instead of fail */
1028         if (ACPI_FAILURE(status))
1029                 return 0;
1030
1031         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1032         if (!data)
1033                 return -ENOMEM;
1034
1035         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1036         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1037         device->driver_data = data;
1038
1039         data->device_id = device_id;
1040         data->video = video;
1041         data->dev = device;
1042         INIT_DELAYED_WORK(&data->switch_brightness_work,
1043                           acpi_video_switch_brightness);
1044
1045         attribute = acpi_video_get_device_attr(video, device_id);
1046
1047         if (attribute && attribute->device_id_scheme) {
1048                 switch (attribute->display_type) {
1049                 case ACPI_VIDEO_DISPLAY_CRT:
1050                         data->flags.crt = 1;
1051                         break;
1052                 case ACPI_VIDEO_DISPLAY_TV:
1053                         data->flags.tvout = 1;
1054                         break;
1055                 case ACPI_VIDEO_DISPLAY_DVI:
1056                         data->flags.dvi = 1;
1057                         break;
1058                 case ACPI_VIDEO_DISPLAY_LCD:
1059                         data->flags.lcd = 1;
1060                         break;
1061                 default:
1062                         data->flags.unknown = 1;
1063                         break;
1064                 }
1065                 if (attribute->bios_can_detect)
1066                         data->flags.bios = 1;
1067         } else {
1068                 /* Check for legacy IDs */
1069                 device_type = acpi_video_get_device_type(video, device_id);
1070                 /* Ignore bits 16 and 18-20 */
1071                 switch (device_type & 0xffe2ffff) {
1072                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1073                         data->flags.crt = 1;
1074                         break;
1075                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1076                         data->flags.lcd = 1;
1077                         break;
1078                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1079                         data->flags.tvout = 1;
1080                         break;
1081                 default:
1082                         data->flags.unknown = 1;
1083                 }
1084         }
1085
1086         acpi_video_device_bind(video, data);
1087         acpi_video_device_find_cap(data);
1088
1089         mutex_lock(&video->device_list_lock);
1090         list_add_tail(&data->entry, &video->video_device_list);
1091         mutex_unlock(&video->device_list_lock);
1092
1093         return status;
1094 }
1095
1096 /*
1097  *  Arg:
1098  *      video   : video bus device
1099  *
1100  *  Return:
1101  *      none
1102  *
1103  *  Enumerate the video device list of the video bus,
1104  *  bind the ids with the corresponding video devices
1105  *  under the video bus.
1106  */
1107
1108 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1109 {
1110         struct acpi_video_device *dev;
1111
1112         mutex_lock(&video->device_list_lock);
1113
1114         list_for_each_entry(dev, &video->video_device_list, entry)
1115                 acpi_video_device_bind(video, dev);
1116
1117         mutex_unlock(&video->device_list_lock);
1118 }
1119
1120 /*
1121  *  Arg:
1122  *      video   : video bus device
1123  *      device  : video output device under the video
1124  *              bus
1125  *
1126  *  Return:
1127  *      none
1128  *
1129  *  Bind the ids with the corresponding video devices
1130  *  under the video bus.
1131  */
1132
1133 static void
1134 acpi_video_device_bind(struct acpi_video_bus *video,
1135                        struct acpi_video_device *device)
1136 {
1137         struct acpi_video_enumerated_device *ids;
1138         int i;
1139
1140         for (i = 0; i < video->attached_count; i++) {
1141                 ids = &video->attached_array[i];
1142                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1143                         ids->bind_info = device;
1144                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1145                 }
1146         }
1147 }
1148
1149 /*
1150  *  Arg:
1151  *      video   : video bus device
1152  *
1153  *  Return:
1154  *      < 0     : error
1155  *
1156  *  Call _DOD to enumerate all devices attached to display adapter
1157  *
1158  */
1159
1160 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1161 {
1162         int status;
1163         int count;
1164         int i;
1165         struct acpi_video_enumerated_device *active_list;
1166         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1167         union acpi_object *dod = NULL;
1168         union acpi_object *obj;
1169
1170         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1171         if (!ACPI_SUCCESS(status)) {
1172                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1173                 return status;
1174         }
1175
1176         dod = buffer.pointer;
1177         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1178                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1179                 status = -EFAULT;
1180                 goto out;
1181         }
1182
1183         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1184                           dod->package.count));
1185
1186         active_list = kcalloc(1 + dod->package.count,
1187                               sizeof(struct acpi_video_enumerated_device),
1188                               GFP_KERNEL);
1189         if (!active_list) {
1190                 status = -ENOMEM;
1191                 goto out;
1192         }
1193
1194         count = 0;
1195         for (i = 0; i < dod->package.count; i++) {
1196                 obj = &dod->package.elements[i];
1197
1198                 if (obj->type != ACPI_TYPE_INTEGER) {
1199                         printk(KERN_ERR PREFIX
1200                                 "Invalid _DOD data in element %d\n", i);
1201                         continue;
1202                 }
1203
1204                 active_list[count].value.int_val = obj->integer.value;
1205                 active_list[count].bind_info = NULL;
1206                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1207                                   (int)obj->integer.value));
1208                 count++;
1209         }
1210
1211         kfree(video->attached_array);
1212
1213         video->attached_array = active_list;
1214         video->attached_count = count;
1215
1216 out:
1217         kfree(buffer.pointer);
1218         return status;
1219 }
1220
1221 static int
1222 acpi_video_get_next_level(struct acpi_video_device *device,
1223                           u32 level_current, u32 event)
1224 {
1225         int min, max, min_above, max_below, i, l, delta = 255;
1226         max = max_below = 0;
1227         min = min_above = 255;
1228         /* Find closest level to level_current */
1229         for (i = 2; i < device->brightness->count; i++) {
1230                 l = device->brightness->levels[i];
1231                 if (abs(l - level_current) < abs(delta)) {
1232                         delta = l - level_current;
1233                         if (!delta)
1234                                 break;
1235                 }
1236         }
1237         /* Ajust level_current to closest available level */
1238         level_current += delta;
1239         for (i = 2; i < device->brightness->count; i++) {
1240                 l = device->brightness->levels[i];
1241                 if (l < min)
1242                         min = l;
1243                 if (l > max)
1244                         max = l;
1245                 if (l < min_above && l > level_current)
1246                         min_above = l;
1247                 if (l > max_below && l < level_current)
1248                         max_below = l;
1249         }
1250
1251         switch (event) {
1252         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1253                 return (level_current < max) ? min_above : min;
1254         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1255                 return (level_current < max) ? min_above : max;
1256         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1257                 return (level_current > min) ? max_below : min;
1258         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1259         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1260                 return 0;
1261         default:
1262                 return level_current;
1263         }
1264 }
1265
1266 static void
1267 acpi_video_switch_brightness(struct work_struct *work)
1268 {
1269         struct acpi_video_device *device = container_of(to_delayed_work(work),
1270                              struct acpi_video_device, switch_brightness_work);
1271         unsigned long long level_current, level_next;
1272         int event = device->switch_brightness_event;
1273         int result = -EINVAL;
1274
1275         /* no warning message if acpi_backlight=vendor or a quirk is used */
1276         if (!acpi_video_verify_backlight_support())
1277                 return;
1278
1279         if (!device->brightness)
1280                 goto out;
1281
1282         result = acpi_video_device_lcd_get_level_current(device,
1283                                                          &level_current,
1284                                                          false);
1285         if (result)
1286                 goto out;
1287
1288         level_next = acpi_video_get_next_level(device, level_current, event);
1289
1290         result = acpi_video_device_lcd_set_level(device, level_next);
1291
1292         if (!result)
1293                 backlight_force_update(device->backlight,
1294                                        BACKLIGHT_UPDATE_HOTKEY);
1295
1296 out:
1297         if (result)
1298                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1299 }
1300
1301 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1302                         void **edid)
1303 {
1304         struct acpi_video_bus *video;
1305         struct acpi_video_device *video_device;
1306         union acpi_object *buffer = NULL;
1307         acpi_status status;
1308         int i, length;
1309
1310         if (!device || !acpi_driver_data(device))
1311                 return -EINVAL;
1312
1313         video = acpi_driver_data(device);
1314
1315         for (i = 0; i < video->attached_count; i++) {
1316                 video_device = video->attached_array[i].bind_info;
1317                 length = 256;
1318
1319                 if (!video_device)
1320                         continue;
1321
1322                 if (!video_device->cap._DDC)
1323                         continue;
1324
1325                 if (type) {
1326                         switch (type) {
1327                         case ACPI_VIDEO_DISPLAY_CRT:
1328                                 if (!video_device->flags.crt)
1329                                         continue;
1330                                 break;
1331                         case ACPI_VIDEO_DISPLAY_TV:
1332                                 if (!video_device->flags.tvout)
1333                                         continue;
1334                                 break;
1335                         case ACPI_VIDEO_DISPLAY_DVI:
1336                                 if (!video_device->flags.dvi)
1337                                         continue;
1338                                 break;
1339                         case ACPI_VIDEO_DISPLAY_LCD:
1340                                 if (!video_device->flags.lcd)
1341                                         continue;
1342                                 break;
1343                         }
1344                 } else if (video_device->device_id != device_id) {
1345                         continue;
1346                 }
1347
1348                 status = acpi_video_device_EDID(video_device, &buffer, length);
1349
1350                 if (ACPI_FAILURE(status) || !buffer ||
1351                     buffer->type != ACPI_TYPE_BUFFER) {
1352                         length = 128;
1353                         status = acpi_video_device_EDID(video_device, &buffer,
1354                                                         length);
1355                         if (ACPI_FAILURE(status) || !buffer ||
1356                             buffer->type != ACPI_TYPE_BUFFER) {
1357                                 continue;
1358                         }
1359                 }
1360
1361                 *edid = buffer->buffer.pointer;
1362                 return length;
1363         }
1364
1365         return -ENODEV;
1366 }
1367 EXPORT_SYMBOL(acpi_video_get_edid);
1368
1369 static int
1370 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1371                            struct acpi_device *device)
1372 {
1373         int status = 0;
1374         struct acpi_device *dev;
1375
1376         /*
1377          * There are systems where video module known to work fine regardless
1378          * of broken _DOD and ignoring returned value here doesn't cause
1379          * any issues later.
1380          */
1381         acpi_video_device_enumerate(video);
1382
1383         list_for_each_entry(dev, &device->children, node) {
1384
1385                 status = acpi_video_bus_get_one_device(dev, video);
1386                 if (status) {
1387                         dev_err(&dev->dev, "Can't attach device\n");
1388                         break;
1389                 }
1390         }
1391         return status;
1392 }
1393
1394 /* acpi_video interface */
1395
1396 /*
1397  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1398  * preform any automatic brightness change on receiving a notification.
1399  */
1400 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1401 {
1402         return acpi_video_bus_DOS(video, 0,
1403                                   acpi_osi_is_win8() ? 1 : 0);
1404 }
1405
1406 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1407 {
1408         return acpi_video_bus_DOS(video, 0,
1409                                   acpi_osi_is_win8() ? 0 : 1);
1410 }
1411
1412 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1413 {
1414         struct acpi_video_bus *video = acpi_driver_data(device);
1415         struct input_dev *input;
1416         int keycode = 0;
1417
1418         if (!video || !video->input)
1419                 return;
1420
1421         input = video->input;
1422
1423         switch (event) {
1424         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1425                                          * most likely via hotkey. */
1426                 keycode = KEY_SWITCHVIDEOMODE;
1427                 break;
1428
1429         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1430                                          * connector. */
1431                 acpi_video_device_enumerate(video);
1432                 acpi_video_device_rebind(video);
1433                 keycode = KEY_SWITCHVIDEOMODE;
1434                 break;
1435
1436         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1437                 keycode = KEY_SWITCHVIDEOMODE;
1438                 break;
1439         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1440                 keycode = KEY_VIDEO_NEXT;
1441                 break;
1442         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1443                 keycode = KEY_VIDEO_PREV;
1444                 break;
1445
1446         default:
1447                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1448                                   "Unsupported event [0x%x]\n", event));
1449                 break;
1450         }
1451
1452         if (acpi_notifier_call_chain(device, event, 0))
1453                 /* Something vetoed the keypress. */
1454                 keycode = 0;
1455
1456         if (keycode) {
1457                 input_report_key(input, keycode, 1);
1458                 input_sync(input);
1459                 input_report_key(input, keycode, 0);
1460                 input_sync(input);
1461         }
1462
1463         return;
1464 }
1465
1466 static void brightness_switch_event(struct acpi_video_device *video_device,
1467                                     u32 event)
1468 {
1469         if (!brightness_switch_enabled)
1470                 return;
1471
1472         video_device->switch_brightness_event = event;
1473         schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1474 }
1475
1476 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1477 {
1478         struct acpi_video_device *video_device = data;
1479         struct acpi_device *device = NULL;
1480         struct acpi_video_bus *bus;
1481         struct input_dev *input;
1482         int keycode = 0;
1483
1484         if (!video_device)
1485                 return;
1486
1487         device = video_device->dev;
1488         bus = video_device->video;
1489         input = bus->input;
1490
1491         switch (event) {
1492         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1493                 brightness_switch_event(video_device, event);
1494                 keycode = KEY_BRIGHTNESS_CYCLE;
1495                 break;
1496         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1497                 brightness_switch_event(video_device, event);
1498                 keycode = KEY_BRIGHTNESSUP;
1499                 break;
1500         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1501                 brightness_switch_event(video_device, event);
1502                 keycode = KEY_BRIGHTNESSDOWN;
1503                 break;
1504         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1505                 brightness_switch_event(video_device, event);
1506                 keycode = KEY_BRIGHTNESS_ZERO;
1507                 break;
1508         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1509                 brightness_switch_event(video_device, event);
1510                 keycode = KEY_DISPLAY_OFF;
1511                 break;
1512         default:
1513                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1514                                   "Unsupported event [0x%x]\n", event));
1515                 break;
1516         }
1517
1518         acpi_notifier_call_chain(device, event, 0);
1519
1520         if (keycode) {
1521                 input_report_key(input, keycode, 1);
1522                 input_sync(input);
1523                 input_report_key(input, keycode, 0);
1524                 input_sync(input);
1525         }
1526
1527         return;
1528 }
1529
1530 static int acpi_video_resume(struct notifier_block *nb,
1531                                 unsigned long val, void *ign)
1532 {
1533         struct acpi_video_bus *video;
1534         struct acpi_video_device *video_device;
1535         int i;
1536
1537         switch (val) {
1538         case PM_HIBERNATION_PREPARE:
1539         case PM_SUSPEND_PREPARE:
1540         case PM_RESTORE_PREPARE:
1541                 return NOTIFY_DONE;
1542         }
1543
1544         video = container_of(nb, struct acpi_video_bus, pm_nb);
1545
1546         dev_info(&video->device->dev, "Restoring backlight state\n");
1547
1548         for (i = 0; i < video->attached_count; i++) {
1549                 video_device = video->attached_array[i].bind_info;
1550                 if (video_device && video_device->backlight)
1551                         acpi_video_set_brightness(video_device->backlight);
1552         }
1553
1554         return NOTIFY_OK;
1555 }
1556
1557 static acpi_status
1558 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1559                         void **return_value)
1560 {
1561         struct acpi_device *device = context;
1562         struct acpi_device *sibling;
1563         int result;
1564
1565         if (handle == device->handle)
1566                 return AE_CTRL_TERMINATE;
1567
1568         result = acpi_bus_get_device(handle, &sibling);
1569         if (result)
1570                 return AE_OK;
1571
1572         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1573                         return AE_ALREADY_EXISTS;
1574
1575         return AE_OK;
1576 }
1577
1578 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1579 {
1580         struct backlight_properties props;
1581         struct pci_dev *pdev;
1582         acpi_handle acpi_parent;
1583         struct device *parent = NULL;
1584         int result;
1585         static int count;
1586         char *name;
1587
1588         result = acpi_video_init_brightness(device);
1589         if (result)
1590                 return;
1591         name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1592         if (!name)
1593                 return;
1594         count++;
1595
1596         acpi_get_parent(device->dev->handle, &acpi_parent);
1597
1598         pdev = acpi_get_pci_dev(acpi_parent);
1599         if (pdev) {
1600                 parent = &pdev->dev;
1601                 pci_dev_put(pdev);
1602         }
1603
1604         memset(&props, 0, sizeof(struct backlight_properties));
1605         props.type = BACKLIGHT_FIRMWARE;
1606         props.max_brightness = device->brightness->count - 3;
1607         device->backlight = backlight_device_register(name,
1608                                                       parent,
1609                                                       device,
1610                                                       &acpi_backlight_ops,
1611                                                       &props);
1612         kfree(name);
1613         if (IS_ERR(device->backlight))
1614                 return;
1615
1616         /*
1617          * Save current brightness level in case we have to restore it
1618          * before acpi_video_device_lcd_set_level() is called next time.
1619          */
1620         device->backlight->props.brightness =
1621                         acpi_video_get_brightness(device->backlight);
1622
1623         device->cooling_dev = thermal_cooling_device_register("LCD",
1624                                 device->dev, &video_cooling_ops);
1625         if (IS_ERR(device->cooling_dev)) {
1626                 /*
1627                  * Set cooling_dev to NULL so we don't crash trying to free it.
1628                  * Also, why the hell we are returning early and not attempt to
1629                  * register video output if cooling device registration failed?
1630                  * -- dtor
1631                  */
1632                 device->cooling_dev = NULL;
1633                 return;
1634         }
1635
1636         dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1637                  device->cooling_dev->id);
1638         result = sysfs_create_link(&device->dev->dev.kobj,
1639                         &device->cooling_dev->device.kobj,
1640                         "thermal_cooling");
1641         if (result)
1642                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1643         result = sysfs_create_link(&device->cooling_dev->device.kobj,
1644                         &device->dev->dev.kobj, "device");
1645         if (result)
1646                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1647 }
1648
1649 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1650 {
1651         struct acpi_video_device *dev;
1652
1653         if (video->backlight_registered)
1654                 return 0;
1655
1656         if (!acpi_video_verify_backlight_support())
1657                 return 0;
1658
1659         mutex_lock(&video->device_list_lock);
1660         list_for_each_entry(dev, &video->video_device_list, entry)
1661                 acpi_video_dev_register_backlight(dev);
1662         mutex_unlock(&video->device_list_lock);
1663
1664         video->backlight_registered = true;
1665
1666         video->pm_nb.notifier_call = acpi_video_resume;
1667         video->pm_nb.priority = 0;
1668         return register_pm_notifier(&video->pm_nb);
1669 }
1670
1671 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1672 {
1673         if (device->backlight) {
1674                 backlight_device_unregister(device->backlight);
1675                 device->backlight = NULL;
1676         }
1677         if (device->brightness) {
1678                 kfree(device->brightness->levels);
1679                 kfree(device->brightness);
1680                 device->brightness = NULL;
1681         }
1682         if (device->cooling_dev) {
1683                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1684                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1685                 thermal_cooling_device_unregister(device->cooling_dev);
1686                 device->cooling_dev = NULL;
1687         }
1688 }
1689
1690 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1691 {
1692         struct acpi_video_device *dev;
1693         int error;
1694
1695         if (!video->backlight_registered)
1696                 return 0;
1697
1698         error = unregister_pm_notifier(&video->pm_nb);
1699
1700         mutex_lock(&video->device_list_lock);
1701         list_for_each_entry(dev, &video->video_device_list, entry)
1702                 acpi_video_dev_unregister_backlight(dev);
1703         mutex_unlock(&video->device_list_lock);
1704
1705         video->backlight_registered = false;
1706
1707         return error;
1708 }
1709
1710 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1711 {
1712         acpi_status status;
1713         struct acpi_device *adev = device->dev;
1714
1715         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1716                                              acpi_video_device_notify, device);
1717         if (ACPI_FAILURE(status))
1718                 dev_err(&adev->dev, "Error installing notify handler\n");
1719         else
1720                 device->flags.notify = 1;
1721 }
1722
1723 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1724 {
1725         struct input_dev *input;
1726         struct acpi_video_device *dev;
1727         int error;
1728
1729         video->input = input = input_allocate_device();
1730         if (!input) {
1731                 error = -ENOMEM;
1732                 goto out;
1733         }
1734
1735         error = acpi_video_bus_start_devices(video);
1736         if (error)
1737                 goto err_free_input;
1738
1739         snprintf(video->phys, sizeof(video->phys),
1740                         "%s/video/input0", acpi_device_hid(video->device));
1741
1742         input->name = acpi_device_name(video->device);
1743         input->phys = video->phys;
1744         input->id.bustype = BUS_HOST;
1745         input->id.product = 0x06;
1746         input->dev.parent = &video->device->dev;
1747         input->evbit[0] = BIT(EV_KEY);
1748         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1749         set_bit(KEY_VIDEO_NEXT, input->keybit);
1750         set_bit(KEY_VIDEO_PREV, input->keybit);
1751         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1752         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1753         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1754         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1755         set_bit(KEY_DISPLAY_OFF, input->keybit);
1756
1757         error = input_register_device(input);
1758         if (error)
1759                 goto err_stop_dev;
1760
1761         mutex_lock(&video->device_list_lock);
1762         list_for_each_entry(dev, &video->video_device_list, entry)
1763                 acpi_video_dev_add_notify_handler(dev);
1764         mutex_unlock(&video->device_list_lock);
1765
1766         return 0;
1767
1768 err_stop_dev:
1769         acpi_video_bus_stop_devices(video);
1770 err_free_input:
1771         input_free_device(input);
1772         video->input = NULL;
1773 out:
1774         return error;
1775 }
1776
1777 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1778 {
1779         if (dev->flags.notify) {
1780                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1781                                            acpi_video_device_notify);
1782                 dev->flags.notify = 0;
1783         }
1784 }
1785
1786 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1787 {
1788         struct acpi_video_device *dev;
1789
1790         mutex_lock(&video->device_list_lock);
1791         list_for_each_entry(dev, &video->video_device_list, entry)
1792                 acpi_video_dev_remove_notify_handler(dev);
1793         mutex_unlock(&video->device_list_lock);
1794
1795         acpi_video_bus_stop_devices(video);
1796         input_unregister_device(video->input);
1797         video->input = NULL;
1798 }
1799
1800 static int acpi_video_backlight_notify(struct notifier_block *nb,
1801                                         unsigned long val, void *bd)
1802 {
1803         struct backlight_device *backlight = bd;
1804         struct acpi_video_bus *video;
1805
1806         /* acpi_video_verify_backlight_support only cares about raw devices */
1807         if (backlight->props.type != BACKLIGHT_RAW)
1808                 return NOTIFY_DONE;
1809
1810         video = container_of(nb, struct acpi_video_bus, backlight_nb);
1811
1812         switch (val) {
1813         case BACKLIGHT_REGISTERED:
1814                 if (!acpi_video_verify_backlight_support())
1815                         acpi_video_bus_unregister_backlight(video);
1816                 break;
1817         case BACKLIGHT_UNREGISTERED:
1818                 acpi_video_bus_register_backlight(video);
1819                 break;
1820         }
1821
1822         return NOTIFY_OK;
1823 }
1824
1825 static int acpi_video_bus_add_backlight_notify_handler(
1826                                                 struct acpi_video_bus *video)
1827 {
1828         int error;
1829
1830         video->backlight_nb.notifier_call = acpi_video_backlight_notify;
1831         video->backlight_nb.priority = 0;
1832         error = backlight_register_notifier(&video->backlight_nb);
1833         if (error == 0)
1834                 video->backlight_notifier_registered = true;
1835
1836         return error;
1837 }
1838
1839 static int acpi_video_bus_remove_backlight_notify_handler(
1840                                                 struct acpi_video_bus *video)
1841 {
1842         if (!video->backlight_notifier_registered)
1843                 return 0;
1844
1845         video->backlight_notifier_registered = false;
1846
1847         return backlight_unregister_notifier(&video->backlight_nb);
1848 }
1849
1850 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1851 {
1852         struct acpi_video_device *dev, *next;
1853
1854         mutex_lock(&video->device_list_lock);
1855         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1856                 list_del(&dev->entry);
1857                 kfree(dev);
1858         }
1859         mutex_unlock(&video->device_list_lock);
1860
1861         return 0;
1862 }
1863
1864 static int instance;
1865
1866 static int acpi_video_bus_add(struct acpi_device *device)
1867 {
1868         struct acpi_video_bus *video;
1869         int error;
1870         acpi_status status;
1871
1872         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1873                                 device->parent->handle, 1,
1874                                 acpi_video_bus_match, NULL,
1875                                 device, NULL);
1876         if (status == AE_ALREADY_EXISTS) {
1877                 printk(KERN_WARNING FW_BUG
1878                         "Duplicate ACPI video bus devices for the"
1879                         " same VGA controller, please try module "
1880                         "parameter \"video.allow_duplicates=1\""
1881                         "if the current driver doesn't work.\n");
1882                 if (!allow_duplicates)
1883                         return -ENODEV;
1884         }
1885
1886         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1887         if (!video)
1888                 return -ENOMEM;
1889
1890         /* a hack to fix the duplicate name "VID" problem on T61 */
1891         if (!strcmp(device->pnp.bus_id, "VID")) {
1892                 if (instance)
1893                         device->pnp.bus_id[3] = '0' + instance;
1894                 instance++;
1895         }
1896         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1897         if (!strcmp(device->pnp.bus_id, "VGA")) {
1898                 if (instance)
1899                         device->pnp.bus_id[3] = '0' + instance;
1900                 instance++;
1901         }
1902
1903         video->device = device;
1904         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1905         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1906         device->driver_data = video;
1907
1908         acpi_video_bus_find_cap(video);
1909         error = acpi_video_bus_check(video);
1910         if (error)
1911                 goto err_free_video;
1912
1913         mutex_init(&video->device_list_lock);
1914         INIT_LIST_HEAD(&video->video_device_list);
1915
1916         error = acpi_video_bus_get_devices(video, device);
1917         if (error)
1918                 goto err_put_video;
1919
1920         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1921                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1922                video->flags.multihead ? "yes" : "no",
1923                video->flags.rom ? "yes" : "no",
1924                video->flags.post ? "yes" : "no");
1925         mutex_lock(&video_list_lock);
1926         list_add_tail(&video->entry, &video_bus_head);
1927         mutex_unlock(&video_list_lock);
1928
1929         acpi_video_bus_register_backlight(video);
1930         acpi_video_bus_add_notify_handler(video);
1931         acpi_video_bus_add_backlight_notify_handler(video);
1932
1933         return 0;
1934
1935 err_put_video:
1936         acpi_video_bus_put_devices(video);
1937         kfree(video->attached_array);
1938 err_free_video:
1939         kfree(video);
1940         device->driver_data = NULL;
1941
1942         return error;
1943 }
1944
1945 static int acpi_video_bus_remove(struct acpi_device *device)
1946 {
1947         struct acpi_video_bus *video = NULL;
1948
1949
1950         if (!device || !acpi_driver_data(device))
1951                 return -EINVAL;
1952
1953         video = acpi_driver_data(device);
1954
1955         acpi_video_bus_remove_backlight_notify_handler(video);
1956         acpi_video_bus_remove_notify_handler(video);
1957         acpi_video_bus_unregister_backlight(video);
1958         acpi_video_bus_put_devices(video);
1959
1960         mutex_lock(&video_list_lock);
1961         list_del(&video->entry);
1962         mutex_unlock(&video_list_lock);
1963
1964         kfree(video->attached_array);
1965         kfree(video);
1966
1967         return 0;
1968 }
1969
1970 static int __init is_i740(struct pci_dev *dev)
1971 {
1972         if (dev->device == 0x00D1)
1973                 return 1;
1974         if (dev->device == 0x7000)
1975                 return 1;
1976         return 0;
1977 }
1978
1979 static int __init intel_opregion_present(void)
1980 {
1981         int opregion = 0;
1982         struct pci_dev *dev = NULL;
1983         u32 address;
1984
1985         for_each_pci_dev(dev) {
1986                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
1987                         continue;
1988                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
1989                         continue;
1990                 /* We don't want to poke around undefined i740 registers */
1991                 if (is_i740(dev))
1992                         continue;
1993                 pci_read_config_dword(dev, 0xfc, &address);
1994                 if (!address)
1995                         continue;
1996                 opregion = 1;
1997         }
1998         return opregion;
1999 }
2000
2001 int acpi_video_register(void)
2002 {
2003         int result = 0;
2004         if (register_count) {
2005                 /*
2006                  * if the function of acpi_video_register is already called,
2007                  * don't register the acpi_vide_bus again and return no error.
2008                  */
2009                 return 0;
2010         }
2011
2012         mutex_init(&video_list_lock);
2013         INIT_LIST_HEAD(&video_bus_head);
2014
2015         result = acpi_bus_register_driver(&acpi_video_bus);
2016         if (result < 0)
2017                 return -ENODEV;
2018
2019         /*
2020          * When the acpi_video_bus is loaded successfully, increase
2021          * the counter reference.
2022          */
2023         register_count = 1;
2024
2025         return 0;
2026 }
2027 EXPORT_SYMBOL(acpi_video_register);
2028
2029 void acpi_video_unregister(void)
2030 {
2031         if (!register_count) {
2032                 /*
2033                  * If the acpi video bus is already unloaded, don't
2034                  * unload it again and return directly.
2035                  */
2036                 return;
2037         }
2038         acpi_bus_unregister_driver(&acpi_video_bus);
2039
2040         register_count = 0;
2041
2042         return;
2043 }
2044 EXPORT_SYMBOL(acpi_video_unregister);
2045
2046 void acpi_video_unregister_backlight(void)
2047 {
2048         struct acpi_video_bus *video;
2049
2050         if (!register_count)
2051                 return;
2052
2053         mutex_lock(&video_list_lock);
2054         list_for_each_entry(video, &video_bus_head, entry)
2055                 acpi_video_bus_unregister_backlight(video);
2056         mutex_unlock(&video_list_lock);
2057 }
2058 EXPORT_SYMBOL(acpi_video_unregister_backlight);
2059
2060 /*
2061  * This is kind of nasty. Hardware using Intel chipsets may require
2062  * the video opregion code to be run first in order to initialise
2063  * state before any ACPI video calls are made. To handle this we defer
2064  * registration of the video class until the opregion code has run.
2065  */
2066
2067 static int __init acpi_video_init(void)
2068 {
2069         dmi_check_system(video_dmi_table);
2070
2071         if (intel_opregion_present())
2072                 return 0;
2073
2074         return acpi_video_register();
2075 }
2076
2077 static void __exit acpi_video_exit(void)
2078 {
2079         acpi_video_unregister();
2080
2081         return;
2082 }
2083
2084 module_init(acpi_video_init);
2085 module_exit(acpi_video_exit);