kernel/drivers/acpi/acpi_video.c

   1 /*
   2  *  video.c - ACPI Video Driver
   3  *
   4  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
   5  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
   6  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/types.h>
  27 #include <linux/list.h>
  28 #include <linux/mutex.h>
  29 #include <linux/input.h>
  30 #include <linux/backlight.h>
  31 #include <linux/thermal.h>
  32 #include <linux/sort.h>
  33 #include <linux/pci.h>
  34 #include <linux/pci_ids.h>
  35 #include <linux/slab.h>
  36 #include <linux/dmi.h>
  37 #include <linux/suspend.h>
  38 #include <linux/acpi.h>
  39 #include <acpi/video.h>
  40 #include <asm/uaccess.h>
  41
  42 #define PREFIX "ACPI: "
  43
  44 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
  45 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
  46 #define ACPI_VIDEO_NOTIFY_SWITCH        0x80
  47 #define ACPI_VIDEO_NOTIFY_PROBE         0x81
  48 #define ACPI_VIDEO_NOTIFY_CYCLE         0x82
  49 #define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT   0x83
  50 #define ACPI_VIDEO_NOTIFY_PREV_OUTPUT   0x84
  51
  52 #define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS      0x85
  53 #define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS        0x86
  54 #define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS        0x87
  55 #define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS       0x88
  56 #define ACPI_VIDEO_NOTIFY_DISPLAY_OFF           0x89
  57
  58 #define MAX_NAME_LEN    20
  59
  60 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  61 ACPI_MODULE_NAME("video");
  62
  63 MODULE_AUTHOR("Bruno Ducrot");
  64 MODULE_DESCRIPTION("ACPI Video Driver");
  65 MODULE_LICENSE("GPL");
  66
  67 static bool brightness_switch_enabled = 1;
  68 module_param(brightness_switch_enabled, bool, 0644);
  69
  70 /*
  71  * By default, we don't allow duplicate ACPI video bus devices
  72  * under the same VGA controller
  73  */
  74 static bool allow_duplicates;
  75 module_param(allow_duplicates, bool, 0644);
  76
  77 static int disable_backlight_sysfs_if = -1;
  78 module_param(disable_backlight_sysfs_if, int, 0444);
  79
  80 static bool device_id_scheme = false;
  81 module_param(device_id_scheme, bool, 0444);
  82
  83 static bool only_lcd = false;
  84 module_param(only_lcd, bool, 0444);
  85
  86 static int register_count;
  87 static DEFINE_MUTEX(register_count_mutex);
  88 static struct mutex video_list_lock;
  89 static struct list_head video_bus_head;
  90 static int acpi_video_bus_add(struct acpi_device *device);
  91 static int acpi_video_bus_remove(struct acpi_device *device);
  92 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
  93 void acpi_video_detect_exit(void);
  94
  95 static const struct acpi_device_id video_device_ids[] = {
  96         {ACPI_VIDEO_HID, 0},
  97         {"", 0},
  98 };
  99 MODULE_DEVICE_TABLE(acpi, video_device_ids);
 100
 101 static struct acpi_driver acpi_video_bus = {
 102         .name = "video",
 103         .class = ACPI_VIDEO_CLASS,
 104         .ids = video_device_ids,
 105         .ops = {
 106                 .add = acpi_video_bus_add,
 107                 .remove = acpi_video_bus_remove,
 108                 .notify = acpi_video_bus_notify,
 109                 },
 110 };
 111
 112 struct acpi_video_bus_flags {
 113         u8 multihead:1;         /* can switch video heads */
 114         u8 rom:1;               /* can retrieve a video rom */
 115         u8 post:1;              /* can configure the head to */
 116         u8 reserved:5;
 117 };
 118
 119 struct acpi_video_bus_cap {
 120         u8 _DOS:1;              /* Enable/Disable output switching */
 121         u8 _DOD:1;              /* Enumerate all devices attached to display adapter */
 122         u8 _ROM:1;              /* Get ROM Data */
 123         u8 _GPD:1;              /* Get POST Device */
 124         u8 _SPD:1;              /* Set POST Device */
 125         u8 _VPO:1;              /* Video POST Options */
 126         u8 reserved:2;
 127 };
 128
 129 struct acpi_video_device_attrib {
 130         u32 display_index:4;    /* A zero-based instance of the Display */
 131         u32 display_port_attachment:4;  /* This field differentiates the display type */
 132         u32 display_type:4;     /* Describe the specific type in use */
 133         u32 vendor_specific:4;  /* Chipset Vendor Specific */
 134         u32 bios_can_detect:1;  /* BIOS can detect the device */
 135         u32 depend_on_vga:1;    /* Non-VGA output device whose power is related to
 136                                    the VGA device. */
 137         u32 pipe_id:3;          /* For VGA multiple-head devices. */
 138         u32 reserved:10;        /* Must be 0 */
 139         u32 device_id_scheme:1; /* Device ID Scheme */
 140 };
 141
 142 struct acpi_video_enumerated_device {
 143         union {
 144                 u32 int_val;
 145                 struct acpi_video_device_attrib attrib;
 146         } value;
 147         struct acpi_video_device *bind_info;
 148 };
 149
 150 struct acpi_video_bus {
 151         struct acpi_device *device;
 152         bool backlight_registered;
 153         u8 dos_setting;
 154         struct acpi_video_enumerated_device *attached_array;
 155         u8 attached_count;
 156         u8 child_count;
 157         struct acpi_video_bus_cap cap;
 158         struct acpi_video_bus_flags flags;
 159         struct list_head video_device_list;
 160         struct mutex device_list_lock;  /* protects video_device_list */
 161         struct list_head entry;
 162         struct input_dev *input;
 163         char phys[32];  /* for input device */
 164         struct notifier_block pm_nb;
 165 };
 166
 167 struct acpi_video_device_flags {
 168         u8 crt:1;
 169         u8 lcd:1;
 170         u8 tvout:1;
 171         u8 dvi:1;
 172         u8 bios:1;
 173         u8 unknown:1;
 174         u8 notify:1;
 175         u8 reserved:1;
 176 };
 177
 178 struct acpi_video_device_cap {
 179         u8 _ADR:1;              /* Return the unique ID */
 180         u8 _BCL:1;              /* Query list of brightness control levels supported */
 181         u8 _BCM:1;              /* Set the brightness level */
 182         u8 _BQC:1;              /* Get current brightness level */
 183         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
 184         u8 _DDC:1;              /* Return the EDID for this device */
 185 };
 186
 187 struct acpi_video_brightness_flags {
 188         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
 189         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
 190         u8 _BQC_use_index:1;            /* _BQC returns an index value */
 191 };
 192
 193 struct acpi_video_device_brightness {
 194         int curr;
 195         int count;
 196         int *levels;
 197         struct acpi_video_brightness_flags flags;
 198 };
 199
 200 struct acpi_video_device {
 201         unsigned long device_id;
 202         struct acpi_video_device_flags flags;
 203         struct acpi_video_device_cap cap;
 204         struct list_head entry;
 205         struct delayed_work switch_brightness_work;
 206         int switch_brightness_event;
 207         struct acpi_video_bus *video;
 208         struct acpi_device *dev;
 209         struct acpi_video_device_brightness *brightness;
 210         struct backlight_device *backlight;
 211         struct thermal_cooling_device *cooling_dev;
 212 };
 213
 214 static const char device_decode[][30] = {
 215         "motherboard VGA device",
 216         "PCI VGA device",
 217         "AGP VGA device",
 218         "UNKNOWN",
 219 };
 220
 221 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 222 static void acpi_video_device_rebind(struct acpi_video_bus *video);
 223 static void acpi_video_device_bind(struct acpi_video_bus *video,
 224                                    struct acpi_video_device *device);
 225 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 226 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 227                         int level);
 228 static int acpi_video_device_lcd_get_level_current(
 229                         struct acpi_video_device *device,
 230                         unsigned long long *level, bool raw);
 231 static int acpi_video_get_next_level(struct acpi_video_device *device,
 232                                      u32 level_current, u32 event);
 233 static void acpi_video_switch_brightness(struct work_struct *work);
 234
 235 /* backlight device sysfs support */
 236 static int acpi_video_get_brightness(struct backlight_device *bd)
 237 {
 238         unsigned long long cur_level;
 239         int i;
 240         struct acpi_video_device *vd = bl_get_data(bd);
 241
 242         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 243                 return -EINVAL;
 244         for (i = 2; i < vd->brightness->count; i++) {
 245                 if (vd->brightness->levels[i] == cur_level)
 246                         /*
 247                          * The first two entries are special - see page 575
 248                          * of the ACPI spec 3.0
 249                          */
 250                         return i - 2;
 251         }
 252         return 0;
 253 }
 254
 255 static int acpi_video_set_brightness(struct backlight_device *bd)
 256 {
 257         int request_level = bd->props.brightness + 2;
 258         struct acpi_video_device *vd = bl_get_data(bd);
 259
 260         cancel_delayed_work(&vd->switch_brightness_work);
 261         return acpi_video_device_lcd_set_level(vd,
 262                                 vd->brightness->levels[request_level]);
 263 }
 264
 265 static const struct backlight_ops acpi_backlight_ops = {
 266         .get_brightness = acpi_video_get_brightness,
 267         .update_status  = acpi_video_set_brightness,
 268 };
 269
 270 /* thermal cooling device callbacks */
 271 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
 272                                long *state)
 273 {
 274         struct acpi_device *device = cooling_dev->devdata;
 275         struct acpi_video_device *video = acpi_driver_data(device);
 276
 277         *state = video->brightness->count - 3;
 278         return 0;
 279 }
 280
 281 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
 282                                long *state)
 283 {
 284         struct acpi_device *device = cooling_dev->devdata;
 285         struct acpi_video_device *video = acpi_driver_data(device);
 286         unsigned long long level;
 287         int offset;
 288
 289         if (acpi_video_device_lcd_get_level_current(video, &level, false))
 290                 return -EINVAL;
 291         for (offset = 2; offset < video->brightness->count; offset++)
 292                 if (level == video->brightness->levels[offset]) {
 293                         *state = video->brightness->count - offset - 1;
 294                         return 0;
 295                 }
 296
 297         return -EINVAL;
 298 }
 299
 300 static int
 301 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 302 {
 303         struct acpi_device *device = cooling_dev->devdata;
 304         struct acpi_video_device *video = acpi_driver_data(device);
 305         int level;
 306
 307         if (state >= video->brightness->count - 2)
 308                 return -EINVAL;
 309
 310         state = video->brightness->count - state;
 311         level = video->brightness->levels[state - 1];
 312         return acpi_video_device_lcd_set_level(video, level);
 313 }
 314
 315 static const struct thermal_cooling_device_ops video_cooling_ops = {
 316         .get_max_state = video_get_max_state,
 317         .get_cur_state = video_get_cur_state,
 318         .set_cur_state = video_set_cur_state,
 319 };
 320
 321 /*
 322  * --------------------------------------------------------------------------
 323  *                             Video Management
 324  * --------------------------------------------------------------------------
 325  */
 326
 327 static int
 328 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
 329                                    union acpi_object **levels)
 330 {
 331         int status;
 332         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 333         union acpi_object *obj;
 334
 335
 336         *levels = NULL;
 337
 338         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
 339         if (!ACPI_SUCCESS(status))
 340                 return status;
 341         obj = (union acpi_object *)buffer.pointer;
 342         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 343                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
 344                 status = -EFAULT;
 345                 goto err;
 346         }
 347
 348         *levels = obj;
 349
 350         return 0;
 351
 352 err:
 353         kfree(buffer.pointer);
 354
 355         return status;
 356 }
 357
 358 static int
 359 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 360 {
 361         int status;
 362         int state;
 363
 364         status = acpi_execute_simple_method(device->dev->handle,
 365                                             "_BCM", level);
 366         if (ACPI_FAILURE(status)) {
 367                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
 368                 return -EIO;
 369         }
 370
 371         device->brightness->curr = level;
 372         for (state = 2; state < device->brightness->count; state++)
 373                 if (level == device->brightness->levels[state]) {
 374                         if (device->backlight)
 375                                 device->backlight->props.brightness = state - 2;
 376                         return 0;
 377                 }
 378
 379         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
 380         return -EINVAL;
 381 }
 382
 383 /*
 384  * For some buggy _BQC methods, we need to add a constant value to
 385  * the _BQC return value to get the actual current brightness level
 386  */
 387
 388 static int bqc_offset_aml_bug_workaround;
 389 static int video_set_bqc_offset(const struct dmi_system_id *d)
 390 {
 391         bqc_offset_aml_bug_workaround = 9;
 392         return 0;
 393 }
 394
 395 static int video_disable_backlight_sysfs_if(
 396         const struct dmi_system_id *d)
 397 {
 398         if (disable_backlight_sysfs_if == -1)
 399                 disable_backlight_sysfs_if = 1;
 400         return 0;
 401 }
 402
 403 static int video_set_device_id_scheme(const struct dmi_system_id *d)
 404 {
 405         device_id_scheme = true;
 406         return 0;
 407 }
 408
 409 static int video_enable_only_lcd(const struct dmi_system_id *d)
 410 {
 411         only_lcd = true;
 412         return 0;
 413 }
 414
 415 static struct dmi_system_id video_dmi_table[] = {
 416         /*
 417          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 418          */
 419         {
 420          .callback = video_set_bqc_offset,
 421          .ident = "Acer Aspire 5720",
 422          .matches = {
 423                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 424                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 425                 },
 426         },
 427         {
 428          .callback = video_set_bqc_offset,
 429          .ident = "Acer Aspire 5710Z",
 430          .matches = {
 431                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 432                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 433                 },
 434         },
 435         {
 436          .callback = video_set_bqc_offset,
 437          .ident = "eMachines E510",
 438          .matches = {
 439                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 440                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 441                 },
 442         },
 443         {
 444          .callback = video_set_bqc_offset,
 445          .ident = "Acer Aspire 5315",
 446          .matches = {
 447                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 448                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 449                 },
 450         },
 451         {
 452          .callback = video_set_bqc_offset,
 453          .ident = "Acer Aspire 7720",
 454          .matches = {
 455                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 456                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 457                 },
 458         },
 459
 460         /*
 461          * Some machines have a broken acpi-video interface for brightness
 462          * control, but still need an acpi_video_device_lcd_set_level() call
 463          * on resume to turn the backlight power on.  We Enable backlight
 464          * control on these systems, but do not register a backlight sysfs
 465          * as brightness control does not work.
 466          */
 467         {
 468          /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
 469          .callback = video_disable_backlight_sysfs_if,
 470          .ident = "Toshiba Portege R700",
 471          .matches = {
 472                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 473                 DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
 474                 },
 475         },
 476         {
 477          /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
 478          .callback = video_disable_backlight_sysfs_if,
 479          .ident = "Toshiba Portege R830",
 480          .matches = {
 481                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 482                 DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
 483                 },
 484         },
 485         {
 486          /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
 487          .callback = video_disable_backlight_sysfs_if,
 488          .ident = "Toshiba Satellite R830",
 489          .matches = {
 490                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 491                 DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
 492                 },
 493         },
 494         /*
 495          * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
 496          * but the IDs actually follow the Device ID Scheme.
 497          */
 498         {
 499          /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 500          .callback = video_set_device_id_scheme,
 501          .ident = "ESPRIMO Mobile M9410",
 502          .matches = {
 503                 DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 504                 DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 505                 },
 506         },
 507         /*
 508          * Some machines have multiple video output devices, but only the one
 509          * that is the type of LCD can do the backlight control so we should not
 510          * register backlight interface for other video output devices.
 511          */
 512         {
 513          /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 514          .callback = video_enable_only_lcd,
 515          .ident = "ESPRIMO Mobile M9410",
 516          .matches = {
 517                 DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 518                 DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 519                 },
 520         },
 521         {}
 522 };
 523
 524 static unsigned long long
 525 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 526                               unsigned long long bqc_value)
 527 {
 528         unsigned long long level;
 529
 530         if (device->brightness->flags._BQC_use_index) {
 531                 /*
 532                  * _BQC returns an index that doesn't account for
 533                  * the first 2 items with special meaning, so we need
 534                  * to compensate for that by offsetting ourselves
 535                  */
 536                 if (device->brightness->flags._BCL_reversed)
 537                         bqc_value = device->brightness->count - 3 - bqc_value;
 538
 539                 level = device->brightness->levels[bqc_value + 2];
 540         } else {
 541                 level = bqc_value;
 542         }
 543
 544         level += bqc_offset_aml_bug_workaround;
 545
 546         return level;
 547 }
 548
 549 static int
 550 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 551                                         unsigned long long *level, bool raw)
 552 {
 553         acpi_status status = AE_OK;
 554         int i;
 555
 556         if (device->cap._BQC || device->cap._BCQ) {
 557                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 558
 559                 status = acpi_evaluate_integer(device->dev->handle, buf,
 560                                                 NULL, level);
 561                 if (ACPI_SUCCESS(status)) {
 562                         if (raw) {
 563                                 /*
 564                                  * Caller has indicated he wants the raw
 565                                  * value returned by _BQC, so don't furtherly
 566                                  * mess with the value.
 567                                  */
 568                                 return 0;
 569                         }
 570
 571                         *level = acpi_video_bqc_value_to_level(device, *level);
 572
 573                         for (i = 2; i < device->brightness->count; i++)
 574                                 if (device->brightness->levels[i] == *level) {
 575                                         device->brightness->curr = *level;
 576                                         return 0;
 577                                 }
 578                         /*
 579                          * BQC returned an invalid level.
 580                          * Stop using it.
 581                          */
 582                         ACPI_WARNING((AE_INFO,
 583                                       "%s returned an invalid level",
 584                                       buf));
 585                         device->cap._BQC = device->cap._BCQ = 0;
 586                 } else {
 587                         /*
 588                          * Fixme:
 589                          * should we return an error or ignore this failure?
 590                          * dev->brightness->curr is a cached value which stores
 591                          * the correct current backlight level in most cases.
 592                          * ACPI video backlight still works w/ buggy _BQC.
 593                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 594                          */
 595                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
 596                         device->cap._BQC = device->cap._BCQ = 0;
 597                 }
 598         }
 599
 600         *level = device->brightness->curr;
 601         return 0;
 602 }
 603
 604 static int
 605 acpi_video_device_EDID(struct acpi_video_device *device,
 606                        union acpi_object **edid, ssize_t length)
 607 {
 608         int status;
 609         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 610         union acpi_object *obj;
 611         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 612         struct acpi_object_list args = { 1, &arg0 };
 613
 614
 615         *edid = NULL;
 616
 617         if (!device)
 618                 return -ENODEV;
 619         if (length == 128)
 620                 arg0.integer.value = 1;
 621         else if (length == 256)
 622                 arg0.integer.value = 2;
 623         else
 624                 return -EINVAL;
 625
 626         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 627         if (ACPI_FAILURE(status))
 628                 return -ENODEV;
 629
 630         obj = buffer.pointer;
 631
 632         if (obj && obj->type == ACPI_TYPE_BUFFER)
 633                 *edid = obj;
 634         else {
 635                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
 636                 status = -EFAULT;
 637                 kfree(obj);
 638         }
 639
 640         return status;
 641 }
 642
 643 /* bus */
 644
 645 /*
 646  *  Arg:
 647  *      video           : video bus device pointer
 648  *      bios_flag       :
 649  *              0.      The system BIOS should NOT automatically switch(toggle)
 650  *                      the active display output.
 651  *              1.      The system BIOS should automatically switch (toggle) the
 652  *                      active display output. No switch event.
 653  *              2.      The _DGS value should be locked.
 654  *              3.      The system BIOS should not automatically switch (toggle) the
 655  *                      active display output, but instead generate the display switch
 656  *                      event notify code.
 657  *      lcd_flag        :
 658  *              0.      The system BIOS should automatically control the brightness level
 659  *                      of the LCD when the power changes from AC to DC
 660  *              1.      The system BIOS should NOT automatically control the brightness
 661  *                      level of the LCD when the power changes from AC to DC.
 662  *  Return Value:
 663  *              -EINVAL wrong arg.
 664  */
 665
 666 static int
 667 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 668 {
 669         acpi_status status;
 670
 671         if (!video->cap._DOS)
 672                 return 0;
 673
 674         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 675                 return -EINVAL;
 676         video->dos_setting = (lcd_flag << 2) | bios_flag;
 677         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 678                                             (lcd_flag << 2) | bios_flag);
 679         if (ACPI_FAILURE(status))
 680                 return -EIO;
 681
 682         return 0;
 683 }
 684
 685 /*
 686  * Simple comparison function used to sort backlight levels.
 687  */
 688
 689 static int
 690 acpi_video_cmp_level(const void *a, const void *b)
 691 {
 692         return *(int *)a - *(int *)b;
 693 }
 694
 695 /*
 696  * Decides if _BQC/_BCQ for this system is usable
 697  *
 698  * We do this by changing the level first and then read out the current
 699  * brightness level, if the value does not match, find out if it is using
 700  * index. If not, clear the _BQC/_BCQ capability.
 701  */
 702 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 703                                 int max_level, int current_level)
 704 {
 705         struct acpi_video_device_brightness *br = device->brightness;
 706         int result;
 707         unsigned long long level;
 708         int test_level;
 709
 710         /* don't mess with existing known broken systems */
 711         if (bqc_offset_aml_bug_workaround)
 712                 return 0;
 713
 714         /*
 715          * Some systems always report current brightness level as maximum
 716          * through _BQC, we need to test another value for them.
 717          */
 718         test_level = current_level == max_level ? br->levels[3] : max_level;
 719
 720         result = acpi_video_device_lcd_set_level(device, test_level);
 721         if (result)
 722                 return result;
 723
 724         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 725         if (result)
 726                 return result;
 727
 728         if (level != test_level) {
 729                 /* buggy _BQC found, need to find out if it uses index */
 730                 if (level < br->count) {
 731                         if (br->flags._BCL_reversed)
 732                                 level = br->count - 3 - level;
 733                         if (br->levels[level + 2] == test_level)
 734                                 br->flags._BQC_use_index = 1;
 735                 }
 736
 737                 if (!br->flags._BQC_use_index)
 738                         device->cap._BQC = device->cap._BCQ = 0;
 739         }
 740
 741         return 0;
 742 }
 743
 744
 745 /*
 746  *  Arg:
 747  *      device  : video output device (LCD, CRT, ..)
 748  *
 749  *  Return Value:
 750  *      Maximum brightness level
 751  *
 752  *  Allocate and initialize device->brightness.
 753  */
 754
 755 static int
 756 acpi_video_init_brightness(struct acpi_video_device *device)
 757 {
 758         union acpi_object *obj = NULL;
 759         int i, max_level = 0, count = 0, level_ac_battery = 0;
 760         unsigned long long level, level_old;
 761         union acpi_object *o;
 762         struct acpi_video_device_brightness *br = NULL;
 763         int result = -EINVAL;
 764         u32 value;
 765
 766         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
 767                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
 768                                                 "LCD brightness level\n"));
 769                 goto out;
 770         }
 771
 772         if (obj->package.count < 2)
 773                 goto out;
 774
 775         br = kzalloc(sizeof(*br), GFP_KERNEL);
 776         if (!br) {
 777                 printk(KERN_ERR "can't allocate memory\n");
 778                 result = -ENOMEM;
 779                 goto out;
 780         }
 781
 782         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
 783                                 GFP_KERNEL);
 784         if (!br->levels) {
 785                 result = -ENOMEM;
 786                 goto out_free;
 787         }
 788
 789         for (i = 0; i < obj->package.count; i++) {
 790                 o = (union acpi_object *)&obj->package.elements[i];
 791                 if (o->type != ACPI_TYPE_INTEGER) {
 792                         printk(KERN_ERR PREFIX "Invalid data\n");
 793                         continue;
 794                 }
 795                 value = (u32) o->integer.value;
 796                 /* Skip duplicate entries */
 797                 if (count > 2 && br->levels[count - 1] == value)
 798                         continue;
 799
 800                 br->levels[count] = value;
 801
 802                 if (br->levels[count] > max_level)
 803                         max_level = br->levels[count];
 804                 count++;
 805         }
 806
 807         /*
 808          * some buggy BIOS don't export the levels
 809          * when machine is on AC/Battery in _BCL package.
 810          * In this case, the first two elements in _BCL packages
 811          * are also supported brightness levels that OS should take care of.
 812          */
 813         for (i = 2; i < count; i++) {
 814                 if (br->levels[i] == br->levels[0])
 815                         level_ac_battery++;
 816                 if (br->levels[i] == br->levels[1])
 817                         level_ac_battery++;
 818         }
 819
 820         if (level_ac_battery < 2) {
 821                 level_ac_battery = 2 - level_ac_battery;
 822                 br->flags._BCL_no_ac_battery_levels = 1;
 823                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
 824                         br->levels[i] = br->levels[i - level_ac_battery];
 825                 count += level_ac_battery;
 826         } else if (level_ac_battery > 2)
 827                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
 828
 829         /* Check if the _BCL package is in a reversed order */
 830         if (max_level == br->levels[2]) {
 831                 br->flags._BCL_reversed = 1;
 832                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
 833                         acpi_video_cmp_level, NULL);
 834         } else if (max_level != br->levels[count - 1])
 835                 ACPI_ERROR((AE_INFO,
 836                             "Found unordered _BCL package"));
 837
 838         br->count = count;
 839         device->brightness = br;
 840
 841         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 842         br->curr = level = max_level;
 843
 844         if (!device->cap._BQC)
 845                 goto set_level;
 846
 847         result = acpi_video_device_lcd_get_level_current(device,
 848                                                          &level_old, true);
 849         if (result)
 850                 goto out_free_levels;
 851
 852         result = acpi_video_bqc_quirk(device, max_level, level_old);
 853         if (result)
 854                 goto out_free_levels;
 855         /*
 856          * cap._BQC may get cleared due to _BQC is found to be broken
 857          * in acpi_video_bqc_quirk, so check again here.
 858          */
 859         if (!device->cap._BQC)
 860                 goto set_level;
 861
 862         level = acpi_video_bqc_value_to_level(device, level_old);
 863         /*
 864          * On some buggy laptops, _BQC returns an uninitialized
 865          * value when invoked for the first time, i.e.
 866          * level_old is invalid (no matter whether it's a level
 867          * or an index). Set the backlight to max_level in this case.
 868          */
 869         for (i = 2; i < br->count; i++)
 870                 if (level == br->levels[i])
 871                         break;
 872         if (i == br->count || !level)
 873                 level = max_level;
 874
 875 set_level:
 876         result = acpi_video_device_lcd_set_level(device, level);
 877         if (result)
 878                 goto out_free_levels;
 879
 880         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 881                           "found %d brightness levels\n", count - 2));
 882         kfree(obj);
 883         return result;
 884
 885 out_free_levels:
 886         kfree(br->levels);
 887 out_free:
 888         kfree(br);
 889 out:
 890         device->brightness = NULL;
 891         kfree(obj);
 892         return result;
 893 }
 894
 895 /*
 896  *  Arg:
 897  *      device  : video output device (LCD, CRT, ..)
 898  *
 899  *  Return Value:
 900  *      None
 901  *
 902  *  Find out all required AML methods defined under the output
 903  *  device.
 904  */
 905
 906 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 907 {
 908         if (acpi_has_method(device->dev->handle, "_ADR"))
 909                 device->cap._ADR = 1;
 910         if (acpi_has_method(device->dev->handle, "_BCL"))
 911                 device->cap._BCL = 1;
 912         if (acpi_has_method(device->dev->handle, "_BCM"))
 913                 device->cap._BCM = 1;
 914         if (acpi_has_method(device->dev->handle, "_BQC")) {
 915                 device->cap._BQC = 1;
 916         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 917                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
 918                 device->cap._BCQ = 1;
 919         }
 920
 921         if (acpi_has_method(device->dev->handle, "_DDC"))
 922                 device->cap._DDC = 1;
 923 }
 924
 925 /*
 926  *  Arg:
 927  *      device  : video output device (VGA)
 928  *
 929  *  Return Value:
 930  *      None
 931  *
 932  *  Find out all required AML methods defined under the video bus device.
 933  */
 934
 935 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
 936 {
 937         if (acpi_has_method(video->device->handle, "_DOS"))
 938                 video->cap._DOS = 1;
 939         if (acpi_has_method(video->device->handle, "_DOD"))
 940                 video->cap._DOD = 1;
 941         if (acpi_has_method(video->device->handle, "_ROM"))
 942                 video->cap._ROM = 1;
 943         if (acpi_has_method(video->device->handle, "_GPD"))
 944                 video->cap._GPD = 1;
 945         if (acpi_has_method(video->device->handle, "_SPD"))
 946                 video->cap._SPD = 1;
 947         if (acpi_has_method(video->device->handle, "_VPO"))
 948                 video->cap._VPO = 1;
 949 }
 950
 951 /*
 952  * Check whether the video bus device has required AML method to
 953  * support the desired features
 954  */
 955
 956 static int acpi_video_bus_check(struct acpi_video_bus *video)
 957 {
 958         acpi_status status = -ENOENT;
 959         struct pci_dev *dev;
 960
 961         if (!video)
 962                 return -EINVAL;
 963
 964         dev = acpi_get_pci_dev(video->device->handle);
 965         if (!dev)
 966                 return -ENODEV;
 967         pci_dev_put(dev);
 968
 969         /*
 970          * Since there is no HID, CID and so on for VGA driver, we have
 971          * to check well known required nodes.
 972          */
 973
 974         /* Does this device support video switching? */
 975         if (video->cap._DOS || video->cap._DOD) {
 976                 if (!video->cap._DOS) {
 977                         printk(KERN_WARNING FW_BUG
 978                                 "ACPI(%s) defines _DOD but not _DOS\n",
 979                                 acpi_device_bid(video->device));
 980                 }
 981                 video->flags.multihead = 1;
 982                 status = 0;
 983         }
 984
 985         /* Does this device support retrieving a video ROM? */
 986         if (video->cap._ROM) {
 987                 video->flags.rom = 1;
 988                 status = 0;
 989         }
 990
 991         /* Does this device support configuring which video device to POST? */
 992         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
 993                 video->flags.post = 1;
 994                 status = 0;
 995         }
 996
 997         return status;
 998 }
 999
1000 /*
1001  * --------------------------------------------------------------------------
1002  *                               Driver Interface
1003  * --------------------------------------------------------------------------
1004  */
1005
1006 /* device interface */
1007 static struct acpi_video_device_attrib *
1008 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1009 {
1010         struct acpi_video_enumerated_device *ids;
1011         int i;
1012
1013         for (i = 0; i < video->attached_count; i++) {
1014                 ids = &video->attached_array[i];
1015                 if ((ids->value.int_val & 0xffff) == device_id)
1016                         return &ids->value.attrib;
1017         }
1018
1019         return NULL;
1020 }
1021
1022 static int
1023 acpi_video_get_device_type(struct acpi_video_bus *video,
1024                            unsigned long device_id)
1025 {
1026         struct acpi_video_enumerated_device *ids;
1027         int i;
1028
1029         for (i = 0; i < video->attached_count; i++) {
1030                 ids = &video->attached_array[i];
1031                 if ((ids->value.int_val & 0xffff) == device_id)
1032                         return ids->value.int_val;
1033         }
1034
1035         return 0;
1036 }
1037
1038 static int
1039 acpi_video_bus_get_one_device(struct acpi_device *device,
1040                               struct acpi_video_bus *video)
1041 {
1042         unsigned long long device_id;
1043         int status, device_type;
1044         struct acpi_video_device *data;
1045         struct acpi_video_device_attrib *attribute;
1046
1047         status =
1048             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1049         /* Some device omits _ADR, we skip them instead of fail */
1050         if (ACPI_FAILURE(status))
1051                 return 0;
1052
1053         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1054         if (!data)
1055                 return -ENOMEM;
1056
1057         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1058         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1059         device->driver_data = data;
1060
1061         data->device_id = device_id;
1062         data->video = video;
1063         data->dev = device;
1064         INIT_DELAYED_WORK(&data->switch_brightness_work,
1065                           acpi_video_switch_brightness);
1066
1067         attribute = acpi_video_get_device_attr(video, device_id);
1068
1069         if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1070                 switch (attribute->display_type) {
1071                 case ACPI_VIDEO_DISPLAY_CRT:
1072                         data->flags.crt = 1;
1073                         break;
1074                 case ACPI_VIDEO_DISPLAY_TV:
1075                         data->flags.tvout = 1;
1076                         break;
1077                 case ACPI_VIDEO_DISPLAY_DVI:
1078                         data->flags.dvi = 1;
1079                         break;
1080                 case ACPI_VIDEO_DISPLAY_LCD:
1081                         data->flags.lcd = 1;
1082                         break;
1083                 default:
1084                         data->flags.unknown = 1;
1085                         break;
1086                 }
1087                 if (attribute->bios_can_detect)
1088                         data->flags.bios = 1;
1089         } else {
1090                 /* Check for legacy IDs */
1091                 device_type = acpi_video_get_device_type(video, device_id);
1092                 /* Ignore bits 16 and 18-20 */
1093                 switch (device_type & 0xffe2ffff) {
1094                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1095                         data->flags.crt = 1;
1096                         break;
1097                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1098                         data->flags.lcd = 1;
1099                         break;
1100                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1101                         data->flags.tvout = 1;
1102                         break;
1103                 default:
1104                         data->flags.unknown = 1;
1105                 }
1106         }
1107
1108         acpi_video_device_bind(video, data);
1109         acpi_video_device_find_cap(data);
1110
1111         mutex_lock(&video->device_list_lock);
1112         list_add_tail(&data->entry, &video->video_device_list);
1113         mutex_unlock(&video->device_list_lock);
1114
1115         return status;
1116 }
1117
1118 /*
1119  *  Arg:
1120  *      video   : video bus device
1121  *
1122  *  Return:
1123  *      none
1124  *
1125  *  Enumerate the video device list of the video bus,
1126  *  bind the ids with the corresponding video devices
1127  *  under the video bus.
1128  */
1129
1130 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1131 {
1132         struct acpi_video_device *dev;
1133
1134         mutex_lock(&video->device_list_lock);
1135
1136         list_for_each_entry(dev, &video->video_device_list, entry)
1137                 acpi_video_device_bind(video, dev);
1138
1139         mutex_unlock(&video->device_list_lock);
1140 }
1141
1142 /*
1143  *  Arg:
1144  *      video   : video bus device
1145  *      device  : video output device under the video
1146  *              bus
1147  *
1148  *  Return:
1149  *      none
1150  *
1151  *  Bind the ids with the corresponding video devices
1152  *  under the video bus.
1153  */
1154
1155 static void
1156 acpi_video_device_bind(struct acpi_video_bus *video,
1157                        struct acpi_video_device *device)
1158 {
1159         struct acpi_video_enumerated_device *ids;
1160         int i;
1161
1162         for (i = 0; i < video->attached_count; i++) {
1163                 ids = &video->attached_array[i];
1164                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1165                         ids->bind_info = device;
1166                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1167                 }
1168         }
1169 }
1170
1171 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1172 {
1173         struct acpi_video_bus *video = device->video;
1174         int i;
1175
1176         /*
1177          * If we have a broken _DOD or we have more than 8 output devices
1178          * under the graphics controller node that we can't proper deal with
1179          * in the operation region code currently, no need to test.
1180          */
1181         if (!video->attached_count || video->child_count > 8)
1182                 return true;
1183
1184         for (i = 0; i < video->attached_count; i++) {
1185                 if ((video->attached_array[i].value.int_val & 0xfff) ==
1186                     (device->device_id & 0xfff))
1187                         return true;
1188         }
1189
1190         return false;
1191 }
1192
1193 /*
1194  *  Arg:
1195  *      video   : video bus device
1196  *
1197  *  Return:
1198  *      < 0     : error
1199  *
1200  *  Call _DOD to enumerate all devices attached to display adapter
1201  *
1202  */
1203
1204 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1205 {
1206         int status;
1207         int count;
1208         int i;
1209         struct acpi_video_enumerated_device *active_list;
1210         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1211         union acpi_object *dod = NULL;
1212         union acpi_object *obj;
1213
1214         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1215         if (!ACPI_SUCCESS(status)) {
1216                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1217                 return status;
1218         }
1219
1220         dod = buffer.pointer;
1221         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1222                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1223                 status = -EFAULT;
1224                 goto out;
1225         }
1226
1227         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1228                           dod->package.count));
1229
1230         active_list = kcalloc(1 + dod->package.count,
1231                               sizeof(struct acpi_video_enumerated_device),
1232                               GFP_KERNEL);
1233         if (!active_list) {
1234                 status = -ENOMEM;
1235                 goto out;
1236         }
1237
1238         count = 0;
1239         for (i = 0; i < dod->package.count; i++) {
1240                 obj = &dod->package.elements[i];
1241
1242                 if (obj->type != ACPI_TYPE_INTEGER) {
1243                         printk(KERN_ERR PREFIX
1244                                 "Invalid _DOD data in element %d\n", i);
1245                         continue;
1246                 }
1247
1248                 active_list[count].value.int_val = obj->integer.value;
1249                 active_list[count].bind_info = NULL;
1250                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1251                                   (int)obj->integer.value));
1252                 count++;
1253         }
1254
1255         kfree(video->attached_array);
1256
1257         video->attached_array = active_list;
1258         video->attached_count = count;
1259
1260 out:
1261         kfree(buffer.pointer);
1262         return status;
1263 }
1264
1265 static int
1266 acpi_video_get_next_level(struct acpi_video_device *device,
1267                           u32 level_current, u32 event)
1268 {
1269         int min, max, min_above, max_below, i, l, delta = 255;
1270         max = max_below = 0;
1271         min = min_above = 255;
1272         /* Find closest level to level_current */
1273         for (i = 2; i < device->brightness->count; i++) {
1274                 l = device->brightness->levels[i];
1275                 if (abs(l - level_current) < abs(delta)) {
1276                         delta = l - level_current;
1277                         if (!delta)
1278                                 break;
1279                 }
1280         }
1281         /* Ajust level_current to closest available level */
1282         level_current += delta;
1283         for (i = 2; i < device->brightness->count; i++) {
1284                 l = device->brightness->levels[i];
1285                 if (l < min)
1286                         min = l;
1287                 if (l > max)
1288                         max = l;
1289                 if (l < min_above && l > level_current)
1290                         min_above = l;
1291                 if (l > max_below && l < level_current)
1292                         max_below = l;
1293         }
1294
1295         switch (event) {
1296         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1297                 return (level_current < max) ? min_above : min;
1298         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1299                 return (level_current < max) ? min_above : max;
1300         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1301                 return (level_current > min) ? max_below : min;
1302         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1303         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1304                 return 0;
1305         default:
1306                 return level_current;
1307         }
1308 }
1309
1310 static void
1311 acpi_video_switch_brightness(struct work_struct *work)
1312 {
1313         struct acpi_video_device *device = container_of(to_delayed_work(work),
1314                              struct acpi_video_device, switch_brightness_work);
1315         unsigned long long level_current, level_next;
1316         int event = device->switch_brightness_event;
1317         int result = -EINVAL;
1318
1319         /* no warning message if acpi_backlight=vendor or a quirk is used */
1320         if (!device->backlight)
1321                 return;
1322
1323         if (!device->brightness)
1324                 goto out;
1325
1326         result = acpi_video_device_lcd_get_level_current(device,
1327                                                          &level_current,
1328                                                          false);
1329         if (result)
1330                 goto out;
1331
1332         level_next = acpi_video_get_next_level(device, level_current, event);
1333
1334         result = acpi_video_device_lcd_set_level(device, level_next);
1335
1336         if (!result)
1337                 backlight_force_update(device->backlight,
1338                                        BACKLIGHT_UPDATE_HOTKEY);
1339
1340 out:
1341         if (result)
1342                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1343 }
1344
1345 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1346                         void **edid)
1347 {
1348         struct acpi_video_bus *video;
1349         struct acpi_video_device *video_device;
1350         union acpi_object *buffer = NULL;
1351         acpi_status status;
1352         int i, length;
1353
1354         if (!device || !acpi_driver_data(device))
1355                 return -EINVAL;
1356
1357         video = acpi_driver_data(device);
1358
1359         for (i = 0; i < video->attached_count; i++) {
1360                 video_device = video->attached_array[i].bind_info;
1361                 length = 256;
1362
1363                 if (!video_device)
1364                         continue;
1365
1366                 if (!video_device->cap._DDC)
1367                         continue;
1368
1369                 if (type) {
1370                         switch (type) {
1371                         case ACPI_VIDEO_DISPLAY_CRT:
1372                                 if (!video_device->flags.crt)
1373                                         continue;
1374                                 break;
1375                         case ACPI_VIDEO_DISPLAY_TV:
1376                                 if (!video_device->flags.tvout)
1377                                         continue;
1378                                 break;
1379                         case ACPI_VIDEO_DISPLAY_DVI:
1380                                 if (!video_device->flags.dvi)
1381                                         continue;
1382                                 break;
1383                         case ACPI_VIDEO_DISPLAY_LCD:
1384                                 if (!video_device->flags.lcd)
1385                                         continue;
1386                                 break;
1387                         }
1388                 } else if (video_device->device_id != device_id) {
1389                         continue;
1390                 }
1391
1392                 status = acpi_video_device_EDID(video_device, &buffer, length);
1393
1394                 if (ACPI_FAILURE(status) || !buffer ||
1395                     buffer->type != ACPI_TYPE_BUFFER) {
1396                         length = 128;
1397                         status = acpi_video_device_EDID(video_device, &buffer,
1398                                                         length);
1399                         if (ACPI_FAILURE(status) || !buffer ||
1400                             buffer->type != ACPI_TYPE_BUFFER) {
1401                                 continue;
1402                         }
1403                 }
1404
1405                 *edid = buffer->buffer.pointer;
1406                 return length;
1407         }
1408
1409         return -ENODEV;
1410 }
1411 EXPORT_SYMBOL(acpi_video_get_edid);
1412
1413 static int
1414 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1415                            struct acpi_device *device)
1416 {
1417         int status = 0;
1418         struct acpi_device *dev;
1419
1420         /*
1421          * There are systems where video module known to work fine regardless
1422          * of broken _DOD and ignoring returned value here doesn't cause
1423          * any issues later.
1424          */
1425         acpi_video_device_enumerate(video);
1426
1427         list_for_each_entry(dev, &device->children, node) {
1428
1429                 status = acpi_video_bus_get_one_device(dev, video);
1430                 if (status) {
1431                         dev_err(&dev->dev, "Can't attach device\n");
1432                         break;
1433                 }
1434                 video->child_count++;
1435         }
1436         return status;
1437 }
1438
1439 /* acpi_video interface */
1440
1441 /*
1442  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1443  * preform any automatic brightness change on receiving a notification.
1444  */
1445 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1446 {
1447         return acpi_video_bus_DOS(video, 0,
1448                                   acpi_osi_is_win8() ? 1 : 0);
1449 }
1450
1451 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1452 {
1453         return acpi_video_bus_DOS(video, 0,
1454                                   acpi_osi_is_win8() ? 0 : 1);
1455 }
1456
1457 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1458 {
1459         struct acpi_video_bus *video = acpi_driver_data(device);
1460         struct input_dev *input;
1461         int keycode = 0;
1462
1463         if (!video || !video->input)
1464                 return;
1465
1466         input = video->input;
1467
1468         switch (event) {
1469         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1470                                          * most likely via hotkey. */
1471                 keycode = KEY_SWITCHVIDEOMODE;
1472                 break;
1473
1474         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1475                                          * connector. */
1476                 acpi_video_device_enumerate(video);
1477                 acpi_video_device_rebind(video);
1478                 keycode = KEY_SWITCHVIDEOMODE;
1479                 break;
1480
1481         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1482                 keycode = KEY_SWITCHVIDEOMODE;
1483                 break;
1484         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1485                 keycode = KEY_VIDEO_NEXT;
1486                 break;
1487         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1488                 keycode = KEY_VIDEO_PREV;
1489                 break;
1490
1491         default:
1492                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1493                                   "Unsupported event [0x%x]\n", event));
1494                 break;
1495         }
1496
1497         if (acpi_notifier_call_chain(device, event, 0))
1498                 /* Something vetoed the keypress. */
1499                 keycode = 0;
1500
1501         if (keycode) {
1502                 input_report_key(input, keycode, 1);
1503                 input_sync(input);
1504                 input_report_key(input, keycode, 0);
1505                 input_sync(input);
1506         }
1507
1508         return;
1509 }
1510
1511 static void brightness_switch_event(struct acpi_video_device *video_device,
1512                                     u32 event)
1513 {
1514         if (!brightness_switch_enabled)
1515                 return;
1516
1517         video_device->switch_brightness_event = event;
1518         schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1519 }
1520
1521 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1522 {
1523         struct acpi_video_device *video_device = data;
1524         struct acpi_device *device = NULL;
1525         struct acpi_video_bus *bus;
1526         struct input_dev *input;
1527         int keycode = 0;
1528
1529         if (!video_device)
1530                 return;
1531
1532         device = video_device->dev;
1533         bus = video_device->video;
1534         input = bus->input;
1535
1536         switch (event) {
1537         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1538                 brightness_switch_event(video_device, event);
1539                 keycode = KEY_BRIGHTNESS_CYCLE;
1540                 break;
1541         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1542                 brightness_switch_event(video_device, event);
1543                 keycode = KEY_BRIGHTNESSUP;
1544                 break;
1545         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1546                 brightness_switch_event(video_device, event);
1547                 keycode = KEY_BRIGHTNESSDOWN;
1548                 break;
1549         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1550                 brightness_switch_event(video_device, event);
1551                 keycode = KEY_BRIGHTNESS_ZERO;
1552                 break;
1553         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1554                 brightness_switch_event(video_device, event);
1555                 keycode = KEY_DISPLAY_OFF;
1556                 break;
1557         default:
1558                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1559                                   "Unsupported event [0x%x]\n", event));
1560                 break;
1561         }
1562
1563         acpi_notifier_call_chain(device, event, 0);
1564
1565         if (keycode) {
1566                 input_report_key(input, keycode, 1);
1567                 input_sync(input);
1568                 input_report_key(input, keycode, 0);
1569                 input_sync(input);
1570         }
1571
1572         return;
1573 }
1574
1575 static int acpi_video_resume(struct notifier_block *nb,
1576                                 unsigned long val, void *ign)
1577 {
1578         struct acpi_video_bus *video;
1579         struct acpi_video_device *video_device;
1580         int i;
1581
1582         switch (val) {
1583         case PM_HIBERNATION_PREPARE:
1584         case PM_SUSPEND_PREPARE:
1585         case PM_RESTORE_PREPARE:
1586                 return NOTIFY_DONE;
1587         }
1588
1589         video = container_of(nb, struct acpi_video_bus, pm_nb);
1590
1591         dev_info(&video->device->dev, "Restoring backlight state\n");
1592
1593         for (i = 0; i < video->attached_count; i++) {
1594                 video_device = video->attached_array[i].bind_info;
1595                 if (video_device && video_device->brightness)
1596                         acpi_video_device_lcd_set_level(video_device,
1597                                         video_device->brightness->curr);
1598         }
1599
1600         return NOTIFY_OK;
1601 }
1602
1603 static acpi_status
1604 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1605                         void **return_value)
1606 {
1607         struct acpi_device *device = context;
1608         struct acpi_device *sibling;
1609         int result;
1610
1611         if (handle == device->handle)
1612                 return AE_CTRL_TERMINATE;
1613
1614         result = acpi_bus_get_device(handle, &sibling);
1615         if (result)
1616                 return AE_OK;
1617
1618         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1619                         return AE_ALREADY_EXISTS;
1620
1621         return AE_OK;
1622 }
1623
1624 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1625 {
1626         struct backlight_properties props;
1627         struct pci_dev *pdev;
1628         acpi_handle acpi_parent;
1629         struct device *parent = NULL;
1630         int result;
1631         static int count;
1632         char *name;
1633
1634         result = acpi_video_init_brightness(device);
1635         if (result)
1636                 return;
1637
1638         if (disable_backlight_sysfs_if > 0)
1639                 return;
1640
1641         name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1642         if (!name)
1643                 return;
1644         count++;
1645
1646         acpi_get_parent(device->dev->handle, &acpi_parent);
1647
1648         pdev = acpi_get_pci_dev(acpi_parent);
1649         if (pdev) {
1650                 parent = &pdev->dev;
1651                 pci_dev_put(pdev);
1652         }
1653
1654         memset(&props, 0, sizeof(struct backlight_properties));
1655         props.type = BACKLIGHT_FIRMWARE;
1656         props.max_brightness = device->brightness->count - 3;
1657         device->backlight = backlight_device_register(name,
1658                                                       parent,
1659                                                       device,
1660                                                       &acpi_backlight_ops,
1661                                                       &props);
1662         kfree(name);
1663         if (IS_ERR(device->backlight)) {
1664                 device->backlight = NULL;
1665                 return;
1666         }
1667
1668         /*
1669          * Save current brightness level in case we have to restore it
1670          * before acpi_video_device_lcd_set_level() is called next time.
1671          */
1672         device->backlight->props.brightness =
1673                         acpi_video_get_brightness(device->backlight);
1674
1675         device->cooling_dev = thermal_cooling_device_register("LCD",
1676                                 device->dev, &video_cooling_ops);
1677         if (IS_ERR(device->cooling_dev)) {
1678                 /*
1679                  * Set cooling_dev to NULL so we don't crash trying to free it.
1680                  * Also, why the hell we are returning early and not attempt to
1681                  * register video output if cooling device registration failed?
1682                  * -- dtor
1683                  */
1684                 device->cooling_dev = NULL;
1685                 return;
1686         }
1687
1688         dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1689                  device->cooling_dev->id);
1690         result = sysfs_create_link(&device->dev->dev.kobj,
1691                         &device->cooling_dev->device.kobj,
1692                         "thermal_cooling");
1693         if (result)
1694                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1695         result = sysfs_create_link(&device->cooling_dev->device.kobj,
1696                         &device->dev->dev.kobj, "device");
1697         if (result)
1698                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1699 }
1700
1701 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1702 {
1703         struct acpi_video_device *dev;
1704         union acpi_object *levels;
1705
1706         mutex_lock(&video->device_list_lock);
1707         list_for_each_entry(dev, &video->video_device_list, entry) {
1708                 if (!acpi_video_device_lcd_query_levels(dev, &levels))
1709                         kfree(levels);
1710         }
1711         mutex_unlock(&video->device_list_lock);
1712 }
1713
1714 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1715 {
1716         /*
1717          * Do not create backlight device for video output
1718          * device that is not in the enumerated list.
1719          */
1720         if (!acpi_video_device_in_dod(dev)) {
1721                 dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1722                 return false;
1723         }
1724
1725         if (only_lcd)
1726                 return dev->flags.lcd;
1727         return true;
1728 }
1729
1730 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1731 {
1732         struct acpi_video_device *dev;
1733
1734         if (video->backlight_registered)
1735                 return 0;
1736
1737         acpi_video_run_bcl_for_osi(video);
1738
1739         if (acpi_video_get_backlight_type() != acpi_backlight_video)
1740                 return 0;
1741
1742         mutex_lock(&video->device_list_lock);
1743         list_for_each_entry(dev, &video->video_device_list, entry) {
1744                 if (acpi_video_should_register_backlight(dev))
1745                         acpi_video_dev_register_backlight(dev);
1746         }
1747         mutex_unlock(&video->device_list_lock);
1748
1749         video->backlight_registered = true;
1750
1751         video->pm_nb.notifier_call = acpi_video_resume;
1752         video->pm_nb.priority = 0;
1753         return register_pm_notifier(&video->pm_nb);
1754 }
1755
1756 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1757 {
1758         if (device->backlight) {
1759                 backlight_device_unregister(device->backlight);
1760                 device->backlight = NULL;
1761         }
1762         if (device->brightness) {
1763                 kfree(device->brightness->levels);
1764                 kfree(device->brightness);
1765                 device->brightness = NULL;
1766         }
1767         if (device->cooling_dev) {
1768                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1769                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1770                 thermal_cooling_device_unregister(device->cooling_dev);
1771                 device->cooling_dev = NULL;
1772         }
1773 }
1774
1775 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1776 {
1777         struct acpi_video_device *dev;
1778         int error;
1779
1780         if (!video->backlight_registered)
1781                 return 0;
1782
1783         error = unregister_pm_notifier(&video->pm_nb);
1784
1785         mutex_lock(&video->device_list_lock);
1786         list_for_each_entry(dev, &video->video_device_list, entry)
1787                 acpi_video_dev_unregister_backlight(dev);
1788         mutex_unlock(&video->device_list_lock);
1789
1790         video->backlight_registered = false;
1791
1792         return error;
1793 }
1794
1795 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1796 {
1797         acpi_status status;
1798         struct acpi_device *adev = device->dev;
1799
1800         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1801                                              acpi_video_device_notify, device);
1802         if (ACPI_FAILURE(status))
1803                 dev_err(&adev->dev, "Error installing notify handler\n");
1804         else
1805                 device->flags.notify = 1;
1806 }
1807
1808 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1809 {
1810         struct input_dev *input;
1811         struct acpi_video_device *dev;
1812         int error;
1813
1814         video->input = input = input_allocate_device();
1815         if (!input) {
1816                 error = -ENOMEM;
1817                 goto out;
1818         }
1819
1820         error = acpi_video_bus_start_devices(video);
1821         if (error)
1822                 goto err_free_input;
1823
1824         snprintf(video->phys, sizeof(video->phys),
1825                         "%s/video/input0", acpi_device_hid(video->device));
1826
1827         input->name = acpi_device_name(video->device);
1828         input->phys = video->phys;
1829         input->id.bustype = BUS_HOST;
1830         input->id.product = 0x06;
1831         input->dev.parent = &video->device->dev;
1832         input->evbit[0] = BIT(EV_KEY);
1833         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1834         set_bit(KEY_VIDEO_NEXT, input->keybit);
1835         set_bit(KEY_VIDEO_PREV, input->keybit);
1836         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1837         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1838         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1839         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1840         set_bit(KEY_DISPLAY_OFF, input->keybit);
1841
1842         error = input_register_device(input);
1843         if (error)
1844                 goto err_stop_dev;
1845
1846         mutex_lock(&video->device_list_lock);
1847         list_for_each_entry(dev, &video->video_device_list, entry)
1848                 acpi_video_dev_add_notify_handler(dev);
1849         mutex_unlock(&video->device_list_lock);
1850
1851         return 0;
1852
1853 err_stop_dev:
1854         acpi_video_bus_stop_devices(video);
1855 err_free_input:
1856         input_free_device(input);
1857         video->input = NULL;
1858 out:
1859         return error;
1860 }
1861
1862 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1863 {
1864         if (dev->flags.notify) {
1865                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1866                                            acpi_video_device_notify);
1867                 dev->flags.notify = 0;
1868         }
1869 }
1870
1871 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1872 {
1873         struct acpi_video_device *dev;
1874
1875         mutex_lock(&video->device_list_lock);
1876         list_for_each_entry(dev, &video->video_device_list, entry)
1877                 acpi_video_dev_remove_notify_handler(dev);
1878         mutex_unlock(&video->device_list_lock);
1879
1880         acpi_video_bus_stop_devices(video);
1881         input_unregister_device(video->input);
1882         video->input = NULL;
1883 }
1884
1885 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1886 {
1887         struct acpi_video_device *dev, *next;
1888
1889         mutex_lock(&video->device_list_lock);
1890         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1891                 list_del(&dev->entry);
1892                 kfree(dev);
1893         }
1894         mutex_unlock(&video->device_list_lock);
1895
1896         return 0;
1897 }
1898
1899 static int instance;
1900
1901 static int acpi_video_bus_add(struct acpi_device *device)
1902 {
1903         struct acpi_video_bus *video;
1904         int error;
1905         acpi_status status;
1906
1907         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1908                                 device->parent->handle, 1,
1909                                 acpi_video_bus_match, NULL,
1910                                 device, NULL);
1911         if (status == AE_ALREADY_EXISTS) {
1912                 printk(KERN_WARNING FW_BUG
1913                         "Duplicate ACPI video bus devices for the"
1914                         " same VGA controller, please try module "
1915                         "parameter \"video.allow_duplicates=1\""
1916                         "if the current driver doesn't work.\n");
1917                 if (!allow_duplicates)
1918                         return -ENODEV;
1919         }
1920
1921         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1922         if (!video)
1923                 return -ENOMEM;
1924
1925         /* a hack to fix the duplicate name "VID" problem on T61 */
1926         if (!strcmp(device->pnp.bus_id, "VID")) {
1927                 if (instance)
1928                         device->pnp.bus_id[3] = '0' + instance;
1929                 instance++;
1930         }
1931         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1932         if (!strcmp(device->pnp.bus_id, "VGA")) {
1933                 if (instance)
1934                         device->pnp.bus_id[3] = '0' + instance;
1935                 instance++;
1936         }
1937
1938         video->device = device;
1939         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1940         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1941         device->driver_data = video;
1942
1943         acpi_video_bus_find_cap(video);
1944         error = acpi_video_bus_check(video);
1945         if (error)
1946                 goto err_free_video;
1947
1948         mutex_init(&video->device_list_lock);
1949         INIT_LIST_HEAD(&video->video_device_list);
1950
1951         error = acpi_video_bus_get_devices(video, device);
1952         if (error)
1953                 goto err_put_video;
1954
1955         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1956                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1957                video->flags.multihead ? "yes" : "no",
1958                video->flags.rom ? "yes" : "no",
1959                video->flags.post ? "yes" : "no");
1960         mutex_lock(&video_list_lock);
1961         list_add_tail(&video->entry, &video_bus_head);
1962         mutex_unlock(&video_list_lock);
1963
1964         acpi_video_bus_register_backlight(video);
1965         acpi_video_bus_add_notify_handler(video);
1966
1967         return 0;
1968
1969 err_put_video:
1970         acpi_video_bus_put_devices(video);
1971         kfree(video->attached_array);
1972 err_free_video:
1973         kfree(video);
1974         device->driver_data = NULL;
1975
1976         return error;
1977 }
1978
1979 static int acpi_video_bus_remove(struct acpi_device *device)
1980 {
1981         struct acpi_video_bus *video = NULL;
1982
1983
1984         if (!device || !acpi_driver_data(device))
1985                 return -EINVAL;
1986
1987         video = acpi_driver_data(device);
1988
1989         acpi_video_bus_remove_notify_handler(video);
1990         acpi_video_bus_unregister_backlight(video);
1991         acpi_video_bus_put_devices(video);
1992
1993         mutex_lock(&video_list_lock);
1994         list_del(&video->entry);
1995         mutex_unlock(&video_list_lock);
1996
1997         kfree(video->attached_array);
1998         kfree(video);
1999
2000         return 0;
2001 }
2002
2003 static int __init is_i740(struct pci_dev *dev)
2004 {
2005         if (dev->device == 0x00D1)
2006                 return 1;
2007         if (dev->device == 0x7000)
2008                 return 1;
2009         return 0;
2010 }
2011
2012 static int __init intel_opregion_present(void)
2013 {
2014         int opregion = 0;
2015         struct pci_dev *dev = NULL;
2016         u32 address;
2017
2018         for_each_pci_dev(dev) {
2019                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2020                         continue;
2021                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2022                         continue;
2023                 /* We don't want to poke around undefined i740 registers */
2024                 if (is_i740(dev))
2025                         continue;
2026                 pci_read_config_dword(dev, 0xfc, &address);
2027                 if (!address)
2028                         continue;
2029                 opregion = 1;
2030         }
2031         return opregion;
2032 }
2033
2034 int acpi_video_register(void)
2035 {
2036         int ret = 0;
2037
2038         mutex_lock(&register_count_mutex);
2039         if (register_count) {
2040                 /*
2041                  * if the function of acpi_video_register is already called,
2042                  * don't register the acpi_vide_bus again and return no error.
2043                  */
2044                 goto leave;
2045         }
2046
2047         mutex_init(&video_list_lock);
2048         INIT_LIST_HEAD(&video_bus_head);
2049
2050         dmi_check_system(video_dmi_table);
2051
2052         ret = acpi_bus_register_driver(&acpi_video_bus);
2053         if (ret)
2054                 goto leave;
2055
2056         /*
2057          * When the acpi_video_bus is loaded successfully, increase
2058          * the counter reference.
2059          */
2060         register_count = 1;
2061
2062 leave:
2063         mutex_unlock(&register_count_mutex);
2064         return ret;
2065 }
2066 EXPORT_SYMBOL(acpi_video_register);
2067
2068 void acpi_video_unregister(void)
2069 {
2070         mutex_lock(&register_count_mutex);
2071         if (register_count) {
2072                 acpi_bus_unregister_driver(&acpi_video_bus);
2073                 register_count = 0;
2074         }
2075         mutex_unlock(&register_count_mutex);
2076 }
2077 EXPORT_SYMBOL(acpi_video_unregister);
2078
2079 void acpi_video_unregister_backlight(void)
2080 {
2081         struct acpi_video_bus *video;
2082
2083         mutex_lock(&register_count_mutex);
2084         if (register_count) {
2085                 mutex_lock(&video_list_lock);
2086                 list_for_each_entry(video, &video_bus_head, entry)
2087                         acpi_video_bus_unregister_backlight(video);
2088                 mutex_unlock(&video_list_lock);
2089         }
2090         mutex_unlock(&register_count_mutex);
2091 }
2092
2093 /*
2094  * This is kind of nasty. Hardware using Intel chipsets may require
2095  * the video opregion code to be run first in order to initialise
2096  * state before any ACPI video calls are made. To handle this we defer
2097  * registration of the video class until the opregion code has run.
2098  */
2099
2100 static int __init acpi_video_init(void)
2101 {
2102         /*
2103          * Let the module load even if ACPI is disabled (e.g. due to
2104          * a broken BIOS) so that i915.ko can still be loaded on such
2105          * old systems without an AcpiOpRegion.
2106          *
2107          * acpi_video_register() will report -ENODEV later as well due
2108          * to acpi_disabled when i915.ko tries to register itself afterwards.
2109          */
2110         if (acpi_disabled)
2111                 return 0;
2112
2113         if (intel_opregion_present())
2114                 return 0;
2115
2116         return acpi_video_register();
2117 }
2118
2119 static void __exit acpi_video_exit(void)
2120 {
2121         acpi_video_detect_exit();
2122         acpi_video_unregister();
2123
2124         return;
2125 }
2126
2127 module_init(acpi_video_init);
2128 module_exit(acpi_video_exit);