drivers/acpi/acpi_video.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  video.c - ACPI Video Driver
   4  *
   5  *  Copyright (C) 2004 Luming Yu <[email protected]>
   6  *  Copyright (C) 2004 Bruno Ducrot <[email protected]>
   7  *  Copyright (C) 2006 Thomas Tuttle <[email protected]>
   8  */
   9
  10 #define pr_fmt(fmt) "ACPI: video: " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/list.h>
  17 #include <linux/mutex.h>
  18 #include <linux/input.h>
  19 #include <linux/backlight.h>
  20 #include <linux/thermal.h>
  21 #include <linux/sort.h>
  22 #include <linux/pci.h>
  23 #include <linux/pci_ids.h>
  24 #include <linux/slab.h>
  25 #include <linux/dmi.h>
  26 #include <linux/suspend.h>
  27 #include <linux/acpi.h>
  28 #include <acpi/video.h>
  29 #include <linux/uaccess.h>
  30
  31 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
  32 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
  33
  34 #define MAX_NAME_LEN    20
  35
  36 MODULE_AUTHOR("Bruno Ducrot");
  37 MODULE_DESCRIPTION("ACPI Video Driver");
  38 MODULE_LICENSE("GPL");
  39
  40 static bool brightness_switch_enabled = true;
  41 module_param(brightness_switch_enabled, bool, 0644);
  42
  43 /*
  44  * By default, we don't allow duplicate ACPI video bus devices
  45  * under the same VGA controller
  46  */
  47 static bool allow_duplicates;
  48 module_param(allow_duplicates, bool, 0644);
  49
  50 static int disable_backlight_sysfs_if = -1;
  51 module_param(disable_backlight_sysfs_if, int, 0444);
  52
  53 #define REPORT_OUTPUT_KEY_EVENTS                0x01
  54 #define REPORT_BRIGHTNESS_KEY_EVENTS            0x02
  55 static int report_key_events = -1;
  56 module_param(report_key_events, int, 0644);
  57 MODULE_PARM_DESC(report_key_events,
  58         "0: none, 1: output changes, 2: brightness changes, 3: all");
  59
  60 static int hw_changes_brightness = -1;
  61 module_param(hw_changes_brightness, int, 0644);
  62 MODULE_PARM_DESC(hw_changes_brightness,
  63         "Set this to 1 on buggy hw which changes the brightness itself when "
  64         "a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
  65
  66 /*
  67  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
  68  * assumed even if not actually set.
  69  */
  70 static bool device_id_scheme = false;
  71 module_param(device_id_scheme, bool, 0444);
  72
  73 static int only_lcd = -1;
  74 module_param(only_lcd, int, 0444);
  75
  76 static int register_count;
  77 static DEFINE_MUTEX(register_count_mutex);
  78 static DEFINE_MUTEX(video_list_lock);
  79 static LIST_HEAD(video_bus_head);
  80 static int acpi_video_bus_add(struct acpi_device *device);
  81 static int acpi_video_bus_remove(struct acpi_device *device);
  82 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
  83 void acpi_video_detect_exit(void);
  84
  85 /*
  86  * Indices in the _BCL method response: the first two items are special,
  87  * the rest are all supported levels.
  88  *
  89  * See page 575 of the ACPI spec 3.0
  90  */
  91 enum acpi_video_level_idx {
  92         ACPI_VIDEO_AC_LEVEL,            /* level when machine has full power */
  93         ACPI_VIDEO_BATTERY_LEVEL,       /* level when machine is on batteries */
  94         ACPI_VIDEO_FIRST_LEVEL,         /* actual supported levels begin here */
  95 };
  96
  97 static const struct acpi_device_id video_device_ids[] = {
  98         {ACPI_VIDEO_HID, 0},
  99         {"", 0},
 100 };
 101 MODULE_DEVICE_TABLE(acpi, video_device_ids);
 102
 103 static struct acpi_driver acpi_video_bus = {
 104         .name = "video",
 105         .class = ACPI_VIDEO_CLASS,
 106         .ids = video_device_ids,
 107         .ops = {
 108                 .add = acpi_video_bus_add,
 109                 .remove = acpi_video_bus_remove,
 110                 .notify = acpi_video_bus_notify,
 111                 },
 112 };
 113
 114 struct acpi_video_bus_flags {
 115         u8 multihead:1;         /* can switch video heads */
 116         u8 rom:1;               /* can retrieve a video rom */
 117         u8 post:1;              /* can configure the head to */
 118         u8 reserved:5;
 119 };
 120
 121 struct acpi_video_bus_cap {
 122         u8 _DOS:1;              /* Enable/Disable output switching */
 123         u8 _DOD:1;              /* Enumerate all devices attached to display adapter */
 124         u8 _ROM:1;              /* Get ROM Data */
 125         u8 _GPD:1;              /* Get POST Device */
 126         u8 _SPD:1;              /* Set POST Device */
 127         u8 _VPO:1;              /* Video POST Options */
 128         u8 reserved:2;
 129 };
 130
 131 struct acpi_video_device_attrib {
 132         u32 display_index:4;    /* A zero-based instance of the Display */
 133         u32 display_port_attachment:4;  /* This field differentiates the display type */
 134         u32 display_type:4;     /* Describe the specific type in use */
 135         u32 vendor_specific:4;  /* Chipset Vendor Specific */
 136         u32 bios_can_detect:1;  /* BIOS can detect the device */
 137         u32 depend_on_vga:1;    /* Non-VGA output device whose power is related to
 138                                    the VGA device. */
 139         u32 pipe_id:3;          /* For VGA multiple-head devices. */
 140         u32 reserved:10;        /* Must be 0 */
 141
 142         /*
 143          * The device ID might not actually follow the scheme described by this
 144          * struct acpi_video_device_attrib. If it does, then this bit
 145          * device_id_scheme is set; otherwise, other fields should be ignored.
 146          *
 147          * (but also see the global flag device_id_scheme)
 148          */
 149         u32 device_id_scheme:1;
 150 };
 151
 152 struct acpi_video_enumerated_device {
 153         union {
 154                 u32 int_val;
 155                 struct acpi_video_device_attrib attrib;
 156         } value;
 157         struct acpi_video_device *bind_info;
 158 };
 159
 160 struct acpi_video_bus {
 161         struct acpi_device *device;
 162         bool backlight_registered;
 163         u8 dos_setting;
 164         struct acpi_video_enumerated_device *attached_array;
 165         u8 attached_count;
 166         u8 child_count;
 167         struct acpi_video_bus_cap cap;
 168         struct acpi_video_bus_flags flags;
 169         struct list_head video_device_list;
 170         struct mutex device_list_lock;  /* protects video_device_list */
 171         struct list_head entry;
 172         struct input_dev *input;
 173         char phys[32];  /* for input device */
 174         struct notifier_block pm_nb;
 175 };
 176
 177 struct acpi_video_device_flags {
 178         u8 crt:1;
 179         u8 lcd:1;
 180         u8 tvout:1;
 181         u8 dvi:1;
 182         u8 bios:1;
 183         u8 unknown:1;
 184         u8 notify:1;
 185         u8 reserved:1;
 186 };
 187
 188 struct acpi_video_device_cap {
 189         u8 _ADR:1;              /* Return the unique ID */
 190         u8 _BCL:1;              /* Query list of brightness control levels supported */
 191         u8 _BCM:1;              /* Set the brightness level */
 192         u8 _BQC:1;              /* Get current brightness level */
 193         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
 194         u8 _DDC:1;              /* Return the EDID for this device */
 195 };
 196
 197 struct acpi_video_device {
 198         unsigned long device_id;
 199         struct acpi_video_device_flags flags;
 200         struct acpi_video_device_cap cap;
 201         struct list_head entry;
 202         struct delayed_work switch_brightness_work;
 203         int switch_brightness_event;
 204         struct acpi_video_bus *video;
 205         struct acpi_device *dev;
 206         struct acpi_video_device_brightness *brightness;
 207         struct backlight_device *backlight;
 208         struct thermal_cooling_device *cooling_dev;
 209 };
 210
 211 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 212 static void acpi_video_device_rebind(struct acpi_video_bus *video);
 213 static void acpi_video_device_bind(struct acpi_video_bus *video,
 214                                    struct acpi_video_device *device);
 215 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 216 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 217                         int level);
 218 static int acpi_video_device_lcd_get_level_current(
 219                         struct acpi_video_device *device,
 220                         unsigned long long *level, bool raw);
 221 static int acpi_video_get_next_level(struct acpi_video_device *device,
 222                                      u32 level_current, u32 event);
 223 static void acpi_video_switch_brightness(struct work_struct *work);
 224
 225 /* backlight device sysfs support */
 226 static int acpi_video_get_brightness(struct backlight_device *bd)
 227 {
 228         unsigned long long cur_level;
 229         int i;
 230         struct acpi_video_device *vd = bl_get_data(bd);
 231
 232         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 233                 return -EINVAL;
 234         for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
 235                 if (vd->brightness->levels[i] == cur_level)
 236                         return i - ACPI_VIDEO_FIRST_LEVEL;
 237         }
 238         return 0;
 239 }
 240
 241 static int acpi_video_set_brightness(struct backlight_device *bd)
 242 {
 243         int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
 244         struct acpi_video_device *vd = bl_get_data(bd);
 245
 246         cancel_delayed_work(&vd->switch_brightness_work);
 247         return acpi_video_device_lcd_set_level(vd,
 248                                 vd->brightness->levels[request_level]);
 249 }
 250
 251 static const struct backlight_ops acpi_backlight_ops = {
 252         .get_brightness = acpi_video_get_brightness,
 253         .update_status  = acpi_video_set_brightness,
 254 };
 255
 256 /* thermal cooling device callbacks */
 257 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
 258                                unsigned long *state)
 259 {
 260         struct acpi_device *device = cooling_dev->devdata;
 261         struct acpi_video_device *video = acpi_driver_data(device);
 262
 263         *state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
 264         return 0;
 265 }
 266
 267 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
 268                                unsigned long *state)
 269 {
 270         struct acpi_device *device = cooling_dev->devdata;
 271         struct acpi_video_device *video = acpi_driver_data(device);
 272         unsigned long long level;
 273         int offset;
 274
 275         if (acpi_video_device_lcd_get_level_current(video, &level, false))
 276                 return -EINVAL;
 277         for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
 278              offset++)
 279                 if (level == video->brightness->levels[offset]) {
 280                         *state = video->brightness->count - offset - 1;
 281                         return 0;
 282                 }
 283
 284         return -EINVAL;
 285 }
 286
 287 static int
 288 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 289 {
 290         struct acpi_device *device = cooling_dev->devdata;
 291         struct acpi_video_device *video = acpi_driver_data(device);
 292         int level;
 293
 294         if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
 295                 return -EINVAL;
 296
 297         state = video->brightness->count - state;
 298         level = video->brightness->levels[state - 1];
 299         return acpi_video_device_lcd_set_level(video, level);
 300 }
 301
 302 static const struct thermal_cooling_device_ops video_cooling_ops = {
 303         .get_max_state = video_get_max_state,
 304         .get_cur_state = video_get_cur_state,
 305         .set_cur_state = video_set_cur_state,
 306 };
 307
 308 /*
 309  * --------------------------------------------------------------------------
 310  *                             Video Management
 311  * --------------------------------------------------------------------------
 312  */
 313
 314 static int
 315 acpi_video_device_lcd_query_levels(acpi_handle handle,
 316                                    union acpi_object **levels)
 317 {
 318         int status;
 319         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 320         union acpi_object *obj;
 321
 322
 323         *levels = NULL;
 324
 325         status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
 326         if (ACPI_FAILURE(status))
 327                 return status;
 328         obj = (union acpi_object *)buffer.pointer;
 329         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 330                 acpi_handle_info(handle, "Invalid _BCL data\n");
 331                 status = -EFAULT;
 332                 goto err;
 333         }
 334
 335         *levels = obj;
 336
 337         return 0;
 338
 339 err:
 340         kfree(buffer.pointer);
 341
 342         return status;
 343 }
 344
 345 static int
 346 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 347 {
 348         int status;
 349         int state;
 350
 351         status = acpi_execute_simple_method(device->dev->handle,
 352                                             "_BCM", level);
 353         if (ACPI_FAILURE(status)) {
 354                 acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
 355                 return -EIO;
 356         }
 357
 358         device->brightness->curr = level;
 359         for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
 360              state++)
 361                 if (level == device->brightness->levels[state]) {
 362                         if (device->backlight)
 363                                 device->backlight->props.brightness =
 364                                         state - ACPI_VIDEO_FIRST_LEVEL;
 365                         return 0;
 366                 }
 367
 368         acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
 369         return -EINVAL;
 370 }
 371
 372 /*
 373  * For some buggy _BQC methods, we need to add a constant value to
 374  * the _BQC return value to get the actual current brightness level
 375  */
 376
 377 static int bqc_offset_aml_bug_workaround;
 378 static int video_set_bqc_offset(const struct dmi_system_id *d)
 379 {
 380         bqc_offset_aml_bug_workaround = 9;
 381         return 0;
 382 }
 383
 384 static int video_disable_backlight_sysfs_if(
 385         const struct dmi_system_id *d)
 386 {
 387         if (disable_backlight_sysfs_if == -1)
 388                 disable_backlight_sysfs_if = 1;
 389         return 0;
 390 }
 391
 392 static int video_set_device_id_scheme(const struct dmi_system_id *d)
 393 {
 394         device_id_scheme = true;
 395         return 0;
 396 }
 397
 398 static int video_enable_only_lcd(const struct dmi_system_id *d)
 399 {
 400         only_lcd = true;
 401         return 0;
 402 }
 403
 404 static int video_set_report_key_events(const struct dmi_system_id *id)
 405 {
 406         if (report_key_events == -1)
 407                 report_key_events = (uintptr_t)id->driver_data;
 408         return 0;
 409 }
 410
 411 static int video_hw_changes_brightness(
 412         const struct dmi_system_id *d)
 413 {
 414         if (hw_changes_brightness == -1)
 415                 hw_changes_brightness = 1;
 416         return 0;
 417 }
 418
 419 static const struct dmi_system_id video_dmi_table[] = {
 420         /*
 421          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 422          */
 423         {
 424          .callback = video_set_bqc_offset,
 425          .ident = "Acer Aspire 5720",
 426          .matches = {
 427                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 428                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 429                 },
 430         },
 431         {
 432          .callback = video_set_bqc_offset,
 433          .ident = "Acer Aspire 5710Z",
 434          .matches = {
 435                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 436                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 437                 },
 438         },
 439         {
 440          .callback = video_set_bqc_offset,
 441          .ident = "eMachines E510",
 442          .matches = {
 443                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 444                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 445                 },
 446         },
 447         {
 448          .callback = video_set_bqc_offset,
 449          .ident = "Acer Aspire 5315",
 450          .matches = {
 451                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 452                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 453                 },
 454         },
 455         {
 456          .callback = video_set_bqc_offset,
 457          .ident = "Acer Aspire 7720",
 458          .matches = {
 459                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 460                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 461                 },
 462         },
 463
 464         /*
 465          * Some machines have a broken acpi-video interface for brightness
 466          * control, but still need an acpi_video_device_lcd_set_level() call
 467          * on resume to turn the backlight power on.  We Enable backlight
 468          * control on these systems, but do not register a backlight sysfs
 469          * as brightness control does not work.
 470          */
 471         {
 472          /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
 473          .callback = video_disable_backlight_sysfs_if,
 474          .ident = "Toshiba Portege R700",
 475          .matches = {
 476                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 477                 DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
 478                 },
 479         },
 480         {
 481          /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
 482          .callback = video_disable_backlight_sysfs_if,
 483          .ident = "Toshiba Portege R830",
 484          .matches = {
 485                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 486                 DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
 487                 },
 488         },
 489         {
 490          /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
 491          .callback = video_disable_backlight_sysfs_if,
 492          .ident = "Toshiba Satellite R830",
 493          .matches = {
 494                 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 495                 DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
 496                 },
 497         },
 498         /*
 499          * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
 500          * but the IDs actually follow the Device ID Scheme.
 501          */
 502         {
 503          /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 504          .callback = video_set_device_id_scheme,
 505          .ident = "ESPRIMO Mobile M9410",
 506          .matches = {
 507                 DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 508                 DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 509                 },
 510         },
 511         /*
 512          * Some machines have multiple video output devices, but only the one
 513          * that is the type of LCD can do the backlight control so we should not
 514          * register backlight interface for other video output devices.
 515          */
 516         {
 517          /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
 518          .callback = video_enable_only_lcd,
 519          .ident = "ESPRIMO Mobile M9410",
 520          .matches = {
 521                 DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
 522                 DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
 523                 },
 524         },
 525         /*
 526          * Some machines report wrong key events on the acpi-bus, suppress
 527          * key event reporting on these.  Note this is only intended to work
 528          * around events which are plain wrong. In some cases we get double
 529          * events, in this case acpi-video is considered the canonical source
 530          * and the events from the other source should be filtered. E.g.
 531          * by calling acpi_video_handles_brightness_key_presses() from the
 532          * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
 533          */
 534         {
 535          .callback = video_set_report_key_events,
 536          .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
 537          .ident = "Dell Vostro V131",
 538          .matches = {
 539                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 540                 DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
 541                 },
 542         },
 543         {
 544          .callback = video_set_report_key_events,
 545          .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
 546          .ident = "Dell Vostro 3350",
 547          .matches = {
 548                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 549                 DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
 550                 },
 551         },
 552         /*
 553          * Some machines change the brightness themselves when a brightness
 554          * hotkey gets pressed, despite us telling them not to. In this case
 555          * acpi_video_device_notify() should only call backlight_force_update(
 556          * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
 557          */
 558         {
 559          /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
 560          .callback = video_hw_changes_brightness,
 561          .ident = "Packard Bell EasyNote MZ35",
 562          .matches = {
 563                 DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
 564                 DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
 565                 },
 566         },
 567         {}
 568 };
 569
 570 static unsigned long long
 571 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 572                               unsigned long long bqc_value)
 573 {
 574         unsigned long long level;
 575
 576         if (device->brightness->flags._BQC_use_index) {
 577                 /*
 578                  * _BQC returns an index that doesn't account for the first 2
 579                  * items with special meaning (see enum acpi_video_level_idx),
 580                  * so we need to compensate for that by offsetting ourselves
 581                  */
 582                 if (device->brightness->flags._BCL_reversed)
 583                         bqc_value = device->brightness->count -
 584                                 ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
 585
 586                 level = device->brightness->levels[bqc_value +
 587                                                    ACPI_VIDEO_FIRST_LEVEL];
 588         } else {
 589                 level = bqc_value;
 590         }
 591
 592         level += bqc_offset_aml_bug_workaround;
 593
 594         return level;
 595 }
 596
 597 static int
 598 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 599                                         unsigned long long *level, bool raw)
 600 {
 601         acpi_status status = AE_OK;
 602         int i;
 603
 604         if (device->cap._BQC || device->cap._BCQ) {
 605                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 606
 607                 status = acpi_evaluate_integer(device->dev->handle, buf,
 608                                                 NULL, level);
 609                 if (ACPI_SUCCESS(status)) {
 610                         if (raw) {
 611                                 /*
 612                                  * Caller has indicated he wants the raw
 613                                  * value returned by _BQC, so don't furtherly
 614                                  * mess with the value.
 615                                  */
 616                                 return 0;
 617                         }
 618
 619                         *level = acpi_video_bqc_value_to_level(device, *level);
 620
 621                         for (i = ACPI_VIDEO_FIRST_LEVEL;
 622                              i < device->brightness->count; i++)
 623                                 if (device->brightness->levels[i] == *level) {
 624                                         device->brightness->curr = *level;
 625                                         return 0;
 626                                 }
 627                         /*
 628                          * BQC returned an invalid level.
 629                          * Stop using it.
 630                          */
 631                         acpi_handle_info(device->dev->handle,
 632                                          "%s returned an invalid level", buf);
 633                         device->cap._BQC = device->cap._BCQ = 0;
 634                 } else {
 635                         /*
 636                          * Fixme:
 637                          * should we return an error or ignore this failure?
 638                          * dev->brightness->curr is a cached value which stores
 639                          * the correct current backlight level in most cases.
 640                          * ACPI video backlight still works w/ buggy _BQC.
 641                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 642                          */
 643                         acpi_handle_info(device->dev->handle,
 644                                          "%s evaluation failed", buf);
 645                         device->cap._BQC = device->cap._BCQ = 0;
 646                 }
 647         }
 648
 649         *level = device->brightness->curr;
 650         return 0;
 651 }
 652
 653 static int
 654 acpi_video_device_EDID(struct acpi_video_device *device,
 655                        union acpi_object **edid, ssize_t length)
 656 {
 657         int status;
 658         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 659         union acpi_object *obj;
 660         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 661         struct acpi_object_list args = { 1, &arg0 };
 662
 663
 664         *edid = NULL;
 665
 666         if (!device)
 667                 return -ENODEV;
 668         if (length == 128)
 669                 arg0.integer.value = 1;
 670         else if (length == 256)
 671                 arg0.integer.value = 2;
 672         else
 673                 return -EINVAL;
 674
 675         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 676         if (ACPI_FAILURE(status))
 677                 return -ENODEV;
 678
 679         obj = buffer.pointer;
 680
 681         if (obj && obj->type == ACPI_TYPE_BUFFER)
 682                 *edid = obj;
 683         else {
 684                 acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
 685                 status = -EFAULT;
 686                 kfree(obj);
 687         }
 688
 689         return status;
 690 }
 691
 692 /* bus */
 693
 694 /*
 695  *  Arg:
 696  *      video           : video bus device pointer
 697  *      bios_flag       :
 698  *              0.      The system BIOS should NOT automatically switch(toggle)
 699  *                      the active display output.
 700  *              1.      The system BIOS should automatically switch (toggle) the
 701  *                      active display output. No switch event.
 702  *              2.      The _DGS value should be locked.
 703  *              3.      The system BIOS should not automatically switch (toggle) the
 704  *                      active display output, but instead generate the display switch
 705  *                      event notify code.
 706  *      lcd_flag        :
 707  *              0.      The system BIOS should automatically control the brightness level
 708  *                      of the LCD when:
 709  *                      - the power changes from AC to DC (ACPI appendix B)
 710  *                      - a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
 711  *              1.      The system BIOS should NOT automatically control the brightness
 712  *                      level of the LCD when:
 713  *                      - the power changes from AC to DC (ACPI appendix B)
 714  *                      - a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
 715  *  Return Value:
 716  *              -EINVAL wrong arg.
 717  */
 718
 719 static int
 720 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 721 {
 722         acpi_status status;
 723
 724         if (!video->cap._DOS)
 725                 return 0;
 726
 727         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 728                 return -EINVAL;
 729         video->dos_setting = (lcd_flag << 2) | bios_flag;
 730         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 731                                             (lcd_flag << 2) | bios_flag);
 732         if (ACPI_FAILURE(status))
 733                 return -EIO;
 734
 735         return 0;
 736 }
 737
 738 /*
 739  * Simple comparison function used to sort backlight levels.
 740  */
 741
 742 static int
 743 acpi_video_cmp_level(const void *a, const void *b)
 744 {
 745         return *(int *)a - *(int *)b;
 746 }
 747
 748 /*
 749  * Decides if _BQC/_BCQ for this system is usable
 750  *
 751  * We do this by changing the level first and then read out the current
 752  * brightness level, if the value does not match, find out if it is using
 753  * index. If not, clear the _BQC/_BCQ capability.
 754  */
 755 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 756                                 int max_level, int current_level)
 757 {
 758         struct acpi_video_device_brightness *br = device->brightness;
 759         int result;
 760         unsigned long long level;
 761         int test_level;
 762
 763         /* don't mess with existing known broken systems */
 764         if (bqc_offset_aml_bug_workaround)
 765                 return 0;
 766
 767         /*
 768          * Some systems always report current brightness level as maximum
 769          * through _BQC, we need to test another value for them. However,
 770          * there is a subtlety:
 771          *
 772          * If the _BCL package ordering is descending, the first level
 773          * (br->levels[2]) is likely to be 0, and if the number of levels
 774          * matches the number of steps, we might confuse a returned level to
 775          * mean the index.
 776          *
 777          * For example:
 778          *
 779          *     current_level = max_level = 100
 780          *     test_level = 0
 781          *     returned level = 100
 782          *
 783          * In this case 100 means the level, not the index, and _BCM failed.
 784          * Still, if the _BCL package ordering is descending, the index of
 785          * level 0 is also 100, so we assume _BQC is indexed, when it's not.
 786          *
 787          * This causes all _BQC calls to return bogus values causing weird
 788          * behavior from the user's perspective.  For example:
 789          *
 790          * xbacklight -set 10; xbacklight -set 20;
 791          *
 792          * would flash to 90% and then slowly down to the desired level (20).
 793          *
 794          * The solution is simple; test anything other than the first level
 795          * (e.g. 1).
 796          */
 797         test_level = current_level == max_level
 798                 ? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
 799                 : max_level;
 800
 801         result = acpi_video_device_lcd_set_level(device, test_level);
 802         if (result)
 803                 return result;
 804
 805         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 806         if (result)
 807                 return result;
 808
 809         if (level != test_level) {
 810                 /* buggy _BQC found, need to find out if it uses index */
 811                 if (level < br->count) {
 812                         if (br->flags._BCL_reversed)
 813                                 level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
 814                         if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
 815                                 br->flags._BQC_use_index = 1;
 816                 }
 817
 818                 if (!br->flags._BQC_use_index)
 819                         device->cap._BQC = device->cap._BCQ = 0;
 820         }
 821
 822         return 0;
 823 }
 824
 825 int acpi_video_get_levels(struct acpi_device *device,
 826                           struct acpi_video_device_brightness **dev_br,
 827                           int *pmax_level)
 828 {
 829         union acpi_object *obj = NULL;
 830         int i, max_level = 0, count = 0, level_ac_battery = 0;
 831         union acpi_object *o;
 832         struct acpi_video_device_brightness *br = NULL;
 833         int result = 0;
 834         u32 value;
 835
 836         if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
 837                 acpi_handle_debug(device->handle,
 838                                   "Could not query available LCD brightness level\n");
 839                 result = -ENODEV;
 840                 goto out;
 841         }
 842
 843         if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
 844                 result = -EINVAL;
 845                 goto out;
 846         }
 847
 848         br = kzalloc(sizeof(*br), GFP_KERNEL);
 849         if (!br) {
 850                 result = -ENOMEM;
 851                 goto out;
 852         }
 853
 854         /*
 855          * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
 856          * in order to account for buggy BIOS which don't export the first two
 857          * special levels (see below)
 858          */
 859         br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
 860                                    sizeof(*br->levels),
 861                                    GFP_KERNEL);
 862         if (!br->levels) {
 863                 result = -ENOMEM;
 864                 goto out_free;
 865         }
 866
 867         for (i = 0; i < obj->package.count; i++) {
 868                 o = (union acpi_object *)&obj->package.elements[i];
 869                 if (o->type != ACPI_TYPE_INTEGER) {
 870                         acpi_handle_info(device->handle, "Invalid data\n");
 871                         continue;
 872                 }
 873                 value = (u32) o->integer.value;
 874                 /* Skip duplicate entries */
 875                 if (count > ACPI_VIDEO_FIRST_LEVEL
 876                     && br->levels[count - 1] == value)
 877                         continue;
 878
 879                 br->levels[count] = value;
 880
 881                 if (br->levels[count] > max_level)
 882                         max_level = br->levels[count];
 883                 count++;
 884         }
 885
 886         /*
 887          * some buggy BIOS don't export the levels
 888          * when machine is on AC/Battery in _BCL package.
 889          * In this case, the first two elements in _BCL packages
 890          * are also supported brightness levels that OS should take care of.
 891          */
 892         for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
 893                 if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
 894                         level_ac_battery++;
 895                 if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
 896                         level_ac_battery++;
 897         }
 898
 899         if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
 900                 level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
 901                 br->flags._BCL_no_ac_battery_levels = 1;
 902                 for (i = (count - 1 + level_ac_battery);
 903                      i >= ACPI_VIDEO_FIRST_LEVEL; i--)
 904                         br->levels[i] = br->levels[i - level_ac_battery];
 905                 count += level_ac_battery;
 906         } else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
 907                 acpi_handle_info(device->handle,
 908                                  "Too many duplicates in _BCL package");
 909
 910         /* Check if the _BCL package is in a reversed order */
 911         if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
 912                 br->flags._BCL_reversed = 1;
 913                 sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
 914                      count - ACPI_VIDEO_FIRST_LEVEL,
 915                      sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
 916                      acpi_video_cmp_level, NULL);
 917         } else if (max_level != br->levels[count - 1])
 918                 acpi_handle_info(device->handle,
 919                                  "Found unordered _BCL package");
 920
 921         br->count = count;
 922         *dev_br = br;
 923         if (pmax_level)
 924                 *pmax_level = max_level;
 925
 926 out:
 927         kfree(obj);
 928         return result;
 929 out_free:
 930         kfree(br);
 931         goto out;
 932 }
 933 EXPORT_SYMBOL(acpi_video_get_levels);
 934
 935 /*
 936  *  Arg:
 937  *      device  : video output device (LCD, CRT, ..)
 938  *
 939  *  Return Value:
 940  *      Maximum brightness level
 941  *
 942  *  Allocate and initialize device->brightness.
 943  */
 944
 945 static int
 946 acpi_video_init_brightness(struct acpi_video_device *device)
 947 {
 948         int i, max_level = 0;
 949         unsigned long long level, level_old;
 950         struct acpi_video_device_brightness *br = NULL;
 951         int result;
 952
 953         result = acpi_video_get_levels(device->dev, &br, &max_level);
 954         if (result)
 955                 return result;
 956         device->brightness = br;
 957
 958         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 959         br->curr = level = max_level;
 960
 961         if (!device->cap._BQC)
 962                 goto set_level;
 963
 964         result = acpi_video_device_lcd_get_level_current(device,
 965                                                          &level_old, true);
 966         if (result)
 967                 goto out_free_levels;
 968
 969         result = acpi_video_bqc_quirk(device, max_level, level_old);
 970         if (result)
 971                 goto out_free_levels;
 972         /*
 973          * cap._BQC may get cleared due to _BQC is found to be broken
 974          * in acpi_video_bqc_quirk, so check again here.
 975          */
 976         if (!device->cap._BQC)
 977                 goto set_level;
 978
 979         level = acpi_video_bqc_value_to_level(device, level_old);
 980         /*
 981          * On some buggy laptops, _BQC returns an uninitialized
 982          * value when invoked for the first time, i.e.
 983          * level_old is invalid (no matter whether it's a level
 984          * or an index). Set the backlight to max_level in this case.
 985          */
 986         for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
 987                 if (level == br->levels[i])
 988                         break;
 989         if (i == br->count || !level)
 990                 level = max_level;
 991
 992 set_level:
 993         result = acpi_video_device_lcd_set_level(device, level);
 994         if (result)
 995                 goto out_free_levels;
 996
 997         acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
 998                           br->count - ACPI_VIDEO_FIRST_LEVEL);
 999
1000         return 0;
1001
1002 out_free_levels:
1003         kfree(br->levels);
1004         kfree(br);
1005         device->brightness = NULL;
1006         return result;
1007 }
1008
1009 /*
1010  *  Arg:
1011  *      device  : video output device (LCD, CRT, ..)
1012  *
1013  *  Return Value:
1014  *      None
1015  *
1016  *  Find out all required AML methods defined under the output
1017  *  device.
1018  */
1019
1020 static void acpi_video_device_find_cap(struct acpi_video_device *device)
1021 {
1022         if (acpi_has_method(device->dev->handle, "_ADR"))
1023                 device->cap._ADR = 1;
1024         if (acpi_has_method(device->dev->handle, "_BCL"))
1025                 device->cap._BCL = 1;
1026         if (acpi_has_method(device->dev->handle, "_BCM"))
1027                 device->cap._BCM = 1;
1028         if (acpi_has_method(device->dev->handle, "_BQC")) {
1029                 device->cap._BQC = 1;
1030         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1031                 acpi_handle_info(device->dev->handle,
1032                                  "_BCQ is used instead of _BQC\n");
1033                 device->cap._BCQ = 1;
1034         }
1035
1036         if (acpi_has_method(device->dev->handle, "_DDC"))
1037                 device->cap._DDC = 1;
1038 }
1039
1040 /*
1041  *  Arg:
1042  *      device  : video output device (VGA)
1043  *
1044  *  Return Value:
1045  *      None
1046  *
1047  *  Find out all required AML methods defined under the video bus device.
1048  */
1049
1050 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1051 {
1052         if (acpi_has_method(video->device->handle, "_DOS"))
1053                 video->cap._DOS = 1;
1054         if (acpi_has_method(video->device->handle, "_DOD"))
1055                 video->cap._DOD = 1;
1056         if (acpi_has_method(video->device->handle, "_ROM"))
1057                 video->cap._ROM = 1;
1058         if (acpi_has_method(video->device->handle, "_GPD"))
1059                 video->cap._GPD = 1;
1060         if (acpi_has_method(video->device->handle, "_SPD"))
1061                 video->cap._SPD = 1;
1062         if (acpi_has_method(video->device->handle, "_VPO"))
1063                 video->cap._VPO = 1;
1064 }
1065
1066 /*
1067  * Check whether the video bus device has required AML method to
1068  * support the desired features
1069  */
1070
1071 static int acpi_video_bus_check(struct acpi_video_bus *video)
1072 {
1073         acpi_status status = -ENOENT;
1074         struct pci_dev *dev;
1075
1076         if (!video)
1077                 return -EINVAL;
1078
1079         dev = acpi_get_pci_dev(video->device->handle);
1080         if (!dev)
1081                 return -ENODEV;
1082         pci_dev_put(dev);
1083
1084         /*
1085          * Since there is no HID, CID and so on for VGA driver, we have
1086          * to check well known required nodes.
1087          */
1088
1089         /* Does this device support video switching? */
1090         if (video->cap._DOS || video->cap._DOD) {
1091                 if (!video->cap._DOS) {
1092                         pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1093                                 acpi_device_bid(video->device));
1094                 }
1095                 video->flags.multihead = 1;
1096                 status = 0;
1097         }
1098
1099         /* Does this device support retrieving a video ROM? */
1100         if (video->cap._ROM) {
1101                 video->flags.rom = 1;
1102                 status = 0;
1103         }
1104
1105         /* Does this device support configuring which video device to POST? */
1106         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1107                 video->flags.post = 1;
1108                 status = 0;
1109         }
1110
1111         return status;
1112 }
1113
1114 /*
1115  * --------------------------------------------------------------------------
1116  *                               Driver Interface
1117  * --------------------------------------------------------------------------
1118  */
1119
1120 /* device interface */
1121 static struct acpi_video_device_attrib *
1122 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1123 {
1124         struct acpi_video_enumerated_device *ids;
1125         int i;
1126
1127         for (i = 0; i < video->attached_count; i++) {
1128                 ids = &video->attached_array[i];
1129                 if ((ids->value.int_val & 0xffff) == device_id)
1130                         return &ids->value.attrib;
1131         }
1132
1133         return NULL;
1134 }
1135
1136 static int
1137 acpi_video_get_device_type(struct acpi_video_bus *video,
1138                            unsigned long device_id)
1139 {
1140         struct acpi_video_enumerated_device *ids;
1141         int i;
1142
1143         for (i = 0; i < video->attached_count; i++) {
1144                 ids = &video->attached_array[i];
1145                 if ((ids->value.int_val & 0xffff) == device_id)
1146                         return ids->value.int_val;
1147         }
1148
1149         return 0;
1150 }
1151
1152 static int
1153 acpi_video_bus_get_one_device(struct acpi_device *device,
1154                               struct acpi_video_bus *video)
1155 {
1156         unsigned long long device_id;
1157         int status, device_type;
1158         struct acpi_video_device *data;
1159         struct acpi_video_device_attrib *attribute;
1160
1161         status =
1162             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1163         /* Some device omits _ADR, we skip them instead of fail */
1164         if (ACPI_FAILURE(status))
1165                 return 0;
1166
1167         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1168         if (!data)
1169                 return -ENOMEM;
1170
1171         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1172         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1173         device->driver_data = data;
1174
1175         data->device_id = device_id;
1176         data->video = video;
1177         data->dev = device;
1178         INIT_DELAYED_WORK(&data->switch_brightness_work,
1179                           acpi_video_switch_brightness);
1180
1181         attribute = acpi_video_get_device_attr(video, device_id);
1182
1183         if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1184                 switch (attribute->display_type) {
1185                 case ACPI_VIDEO_DISPLAY_CRT:
1186                         data->flags.crt = 1;
1187                         break;
1188                 case ACPI_VIDEO_DISPLAY_TV:
1189                         data->flags.tvout = 1;
1190                         break;
1191                 case ACPI_VIDEO_DISPLAY_DVI:
1192                         data->flags.dvi = 1;
1193                         break;
1194                 case ACPI_VIDEO_DISPLAY_LCD:
1195                         data->flags.lcd = 1;
1196                         break;
1197                 default:
1198                         data->flags.unknown = 1;
1199                         break;
1200                 }
1201                 if (attribute->bios_can_detect)
1202                         data->flags.bios = 1;
1203         } else {
1204                 /* Check for legacy IDs */
1205                 device_type = acpi_video_get_device_type(video, device_id);
1206                 /* Ignore bits 16 and 18-20 */
1207                 switch (device_type & 0xffe2ffff) {
1208                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1209                         data->flags.crt = 1;
1210                         break;
1211                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1212                         data->flags.lcd = 1;
1213                         break;
1214                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1215                         data->flags.tvout = 1;
1216                         break;
1217                 default:
1218                         data->flags.unknown = 1;
1219                 }
1220         }
1221
1222         acpi_video_device_bind(video, data);
1223         acpi_video_device_find_cap(data);
1224
1225         mutex_lock(&video->device_list_lock);
1226         list_add_tail(&data->entry, &video->video_device_list);
1227         mutex_unlock(&video->device_list_lock);
1228
1229         return status;
1230 }
1231
1232 /*
1233  *  Arg:
1234  *      video   : video bus device
1235  *
1236  *  Return:
1237  *      none
1238  *
1239  *  Enumerate the video device list of the video bus,
1240  *  bind the ids with the corresponding video devices
1241  *  under the video bus.
1242  */
1243
1244 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1245 {
1246         struct acpi_video_device *dev;
1247
1248         mutex_lock(&video->device_list_lock);
1249
1250         list_for_each_entry(dev, &video->video_device_list, entry)
1251                 acpi_video_device_bind(video, dev);
1252
1253         mutex_unlock(&video->device_list_lock);
1254 }
1255
1256 /*
1257  *  Arg:
1258  *      video   : video bus device
1259  *      device  : video output device under the video
1260  *              bus
1261  *
1262  *  Return:
1263  *      none
1264  *
1265  *  Bind the ids with the corresponding video devices
1266  *  under the video bus.
1267  */
1268
1269 static void
1270 acpi_video_device_bind(struct acpi_video_bus *video,
1271                        struct acpi_video_device *device)
1272 {
1273         struct acpi_video_enumerated_device *ids;
1274         int i;
1275
1276         for (i = 0; i < video->attached_count; i++) {
1277                 ids = &video->attached_array[i];
1278                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1279                         ids->bind_info = device;
1280                         acpi_handle_debug(video->device->handle, "%s: %d\n",
1281                                           __func__, i);
1282                 }
1283         }
1284 }
1285
1286 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1287 {
1288         struct acpi_video_bus *video = device->video;
1289         int i;
1290
1291         /*
1292          * If we have a broken _DOD or we have more than 8 output devices
1293          * under the graphics controller node that we can't proper deal with
1294          * in the operation region code currently, no need to test.
1295          */
1296         if (!video->attached_count || video->child_count > 8)
1297                 return true;
1298
1299         for (i = 0; i < video->attached_count; i++) {
1300                 if ((video->attached_array[i].value.int_val & 0xfff) ==
1301                     (device->device_id & 0xfff))
1302                         return true;
1303         }
1304
1305         return false;
1306 }
1307
1308 /*
1309  *  Arg:
1310  *      video   : video bus device
1311  *
1312  *  Return:
1313  *      < 0     : error
1314  *
1315  *  Call _DOD to enumerate all devices attached to display adapter
1316  *
1317  */
1318
1319 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1320 {
1321         int status;
1322         int count;
1323         int i;
1324         struct acpi_video_enumerated_device *active_list;
1325         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1326         union acpi_object *dod = NULL;
1327         union acpi_object *obj;
1328
1329         if (!video->cap._DOD)
1330                 return AE_NOT_EXIST;
1331
1332         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1333         if (ACPI_FAILURE(status)) {
1334                 acpi_handle_info(video->device->handle,
1335                                  "_DOD evaluation failed: %s\n",
1336                                  acpi_format_exception(status));
1337                 return status;
1338         }
1339
1340         dod = buffer.pointer;
1341         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1342                 acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1343                 status = -EFAULT;
1344                 goto out;
1345         }
1346
1347         acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1348                           dod->package.count);
1349
1350         active_list = kcalloc(1 + dod->package.count,
1351                               sizeof(struct acpi_video_enumerated_device),
1352                               GFP_KERNEL);
1353         if (!active_list) {
1354                 status = -ENOMEM;
1355                 goto out;
1356         }
1357
1358         count = 0;
1359         for (i = 0; i < dod->package.count; i++) {
1360                 obj = &dod->package.elements[i];
1361
1362                 if (obj->type != ACPI_TYPE_INTEGER) {
1363                         acpi_handle_info(video->device->handle,
1364                                          "Invalid _DOD data in element %d\n", i);
1365                         continue;
1366                 }
1367
1368                 active_list[count].value.int_val = obj->integer.value;
1369                 active_list[count].bind_info = NULL;
1370
1371                 acpi_handle_debug(video->device->handle,
1372                                   "_DOD element[%d] = %d\n", i,
1373                                   (int)obj->integer.value);
1374
1375                 count++;
1376         }
1377
1378         kfree(video->attached_array);
1379
1380         video->attached_array = active_list;
1381         video->attached_count = count;
1382
1383 out:
1384         kfree(buffer.pointer);
1385         return status;
1386 }
1387
1388 static int
1389 acpi_video_get_next_level(struct acpi_video_device *device,
1390                           u32 level_current, u32 event)
1391 {
1392         int min, max, min_above, max_below, i, l, delta = 255;
1393         max = max_below = 0;
1394         min = min_above = 255;
1395         /* Find closest level to level_current */
1396         for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1397                 l = device->brightness->levels[i];
1398                 if (abs(l - level_current) < abs(delta)) {
1399                         delta = l - level_current;
1400                         if (!delta)
1401                                 break;
1402                 }
1403         }
1404         /* Adjust level_current to closest available level */
1405         level_current += delta;
1406         for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1407                 l = device->brightness->levels[i];
1408                 if (l < min)
1409                         min = l;
1410                 if (l > max)
1411                         max = l;
1412                 if (l < min_above && l > level_current)
1413                         min_above = l;
1414                 if (l > max_below && l < level_current)
1415                         max_below = l;
1416         }
1417
1418         switch (event) {
1419         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1420                 return (level_current < max) ? min_above : min;
1421         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1422                 return (level_current < max) ? min_above : max;
1423         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1424                 return (level_current > min) ? max_below : min;
1425         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1426         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1427                 return 0;
1428         default:
1429                 return level_current;
1430         }
1431 }
1432
1433 static void
1434 acpi_video_switch_brightness(struct work_struct *work)
1435 {
1436         struct acpi_video_device *device = container_of(to_delayed_work(work),
1437                              struct acpi_video_device, switch_brightness_work);
1438         unsigned long long level_current, level_next;
1439         int event = device->switch_brightness_event;
1440         int result = -EINVAL;
1441
1442         /* no warning message if acpi_backlight=vendor or a quirk is used */
1443         if (!device->backlight)
1444                 return;
1445
1446         if (!device->brightness)
1447                 goto out;
1448
1449         result = acpi_video_device_lcd_get_level_current(device,
1450                                                          &level_current,
1451                                                          false);
1452         if (result)
1453                 goto out;
1454
1455         level_next = acpi_video_get_next_level(device, level_current, event);
1456
1457         result = acpi_video_device_lcd_set_level(device, level_next);
1458
1459         if (!result)
1460                 backlight_force_update(device->backlight,
1461                                        BACKLIGHT_UPDATE_HOTKEY);
1462
1463 out:
1464         if (result)
1465                 acpi_handle_info(device->dev->handle,
1466                                  "Failed to switch brightness\n");
1467 }
1468
1469 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1470                         void **edid)
1471 {
1472         struct acpi_video_bus *video;
1473         struct acpi_video_device *video_device;
1474         union acpi_object *buffer = NULL;
1475         acpi_status status;
1476         int i, length;
1477
1478         if (!device || !acpi_driver_data(device))
1479                 return -EINVAL;
1480
1481         video = acpi_driver_data(device);
1482
1483         for (i = 0; i < video->attached_count; i++) {
1484                 video_device = video->attached_array[i].bind_info;
1485                 length = 256;
1486
1487                 if (!video_device)
1488                         continue;
1489
1490                 if (!video_device->cap._DDC)
1491                         continue;
1492
1493                 if (type) {
1494                         switch (type) {
1495                         case ACPI_VIDEO_DISPLAY_CRT:
1496                                 if (!video_device->flags.crt)
1497                                         continue;
1498                                 break;
1499                         case ACPI_VIDEO_DISPLAY_TV:
1500                                 if (!video_device->flags.tvout)
1501                                         continue;
1502                                 break;
1503                         case ACPI_VIDEO_DISPLAY_DVI:
1504                                 if (!video_device->flags.dvi)
1505                                         continue;
1506                                 break;
1507                         case ACPI_VIDEO_DISPLAY_LCD:
1508                                 if (!video_device->flags.lcd)
1509                                         continue;
1510                                 break;
1511                         }
1512                 } else if (video_device->device_id != device_id) {
1513                         continue;
1514                 }
1515
1516                 status = acpi_video_device_EDID(video_device, &buffer, length);
1517
1518                 if (ACPI_FAILURE(status) || !buffer ||
1519                     buffer->type != ACPI_TYPE_BUFFER) {
1520                         length = 128;
1521                         status = acpi_video_device_EDID(video_device, &buffer,
1522                                                         length);
1523                         if (ACPI_FAILURE(status) || !buffer ||
1524                             buffer->type != ACPI_TYPE_BUFFER) {
1525                                 continue;
1526                         }
1527                 }
1528
1529                 *edid = buffer->buffer.pointer;
1530                 return length;
1531         }
1532
1533         return -ENODEV;
1534 }
1535 EXPORT_SYMBOL(acpi_video_get_edid);
1536
1537 static int
1538 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1539                            struct acpi_device *device)
1540 {
1541         int status = 0;
1542         struct acpi_device *dev;
1543
1544         /*
1545          * There are systems where video module known to work fine regardless
1546          * of broken _DOD and ignoring returned value here doesn't cause
1547          * any issues later.
1548          */
1549         acpi_video_device_enumerate(video);
1550
1551         list_for_each_entry(dev, &device->children, node) {
1552
1553                 status = acpi_video_bus_get_one_device(dev, video);
1554                 if (status) {
1555                         dev_err(&dev->dev, "Can't attach device\n");
1556                         break;
1557                 }
1558                 video->child_count++;
1559         }
1560         return status;
1561 }
1562
1563 /* acpi_video interface */
1564
1565 /*
1566  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1567  * perform any automatic brightness change on receiving a notification.
1568  */
1569 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1570 {
1571         return acpi_video_bus_DOS(video, 0,
1572                                   acpi_osi_is_win8() ? 1 : 0);
1573 }
1574
1575 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1576 {
1577         return acpi_video_bus_DOS(video, 0,
1578                                   acpi_osi_is_win8() ? 0 : 1);
1579 }
1580
1581 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1582 {
1583         struct acpi_video_bus *video = acpi_driver_data(device);
1584         struct input_dev *input;
1585         int keycode = 0;
1586
1587         if (!video || !video->input)
1588                 return;
1589
1590         input = video->input;
1591
1592         switch (event) {
1593         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1594                                          * most likely via hotkey. */
1595                 keycode = KEY_SWITCHVIDEOMODE;
1596                 break;
1597
1598         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1599                                          * connector. */
1600                 acpi_video_device_enumerate(video);
1601                 acpi_video_device_rebind(video);
1602                 keycode = KEY_SWITCHVIDEOMODE;
1603                 break;
1604
1605         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1606                 keycode = KEY_SWITCHVIDEOMODE;
1607                 break;
1608         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1609                 keycode = KEY_VIDEO_NEXT;
1610                 break;
1611         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1612                 keycode = KEY_VIDEO_PREV;
1613                 break;
1614
1615         default:
1616                 acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1617                                   event);
1618                 break;
1619         }
1620
1621         if (acpi_notifier_call_chain(device, event, 0))
1622                 /* Something vetoed the keypress. */
1623                 keycode = 0;
1624
1625         if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1626                 input_report_key(input, keycode, 1);
1627                 input_sync(input);
1628                 input_report_key(input, keycode, 0);
1629                 input_sync(input);
1630         }
1631 }
1632
1633 static void brightness_switch_event(struct acpi_video_device *video_device,
1634                                     u32 event)
1635 {
1636         if (!brightness_switch_enabled)
1637                 return;
1638
1639         video_device->switch_brightness_event = event;
1640         schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1641 }
1642
1643 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1644 {
1645         struct acpi_video_device *video_device = data;
1646         struct acpi_device *device = NULL;
1647         struct acpi_video_bus *bus;
1648         struct input_dev *input;
1649         int keycode = 0;
1650
1651         if (!video_device)
1652                 return;
1653
1654         device = video_device->dev;
1655         bus = video_device->video;
1656         input = bus->input;
1657
1658         if (hw_changes_brightness > 0) {
1659                 if (video_device->backlight)
1660                         backlight_force_update(video_device->backlight,
1661                                                BACKLIGHT_UPDATE_HOTKEY);
1662                 acpi_notifier_call_chain(device, event, 0);
1663                 return;
1664         }
1665
1666         switch (event) {
1667         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1668                 brightness_switch_event(video_device, event);
1669                 keycode = KEY_BRIGHTNESS_CYCLE;
1670                 break;
1671         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1672                 brightness_switch_event(video_device, event);
1673                 keycode = KEY_BRIGHTNESSUP;
1674                 break;
1675         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1676                 brightness_switch_event(video_device, event);
1677                 keycode = KEY_BRIGHTNESSDOWN;
1678                 break;
1679         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1680                 brightness_switch_event(video_device, event);
1681                 keycode = KEY_BRIGHTNESS_ZERO;
1682                 break;
1683         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1684                 brightness_switch_event(video_device, event);
1685                 keycode = KEY_DISPLAY_OFF;
1686                 break;
1687         default:
1688                 acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1689                 break;
1690         }
1691
1692         acpi_notifier_call_chain(device, event, 0);
1693
1694         if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1695                 input_report_key(input, keycode, 1);
1696                 input_sync(input);
1697                 input_report_key(input, keycode, 0);
1698                 input_sync(input);
1699         }
1700 }
1701
1702 static int acpi_video_resume(struct notifier_block *nb,
1703                                 unsigned long val, void *ign)
1704 {
1705         struct acpi_video_bus *video;
1706         struct acpi_video_device *video_device;
1707         int i;
1708
1709         switch (val) {
1710         case PM_HIBERNATION_PREPARE:
1711         case PM_SUSPEND_PREPARE:
1712         case PM_RESTORE_PREPARE:
1713                 return NOTIFY_DONE;
1714         }
1715
1716         video = container_of(nb, struct acpi_video_bus, pm_nb);
1717
1718         dev_info(&video->device->dev, "Restoring backlight state\n");
1719
1720         for (i = 0; i < video->attached_count; i++) {
1721                 video_device = video->attached_array[i].bind_info;
1722                 if (video_device && video_device->brightness)
1723                         acpi_video_device_lcd_set_level(video_device,
1724                                         video_device->brightness->curr);
1725         }
1726
1727         return NOTIFY_OK;
1728 }
1729
1730 static acpi_status
1731 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1732                         void **return_value)
1733 {
1734         struct acpi_device *device = context;
1735         struct acpi_device *sibling;
1736         int result;
1737
1738         if (handle == device->handle)
1739                 return AE_CTRL_TERMINATE;
1740
1741         result = acpi_bus_get_device(handle, &sibling);
1742         if (result)
1743                 return AE_OK;
1744
1745         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1746                         return AE_ALREADY_EXISTS;
1747
1748         return AE_OK;
1749 }
1750
1751 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1752 {
1753         struct backlight_properties props;
1754         struct pci_dev *pdev;
1755         acpi_handle acpi_parent;
1756         struct device *parent = NULL;
1757         int result;
1758         static int count;
1759         char *name;
1760
1761         result = acpi_video_init_brightness(device);
1762         if (result)
1763                 return;
1764
1765         if (disable_backlight_sysfs_if > 0)
1766                 return;
1767
1768         name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1769         if (!name)
1770                 return;
1771         count++;
1772
1773         acpi_get_parent(device->dev->handle, &acpi_parent);
1774
1775         pdev = acpi_get_pci_dev(acpi_parent);
1776         if (pdev) {
1777                 parent = &pdev->dev;
1778                 pci_dev_put(pdev);
1779         }
1780
1781         memset(&props, 0, sizeof(struct backlight_properties));
1782         props.type = BACKLIGHT_FIRMWARE;
1783         props.max_brightness =
1784                 device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1785         device->backlight = backlight_device_register(name,
1786                                                       parent,
1787                                                       device,
1788                                                       &acpi_backlight_ops,
1789                                                       &props);
1790         kfree(name);
1791         if (IS_ERR(device->backlight)) {
1792                 device->backlight = NULL;
1793                 return;
1794         }
1795
1796         /*
1797          * Save current brightness level in case we have to restore it
1798          * before acpi_video_device_lcd_set_level() is called next time.
1799          */
1800         device->backlight->props.brightness =
1801                         acpi_video_get_brightness(device->backlight);
1802
1803         device->cooling_dev = thermal_cooling_device_register("LCD",
1804                                 device->dev, &video_cooling_ops);
1805         if (IS_ERR(device->cooling_dev)) {
1806                 /*
1807                  * Set cooling_dev to NULL so we don't crash trying to free it.
1808                  * Also, why the hell we are returning early and not attempt to
1809                  * register video output if cooling device registration failed?
1810                  * -- dtor
1811                  */
1812                 device->cooling_dev = NULL;
1813                 return;
1814         }
1815
1816         dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1817                  device->cooling_dev->id);
1818         result = sysfs_create_link(&device->dev->dev.kobj,
1819                         &device->cooling_dev->device.kobj,
1820                         "thermal_cooling");
1821         if (result)
1822                 pr_info("sysfs link creation failed\n");
1823
1824         result = sysfs_create_link(&device->cooling_dev->device.kobj,
1825                         &device->dev->dev.kobj, "device");
1826         if (result)
1827                 pr_info("Reverse sysfs link creation failed\n");
1828 }
1829
1830 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1831 {
1832         struct acpi_video_device *dev;
1833         union acpi_object *levels;
1834
1835         mutex_lock(&video->device_list_lock);
1836         list_for_each_entry(dev, &video->video_device_list, entry) {
1837                 if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1838                         kfree(levels);
1839         }
1840         mutex_unlock(&video->device_list_lock);
1841 }
1842
1843 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1844 {
1845         /*
1846          * Do not create backlight device for video output
1847          * device that is not in the enumerated list.
1848          */
1849         if (!acpi_video_device_in_dod(dev)) {
1850                 dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1851                 return false;
1852         }
1853
1854         if (only_lcd)
1855                 return dev->flags.lcd;
1856         return true;
1857 }
1858
1859 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1860 {
1861         struct acpi_video_device *dev;
1862
1863         if (video->backlight_registered)
1864                 return 0;
1865
1866         acpi_video_run_bcl_for_osi(video);
1867
1868         if (acpi_video_get_backlight_type() != acpi_backlight_video)
1869                 return 0;
1870
1871         mutex_lock(&video->device_list_lock);
1872         list_for_each_entry(dev, &video->video_device_list, entry) {
1873                 if (acpi_video_should_register_backlight(dev))
1874                         acpi_video_dev_register_backlight(dev);
1875         }
1876         mutex_unlock(&video->device_list_lock);
1877
1878         video->backlight_registered = true;
1879
1880         video->pm_nb.notifier_call = acpi_video_resume;
1881         video->pm_nb.priority = 0;
1882         return register_pm_notifier(&video->pm_nb);
1883 }
1884
1885 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1886 {
1887         if (device->backlight) {
1888                 backlight_device_unregister(device->backlight);
1889                 device->backlight = NULL;
1890         }
1891         if (device->brightness) {
1892                 kfree(device->brightness->levels);
1893                 kfree(device->brightness);
1894                 device->brightness = NULL;
1895         }
1896         if (device->cooling_dev) {
1897                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1898                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1899                 thermal_cooling_device_unregister(device->cooling_dev);
1900                 device->cooling_dev = NULL;
1901         }
1902 }
1903
1904 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1905 {
1906         struct acpi_video_device *dev;
1907         int error;
1908
1909         if (!video->backlight_registered)
1910                 return 0;
1911
1912         error = unregister_pm_notifier(&video->pm_nb);
1913
1914         mutex_lock(&video->device_list_lock);
1915         list_for_each_entry(dev, &video->video_device_list, entry)
1916                 acpi_video_dev_unregister_backlight(dev);
1917         mutex_unlock(&video->device_list_lock);
1918
1919         video->backlight_registered = false;
1920
1921         return error;
1922 }
1923
1924 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1925 {
1926         acpi_status status;
1927         struct acpi_device *adev = device->dev;
1928
1929         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1930                                              acpi_video_device_notify, device);
1931         if (ACPI_FAILURE(status))
1932                 dev_err(&adev->dev, "Error installing notify handler\n");
1933         else
1934                 device->flags.notify = 1;
1935 }
1936
1937 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1938 {
1939         struct input_dev *input;
1940         struct acpi_video_device *dev;
1941         int error;
1942
1943         video->input = input = input_allocate_device();
1944         if (!input) {
1945                 error = -ENOMEM;
1946                 goto out;
1947         }
1948
1949         error = acpi_video_bus_start_devices(video);
1950         if (error)
1951                 goto err_free_input;
1952
1953         snprintf(video->phys, sizeof(video->phys),
1954                         "%s/video/input0", acpi_device_hid(video->device));
1955
1956         input->name = acpi_device_name(video->device);
1957         input->phys = video->phys;
1958         input->id.bustype = BUS_HOST;
1959         input->id.product = 0x06;
1960         input->dev.parent = &video->device->dev;
1961         input->evbit[0] = BIT(EV_KEY);
1962         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1963         set_bit(KEY_VIDEO_NEXT, input->keybit);
1964         set_bit(KEY_VIDEO_PREV, input->keybit);
1965         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1966         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1967         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1968         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1969         set_bit(KEY_DISPLAY_OFF, input->keybit);
1970
1971         error = input_register_device(input);
1972         if (error)
1973                 goto err_stop_dev;
1974
1975         mutex_lock(&video->device_list_lock);
1976         list_for_each_entry(dev, &video->video_device_list, entry)
1977                 acpi_video_dev_add_notify_handler(dev);
1978         mutex_unlock(&video->device_list_lock);
1979
1980         return 0;
1981
1982 err_stop_dev:
1983         acpi_video_bus_stop_devices(video);
1984 err_free_input:
1985         input_free_device(input);
1986         video->input = NULL;
1987 out:
1988         return error;
1989 }
1990
1991 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1992 {
1993         if (dev->flags.notify) {
1994                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1995                                            acpi_video_device_notify);
1996                 dev->flags.notify = 0;
1997         }
1998 }
1999
2000 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
2001 {
2002         struct acpi_video_device *dev;
2003
2004         mutex_lock(&video->device_list_lock);
2005         list_for_each_entry(dev, &video->video_device_list, entry)
2006                 acpi_video_dev_remove_notify_handler(dev);
2007         mutex_unlock(&video->device_list_lock);
2008
2009         acpi_video_bus_stop_devices(video);
2010         input_unregister_device(video->input);
2011         video->input = NULL;
2012 }
2013
2014 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2015 {
2016         struct acpi_video_device *dev, *next;
2017
2018         mutex_lock(&video->device_list_lock);
2019         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2020                 list_del(&dev->entry);
2021                 kfree(dev);
2022         }
2023         mutex_unlock(&video->device_list_lock);
2024
2025         return 0;
2026 }
2027
2028 static int instance;
2029
2030 static int acpi_video_bus_add(struct acpi_device *device)
2031 {
2032         struct acpi_video_bus *video;
2033         int error;
2034         acpi_status status;
2035
2036         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2037                                 device->parent->handle, 1,
2038                                 acpi_video_bus_match, NULL,
2039                                 device, NULL);
2040         if (status == AE_ALREADY_EXISTS) {
2041                 pr_info(FW_BUG
2042                         "Duplicate ACPI video bus devices for the"
2043                         " same VGA controller, please try module "
2044                         "parameter \"video.allow_duplicates=1\""
2045                         "if the current driver doesn't work.\n");
2046                 if (!allow_duplicates)
2047                         return -ENODEV;
2048         }
2049
2050         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2051         if (!video)
2052                 return -ENOMEM;
2053
2054         /* a hack to fix the duplicate name "VID" problem on T61 */
2055         if (!strcmp(device->pnp.bus_id, "VID")) {
2056                 if (instance)
2057                         device->pnp.bus_id[3] = '0' + instance;
2058                 instance++;
2059         }
2060         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2061         if (!strcmp(device->pnp.bus_id, "VGA")) {
2062                 if (instance)
2063                         device->pnp.bus_id[3] = '0' + instance;
2064                 instance++;
2065         }
2066
2067         video->device = device;
2068         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2069         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2070         device->driver_data = video;
2071
2072         acpi_video_bus_find_cap(video);
2073         error = acpi_video_bus_check(video);
2074         if (error)
2075                 goto err_free_video;
2076
2077         mutex_init(&video->device_list_lock);
2078         INIT_LIST_HEAD(&video->video_device_list);
2079
2080         error = acpi_video_bus_get_devices(video, device);
2081         if (error)
2082                 goto err_put_video;
2083
2084         pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2085                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2086                video->flags.multihead ? "yes" : "no",
2087                video->flags.rom ? "yes" : "no",
2088                video->flags.post ? "yes" : "no");
2089         mutex_lock(&video_list_lock);
2090         list_add_tail(&video->entry, &video_bus_head);
2091         mutex_unlock(&video_list_lock);
2092
2093         acpi_video_bus_register_backlight(video);
2094         acpi_video_bus_add_notify_handler(video);
2095
2096         return 0;
2097
2098 err_put_video:
2099         acpi_video_bus_put_devices(video);
2100         kfree(video->attached_array);
2101 err_free_video:
2102         kfree(video);
2103         device->driver_data = NULL;
2104
2105         return error;
2106 }
2107
2108 static int acpi_video_bus_remove(struct acpi_device *device)
2109 {
2110         struct acpi_video_bus *video = NULL;
2111
2112
2113         if (!device || !acpi_driver_data(device))
2114                 return -EINVAL;
2115
2116         video = acpi_driver_data(device);
2117
2118         acpi_video_bus_remove_notify_handler(video);
2119         acpi_video_bus_unregister_backlight(video);
2120         acpi_video_bus_put_devices(video);
2121
2122         mutex_lock(&video_list_lock);
2123         list_del(&video->entry);
2124         mutex_unlock(&video_list_lock);
2125
2126         kfree(video->attached_array);
2127         kfree(video);
2128
2129         return 0;
2130 }
2131
2132 static int __init is_i740(struct pci_dev *dev)
2133 {
2134         if (dev->device == 0x00D1)
2135                 return 1;
2136         if (dev->device == 0x7000)
2137                 return 1;
2138         return 0;
2139 }
2140
2141 static int __init intel_opregion_present(void)
2142 {
2143         int opregion = 0;
2144         struct pci_dev *dev = NULL;
2145         u32 address;
2146
2147         for_each_pci_dev(dev) {
2148                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2149                         continue;
2150                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2151                         continue;
2152                 /* We don't want to poke around undefined i740 registers */
2153                 if (is_i740(dev))
2154                         continue;
2155                 pci_read_config_dword(dev, 0xfc, &address);
2156                 if (!address)
2157                         continue;
2158                 opregion = 1;
2159         }
2160         return opregion;
2161 }
2162
2163 /* Check if the chassis-type indicates there is no builtin LCD panel */
2164 static bool dmi_is_desktop(void)
2165 {
2166         const char *chassis_type;
2167         unsigned long type;
2168
2169         chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2170         if (!chassis_type)
2171                 return false;
2172
2173         if (kstrtoul(chassis_type, 10, &type) != 0)
2174                 return false;
2175
2176         switch (type) {
2177         case 0x03: /* Desktop */
2178         case 0x04: /* Low Profile Desktop */
2179         case 0x05: /* Pizza Box */
2180         case 0x06: /* Mini Tower */
2181         case 0x07: /* Tower */
2182         case 0x10: /* Lunch Box */
2183         case 0x11: /* Main Server Chassis */
2184                 return true;
2185         }
2186
2187         return false;
2188 }
2189
2190 /*
2191  * We're seeing a lot of bogus backlight interfaces on newer machines
2192  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2193  * lcd flag fixes this, enable this by default on any machines which are:
2194  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2195  *     normally the acpi_video code should not register there anyways); *and*
2196  * 2.1 Report a desktop/server DMI chassis-type, or
2197  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2198        backlight control)
2199  */
2200 static bool should_check_lcd_flag(void)
2201 {
2202         if (!acpi_osi_is_win8())
2203                 return false;
2204
2205         if (dmi_is_desktop())
2206                 return true;
2207
2208         if (acpi_reduced_hardware())
2209                 return true;
2210
2211         return false;
2212 }
2213
2214 int acpi_video_register(void)
2215 {
2216         int ret = 0;
2217
2218         mutex_lock(&register_count_mutex);
2219         if (register_count) {
2220                 /*
2221                  * if the function of acpi_video_register is already called,
2222                  * don't register the acpi_video_bus again and return no error.
2223                  */
2224                 goto leave;
2225         }
2226
2227         if (only_lcd == -1)
2228                 only_lcd = should_check_lcd_flag();
2229
2230         dmi_check_system(video_dmi_table);
2231
2232         ret = acpi_bus_register_driver(&acpi_video_bus);
2233         if (ret)
2234                 goto leave;
2235
2236         /*
2237          * When the acpi_video_bus is loaded successfully, increase
2238          * the counter reference.
2239          */
2240         register_count = 1;
2241
2242 leave:
2243         mutex_unlock(&register_count_mutex);
2244         return ret;
2245 }
2246 EXPORT_SYMBOL(acpi_video_register);
2247
2248 void acpi_video_unregister(void)
2249 {
2250         mutex_lock(&register_count_mutex);
2251         if (register_count) {
2252                 acpi_bus_unregister_driver(&acpi_video_bus);
2253                 register_count = 0;
2254         }
2255         mutex_unlock(&register_count_mutex);
2256 }
2257 EXPORT_SYMBOL(acpi_video_unregister);
2258
2259 void acpi_video_unregister_backlight(void)
2260 {
2261         struct acpi_video_bus *video;
2262
2263         mutex_lock(&register_count_mutex);
2264         if (register_count) {
2265                 mutex_lock(&video_list_lock);
2266                 list_for_each_entry(video, &video_bus_head, entry)
2267                         acpi_video_bus_unregister_backlight(video);
2268                 mutex_unlock(&video_list_lock);
2269         }
2270         mutex_unlock(&register_count_mutex);
2271 }
2272
2273 bool acpi_video_handles_brightness_key_presses(void)
2274 {
2275         bool have_video_busses;
2276
2277         mutex_lock(&video_list_lock);
2278         have_video_busses = !list_empty(&video_bus_head);
2279         mutex_unlock(&video_list_lock);
2280
2281         return have_video_busses &&
2282                (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2283 }
2284 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2285
2286 /*
2287  * This is kind of nasty. Hardware using Intel chipsets may require
2288  * the video opregion code to be run first in order to initialise
2289  * state before any ACPI video calls are made. To handle this we defer
2290  * registration of the video class until the opregion code has run.
2291  */
2292
2293 static int __init acpi_video_init(void)
2294 {
2295         /*
2296          * Let the module load even if ACPI is disabled (e.g. due to
2297          * a broken BIOS) so that i915.ko can still be loaded on such
2298          * old systems without an AcpiOpRegion.
2299          *
2300          * acpi_video_register() will report -ENODEV later as well due
2301          * to acpi_disabled when i915.ko tries to register itself afterwards.
2302          */
2303         if (acpi_disabled)
2304                 return 0;
2305
2306         if (intel_opregion_present())
2307                 return 0;
2308
2309         return acpi_video_register();
2310 }
2311
2312 static void __exit acpi_video_exit(void)
2313 {
2314         acpi_video_detect_exit();
2315         acpi_video_unregister();
2316 }
2317
2318 module_init(acpi_video_init);
2319 module_exit(acpi_video_exit);